Respect existing .egg-link files in site packages (#4082)

## Summary

As with other `.egg-info` and `.egg-link` distributions, it's easy to
support _existing_ `.egg-link` files. Like pip, we refuse to uninstall
these, since there's no way to know which files are part of the
distribution.

Closes https://github.com/astral-sh/uv/issues/4059.

## Test Plan

Verify that `vtk` is included here, which is installed as a `.egg-link`
file:

```
> conda create -c conda-forge -n uv-test python h5py vtk pyside6 cftime psutil

> cargo run pip freeze --python /opt/homebrew/Caskroom/miniforge/base/envs/uv-test/bin/python
aiohttp @ file:///Users/runner/miniforge3/conda-bld/aiohttp_1713964997382/work
aiosignal @ file:///home/conda/feedstock_root/build_artifacts/aiosignal_1667935791922/work
attrs @ file:///home/conda/feedstock_root/build_artifacts/attrs_1704011227531/work
cached-property @ file:///home/conda/feedstock_root/build_artifacts/cached_property_1615209429212/work
cftime @ file:///Users/runner/miniforge3/conda-bld/cftime_1715919201099/work
frozenlist @ file:///Users/runner/miniforge3/conda-bld/frozenlist_1702645558715/work
h5py @ file:///Users/runner/miniforge3/conda-bld/h5py_1715968397721/work
idna @ file:///home/conda/feedstock_root/build_artifacts/idna_1713279365350/work
loguru @ file:///Users/runner/miniforge3/conda-bld/loguru_1695547410953/work
msgpack @ file:///Users/runner/miniforge3/conda-bld/msgpack-python_1715670632250/work
multidict @ file:///Users/runner/miniforge3/conda-bld/multidict_1707040780513/work
numpy @ file:///Users/runner/miniforge3/conda-bld/numpy_1707225421156/work/dist/numpy-1.26.4-cp312-cp312-macosx_11_0_arm64.whl
pip==24.0
psutil @ file:///Users/runner/miniforge3/conda-bld/psutil_1705722460205/work
pyside6==6.7.1
setuptools==70.0.0
shiboken6==6.7.1
vtk==9.2.6
wheel==0.43.0
wslink @ file:///home/conda/feedstock_root/build_artifacts/wslink_1716591560747/work
yarl @ file:///Users/runner/miniforge3/conda-bld/yarl_1705508643525/work
```

crates/distribution-types/src/installed.rs

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 
@@ -20,8 +21,10 @@ pub enum InstalledDist {
     Registry(InstalledRegistryDist),
     /// The distribution was derived from an arbitrary URL.
     Url(InstalledDirectUrlDist),
+    /// The distribution was derived from pre-existing `.egg-info` file (as installed by distutils).
+    EggInfoFile(InstalledEggInfoFile),
     /// The distribution was derived from pre-existing `.egg-info` directory.
-    EggInfo(InstalledEggInfo),
+    EggInfoDirectory(InstalledEggInfoDirectory),
     /// The distribution was derived from an `.egg-link` pointer.
     LegacyEditable(InstalledLegacyEditable),
 }
@@ -44,7 +47,14 @@ pub struct InstalledDirectUrlDist {
 }
 
 #[derive(Debug, Clone)]
-pub struct InstalledEggInfo {
+pub struct InstalledEggInfoFile {
+    pub name: PackageName,
+    pub version: Version,
+    pub path: PathBuf,
+}
+
+#[derive(Debug, Clone)]
+pub struct InstalledEggInfoDirectory {
     pub name: PackageName,
     pub version: Version,
     pub path: PathBuf,
@@ -107,27 +117,49 @@ impl InstalledDist {
             };
         }
 
-        // Ex) `zstandard-0.22.0-py3.12.egg-info`
         if path.extension().is_some_and(|ext| ext == "egg-info") {
-            let Some(file_stem) = path.file_stem() else {
+            // Ex) `zstandard-0.22.0-py3.12.egg-info`
-                return Ok(None);
+            if path.is_dir() {
-            };
+                let Some(file_stem) = path.file_stem() else {
-            let Some(file_stem) = file_stem.to_str() else {
+                    return Ok(None);
-                return Ok(None);
+                };
-            };
+                let Some(file_stem) = file_stem.to_str() else {
-            let Some((name, version_python)) = file_stem.split_once('-') else {
+                    return Ok(None);
-                return Ok(None);
+                };
-            };
+                let Some((name, version_python)) = file_stem.split_once('-') else {
-            let Some((version, _)) = version_python.split_once('-') else {
+                    return Ok(None);
-                return Ok(None);
+                };
-            };
+                let Some((version, _)) = version_python.split_once('-') else {
-            let name = PackageName::from_str(name)?;
+                    return Ok(None);
-            let version = Version::from_str(version).map_err(|err| anyhow!(err))?;
+                };
-            return Ok(Some(Self::EggInfo(InstalledEggInfo {
+                let name = PackageName::from_str(name)?;
-                name,
+                let version = Version::from_str(version).map_err(|err| anyhow!(err))?;
-                version,
+                return Ok(Some(Self::EggInfoDirectory(InstalledEggInfoDirectory {
-                path: path.to_path_buf(),
+                    name,
-            })));
+                    version,
+                    path: path.to_path_buf(),
+                })));
+            }
+
+            // Ex) `vtk-9.2.6.egg-info`
+            if path.is_file() {
+                let Some(file_stem) = path.file_stem() else {
+                    return Ok(None);
+                };
+                let Some(file_stem) = file_stem.to_str() else {
+                    return Ok(None);
+                };
+                let Some((name, version)) = file_stem.split_once('-') else {
+                    return Ok(None);
+                };
+                let name = PackageName::from_str(name)?;
+                let version = Version::from_str(version).map_err(|err| anyhow!(err))?;
+                return Ok(Some(Self::EggInfoFile(InstalledEggInfoFile {
+                    name,
+                    version,
+                    path: path.to_path_buf(),
+                })));
+            }
         }
 
         // Ex) `zstandard.egg-link`
@@ -199,7 +231,8 @@ impl InstalledDist {
         match self {
             Self::Registry(dist) => &dist.path,
             Self::Url(dist) => &dist.path,
-            Self::EggInfo(dist) => &dist.path,
+            Self::EggInfoDirectory(dist) => &dist.path,
+            Self::EggInfoFile(dist) => &dist.path,
             Self::LegacyEditable(dist) => &dist.egg_info,
         }
     }
@@ -209,7 +242,8 @@ impl InstalledDist {
         match self {
             Self::Registry(dist) => &dist.version,
             Self::Url(dist) => &dist.version,
-            Self::EggInfo(dist) => &dist.version,
+            Self::EggInfoDirectory(dist) => &dist.version,
+            Self::EggInfoFile(dist) => &dist.version,
             Self::LegacyEditable(dist) => &dist.version,
         }
     }
@@ -238,13 +272,14 @@ impl InstalledDist {
                     )
                 })
             }
-            Self::EggInfo(_) | Self::LegacyEditable(_) => {
+            Self::EggInfoFile(_) | Self::EggInfoDirectory(_) | Self::LegacyEditable(_) => {
                 let path = match self {
-                    Self::EggInfo(dist) => dist.path.join("PKG-INFO"),
+                    Self::EggInfoFile(dist) => Cow::Borrowed(&dist.path),
-                    Self::LegacyEditable(dist) => dist.egg_info.join("PKG-INFO"),
+                    Self::EggInfoDirectory(dist) => Cow::Owned(dist.path.join("PKG-INFO")),
+                    Self::LegacyEditable(dist) => Cow::Owned(dist.egg_info.join("PKG-INFO")),
                     _ => unreachable!(),
                 };
-                let contents = fs::read(&path)?;
+                let contents = fs::read(path.as_ref())?;
                 pypi_types::Metadata23::parse_metadata(&contents).with_context(|| {
                     format!(
                         "Failed to parse `PKG-INFO` file at: {}",
@@ -278,7 +313,8 @@ impl InstalledDist {
         match self {
             Self::Registry(_) => None,
             Self::Url(dist) => dist.editable.then_some(&dist.url),
-            Self::EggInfo(_) => None,
+            Self::EggInfoFile(_) => None,
+            Self::EggInfoDirectory(_) => None,
             Self::LegacyEditable(dist) => Some(&dist.target_url),
         }
     }
@@ -288,7 +324,8 @@ impl InstalledDist {
         match self {
             Self::Registry(_) => false,
             Self::Url(dist) => matches!(&*dist.direct_url, DirectUrl::LocalDirectory { .. }),
-            Self::EggInfo(_) => false,
+            Self::EggInfoFile(_) => false,
+            Self::EggInfoDirectory(_) => false,
             Self::LegacyEditable(_) => true,
         }
     }
@@ -312,7 +349,13 @@ impl Name for InstalledDirectUrlDist {
     }
 }
 
-impl Name for InstalledEggInfo {
+impl Name for InstalledEggInfoFile {
+    fn name(&self) -> &PackageName {
+        &self.name
+    }
+}
+
+impl Name for InstalledEggInfoDirectory {
     fn name(&self) -> &PackageName {
         &self.name
     }
@@ -329,7 +372,8 @@ impl Name for InstalledDist {
         match self {
             Self::Registry(dist) => dist.name(),
             Self::Url(dist) => dist.name(),
-            Self::EggInfo(dist) => dist.name(),
+            Self::EggInfoDirectory(dist) => dist.name(),
+            Self::EggInfoFile(dist) => dist.name(),
             Self::LegacyEditable(dist) => dist.name(),
         }
     }
@@ -347,7 +391,13 @@ impl InstalledMetadata for InstalledDirectUrlDist {
     }
 }
 
-impl InstalledMetadata for InstalledEggInfo {
+impl InstalledMetadata for InstalledEggInfoFile {
+    fn installed_version(&self) -> InstalledVersion {
+        InstalledVersion::Version(&self.version)
+    }
+}
+
+impl InstalledMetadata for InstalledEggInfoDirectory {
     fn installed_version(&self) -> InstalledVersion {
         InstalledVersion::Version(&self.version)
     }
@@ -364,7 +414,8 @@ impl InstalledMetadata for InstalledDist {
         match self {
             Self::Registry(dist) => dist.installed_version(),
             Self::Url(dist) => dist.installed_version(),
-            Self::EggInfo(dist) => dist.installed_version(),
+            Self::EggInfoFile(dist) => dist.installed_version(),
+            Self::EggInfoDirectory(dist) => dist.installed_version(),
             Self::LegacyEditable(dist) => dist.installed_version(),
         }
     }

crates/distribution-types/src/traits.rs

@@ -7,9 +7,9 @@ use crate::error::Error;
 use crate::{
     BuiltDist, CachedDirectUrlDist, CachedDist, CachedRegistryDist, DirectUrlBuiltDist,
     DirectUrlSourceDist, Dist, DistributionId, GitSourceDist, InstalledDirectUrlDist,
-    InstalledDist, InstalledRegistryDist, InstalledVersion, LocalDist, PackageId, PathBuiltDist,
+    InstalledDist, InstalledEggInfoDirectory, InstalledEggInfoFile, InstalledLegacyEditable,
-    PathSourceDist, RegistryBuiltWheel, RegistrySourceDist, ResourceId, SourceDist, VersionId,
+    InstalledRegistryDist, InstalledVersion, LocalDist, PackageId, PathBuiltDist, PathSourceDist,
-    VersionOrUrlRef,
+    RegistryBuiltWheel, RegistrySourceDist, ResourceId, SourceDist, VersionId, VersionOrUrlRef,
 };
 
 pub trait Name {
@@ -189,6 +189,24 @@ impl std::fmt::Display for InstalledRegistryDist {
     }
 }
 
+impl std::fmt::Display for InstalledEggInfoFile {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}{}", self.name(), self.installed_version())
+    }
+}
+
+impl std::fmt::Display for InstalledEggInfoDirectory {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}{}", self.name(), self.installed_version())
+    }
+}
+
+impl std::fmt::Display for InstalledLegacyEditable {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}{}", self.name(), self.installed_version())
+    }
+}
+
 impl std::fmt::Display for PathBuiltDist {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "{}{}", self.name(), self.version_or_url())

crates/uv-installer/src/site_packages.rs

@@ -52,10 +52,9 @@ impl SitePackages {
                         .filter_map(|read_dir| match read_dir {
                             Ok(entry) => match entry.file_type() {
                                 Ok(file_type) => (file_type.is_dir()
-                                    || entry
+                                    || entry.path().extension().map_or(false, |ext| {
-                                        .path()
+                                        ext == "egg-link" || ext == "egg-info"
-                                        .extension()
+                                    }))
-                                        .map_or(false, |ext| ext == "egg-link"))
                                 .then_some(Ok(entry.path())),
                                 Err(err) => Some(Err(err)),
                             },

crates/uv-installer/src/uninstall.rs

@@ -1,4 +1,4 @@
-use distribution_types::InstalledDist;
+use distribution_types::{InstalledDist, InstalledEggInfoFile};
 
 /// Uninstall a package from the specified Python environment.
 pub async fn uninstall(
@@ -8,12 +8,13 @@ pub async fn uninstall(
         let dist = dist.clone();
         move || match dist {
             InstalledDist::Registry(_) | InstalledDist::Url(_) => {
-                install_wheel_rs::uninstall_wheel(dist.path())
+                Ok(install_wheel_rs::uninstall_wheel(dist.path())?)
             }
-            InstalledDist::EggInfo(_) => install_wheel_rs::uninstall_egg(dist.path()),
+            InstalledDist::EggInfoDirectory(_) => Ok(install_wheel_rs::uninstall_egg(dist.path())?),
             InstalledDist::LegacyEditable(dist) => {
-                install_wheel_rs::uninstall_legacy_editable(&dist.egg_link)
+                Ok(install_wheel_rs::uninstall_legacy_editable(&dist.egg_link)?)
             }
+            InstalledDist::EggInfoFile(dist) => Err(UninstallError::Distutils(dist)),
         }
     })
     .await??;
@@ -23,6 +24,8 @@ pub async fn uninstall(
 
 #[derive(thiserror::Error, Debug)]
 pub enum UninstallError {
+    #[error("Unable to uninstall `{0}`. distutils-installed distributions do not include the metadata required to uninstall safely.")]
+    Distutils(InstalledEggInfoFile),
     #[error(transparent)]
     Uninstall(#[from] install_wheel_rs::Error),
     #[error(transparent)]

crates/uv/src/commands/pip/freeze.rs

@@ -57,7 +57,10 @@ pub(crate) fn pip_freeze(
                     writeln!(printer.stdout(), "{} @ {}", dist.name().bold(), dist.url)?;
                 }
             }
-            InstalledDist::EggInfo(dist) => {
+            InstalledDist::EggInfoFile(dist) => {
+                writeln!(printer.stdout(), "{}=={}", dist.name().bold(), dist.version)?;
+            }
+            InstalledDist::EggInfoDirectory(dist) => {
                 writeln!(printer.stdout(), "{}=={}", dist.name().bold(), dist.version)?;
             }
             InstalledDist::LegacyEditable(dist) => {