Enforce extension validity at parse time (#5888)

## Summary

This PR adds a `DistExtension` field to some of our distribution types,
which requires that we validate that the file type is known and
supported when parsing (rather than when attempting to unzip). It
removes a bunch of extension parsing from the code too, in favor of
doing it once upfront.

Closes https://github.com/astral-sh/uv/issues/5858.

Cargo.lock

@@ -2812,6 +2812,7 @@ version = "0.0.1"
 dependencies = [
  "anyhow",
  "chrono",
+ "distribution-filename",
  "indexmap",
  "itertools 0.13.0",
  "mailparse",
@@ -4816,6 +4817,7 @@ version = "0.0.1"
 dependencies = [
  "async-compression",
  "async_zip",
+ "distribution-filename",
  "fs-err",
  "futures",
  "md-5",
@@ -4945,6 +4947,7 @@ dependencies = [
  "cache-key",
  "clap",
  "configparser",
+ "distribution-filename",
  "fs-err",
  "futures",
  "indoc",

crates/distribution-filename/src/extension.rs

@@ -0,0 +1,99 @@
+use std::fmt::{Display, Formatter};
+use std::path::Path;
+
+use serde::{Deserialize, Serialize};
+use thiserror::Error;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum DistExtension {
+    Wheel,
+    Source(SourceDistExtension),
+}
+
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    PartialEq,
+    Eq,
+    PartialOrd,
+    Ord,
+    Hash,
+    Serialize,
+    Deserialize,
+    rkyv::Archive,
+    rkyv::Deserialize,
+    rkyv::Serialize,
+)]
+#[archive(check_bytes)]
+#[archive_attr(derive(Debug))]
+pub enum SourceDistExtension {
+    Zip,
+    TarGz,
+    TarBz2,
+    TarXz,
+    TarZst,
+}
+
+impl DistExtension {
+    /// Extract the [`DistExtension`] from a path.
+    pub fn from_path(path: impl AsRef<Path>) -> Result<Self, ExtensionError> {
+        let Some(extension) = path.as_ref().extension().and_then(|ext| ext.to_str()) else {
+            return Err(ExtensionError::Dist);
+        };
+
+        match extension {
+            "whl" => Ok(Self::Wheel),
+            _ => SourceDistExtension::from_path(path)
+                .map(Self::Source)
+                .map_err(|_| ExtensionError::Dist),
+        }
+    }
+}
+
+impl SourceDistExtension {
+    /// Extract the [`SourceDistExtension`] from a path.
+    pub fn from_path(path: impl AsRef<Path>) -> Result<Self, ExtensionError> {
+        /// Returns true if the path is a tar file (e.g., `.tar.gz`).
+        fn is_tar(path: &Path) -> bool {
+            path.file_stem().is_some_and(|stem| {
+                Path::new(stem)
+                    .extension()
+                    .is_some_and(|ext| ext.eq_ignore_ascii_case("tar"))
+            })
+        }
+
+        let Some(extension) = path.as_ref().extension().and_then(|ext| ext.to_str()) else {
+            return Err(ExtensionError::SourceDist);
+        };
+
+        match extension {
+            "zip" => Ok(Self::Zip),
+            "gz" if is_tar(path.as_ref()) => Ok(Self::TarGz),
+            "bz2" if is_tar(path.as_ref()) => Ok(Self::TarBz2),
+            "xz" if is_tar(path.as_ref()) => Ok(Self::TarXz),
+            "zst" if is_tar(path.as_ref()) => Ok(Self::TarZst),
+            _ => Err(ExtensionError::SourceDist),
+        }
+    }
+}
+
+impl Display for SourceDistExtension {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Zip => f.write_str("zip"),
+            Self::TarGz => f.write_str("tar.gz"),
+            Self::TarBz2 => f.write_str("tar.bz2"),
+            Self::TarXz => f.write_str("tar.xz"),
+            Self::TarZst => f.write_str("tar.zst"),
+        }
+    }
+}
+
+#[derive(Error, Debug)]
+pub enum ExtensionError {
+    #[error("`.whl`, `.zip`, `.tar.gz`, `.tar.bz2`, `.tar.xz`, or `.tar.zst`")]
+    Dist,
+    #[error("`.zip`, `.tar.gz`, `.tar.bz2`, `.tar.xz`, or `.tar.zst`")]
+    SourceDist,
+}

crates/distribution-filename/src/lib.rs

@@ -5,11 +5,13 @@ use uv_normalize::PackageName;
 
 pub use build_tag::{BuildTag, BuildTagError};
 pub use egg::{EggInfoFilename, EggInfoFilenameError};
-pub use source_dist::{SourceDistExtension, SourceDistFilename, SourceDistFilenameError};
+pub use extension::{DistExtension, ExtensionError, SourceDistExtension};
+pub use source_dist::SourceDistFilename;
 pub use wheel::{WheelFilename, WheelFilenameError};
 
 mod build_tag;
 mod egg;
+mod extension;
 mod source_dist;
 mod wheel;
 
@@ -22,14 +24,21 @@ pub enum DistFilename {
 impl DistFilename {
     /// Parse a filename as wheel or source dist name.
     pub fn try_from_filename(filename: &str, package_name: &PackageName) -> Option<Self> {
+        match DistExtension::from_path(filename) {
+            Ok(DistExtension::Wheel) => {
                 if let Ok(filename) = WheelFilename::from_str(filename) {
-            Some(Self::WheelFilename(filename))
+                    return Some(Self::WheelFilename(filename));
-        } else if let Ok(filename) = SourceDistFilename::parse(filename, package_name) {
-            Some(Self::SourceDistFilename(filename))
-        } else {
-            None
                 }
             }
+            Ok(DistExtension::Source(extension)) => {
+                if let Ok(filename) = SourceDistFilename::parse(filename, extension, package_name) {
+                    return Some(Self::SourceDistFilename(filename));
+                }
+            }
+            Err(_) => {}
+        }
+        None
+    }
 
     /// Like [`DistFilename::try_from_normalized_filename`], but without knowing the package name.
     ///

crates/distribution-filename/src/source_dist.rs

@@ -1,69 +1,12 @@
 use std::fmt::{Display, Formatter};
 use std::str::FromStr;
 
+use crate::SourceDistExtension;
+use pep440_rs::{Version, VersionParseError};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
-
-use pep440_rs::{Version, VersionParseError};
 use uv_normalize::{InvalidNameError, PackageName};
 
-#[derive(
-    Clone,
-    Debug,
-    PartialEq,
-    Eq,
-    Serialize,
-    Deserialize,
-    rkyv::Archive,
-    rkyv::Deserialize,
-    rkyv::Serialize,
-)]
-#[archive(check_bytes)]
-#[archive_attr(derive(Debug))]
-pub enum SourceDistExtension {
-    Zip,
-    TarGz,
-    TarBz2,
-}
-
-impl FromStr for SourceDistExtension {
-    type Err = String;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Ok(match s {
-            "zip" => Self::Zip,
-            "tar.gz" => Self::TarGz,
-            "tar.bz2" => Self::TarBz2,
-            other => return Err(other.to_string()),
-        })
-    }
-}
-
-impl Display for SourceDistExtension {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Self::Zip => f.write_str("zip"),
-            Self::TarGz => f.write_str("tar.gz"),
-            Self::TarBz2 => f.write_str("tar.bz2"),
-        }
-    }
-}
-
-impl SourceDistExtension {
-    pub fn from_filename(filename: &str) -> Option<(&str, Self)> {
-        if let Some(stem) = filename.strip_suffix(".zip") {
-            return Some((stem, Self::Zip));
-        }
-        if let Some(stem) = filename.strip_suffix(".tar.gz") {
-            return Some((stem, Self::TarGz));
-        }
-        if let Some(stem) = filename.strip_suffix(".tar.bz2") {
-            return Some((stem, Self::TarBz2));
-        }
-        None
-    }
-}
-
 /// Note that this is a normalized and not an exact representation, keep the original string if you
 /// need the latter.
 #[derive(
@@ -90,14 +33,18 @@ impl SourceDistFilename {
     /// these (consider e.g. `a-1-1.zip`)
     pub fn parse(
         filename: &str,
+        extension: SourceDistExtension,
         package_name: &PackageName,
     ) -> Result<Self, SourceDistFilenameError> {
-        let Some((stem, extension)) = SourceDistExtension::from_filename(filename) else {
+        // Drop the extension (e.g., given `tar.gz`, drop `.tar.gz`).
+        if filename.len() <= extension.to_string().len() + 1 {
             return Err(SourceDistFilenameError {
                 filename: filename.to_string(),
                 kind: SourceDistFilenameErrorKind::Extension,
             });
-        };
+        }
+
+        let stem = &filename[..(filename.len() - (extension.to_string().len() + 1))];
 
         if stem.len() <= package_name.as_ref().len() + "-".len() {
             return Err(SourceDistFilenameError {
@@ -138,13 +85,23 @@ impl SourceDistFilename {
     /// Source dist filenames can be ambiguous, e.g. `a-1-1.tar.gz`. Without knowing the package name, we assume that
     /// source dist filename version doesn't contain minus (the version is normalized).
     pub fn parsed_normalized_filename(filename: &str) -> Result<Self, SourceDistFilenameError> {
-        let Some((stem, extension)) = SourceDistExtension::from_filename(filename) else {
+        let Ok(extension) = SourceDistExtension::from_path(filename) else {
             return Err(SourceDistFilenameError {
                 filename: filename.to_string(),
                 kind: SourceDistFilenameErrorKind::Extension,
             });
         };
 
+        // Drop the extension (e.g., given `tar.gz`, drop `.tar.gz`).
+        if filename.len() <= extension.to_string().len() + 1 {
+            return Err(SourceDistFilenameError {
+                filename: filename.to_string(),
+                kind: SourceDistFilenameErrorKind::Extension,
+            });
+        }
+
+        let stem = &filename[..(filename.len() - (extension.to_string().len() + 1))];
+
         let Some((package_name, version)) = stem.rsplit_once('-') else {
             return Err(SourceDistFilenameError {
                 filename: filename.to_string(),
@@ -197,7 +154,7 @@ impl Display for SourceDistFilenameError {
 enum SourceDistFilenameErrorKind {
     #[error("Name doesn't start with package name {0}")]
     Filename(PackageName),
-    #[error("Source distributions filenames must end with .zip, .tar.gz, or .tar.bz2")]
+    #[error("File extension is invalid")]
     Extension,
     #[error("Version section is invalid")]
     Version(#[from] VersionParseError),
@@ -213,7 +170,7 @@ mod tests {
 
     use uv_normalize::PackageName;
 
-    use crate::SourceDistFilename;
+    use crate::{SourceDistExtension, SourceDistFilename};
 
     /// Only test already normalized names since the parsing is lossy
     #[test]
@@ -223,9 +180,15 @@ mod tests {
             "foo-lib-1.2.3a3.zip",
             "foo-lib-1.2.3.tar.gz",
             "foo-lib-1.2.3.tar.bz2",
+            "foo-lib-1.2.3.tar.zst",
         ] {
+            let ext = SourceDistExtension::from_path(normalized).unwrap();
             assert_eq!(
-                SourceDistFilename::parse(normalized, &PackageName::from_str("foo_lib").unwrap())
+                SourceDistFilename::parse(
+                    normalized,
+                    ext,
+                    &PackageName::from_str("foo_lib").unwrap()
+                )
                 .unwrap()
                 .to_string(),
                 normalized
@@ -235,18 +198,22 @@ mod tests {
 
     #[test]
     fn errors() {
-        for invalid in ["b-1.2.3.zip", "a-1.2.3-gamma.3.zip", "a-1.2.3.tar.zstd"] {
+        for invalid in ["b-1.2.3.zip", "a-1.2.3-gamma.3.zip"] {
+            let ext = SourceDistExtension::from_path(invalid).unwrap();
             assert!(
-                SourceDistFilename::parse(invalid, &PackageName::from_str("a").unwrap()).is_err()
+                SourceDistFilename::parse(invalid, ext, &PackageName::from_str("a").unwrap())
+                    .is_err()
             );
         }
     }
 
     #[test]
-    fn name_to_long() {
+    fn name_too_long() {
-        assert!(
+        assert!(SourceDistFilename::parse(
-            SourceDistFilename::parse("foo.zip", &PackageName::from_str("foo-lib").unwrap())
+            "foo.zip",
-                .is_err()
+            SourceDistExtension::Zip,
-        );
+            &PackageName::from_str("foo-lib").unwrap()
+        )
+        .is_err());
     }
 }

crates/distribution-types/src/buildable.rs

@@ -1,6 +1,7 @@
 use std::borrow::Cow;
 use std::path::Path;
 
+use distribution_filename::SourceDistExtension;
 use pep440_rs::Version;
 use pep508_rs::VerbatimUrl;
 use url::Url;
@@ -109,6 +110,8 @@ impl std::fmt::Display for SourceUrl<'_> {
 #[derive(Debug, Clone)]
 pub struct DirectSourceUrl<'a> {
     pub url: &'a Url,
+    pub subdirectory: Option<&'a Path>,
+    pub ext: SourceDistExtension,
 }
 
 impl std::fmt::Display for DirectSourceUrl<'_> {
@@ -146,6 +149,7 @@ impl<'a> From<&'a GitSourceDist> for GitSourceUrl<'a> {
 pub struct PathSourceUrl<'a> {
     pub url: &'a Url,
     pub path: Cow<'a, Path>,
+    pub ext: SourceDistExtension,
 }
 
 impl std::fmt::Display for PathSourceUrl<'_> {
@@ -159,6 +163,7 @@ impl<'a> From<&'a PathSourceDist> for PathSourceUrl<'a> {
         Self {
             url: &dist.url,
             path: Cow::Borrowed(&dist.install_path),
+            ext: dist.ext,
         }
     }
 }

crates/distribution-types/src/lib.rs

@@ -38,7 +38,7 @@ use std::str::FromStr;
 
 use url::Url;
 
-use distribution_filename::WheelFilename;
+use distribution_filename::{DistExtension, SourceDistExtension, WheelFilename};
 use pep440_rs::Version;
 use pep508_rs::{Pep508Url, VerbatimUrl};
 use pypi_types::{ParsedUrl, VerbatimParsedUrl};
@@ -228,6 +228,8 @@ pub struct RegistrySourceDist {
     pub name: PackageName,
     pub version: Version,
     pub file: Box<File>,
+    /// The file extension, e.g. `tar.gz`, `zip`, etc.
+    pub ext: SourceDistExtension,
     pub index: IndexUrl,
     /// When an sdist is selected, it may be the case that there were
     /// available wheels too. There are many reasons why a wheel might not
@@ -249,6 +251,8 @@ pub struct DirectUrlSourceDist {
     pub location: Url,
     /// The subdirectory within the archive in which the source distribution is located.
     pub subdirectory: Option<PathBuf>,
+    /// The file extension, e.g. `tar.gz`, `zip`, etc.
+    pub ext: SourceDistExtension,
     /// The URL as it was provided by the user, including the subdirectory fragment.
     pub url: VerbatimUrl,
 }
@@ -275,6 +279,8 @@ pub struct PathSourceDist {
     /// which we use for locking. Unlike `given` on the verbatim URL all environment variables
     /// are resolved, and unlike the install path, we did not yet join it on the base directory.
     pub lock_path: PathBuf,
+    /// The file extension, e.g. `tar.gz`, `zip`, etc.
+    pub ext: SourceDistExtension,
     /// The URL as it was provided by the user.
     pub url: VerbatimUrl,
 }
@@ -303,11 +309,10 @@ impl Dist {
         url: VerbatimUrl,
         location: Url,
         subdirectory: Option<PathBuf>,
+        ext: DistExtension,
     ) -> Result<Dist, Error> {
-        if Path::new(url.path())
+        match ext {
-            .extension()
+            DistExtension::Wheel => {
-            .is_some_and(|ext| ext.eq_ignore_ascii_case("whl"))
-        {
                 // Validate that the name in the wheel matches that of the requirement.
                 let filename = WheelFilename::from_str(&url.filename()?)?;
                 if filename.name != name {
@@ -323,15 +328,18 @@ impl Dist {
                     location,
                     url,
                 })))
-        } else {
+            }
+            DistExtension::Source(ext) => {
                 Ok(Self::Source(SourceDist::DirectUrl(DirectUrlSourceDist {
                     name,
                     location,
                     subdirectory,
+                    ext,
                     url,
                 })))
             }
         }
+    }
 
     /// A local built or source distribution from a `file://` URL.
     pub fn from_file_url(
@@ -339,6 +347,7 @@ impl Dist {
         url: VerbatimUrl,
         install_path: &Path,
         lock_path: &Path,
+        ext: DistExtension,
     ) -> Result<Dist, Error> {
         // Store the canonicalized path, which also serves to validate that it exists.
         let canonicalized_path = match install_path.canonicalize() {
@@ -350,10 +359,8 @@ impl Dist {
         };
 
         // Determine whether the path represents a built or source distribution.
-        if canonicalized_path
+        match ext {
-            .extension()
+            DistExtension::Wheel => {
-            .is_some_and(|ext| ext.eq_ignore_ascii_case("whl"))
-        {
                 // Validate that the name in the wheel matches that of the requirement.
                 let filename = WheelFilename::from_str(&url.filename()?)?;
                 if filename.name != name {
@@ -368,13 +375,14 @@ impl Dist {
                     path: canonicalized_path,
                     url,
                 })))
-        } else {
+            }
-            Ok(Self::Source(SourceDist::Path(PathSourceDist {
+            DistExtension::Source(ext) => Ok(Self::Source(SourceDist::Path(PathSourceDist {
                 name,
                 install_path: canonicalized_path.clone(),
                 lock_path: lock_path.to_path_buf(),
+                ext,
                 url,
-            })))
+            }))),
         }
     }
 
@@ -423,12 +431,20 @@ impl Dist {
     /// Create a [`Dist`] for a URL-based distribution.
     pub fn from_url(name: PackageName, url: VerbatimParsedUrl) -> Result<Self, Error> {
         match url.parsed_url {
-            ParsedUrl::Archive(archive) => {
+            ParsedUrl::Archive(archive) => Self::from_http_url(
-                Self::from_http_url(name, url.verbatim, archive.url, archive.subdirectory)
+                name,
-            }
+                url.verbatim,
-            ParsedUrl::Path(file) => {
+                archive.url,
-                Self::from_file_url(name, url.verbatim, &file.install_path, &file.lock_path)
+                archive.subdirectory,
-            }
+                archive.ext,
+            ),
+            ParsedUrl::Path(file) => Self::from_file_url(
+                name,
+                url.verbatim,
+                &file.install_path,
+                &file.lock_path,
+                file.ext,
+            ),
             ParsedUrl::Directory(directory) => Self::from_directory_url(
                 name,
                 url.verbatim,
@@ -1262,7 +1278,7 @@ mod test {
             std::mem::size_of::<BuiltDist>()
         );
         assert!(
-            std::mem::size_of::<SourceDist>() <= 256,
+            std::mem::size_of::<SourceDist>() <= 264,
             "{}",
             std::mem::size_of::<SourceDist>()
         );

crates/distribution-types/src/resolution.rs

@@ -1,6 +1,6 @@
-use std::collections::BTreeMap;
+use distribution_filename::DistExtension;
-
 use pypi_types::{HashDigest, Requirement, RequirementSource};
+use std::collections::BTreeMap;
 use uv_normalize::{ExtraName, GroupName, PackageName};
 
 use crate::{BuiltDist, Diagnostic, Dist, Name, ResolvedDist, SourceDist};
@@ -143,12 +143,14 @@ impl From<&ResolvedDist> for Requirement {
                         url: wheel.url.clone(),
                         location,
                         subdirectory: None,
+                        ext: DistExtension::Wheel,
                     }
                 }
                 Dist::Built(BuiltDist::Path(wheel)) => RequirementSource::Path {
                     install_path: wheel.path.clone(),
                     lock_path: wheel.path.clone(),
                     url: wheel.url.clone(),
+                    ext: DistExtension::Wheel,
                 },
                 Dist::Source(SourceDist::Registry(sdist)) => RequirementSource::Registry {
                     specifier: pep440_rs::VersionSpecifiers::from(
@@ -163,6 +165,7 @@ impl From<&ResolvedDist> for Requirement {
                         url: sdist.url.clone(),
                         location,
                         subdirectory: sdist.subdirectory.clone(),
+                        ext: DistExtension::Source(sdist.ext),
                     }
                 }
                 Dist::Source(SourceDist::Git(sdist)) => RequirementSource::Git {
@@ -176,6 +179,7 @@ impl From<&ResolvedDist> for Requirement {
                     install_path: sdist.install_path.clone(),
                     lock_path: sdist.lock_path.clone(),
                     url: sdist.url.clone(),
+                    ext: DistExtension::Source(sdist.ext),
                 },
                 Dist::Source(SourceDist::Directory(sdist)) => RequirementSource::Directory {
                     install_path: sdist.install_path.clone(),

crates/pep508-rs/src/lib.rs

@@ -693,6 +693,11 @@ fn looks_like_unnamed_requirement(cursor: &mut Cursor) -> bool {
         return true;
     }
 
+    // Ex) `foo/bar`
+    if expanded.contains('/') || expanded.contains('\\') {
+        return true;
+    }
+
     false
 }
 
@@ -1010,7 +1015,7 @@ fn parse_pep508_requirement<T: Pep508Url>(
             // a package name. pip supports this in `requirements.txt`, but it doesn't adhere to
             // the PEP 508 grammar.
             let mut clone = cursor.clone().at(start);
-            return if parse_url::<T>(&mut clone, working_dir).is_ok() {
+            return if looks_like_unnamed_requirement(&mut clone) {
                 Err(Pep508Error {
                     message: Pep508ErrorSource::UnsupportedRequirement("URL requirement must be preceded by a package name. Add the name of the package before the URL (e.g., `package_name @ https://...`).".to_string()),
                     start,

crates/pypi-types/Cargo.toml

@@ -13,6 +13,7 @@ license = { workspace = true }
 workspace = true
 
 [dependencies]
+distribution-filename = { workspace = true }
 pep440_rs = { workspace = true }
 pep508_rs = { workspace = true }
 uv-fs = { workspace = true, features = ["serde"] }

crates/pypi-types/src/parsed_url.rs

@@ -1,9 +1,9 @@
+use distribution_filename::{DistExtension, ExtensionError};
+use pep508_rs::{Pep508Url, UnnamedRequirementUrl, VerbatimUrl, VerbatimUrlError};
 use std::fmt::{Display, Formatter};
 use std::path::{Path, PathBuf};
 use thiserror::Error;
 use url::{ParseError, Url};
-
-use pep508_rs::{Pep508Url, UnnamedRequirementUrl, VerbatimUrl, VerbatimUrlError};
 use uv_git::{GitReference, GitSha, GitUrl, OidParseError};
 
 use crate::{ArchiveInfo, DirInfo, DirectUrl, VcsInfo, VcsKind};
@@ -13,17 +13,21 @@ pub enum ParsedUrlError {
     #[error("Unsupported URL prefix `{prefix}` in URL: `{url}` ({message})")]
     UnsupportedUrlPrefix {
         prefix: String,
-        url: Url,
+        url: String,
         message: &'static str,
     },
     #[error("Invalid path in file URL: `{0}`")]
-    InvalidFileUrl(Url),
+    InvalidFileUrl(String),
     #[error("Failed to parse Git reference from URL: `{0}`")]
-    GitShaParse(Url, #[source] OidParseError),
+    GitShaParse(String, #[source] OidParseError),
     #[error("Not a valid URL: `{0}`")]
     UrlParse(String, #[source] ParseError),
     #[error(transparent)]
     VerbatimUrl(#[from] VerbatimUrlError),
+    #[error("Expected direct URL (`{0}`) to end in a supported file extension: {1}")]
+    MissingExtensionUrl(String, ExtensionError),
+    #[error("Expected path (`{0}`) to end in a supported file extension: {1}")]
+    MissingExtensionPath(PathBuf, ExtensionError),
 }
 
 #[derive(Debug, Clone, Hash, PartialEq, PartialOrd, Eq, Ord)]
@@ -75,6 +79,9 @@ impl UnnamedRequirementUrl for VerbatimParsedUrl {
                 url: verbatim.to_url(),
                 install_path: verbatim.as_path()?,
                 lock_path: path.as_ref().to_path_buf(),
+                ext: DistExtension::from_path(&path).map_err(|err| {
+                    ParsedUrlError::MissingExtensionPath(path.as_ref().to_path_buf(), err)
+                })?,
             })
         };
         Ok(Self {
@@ -103,6 +110,9 @@ impl UnnamedRequirementUrl for VerbatimParsedUrl {
                 url: verbatim.to_url(),
                 install_path: verbatim.as_path()?,
                 lock_path: path.as_ref().to_path_buf(),
+                ext: DistExtension::from_path(&path).map_err(|err| {
+                    ParsedUrlError::MissingExtensionPath(path.as_ref().to_path_buf(), err)
+                })?,
             })
         };
         Ok(Self {
@@ -181,15 +191,23 @@ pub struct ParsedPathUrl {
     /// which we use for locking. Unlike `given` on the verbatim URL all environment variables
     /// are resolved, and unlike the install path, we did not yet join it on the base directory.
     pub lock_path: PathBuf,
+    /// The file extension, e.g. `tar.gz`, `zip`, etc.
+    pub ext: DistExtension,
 }
 
 impl ParsedPathUrl {
     /// Construct a [`ParsedPathUrl`] from a path requirement source.
-    pub fn from_source(install_path: PathBuf, lock_path: PathBuf, url: Url) -> Self {
+    pub fn from_source(
+        install_path: PathBuf,
+        lock_path: PathBuf,
+        ext: DistExtension,
+        url: Url,
+    ) -> Self {
         Self {
             url,
             install_path,
             lock_path,
+            ext,
         }
     }
 }
@@ -258,7 +276,7 @@ impl ParsedGitUrl {
 impl TryFrom<Url> for ParsedGitUrl {
     type Error = ParsedUrlError;
 
-    /// Supports URLS with and without the `git+` prefix.
+    /// Supports URLs with and without the `git+` prefix.
     ///
     /// When the URL includes a prefix, it's presumed to come from a PEP 508 requirement; when it's
     /// excluded, it's presumed to come from `tool.uv.sources`.
@@ -271,7 +289,7 @@ impl TryFrom<Url> for ParsedGitUrl {
             .unwrap_or(url_in.as_str());
         let url = Url::parse(url).map_err(|err| ParsedUrlError::UrlParse(url.to_string(), err))?;
         let url = GitUrl::try_from(url)
-            .map_err(|err| ParsedUrlError::GitShaParse(url_in.clone(), err))?;
+            .map_err(|err| ParsedUrlError::GitShaParse(url_in.to_string(), err))?;
         Ok(Self { url, subdirectory })
     }
 }
@@ -286,22 +304,32 @@ impl TryFrom<Url> for ParsedGitUrl {
 pub struct ParsedArchiveUrl {
     pub url: Url,
     pub subdirectory: Option<PathBuf>,
+    pub ext: DistExtension,
 }
 
 impl ParsedArchiveUrl {
     /// Construct a [`ParsedArchiveUrl`] from a URL requirement source.
-    pub fn from_source(location: Url, subdirectory: Option<PathBuf>) -> Self {
+    pub fn from_source(location: Url, subdirectory: Option<PathBuf>, ext: DistExtension) -> Self {
         Self {
             url: location,
             subdirectory,
+            ext,
         }
     }
 }
 
-impl From<Url> for ParsedArchiveUrl {
+impl TryFrom<Url> for ParsedArchiveUrl {
-    fn from(url: Url) -> Self {
+    type Error = ParsedUrlError;
+
+    fn try_from(url: Url) -> Result<Self, Self::Error> {
         let subdirectory = get_subdirectory(&url);
-        Self { url, subdirectory }
+        let ext = DistExtension::from_path(url.path())
+            .map_err(|err| ParsedUrlError::MissingExtensionUrl(url.to_string(), err))?;
+        Ok(Self {
+            url,
+            subdirectory,
+            ext,
+        })
     }
 }
 
@@ -328,22 +356,22 @@ impl TryFrom<Url> for ParsedUrl {
                 "git" => Ok(Self::Git(ParsedGitUrl::try_from(url)?)),
                 "bzr" => Err(ParsedUrlError::UnsupportedUrlPrefix {
                     prefix: prefix.to_string(),
-                    url: url.clone(),
+                    url: url.to_string(),
                     message: "Bazaar is not supported",
                 }),
                 "hg" => Err(ParsedUrlError::UnsupportedUrlPrefix {
                     prefix: prefix.to_string(),
-                    url: url.clone(),
+                    url: url.to_string(),
                     message: "Mercurial is not supported",
                 }),
                 "svn" => Err(ParsedUrlError::UnsupportedUrlPrefix {
                     prefix: prefix.to_string(),
-                    url: url.clone(),
+                    url: url.to_string(),
                     message: "Subversion is not supported",
                 }),
                 _ => Err(ParsedUrlError::UnsupportedUrlPrefix {
                     prefix: prefix.to_string(),
-                    url: url.clone(),
+                    url: url.to_string(),
                     message: "Unknown scheme",
                 }),
             }
@@ -355,7 +383,7 @@ impl TryFrom<Url> for ParsedUrl {
         } else if url.scheme().eq_ignore_ascii_case("file") {
             let path = url
                 .to_file_path()
-                .map_err(|()| ParsedUrlError::InvalidFileUrl(url.clone()))?;
+                .map_err(|()| ParsedUrlError::InvalidFileUrl(url.to_string()))?;
             let is_dir = if let Ok(metadata) = path.metadata() {
                 metadata.is_dir()
             } else {
@@ -371,12 +399,14 @@ impl TryFrom<Url> for ParsedUrl {
             } else {
                 Ok(Self::Path(ParsedPathUrl {
                     url,
+                    ext: DistExtension::from_path(&path)
+                        .map_err(|err| ParsedUrlError::MissingExtensionPath(path.clone(), err))?,
                     install_path: path.clone(),
                     lock_path: path,
                 }))
             }
         } else {
-            Ok(Self::Archive(ParsedArchiveUrl::from(url)))
+            Ok(Self::Archive(ParsedArchiveUrl::try_from(url)?))
         }
     }
 }

crates/pypi-types/src/requirement.rs

@@ -2,17 +2,18 @@ use std::fmt::{Display, Formatter};
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 
-use thiserror::Error;
+use distribution_filename::DistExtension;
-use url::Url;
-
 use pep440_rs::VersionSpecifiers;
 use pep508_rs::{MarkerEnvironment, MarkerTree, RequirementOrigin, VerbatimUrl, VersionOrUrl};
+use thiserror::Error;
+use url::Url;
 use uv_fs::PortablePathBuf;
 use uv_git::{GitReference, GitSha, GitUrl};
 use uv_normalize::{ExtraName, PackageName};
 
 use crate::{
-    ParsedArchiveUrl, ParsedDirectoryUrl, ParsedGitUrl, ParsedPathUrl, ParsedUrl, VerbatimParsedUrl,
+    ParsedArchiveUrl, ParsedDirectoryUrl, ParsedGitUrl, ParsedPathUrl, ParsedUrl, ParsedUrlError,
+    VerbatimParsedUrl,
 };
 
 #[derive(Debug, Error)]
@@ -20,6 +21,8 @@ pub enum RequirementError {
     #[error(transparent)]
     VerbatimUrlError(#[from] pep508_rs::VerbatimUrlError),
     #[error(transparent)]
+    ParsedUrlError(#[from] ParsedUrlError),
+    #[error(transparent)]
     UrlParseError(#[from] url::ParseError),
     #[error(transparent)]
     OidParseError(#[from] uv_git::OidParseError),
@@ -95,13 +98,15 @@ impl From<Requirement> for pep508_rs::Requirement<VerbatimParsedUrl> {
                     Some(VersionOrUrl::VersionSpecifier(specifier))
                 }
                 RequirementSource::Url {
-                    subdirectory,
                     location,
+                    subdirectory,
+                    ext,
                     url,
                 } => Some(VersionOrUrl::Url(VerbatimParsedUrl {
                     parsed_url: ParsedUrl::Archive(ParsedArchiveUrl {
                         url: location,
                         subdirectory,
+                        ext,
                     }),
                     verbatim: url,
                 })),
@@ -128,12 +133,14 @@ impl From<Requirement> for pep508_rs::Requirement<VerbatimParsedUrl> {
                 RequirementSource::Path {
                     install_path,
                     lock_path,
+                    ext,
                     url,
                 } => Some(VersionOrUrl::Url(VerbatimParsedUrl {
                     parsed_url: ParsedUrl::Path(ParsedPathUrl {
                         url: url.to_url(),
                         install_path,
                         lock_path,
+                        ext,
                     }),
                     verbatim: url,
                 })),
@@ -259,11 +266,13 @@ pub enum RequirementSource {
     /// e.g. `foo @ https://example.org/foo-1.0-py3-none-any.whl`, or a source distribution,
     /// e.g.`foo @ https://example.org/foo-1.0.zip`.
     Url {
+        /// The remote location of the archive file, without subdirectory fragment.
+        location: Url,
         /// For source distributions, the path to the distribution if it is not in the archive
         /// root.
         subdirectory: Option<PathBuf>,
-        /// The remote location of the archive file, without subdirectory fragment.
+        /// The file extension, e.g. `tar.gz`, `zip`, etc.
-        location: Url,
+        ext: DistExtension,
         /// The PEP 508 style URL in the format
         /// `<scheme>://<domain>/<path>#subdirectory=<subdirectory>`.
         url: VerbatimUrl,
@@ -292,6 +301,8 @@ pub enum RequirementSource {
         /// which we use for locking. Unlike `given` on the verbatim URL all environment variables
         /// are resolved, and unlike the install path, we did not yet join it on the base directory.
         lock_path: PathBuf,
+        /// The file extension, e.g. `tar.gz`, `zip`, etc.
+        ext: DistExtension,
         /// The PEP 508 style URL in the format
         /// `file:///<path>#subdirectory=<subdirectory>`.
         url: VerbatimUrl,
@@ -321,6 +332,7 @@ impl RequirementSource {
             ParsedUrl::Path(local_file) => RequirementSource::Path {
                 install_path: local_file.install_path.clone(),
                 lock_path: local_file.lock_path.clone(),
+                ext: local_file.ext,
                 url,
             },
             ParsedUrl::Directory(directory) => RequirementSource::Directory {
@@ -340,6 +352,7 @@ impl RequirementSource {
                 url,
                 location: archive.url,
                 subdirectory: archive.subdirectory,
+                ext: archive.ext,
             },
         }
     }
@@ -347,7 +360,7 @@ impl RequirementSource {
     /// Construct a [`RequirementSource`] for a URL source, given a URL parsed into components.
     pub fn from_verbatim_parsed_url(parsed_url: ParsedUrl) -> Self {
         let verbatim_url = VerbatimUrl::from_url(Url::from(parsed_url.clone()));
-        RequirementSource::from_parsed_url(parsed_url, verbatim_url)
+        Self::from_parsed_url(parsed_url, verbatim_url)
     }
 
     /// Convert the source to a [`VerbatimParsedUrl`], if it's a URL source.
@@ -355,24 +368,28 @@ impl RequirementSource {
         match &self {
             Self::Registry { .. } => None,
             Self::Url {
-                subdirectory,
                 location,
+                subdirectory,
+                ext,
                 url,
             } => Some(VerbatimParsedUrl {
                 parsed_url: ParsedUrl::Archive(ParsedArchiveUrl::from_source(
                     location.clone(),
                     subdirectory.clone(),
+                    *ext,
                 )),
                 verbatim: url.clone(),
             }),
             Self::Path {
                 install_path,
                 lock_path,
+                ext,
                 url,
             } => Some(VerbatimParsedUrl {
                 parsed_url: ParsedUrl::Path(ParsedPathUrl::from_source(
                     install_path.clone(),
                     lock_path.clone(),
+                    *ext,
                     url.to_url(),
                 )),
                 verbatim: url.clone(),
@@ -504,6 +521,7 @@ impl From<RequirementSource> for RequirementSourceWire {
             RequirementSource::Url {
                 subdirectory,
                 location,
+                ext: _,
                 url: _,
             } => Self::Direct {
                 url: location,
@@ -564,6 +582,7 @@ impl From<RequirementSource> for RequirementSourceWire {
             RequirementSource::Path {
                 install_path,
                 lock_path: _,
+                ext: _,
                 url: _,
             } => Self::Path {
                 path: PortablePathBuf::from(install_path),
@@ -626,13 +645,17 @@ impl TryFrom<RequirementSourceWire> for RequirementSource {
             }
             RequirementSourceWire::Direct { url, subdirectory } => Ok(Self::Url {
                 url: VerbatimUrl::from_url(url.clone()),
-                subdirectory: subdirectory.map(PathBuf::from),
                 location: url.clone(),
+                subdirectory: subdirectory.map(PathBuf::from),
+                ext: DistExtension::from_path(url.path())
+                    .map_err(|err| ParsedUrlError::MissingExtensionUrl(url.to_string(), err))?,
             }),
             RequirementSourceWire::Path { path } => {
                 let path = PathBuf::from(path);
                 Ok(Self::Path {
                     url: VerbatimUrl::from_path(path.as_path())?,
+                    ext: DistExtension::from_path(path.as_path())
+                        .map_err(|err| ParsedUrlError::MissingExtensionPath(path.clone(), err))?,
                     install_path: path.clone(),
                     lock_path: path,
                 })

crates/requirements-txt/src/lib.rs

@@ -1459,7 +1459,40 @@ mod test {
         let temp_dir = assert_fs::TempDir::new()?;
         let requirements_txt = temp_dir.child("requirements.txt");
         requirements_txt.write_str(indoc! {"
-            -e http://localhost:8080/
+            -e https://localhost:8080/
+        "})?;
+
+        let error = RequirementsTxt::parse(
+            requirements_txt.path(),
+            temp_dir.path(),
+            &BaseClientBuilder::new(),
+        )
+        .await
+        .unwrap_err();
+        let errors = anyhow::Error::new(error).chain().join("\n");
+
+        let requirement_txt = regex::escape(&requirements_txt.path().user_display().to_string());
+        let filters = vec![(requirement_txt.as_str(), "<REQUIREMENTS_TXT>")];
+        insta::with_settings!({
+            filters => filters
+        }, {
+            insta::assert_snapshot!(errors, @r###"
+            Couldn't parse requirement in `<REQUIREMENTS_TXT>` at position 3
+            Expected direct URL (`https://localhost:8080/`) to end in a supported file extension: `.whl`, `.zip`, `.tar.gz`, `.tar.bz2`, `.tar.xz`, or `.tar.zst`
+            https://localhost:8080/
+            ^^^^^^^^^^^^^^^^^^^^^^^
+            "###);
+        });
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn unsupported_editable_extension() -> Result<()> {
+        let temp_dir = assert_fs::TempDir::new()?;
+        let requirements_txt = temp_dir.child("requirements.txt");
+        requirements_txt.write_str(indoc! {"
+            -e https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6.tar.gz
         "})?;
 
         let error = RequirementsTxt::parse(
@@ -1478,7 +1511,7 @@ mod test {
         }, {
             insta::assert_snapshot!(errors, @r###"
             Unsupported editable requirement in `<REQUIREMENTS_TXT>`
-            Editable must refer to a local directory, not an HTTPS URL: `http://localhost:8080/`
+            Editable must refer to a local directory, not an HTTPS URL: `https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6.tar.gz`
             "###);
         });
 

crates/requirements-txt/src/snapshots/requirements_txt__test__line-endings-whitespace.txt.snap

@@ -36,9 +36,10 @@ RequirementsTxt {
                     version_or_url: Some(
                         Url(
                             VerbatimParsedUrl {
-                                parsed_url: Archive(
+                                parsed_url: Git(
-                                    ParsedArchiveUrl {
+                                    ParsedGitUrl {
-                                        url: Url {
+                                        url: GitUrl {
+                                            repository: Url {
                                                 scheme: "https",
                                                 cannot_be_a_base: false,
                                                 username: "",
@@ -49,16 +50,19 @@ RequirementsTxt {
                                                     ),
                                                 ),
                                                 port: None,
-                                            path: "/pandas-dev/pandas",
+                                                path: "/pandas-dev/pandas.git",
                                                 query: None,
                                                 fragment: None,
                                             },
+                                            reference: DefaultBranch,
+                                            precise: None,
+                                        },
                                         subdirectory: None,
                                     },
                                 ),
                                 verbatim: VerbatimUrl {
                                     url: Url {
-                                        scheme: "https",
+                                        scheme: "git+https",
                                         cannot_be_a_base: false,
                                         username: "",
                                         password: None,
@@ -68,12 +72,12 @@ RequirementsTxt {
                                             ),
                                         ),
                                         port: None,
-                                        path: "/pandas-dev/pandas",
+                                        path: "/pandas-dev/pandas.git",
                                         query: None,
                                         fragment: None,
                                     },
                                     given: Some(
-                                        "https://github.com/pandas-dev/pandas",
+                                        "git+https://github.com/pandas-dev/pandas.git",
                                     ),
                                 },
                             },

crates/requirements-txt/src/snapshots/requirements_txt__test__parse-whitespace.txt.snap

@@ -36,9 +36,10 @@ RequirementsTxt {
                     version_or_url: Some(
                         Url(
                             VerbatimParsedUrl {
-                                parsed_url: Archive(
+                                parsed_url: Git(
-                                    ParsedArchiveUrl {
+                                    ParsedGitUrl {
-                                        url: Url {
+                                        url: GitUrl {
+                                            repository: Url {
                                                 scheme: "https",
                                                 cannot_be_a_base: false,
                                                 username: "",
@@ -49,16 +50,19 @@ RequirementsTxt {
                                                     ),
                                                 ),
                                                 port: None,
-                                            path: "/pandas-dev/pandas",
+                                                path: "/pandas-dev/pandas.git",
                                                 query: None,
                                                 fragment: None,
                                             },
+                                            reference: DefaultBranch,
+                                            precise: None,
+                                        },
                                         subdirectory: None,
                                     },
                                 ),
                                 verbatim: VerbatimUrl {
                                     url: Url {
-                                        scheme: "https",
+                                        scheme: "git+https",
                                         cannot_be_a_base: false,
                                         username: "",
                                         password: None,
@@ -68,12 +72,12 @@ RequirementsTxt {
                                             ),
                                         ),
                                         port: None,
-                                        path: "/pandas-dev/pandas",
+                                        path: "/pandas-dev/pandas.git",
                                         query: None,
                                         fragment: None,
                                     },
                                     given: Some(
-                                        "https://github.com/pandas-dev/pandas",
+                                        "git+https://github.com/pandas-dev/pandas.git",
                                     ),
                                 },
                             },

crates/requirements-txt/test-data/requirements-txt/whitespace.txt

@@ -16,7 +16,7 @@
 
 \
 
-pandas  [tabulate]  @  https://github.com/pandas-dev/pandas \
+pandas  [tabulate]  @  git+https://github.com/pandas-dev/pandas.git \
  # üh
 
 

crates/uv-cache/src/lib.rs

@@ -691,7 +691,7 @@ impl CacheBucket {
             Self::Interpreter => "interpreter-v2",
             // Note that when bumping this, you'll also need to bump it
             // in crates/uv/tests/cache_clean.rs.
-            Self::Simple => "simple-v11",
+            Self::Simple => "simple-v12",
             Self::Wheels => "wheels-v1",
             Self::Archive => "archive-v0",
             Self::Builds => "builds-v0",

crates/uv-client/src/registry_client.rs

@@ -718,9 +718,12 @@ impl SimpleMetadata {
 
         // Group the distributions by version and kind
         for file in files {
-            if let Some(filename) =
+            let Some(filename) =
                 DistFilename::try_from_filename(file.filename.as_str(), package_name)
-            {
+            else {
+                warn!("Skipping file for {package_name}: {}", file.filename);
+                continue;
+            };
             let version = match filename {
                 DistFilename::SourceDistFilename(ref inner) => &inner.version,
                 DistFilename::WheelFilename(ref inner) => &inner.version,
@@ -744,7 +747,6 @@ impl SimpleMetadata {
                 }
             }
         }
-        }
         Self(
             map.into_iter()
                 .map(|(version, files)| SimpleMetadatum { version, files })

crates/uv-distribution/src/error.rs

@@ -7,7 +7,7 @@ use zip::result::ZipError;
 use crate::metadata::MetadataError;
 use distribution_filename::WheelFilenameError;
 use pep440_rs::Version;
-use pypi_types::HashDigest;
+use pypi_types::{HashDigest, ParsedUrlError};
 use uv_client::WrappedReqwestError;
 use uv_fs::Simplified;
 use uv_normalize::PackageName;
@@ -23,6 +23,8 @@ pub enum Error {
     #[error("Expected an absolute path, but received: {}", _0.user_display())]
     RelativePath(PathBuf),
     #[error(transparent)]
+    ParsedUrl(#[from] ParsedUrlError),
+    #[error(transparent)]
     JoinRelativeUrl(#[from] pypi_types::JoinRelativeError),
     #[error("Expected a file URL, but received: {0}")]
     NonFileUrl(Url),

crates/uv-distribution/src/metadata/lowering.rs

@@ -2,13 +2,13 @@ use std::collections::BTreeMap;
 use std::io;
 use std::path::{Path, PathBuf};
 
+use distribution_filename::DistExtension;
 use path_absolutize::Absolutize;
-use thiserror::Error;
-use url::Url;
-
 use pep440_rs::VersionSpecifiers;
 use pep508_rs::{VerbatimUrl, VersionOrUrl};
-use pypi_types::{Requirement, RequirementSource, VerbatimParsedUrl};
+use pypi_types::{ParsedUrlError, Requirement, RequirementSource, VerbatimParsedUrl};
+use thiserror::Error;
+use url::Url;
 use uv_configuration::PreviewMode;
 use uv_fs::{relative_to, Simplified};
 use uv_git::GitReference;
@@ -41,6 +41,8 @@ pub enum LoweringError {
     WorkspaceFalse,
     #[error("Editable must refer to a local directory, not a file: `{0}`")]
     EditableFile(String),
+    #[error(transparent)]
+    ParsedUrl(#[from] ParsedUrlError),
     #[error(transparent)] // Function attaches the context
     RelativeTo(io::Error),
 }
@@ -155,10 +157,14 @@ pub(crate) fn lower_requirement(
                 verbatim_url.set_fragment(Some(subdirectory));
             }
 
+            let ext = DistExtension::from_path(url.path())
+                .map_err(|err| ParsedUrlError::MissingExtensionUrl(url.to_string(), err))?;
+
             let verbatim_url = VerbatimUrl::from_url(verbatim_url);
             RequirementSource::Url {
                 location: url,
                 subdirectory: subdirectory.map(PathBuf::from),
+                ext,
                 url: verbatim_url,
             }
         }
@@ -290,6 +296,8 @@ fn path_source(
         Ok(RequirementSource::Path {
             install_path: absolute_path,
             lock_path: relative_to_workspace,
+            ext: DistExtension::from_path(path)
+                .map_err(|err| ParsedUrlError::MissingExtensionPath(path.to_path_buf(), err))?,
             url,
         })
     }

crates/uv-distribution/src/source/mod.rs

@@ -13,14 +13,14 @@ use tracing::{debug, info_span, instrument, Instrument};
 use url::Url;
 use zip::ZipArchive;
 
-use distribution_filename::WheelFilename;
+use distribution_filename::{SourceDistExtension, WheelFilename};
 use distribution_types::{
     BuildableSource, DirectorySourceUrl, FileLocation, GitSourceUrl, HashPolicy, Hashed,
     PathSourceUrl, RemoteSource, SourceDist, SourceUrl,
 };
 use install_wheel_rs::metadata::read_archive_metadata;
 use platform_tags::Tags;
-use pypi_types::{HashDigest, Metadata23, ParsedArchiveUrl};
+use pypi_types::{HashDigest, Metadata23};
 use uv_cache::{
     ArchiveTimestamp, CacheBucket, CacheEntry, CacheShard, CachedByTimestamp, Timestamp, WheelCache,
 };
@@ -111,6 +111,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
                                 &PathSourceUrl {
                                     url: &url,
                                     path: Cow::Borrowed(path),
+                                    ext: dist.ext,
                                 },
                                 &cache_shard,
                                 tags,
@@ -132,6 +133,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
                             &PathSourceUrl {
                                 url: &url,
                                 path: Cow::Owned(path),
+                                ext: dist.ext,
                             },
                             &cache_shard,
                             tags,
@@ -147,6 +149,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
                     &url,
                     &cache_shard,
                     None,
+                    dist.ext,
                     tags,
                     hashes,
                     client,
@@ -156,21 +159,20 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
             }
             BuildableSource::Dist(SourceDist::DirectUrl(dist)) => {
                 let filename = dist.filename().expect("Distribution must have a filename");
-                let ParsedArchiveUrl { url, subdirectory } =
-                    ParsedArchiveUrl::from(dist.url.to_url());
 
                 // For direct URLs, cache directly under the hash of the URL itself.
                 let cache_shard = self.build_context.cache().shard(
                     CacheBucket::SourceDistributions,
-                    WheelCache::Url(&url).root(),
+                    WheelCache::Url(&dist.url).root(),
                 );
 
                 self.url(
                     source,
                     &filename,
-                    &url,
+                    &dist.url,
                     &cache_shard,
-                    subdirectory.as_deref(),
+                    dist.subdirectory.as_deref(),
+                    dist.ext,
                     tags,
                     hashes,
                     client,
@@ -208,21 +210,20 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
                     .url
                     .filename()
                     .expect("Distribution must have a filename");
-                let ParsedArchiveUrl { url, subdirectory } =
-                    ParsedArchiveUrl::from(resource.url.clone());
 
                 // For direct URLs, cache directly under the hash of the URL itself.
                 let cache_shard = self.build_context.cache().shard(
                     CacheBucket::SourceDistributions,
-                    WheelCache::Url(&url).root(),
+                    WheelCache::Url(resource.url).root(),
                 );
 
                 self.url(
                     source,
                     &filename,
-                    &url,
+                    resource.url,
                     &cache_shard,
-                    subdirectory.as_deref(),
+                    resource.subdirectory,
+                    resource.ext,
                     tags,
                     hashes,
                     client,
@@ -287,6 +288,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
                                 &PathSourceUrl {
                                     url: &url,
                                     path: Cow::Borrowed(path),
+                                    ext: dist.ext,
                                 },
                                 &cache_shard,
                                 hashes,
@@ -307,6 +309,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
                             &PathSourceUrl {
                                 url: &url,
                                 path: Cow::Owned(path),
+                                ext: dist.ext,
                             },
                             &cache_shard,
                             hashes,
@@ -321,6 +324,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
                     &url,
                     &cache_shard,
                     None,
+                    dist.ext,
                     hashes,
                     client,
                 )
@@ -329,21 +333,20 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
             }
             BuildableSource::Dist(SourceDist::DirectUrl(dist)) => {
                 let filename = dist.filename().expect("Distribution must have a filename");
-                let ParsedArchiveUrl { url, subdirectory } =
-                    ParsedArchiveUrl::from(dist.url.to_url());
 
                 // For direct URLs, cache directly under the hash of the URL itself.
                 let cache_shard = self.build_context.cache().shard(
                     CacheBucket::SourceDistributions,
-                    WheelCache::Url(&url).root(),
+                    WheelCache::Url(&dist.url).root(),
                 );
 
                 self.url_metadata(
                     source,
                     &filename,
-                    &url,
+                    &dist.url,
                     &cache_shard,
-                    subdirectory.as_deref(),
+                    dist.subdirectory.as_deref(),
+                    dist.ext,
                     hashes,
                     client,
                 )
@@ -374,21 +377,20 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
                     .url
                     .filename()
                     .expect("Distribution must have a filename");
-                let ParsedArchiveUrl { url, subdirectory } =
-                    ParsedArchiveUrl::from(resource.url.clone());
 
                 // For direct URLs, cache directly under the hash of the URL itself.
                 let cache_shard = self.build_context.cache().shard(
                     CacheBucket::SourceDistributions,
-                    WheelCache::Url(&url).root(),
+                    WheelCache::Url(resource.url).root(),
                 );
 
                 self.url_metadata(
                     source,
                     &filename,
-                    &url,
+                    resource.url,
                     &cache_shard,
-                    subdirectory.as_deref(),
+                    resource.subdirectory,
+                    resource.ext,
                     hashes,
                     client,
                 )
@@ -441,6 +443,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
         url: &'data Url,
         cache_shard: &CacheShard,
         subdirectory: Option<&'data Path>,
+        ext: SourceDistExtension,
         tags: &Tags,
         hashes: HashPolicy<'_>,
         client: &ManagedClient<'_>,
@@ -449,7 +452,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
 
         // Fetch the revision for the source distribution.
         let revision = self
-            .url_revision(source, filename, url, cache_shard, hashes, client)
+            .url_revision(source, filename, ext, url, cache_shard, hashes, client)
             .await?;
 
         // Before running the build, check that the hashes match.
@@ -512,6 +515,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
         url: &'data Url,
         cache_shard: &CacheShard,
         subdirectory: Option<&'data Path>,
+        ext: SourceDistExtension,
         hashes: HashPolicy<'_>,
         client: &ManagedClient<'_>,
     ) -> Result<ArchiveMetadata, Error> {
@@ -519,7 +523,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
 
         // Fetch the revision for the source distribution.
         let revision = self
-            .url_revision(source, filename, url, cache_shard, hashes, client)
+            .url_revision(source, filename, ext, url, cache_shard, hashes, client)
             .await?;
 
         // Before running the build, check that the hashes match.
@@ -600,6 +604,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
         &self,
         source: &BuildableSource<'_>,
         filename: &str,
+        ext: SourceDistExtension,
         url: &Url,
         cache_shard: &CacheShard,
         hashes: HashPolicy<'_>,
@@ -626,7 +631,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
                 debug!("Downloading source distribution: {source}");
                 let entry = cache_shard.shard(revision.id()).entry(filename);
                 let hashes = self
-                    .download_archive(response, source, filename, entry.path(), hashes)
+                    .download_archive(response, source, filename, ext, entry.path(), hashes)
                     .await?;
 
                 Ok(revision.with_hashes(hashes))
@@ -859,7 +864,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
         debug!("Unpacking source distribution: {source}");
         let entry = cache_shard.shard(revision.id()).entry("source");
         let hashes = self
-            .persist_archive(&resource.path, entry.path(), hashes)
+            .persist_archive(&resource.path, resource.ext, entry.path(), hashes)
             .await?;
         let revision = revision.with_hashes(hashes);
 
@@ -1306,6 +1311,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
         response: Response,
         source: &BuildableSource<'_>,
         filename: &str,
+        ext: SourceDistExtension,
         target: &Path,
         hashes: HashPolicy<'_>,
     ) -> Result<Vec<HashDigest>, Error> {
@@ -1327,7 +1333,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
 
         // Download and unzip the source distribution into a temporary directory.
         let span = info_span!("download_source_dist", filename = filename, source_dist = %source);
-        uv_extract::stream::archive(&mut hasher, filename, temp_dir.path()).await?;
+        uv_extract::stream::archive(&mut hasher, ext, temp_dir.path()).await?;
         drop(span);
 
         // If necessary, exhaust the reader to compute the hash.
@@ -1359,6 +1365,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
     async fn persist_archive(
         &self,
         path: &Path,
+        ext: SourceDistExtension,
         target: &Path,
         hashes: HashPolicy<'_>,
     ) -> Result<Vec<HashDigest>, Error> {
@@ -1380,7 +1387,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
         let mut hasher = uv_extract::hash::HashReader::new(reader, &mut hashers);
 
         // Unzip the archive into a temporary directory.
-        uv_extract::stream::archive(&mut hasher, path, &temp_dir.path()).await?;
+        uv_extract::stream::archive(&mut hasher, ext, &temp_dir.path()).await?;
 
         // If necessary, exhaust the reader to compute the hash.
         if !hashes.is_none() {

crates/uv-extract/Cargo.toml

@@ -13,6 +13,7 @@ license = { workspace = true }
 workspace = true
 
 [dependencies]
+distribution-filename = { workspace = true }
 pypi-types = { workspace = true }
 
 async-compression = { workspace = true, features = ["bzip2", "gzip", "zstd", "xz"] }

crates/uv-extract/src/stream.rs

@@ -1,13 +1,13 @@
 use std::path::Path;
 use std::pin::Pin;
 
+use crate::Error;
+use distribution_filename::SourceDistExtension;
 use futures::StreamExt;
 use rustc_hash::FxHashSet;
 use tokio_util::compat::{FuturesAsyncReadCompatExt, TokioAsyncReadCompatExt};
 use tracing::warn;
 
-use crate::Error;
-
 const DEFAULT_BUF_SIZE: usize = 128 * 1024;
 
 /// Unzip a `.zip` archive into the target directory, without requiring `Seek`.
@@ -231,77 +231,25 @@ pub async fn untar_xz<R: tokio::io::AsyncRead + Unpin>(
 /// without requiring `Seek`.
 pub async fn archive<R: tokio::io::AsyncRead + Unpin>(
     reader: R,
-    source: impl AsRef<Path>,
+    ext: SourceDistExtension,
     target: impl AsRef<Path>,
 ) -> Result<(), Error> {
-    // `.zip`
+    match ext {
-    if source
+        SourceDistExtension::Zip => {
-        .as_ref()
-        .extension()
-        .is_some_and(|ext| ext.eq_ignore_ascii_case("zip"))
-    {
             unzip(reader, target).await?;
-        return Ok(());
         }
-
+        SourceDistExtension::TarGz => {
-    // `.tar.gz`
-    if source
-        .as_ref()
-        .extension()
-        .is_some_and(|ext| ext.eq_ignore_ascii_case("gz"))
-        && source.as_ref().file_stem().is_some_and(|stem| {
-            Path::new(stem)
-                .extension()
-                .is_some_and(|ext| ext.eq_ignore_ascii_case("tar"))
-        })
-    {
             untar_gz(reader, target).await?;
-        return Ok(());
         }
-
+        SourceDistExtension::TarBz2 => {
-    // `.tar.bz2`
-    if source
-        .as_ref()
-        .extension()
-        .is_some_and(|ext| ext.eq_ignore_ascii_case("bz2"))
-        && source.as_ref().file_stem().is_some_and(|stem| {
-            Path::new(stem)
-                .extension()
-                .is_some_and(|ext| ext.eq_ignore_ascii_case("tar"))
-        })
-    {
             untar_bz2(reader, target).await?;
-        return Ok(());
         }
-    // `.tar.zst`
+        SourceDistExtension::TarXz => {
-    if source
-        .as_ref()
-        .extension()
-        .is_some_and(|ext| ext.eq_ignore_ascii_case("zst"))
-        && source.as_ref().file_stem().is_some_and(|stem| {
-            Path::new(stem)
-                .extension()
-                .is_some_and(|ext| ext.eq_ignore_ascii_case("tar"))
-        })
-    {
-        untar_zst(reader, target).await?;
-        return Ok(());
-    }
-
-    // `.tar.xz`
-    if source
-        .as_ref()
-        .extension()
-        .is_some_and(|ext| ext.eq_ignore_ascii_case("xz"))
-        && source.as_ref().file_stem().is_some_and(|stem| {
-            Path::new(stem)
-                .extension()
-                .is_some_and(|ext| ext.eq_ignore_ascii_case("tar"))
-        })
-    {
             untar_xz(reader, target).await?;
-        return Ok(());
         }
-
+        SourceDistExtension::TarZst => {
-    Err(Error::UnsupportedArchive(source.as_ref().to_path_buf()))
+            untar_zst(reader, target).await?;
+        }
+    }
+    Ok(())
 }

crates/uv-installer/src/plan.rs

@@ -1,12 +1,11 @@
 use std::collections::hash_map::Entry;
-use std::path::Path;
 use std::str::FromStr;
 
 use anyhow::{bail, Result};
 use rustc_hash::{FxBuildHasher, FxHashMap};
 use tracing::debug;
 
-use distribution_filename::WheelFilename;
+use distribution_filename::{DistExtension, WheelFilename};
 use distribution_types::{
     CachedDirectUrlDist, CachedDist, DirectUrlBuiltDist, DirectUrlSourceDist, DirectorySourceDist,
     Error, GitSourceDist, Hashed, IndexLocations, InstalledDist, Name, PathBuiltDist,
@@ -152,15 +151,13 @@ impl<'a> Planner<'a> {
                     }
                 }
                 RequirementSource::Url {
-                    subdirectory,
                     location,
+                    subdirectory,
+                    ext,
                     url,
                 } => {
-                    // Check if we have a wheel or a source distribution.
+                    match ext {
-                    if Path::new(url.path())
+                        DistExtension::Wheel => {
-                        .extension()
-                        .is_some_and(|ext| ext.eq_ignore_ascii_case("whl"))
-                    {
                             // Validate that the name in the wheel matches that of the requirement.
                             let filename = WheelFilename::from_str(&url.filename()?)?;
                             if filename.name != requirement.name {
@@ -217,11 +214,13 @@ impl<'a> Planner<'a> {
                                     continue;
                                 }
                             }
-                    } else {
+                        }
+                        DistExtension::Source(ext) => {
                             let sdist = DirectUrlSourceDist {
                                 name: requirement.name.clone(),
                                 location: location.clone(),
                                 subdirectory: subdirectory.clone(),
+                                ext: *ext,
                                 url: url.clone(),
                             };
                             // Find the most-compatible wheel from the cache, since we don't know
@@ -234,6 +233,7 @@ impl<'a> Planner<'a> {
                             }
                         }
                     }
+                }
                 RequirementSource::Git {
                     repository,
                     reference,
@@ -300,6 +300,7 @@ impl<'a> Planner<'a> {
                 }
 
                 RequirementSource::Path {
+                    ext,
                     url,
                     install_path,
                     lock_path,
@@ -313,11 +314,8 @@ impl<'a> Planner<'a> {
                         Err(err) => return Err(err.into()),
                     };
 
-                    // Check if we have a wheel or a source distribution.
+                    match ext {
-                    if path
+                        DistExtension::Wheel => {
-                        .extension()
-                        .is_some_and(|ext| ext.eq_ignore_ascii_case("whl"))
-                    {
                             // Validate that the name in the wheel matches that of the requirement.
                             let filename = WheelFilename::from_str(&url.filename()?)?;
                             if filename.name != requirement.name {
@@ -370,18 +368,22 @@ impl<'a> Planner<'a> {
                                             cache.archive(&archive.id),
                                         );
 
-                                    debug!("Path wheel requirement already cached: {cached_dist}");
+                                        debug!(
+                                            "Path wheel requirement already cached: {cached_dist}"
+                                        );
                                         cached.push(CachedDist::Url(cached_dist));
                                         continue;
                                     }
                                 }
                             }
-                    } else {
+                        }
+                        DistExtension::Source(ext) => {
                             let sdist = PathSourceDist {
                                 name: requirement.name.clone(),
                                 url: url.clone(),
                                 install_path: path,
                                 lock_path: lock_path.clone(),
+                                ext: *ext,
                             };
 
                             // Find the most-compatible wheel from the cache, since we don't know
@@ -395,6 +397,7 @@ impl<'a> Planner<'a> {
                         }
                     }
                 }
+            }
 
             debug!("Identified uncached requirement: {requirement}");
             remote.push(requirement.clone());

crates/uv-installer/src/satisfies.rs

@@ -44,6 +44,7 @@ impl RequirementSatisfaction {
                 // records `"url": "https://github.com/tqdm/tqdm"` in `direct_url.json`.
                 location: requested_url,
                 subdirectory: requested_subdirectory,
+                ext: _,
                 url: _,
             } => {
                 let InstalledDist::Url(InstalledDirectUrlDist {
@@ -150,6 +151,7 @@ impl RequirementSatisfaction {
             RequirementSource::Path {
                 install_path: requested_path,
                 lock_path: _,
+                ext: _,
                 url: _,
             } => {
                 let InstalledDist::Url(InstalledDirectUrlDist { direct_url, .. }) = &distribution

crates/uv-python/Cargo.toml

@@ -14,14 +14,15 @@ workspace = true
 
 [dependencies]
 cache-key = { workspace = true }
+distribution-filename = { workspace = true }
 install-wheel-rs = { workspace = true }
 pep440_rs = { workspace = true }
 pep508_rs = { workspace = true }
 platform-tags = { workspace = true }
 pypi-types = { workspace = true }
 uv-cache = { workspace = true }
-uv-configuration = { workspace = true }
 uv-client = { workspace = true }
+uv-configuration = { workspace = true }
 uv-extract = { workspace = true }
 uv-fs = { workspace = true }
 uv-state = { workspace = true }

crates/uv-python/src/downloads.rs

@@ -5,15 +5,15 @@ use std::pin::Pin;
 use std::str::FromStr;
 use std::task::{Context, Poll};
 
+use distribution_filename::{ExtensionError, SourceDistExtension};
 use futures::TryStreamExt;
 use owo_colors::OwoColorize;
+use pypi_types::{HashAlgorithm, HashDigest};
 use thiserror::Error;
 use tokio::io::{AsyncRead, ReadBuf};
 use tokio_util::compat::FuturesAsyncReadCompatExt;
 use tracing::{debug, instrument};
 use url::Url;
-
-use pypi_types::{HashAlgorithm, HashDigest};
 use uv_cache::Cache;
 use uv_client::WrappedReqwestError;
 use uv_extract::hash::Hasher;
@@ -32,6 +32,8 @@ pub enum Error {
     Io(#[from] io::Error),
     #[error(transparent)]
     ImplementationError(#[from] ImplementationError),
+    #[error("Expected download URL (`{0}`) to end in a supported file extension: {1}")]
+    MissingExtension(String, ExtensionError),
     #[error("Invalid Python version: {0}")]
     InvalidPythonVersion(String),
     #[error("Invalid request key (too many parts): {0}")]
@@ -423,6 +425,8 @@ impl ManagedPythonDownload {
         }
 
         let filename = url.path_segments().unwrap().last().unwrap();
+        let ext = SourceDistExtension::from_path(filename)
+            .map_err(|err| Error::MissingExtension(url.to_string(), err))?;
         let response = client.get(url.clone()).send().await?;
 
         // Ensure the request was successful.
@@ -458,12 +462,12 @@ impl ManagedPythonDownload {
         match progress {
             Some((&reporter, progress)) => {
                 let mut reader = ProgressReader::new(&mut hasher, progress, reporter);
-                uv_extract::stream::archive(&mut reader, filename, temp_dir.path())
+                uv_extract::stream::archive(&mut reader, ext, temp_dir.path())
                     .await
                     .map_err(|err| Error::ExtractError(filename.to_string(), err))?;
             }
             None => {
-                uv_extract::stream::archive(&mut hasher, filename, temp_dir.path())
+                uv_extract::stream::archive(&mut hasher, ext, temp_dir.path())
                     .await
                     .map_err(|err| Error::ExtractError(filename.to_string(), err))?;
             }

crates/uv-requirements/src/lookahead.rs

@@ -247,12 +247,14 @@ fn required_dist(requirement: &Requirement) -> Result<Option<Dist>, distribution
         RequirementSource::Url {
             subdirectory,
             location,
+            ext,
             url,
         } => Dist::from_http_url(
             requirement.name.clone(),
             url.clone(),
             location.clone(),
             subdirectory.clone(),
+            *ext,
         )?,
         RequirementSource::Git {
             repository,
@@ -276,12 +278,14 @@ fn required_dist(requirement: &Requirement) -> Result<Option<Dist>, distribution
         RequirementSource::Path {
             install_path,
             lock_path,
+            ext,
             url,
         } => Dist::from_file_url(
             requirement.name.clone(),
             url.clone(),
             install_path,
             lock_path,
+            *ext,
         )?,
         RequirementSource::Directory {
             install_path,

crates/uv-requirements/src/unnamed.rs

@@ -9,7 +9,7 @@ use serde::Deserialize;
 use tracing::debug;
 use url::Host;
 
-use distribution_filename::{SourceDistFilename, WheelFilename};
+use distribution_filename::{DistExtension, SourceDistFilename, WheelFilename};
 use distribution_types::{
     BuildableSource, DirectSourceUrl, DirectorySourceUrl, GitSourceUrl, PathSourceUrl,
     RemoteSource, SourceUrl, UnresolvedRequirement, UnresolvedRequirementSpecification, VersionId,
@@ -260,13 +260,28 @@ impl<'a, Context: BuildContext> NamedRequirementsResolver<'a, Context> {
                     editable: parsed_directory_url.editable,
                 })
             }
-            ParsedUrl::Path(parsed_path_url) => SourceUrl::Path(PathSourceUrl {
+            ParsedUrl::Path(parsed_path_url) => {
+                let ext = match parsed_path_url.ext {
+                    DistExtension::Source(ext) => ext,
+                    DistExtension::Wheel => unreachable!(),
+                };
+                SourceUrl::Path(PathSourceUrl {
                     url: &requirement.url.verbatim,
                     path: Cow::Borrowed(&parsed_path_url.install_path),
-            }),
+                    ext,
-            ParsedUrl::Archive(parsed_archive_url) => SourceUrl::Direct(DirectSourceUrl {
+                })
+            }
+            ParsedUrl::Archive(parsed_archive_url) => {
+                let ext = match parsed_archive_url.ext {
+                    DistExtension::Source(ext) => ext,
+                    DistExtension::Wheel => unreachable!(),
+                };
+                SourceUrl::Direct(DirectSourceUrl {
                     url: &parsed_archive_url.url,
-            }),
+                    subdirectory: parsed_archive_url.subdirectory.as_deref(),
+                    ext,
+                })
+            }
             ParsedUrl::Git(parsed_git_url) => SourceUrl::Git(GitSourceUrl {
                 url: &requirement.url.verbatim,
                 git: &parsed_git_url.url,

crates/uv-resolver/src/error.rs

@@ -65,6 +65,9 @@ pub enum ResolveError {
     #[error(transparent)]
     DistributionType(#[from] distribution_types::Error),
 
+    #[error(transparent)]
+    ParsedUrl(#[from] pypi_types::ParsedUrlError),
+
     #[error("Failed to download `{0}`")]
     Fetch(Box<BuiltDist>, #[source] uv_distribution::Error),
 

crates/uv-resolver/src/flat_index.rs

@@ -96,6 +96,7 @@ impl FlatIndex {
                 let dist = RegistrySourceDist {
                     name: filename.name.clone(),
                     version: filename.version.clone(),
+                    ext: filename.extension,
                     file: Box::new(file),
                     index,
                     wheels: vec![],

crates/uv-resolver/src/lock.rs

@@ -15,7 +15,7 @@ use toml_edit::{value, Array, ArrayOfTables, InlineTable, Item, Table, Value};
 use url::Url;
 
 use cache_key::RepositoryUrl;
-use distribution_filename::WheelFilename;
+use distribution_filename::{DistExtension, ExtensionError, SourceDistExtension, WheelFilename};
 use distribution_types::{
     BuiltDist, DirectUrlBuiltDist, DirectUrlSourceDist, DirectorySourceDist, Dist,
     DistributionMetadata, FileLocation, GitSourceDist, HashComparison, IndexUrl, Name,
@@ -791,6 +791,7 @@ impl Package {
                     let url = Url::from(ParsedArchiveUrl {
                         url: url.to_url(),
                         subdirectory: direct.subdirectory.as_ref().map(PathBuf::from),
+                        ext: DistExtension::Wheel,
                     });
                     let direct_dist = DirectUrlBuiltDist {
                         filename,
@@ -843,6 +844,7 @@ impl Package {
                     url: verbatim_url(workspace_root.join(path), &self.id)?,
                     install_path: workspace_root.join(path),
                     lock_path: path.clone(),
+                    ext: SourceDistExtension::from_path(path)?,
                 };
                 distribution_types::SourceDist::Path(path_dist)
             }
@@ -895,14 +897,18 @@ impl Package {
                 distribution_types::SourceDist::Git(git_dist)
             }
             Source::Direct(url, direct) => {
+                let ext = SourceDistExtension::from_path(url.as_ref())?;
+                let subdirectory = direct.subdirectory.as_ref().map(PathBuf::from);
                 let url = Url::from(ParsedArchiveUrl {
                     url: url.to_url(),
-                    subdirectory: direct.subdirectory.as_ref().map(PathBuf::from),
+                    subdirectory: subdirectory.clone(),
+                    ext: DistExtension::Source(ext),
                 });
                 let direct_dist = DirectUrlSourceDist {
                     name: self.id.name.clone(),
                     location: url.clone(),
-                    subdirectory: direct.subdirectory.as_ref().map(PathBuf::from),
+                    subdirectory: subdirectory.clone(),
+                    ext,
                     url: VerbatimUrl::from_url(url),
                 };
                 distribution_types::SourceDist::DirectUrl(direct_dist)
@@ -920,6 +926,7 @@ impl Package {
                     .ok_or_else(|| LockErrorKind::MissingFilename {
                         id: self.id.clone(),
                     })?;
+                let ext = SourceDistExtension::from_path(filename.as_ref())?;
                 let file = Box::new(distribution_types::File {
                     dist_info_metadata: false,
                     filename: filename.to_string(),
@@ -939,6 +946,7 @@ impl Package {
                     name: self.id.name.clone(),
                     version: self.id.version.clone(),
                     file,
+                    ext,
                     index,
                     wheels: vec![],
                 };
@@ -2232,6 +2240,7 @@ impl Dependency {
                 let parsed_url = ParsedUrl::Archive(ParsedArchiveUrl {
                     url: url.to_url(),
                     subdirectory: direct.subdirectory.as_ref().map(PathBuf::from),
+                    ext: DistExtension::from_path(url.as_ref())?,
                 });
                 RequirementSource::from_verbatim_parsed_url(parsed_url)
             }
@@ -2239,6 +2248,7 @@ impl Dependency {
                 lock_path: path.clone(),
                 install_path: workspace_root.join(path),
                 url: verbatim_url(workspace_root.join(path), &self.package_id)?,
+                ext: DistExtension::from_path(path)?,
             },
             Source::Directory(ref path) => RequirementSource::Directory {
                 editable: false,
@@ -2459,6 +2469,10 @@ enum LockErrorKind {
         #[source]
         ToUrlError,
     ),
+    /// An error that occurs when the extension can't be determined
+    /// for a given wheel or source distribution.
+    #[error("failed to parse file extension; expected one of: {0}")]
+    MissingExtension(#[from] ExtensionError),
     /// Failed to parse a git source URL.
     #[error("failed to parse source git URL")]
     InvalidGitSourceUrl(

crates/uv-resolver/src/pubgrub/dependencies.rs

@@ -106,11 +106,13 @@ impl PubGrubRequirement {
             RequirementSource::Url {
                 subdirectory,
                 location,
+                ext,
                 url,
             } => {
                 let parsed_url = ParsedUrl::Archive(ParsedArchiveUrl::from_source(
                     location.clone(),
                     subdirectory.clone(),
+                    *ext,
                 ));
                 (url, parsed_url)
             }
@@ -130,6 +132,7 @@ impl PubGrubRequirement {
                 (url, parsed_url)
             }
             RequirementSource::Path {
+                ext,
                 url,
                 install_path,
                 lock_path,
@@ -137,6 +140,7 @@ impl PubGrubRequirement {
                 let parsed_url = ParsedUrl::Path(ParsedPathUrl::from_source(
                     install_path.clone(),
                     lock_path.clone(),
+                    *ext,
                     url.to_url(),
                 ));
                 (url, parsed_url)

crates/uv-resolver/src/version_map.rs

@@ -391,6 +391,7 @@ impl VersionMapLazy {
                         let dist = RegistrySourceDist {
                             name: filename.name.clone(),
                             version: filename.version.clone(),
+                            ext: filename.extension,
                             file: Box::new(file),
                             index: self.index.clone(),
                             wheels: vec![],

crates/uv/tests/cache_clean.rs

@@ -57,7 +57,7 @@ fn clean_package_pypi() -> Result<()> {
     // Assert that the `.rkyv` file is created for `iniconfig`.
     let rkyv = context
         .cache_dir
-        .child("simple-v11")
+        .child("simple-v12")
         .child("pypi")
         .child("iniconfig.rkyv");
     assert!(
@@ -104,7 +104,7 @@ fn clean_package_index() -> Result<()> {
     // Assert that the `.rkyv` file is created for `iniconfig`.
     let rkyv = context
         .cache_dir
-        .child("simple-v11")
+        .child("simple-v12")
         .child("index")
         .child("e8208120cae3ba69")
         .child("iniconfig.rkyv");

crates/uv/tests/pip_compile.rs

@@ -11482,7 +11482,7 @@ fn tool_uv_sources() -> Result<()> {
             "boltons==24.0.0"
         ]
         dont_install_me = [
-            "broken @ https://example.org/does/not/exist"
+            "broken @ https://example.org/does/not/exist.tar.gz"
         ]
 
         [tool.uv.sources]
@@ -11540,6 +11540,66 @@ fn tool_uv_sources() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn invalid_tool_uv_sources() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    // Write an invalid extension on a PEP 508 URL.
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(indoc! {r#"
+        [project]
+        name = "project"
+        version = "0.0.0"
+        dependencies = [
+          "urllib3 @ https://files.pythonhosted.org/packages/a2/73/a68704750a7679d0b6d3ad7aa8d4da8e14e151ae82e6fee774e6e0d05ec8/urllib3-2.2.1-py3-none-any.tar.baz",
+        ]
+    "#})?;
+
+    uv_snapshot!(context.filters(), context.pip_compile()
+        .arg("--preview")
+        .arg(context.temp_dir.join("pyproject.toml")), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: Failed to parse metadata from built wheel
+      Caused by: Expected direct URL (`https://files.pythonhosted.org/packages/a2/73/a68704750a7679d0b6d3ad7aa8d4da8e14e151ae82e6fee774e6e0d05ec8/urllib3-2.2.1-py3-none-any.tar.baz`) to end in a supported file extension: `.whl`, `.zip`, `.tar.gz`, `.tar.bz2`, `.tar.xz`, or `.tar.zst`
+    urllib3 @ https://files.pythonhosted.org/packages/a2/73/a68704750a7679d0b6d3ad7aa8d4da8e14e151ae82e6fee774e6e0d05ec8/urllib3-2.2.1-py3-none-any.tar.baz
+              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    "###
+    );
+
+    // Write an invalid extension on a source.
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(indoc! {r#"
+        [project]
+        name = "project"
+        version = "0.0.0"
+        dependencies = [
+          "urllib3",
+        ]
+
+        [tool.uv.sources]
+        urllib3 = { url = "https://files.pythonhosted.org/packages/a2/73/a68704750a7679d0b6d3ad7aa8d4da8e14e151ae82e6fee774e6e0d05ec8/urllib3-2.2.1-py3-none-any.tar.baz" }
+    "#})?;
+
+    uv_snapshot!(context.filters(), context.pip_compile()
+        .arg("--preview")
+        .arg(context.temp_dir.join("pyproject.toml")), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: Failed to parse entry for: `urllib3`
+      Caused by: Expected direct URL (`https://files.pythonhosted.org/packages/a2/73/a68704750a7679d0b6d3ad7aa8d4da8e14e151ae82e6fee774e6e0d05ec8/urllib3-2.2.1-py3-none-any.tar.baz`) to end in a supported file extension: `.whl`, `.zip`, `.tar.gz`, `.tar.bz2`, `.tar.xz`, or `.tar.zst`
+    "###
+    );
+
+    Ok(())
+}
+
 /// Check that a dynamic `pyproject.toml` is supported a compile input file.
 #[test]
 fn dynamic_pyproject_toml() -> Result<()> {

crates/uv/tests/pip_install.rs

@@ -5676,7 +5676,7 @@ fn tool_uv_sources() -> Result<()> {
             "boltons==24.0.0"
         ]
         dont_install_me = [
-            "broken @ https://example.org/does/not/exist"
+            "broken @ https://example.org/does/not/exist.tar.gz"
         ]
 
         [tool.uv.sources]
@@ -6417,3 +6417,43 @@ fn install_build_isolation_package() -> Result<()> {
 
     Ok(())
 }
+
+/// Install a package with an unsupported extension.
+#[test]
+fn invalid_extension() {
+    let context = TestContext::new("3.8");
+
+    uv_snapshot!(context.filters(), context.pip_install()
+        .arg("ruff @ https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6.tar.baz")
+        , @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: Failed to parse: `ruff @ https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6.tar.baz`
+      Caused by: Expected direct URL (`https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6.tar.baz`) to end in a supported file extension: `.whl`, `.zip`, `.tar.gz`, `.tar.bz2`, `.tar.xz`, or `.tar.zst`
+    ruff @ https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6.tar.baz
+           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    "###);
+}
+
+/// Install a package without unsupported extension.
+#[test]
+fn no_extension() {
+    let context = TestContext::new("3.8");
+
+    uv_snapshot!(context.filters(), context.pip_install()
+        .arg("ruff @ https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6")
+        , @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: Failed to parse: `ruff @ https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6`
+      Caused by: Expected direct URL (`https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6`) to end in a supported file extension: `.whl`, `.zip`, `.tar.gz`, `.tar.bz2`, `.tar.xz`, or `.tar.zst`
+    ruff @ https://files.pythonhosted.org/packages/f7/69/96766da2cdb5605e6a31ef2734aff0be17901cefb385b885c2ab88896d76/ruff-0.5.6
+           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    "###);
+}