Add a universal resolution mode to pip compile (#4505)

## Summary

This needs more tests and a few more changes, but checkpointing it for
now.

crates/uv-cli/src/lib.rs

@@ -568,6 +568,15 @@ pub struct PipCompileArgs {
     #[arg(long)]
     pub python_platform: Option<TargetTriple>,
 
+    /// Perform a universal resolution, attempting to generate a single `requirements.txt` output
+    /// file that is compatible with all operating systems, architectures and supported Python
+    /// versions.
+    #[arg(long, overrides_with("no_universal"))]
+    pub universal: bool,
+
+    #[arg(long, overrides_with("universal"), hide = true)]
+    pub no_universal: bool,
+
     /// Specify a package to omit from the output resolution. Its dependencies will still be
     /// included in the resolution. Equivalent to pip-compile's `--unsafe-package` option.
     #[arg(long, alias = "unsafe-package")]

crates/uv-resolver/src/python_requirement.rs

@@ -1,5 +1,5 @@
-use pep440_rs::VersionSpecifiers;
-use pep508_rs::StringVersion;
+use pep440_rs::{Operator, Version, VersionSpecifier, VersionSpecifiers};
+use pep508_rs::{MarkerExpression, MarkerTree, MarkerValueVersion, StringVersion};
 use uv_toolchain::{Interpreter, PythonVersion};
 
 use crate::RequiresPython;
@@ -59,10 +59,32 @@ impl PythonRequirement {
         self.target.as_ref()
     }
 
-    /// Return the target version of Python as a "requires python" type,
-    /// if available.
-    pub(crate) fn requires_python(&self) -> Option<&RequiresPython> {
-        self.target().and_then(|target| target.as_requires_python())
+    /// Return a [`MarkerTree`] representing the Python requirement.
+    ///
+    /// See: [`RequiresPython::to_marker_tree`]
+    pub fn to_marker_tree(&self) -> MarkerTree {
+        let version = match &self.target {
+            None => self.installed.version.clone(),
+            Some(PythonTarget::Version(version)) => version.version.clone(),
+            Some(PythonTarget::RequiresPython(requires_python)) => {
+                return requires_python.to_marker_tree()
+            }
+        };
+
+        let version_major_minor_only = Version::new(version.release().iter().take(2));
+        let expr_python_version = MarkerExpression::Version {
+            key: MarkerValueVersion::PythonVersion,
+            specifier: VersionSpecifier::from_version(Operator::Equal, version_major_minor_only)
+                .unwrap(),
+        };
+        let expr_python_full_version = MarkerExpression::Version {
+            key: MarkerValueVersion::PythonFullVersion,
+            specifier: VersionSpecifier::from_version(Operator::Equal, version).unwrap(),
+        };
+        MarkerTree::And(vec![
+            MarkerTree::Expression(expr_python_version),
+            MarkerTree::Expression(expr_python_full_version),
+        ])
     }
 }
 

crates/uv-resolver/src/resolver/mod.rs

@@ -48,7 +48,6 @@ use crate::pubgrub::{
     PubGrubPriorities, PubGrubPython, PubGrubSpecifier,
 };
 use crate::python_requirement::PythonRequirement;
-use crate::requires_python::RequiresPython;
 use crate::resolution::ResolutionGraph;
 pub(crate) use crate::resolver::availability::{
     IncompletePackage, ResolverVersion, UnavailablePackage, UnavailableReason, UnavailableVersion,
@@ -193,12 +192,7 @@ impl<Provider: ResolverProvider, InstalledPackages: InstalledPackagesProvider>
         let requires_python = if markers.is_some() {
             None
         } else {
-            Some(
-                python_requirement
-                    .requires_python()
-                    .map(RequiresPython::to_marker_tree)
-                    .unwrap_or_else(|| MarkerTree::And(vec![])),
-            )
+            Some(python_requirement.to_marker_tree())
         };
         let state = ResolverState {
             index: index.clone(),

crates/uv-settings/src/settings.rs

@@ -177,6 +177,7 @@ pub struct PipOptions {
     pub config_settings: Option<ConfigSettings>,
     pub python_version: Option<PythonVersion>,
     pub python_platform: Option<TargetTriple>,
+    pub universal: Option<bool>,
     pub exclude_newer: Option<ExcludeNewer>,
     pub no_emit_package: Option<Vec<PackageName>>,
     pub emit_index_url: Option<bool>,

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

@@ -77,6 +77,7 @@ pub(crate) async fn pip_compile(
     build_options: BuildOptions,
     python_version: Option<PythonVersion>,
     python_platform: Option<TargetTriple>,
+    universal: bool,
     exclude_newer: Option<ExcludeNewer>,
     annotation_style: AnnotationStyle,
     link_mode: LinkMode,
@@ -219,7 +220,13 @@ pub(crate) async fn pip_compile(
     };
 
     // Determine the environment for the resolution.
-    let (tags, markers) = resolution_environment(python_version, python_platform, &interpreter)?;
+    let (tags, markers) = if universal {
+        (None, None)
+    } else {
+        let (tags, markers) =
+            resolution_environment(python_version, python_platform, &interpreter)?;
+        (Some(tags), Some(markers))
+    };
 
     // Generate, but don't enforce hashes for the requirements.
     let hasher = if generate_hashes {
@@ -247,7 +254,7 @@ pub(crate) async fn pip_compile(
         .index_urls(index_locations.index_urls())
         .index_strategy(index_strategy)
         .keyring(keyring_provider)
-        .markers(&markers)
+        .markers(interpreter.markers())
         .platform(interpreter.platform())
         .build();
 
@@ -262,7 +269,7 @@ pub(crate) async fn pip_compile(
     let flat_index = {
         let client = FlatIndexClient::new(&client, &cache);
         let entries = client.fetch(index_locations.flat_index()).await?;
-        FlatIndex::from_entries(entries, Some(&tags), &hasher, &build_options)
+        FlatIndex::from_entries(entries, tags.as_deref(), &hasher, &build_options)
     };
 
     // Track in-flight downloads, builds, etc., across resolutions.
@@ -319,8 +326,8 @@ pub(crate) async fn pip_compile(
         &hasher,
         &Reinstall::None,
         &upgrade,
-        Some(&tags),
-        Some(&markers),
+        tags.as_deref(),
+        markers.as_deref(),
         python_requirement,
         &client,
         &flat_index,
@@ -368,13 +375,15 @@ pub(crate) async fn pip_compile(
     }
 
     if include_marker_expression {
-        let relevant_markers = resolution.marker_tree(&top_level_index, &markers)?;
-        writeln!(
-            writer,
-            "{}",
-            "# Pinned dependencies known to be valid for:".green()
-        )?;
-        writeln!(writer, "{}", format!("#    {relevant_markers}").green())?;
+        if let Some(markers) = markers.as_deref() {
+            let relevant_markers = resolution.marker_tree(&top_level_index, markers)?;
+            writeln!(
+                writer,
+                "{}",
+                "# Pinned dependencies known to be valid for:".green()
+            )?;
+            writeln!(writer, "{}", format!("#    {relevant_markers}").green())?;
+        }
     }
 
     let mut wrote_preamble = false;
@@ -439,11 +448,11 @@ pub(crate) async fn pip_compile(
         "{}",
         DisplayResolutionGraph::new(
             &resolution,
-            Some(&markers),
+            markers.as_deref(),
             &no_emit_packages,
             generate_hashes,
             include_extras,
-            include_markers,
+            include_markers || universal,
             include_annotations,
             include_index_annotation,
             annotation_style,

crates/uv/src/main.rs

@@ -282,6 +282,7 @@ async fn run() -> Result<ExitStatus> {
                 args.settings.build_options,
                 args.settings.python_version,
                 args.settings.python_platform,
+                args.settings.universal,
                 args.settings.exclude_newer,
                 args.settings.annotation_style,
                 args.settings.link_mode,

crates/uv/src/settings.rs

@@ -525,6 +525,8 @@ impl PipCompileSettings {
             only_binary,
             python_version,
             python_platform,
+            universal,
+            no_universal,
             no_emit_package,
             emit_index_url,
             no_emit_index_url,
@@ -583,6 +585,7 @@ impl PipCompileSettings {
                     legacy_setup_py: flag(legacy_setup_py, no_legacy_setup_py),
                     python_version,
                     python_platform,
+                    universal: flag(universal, no_universal),
                     no_emit_package,
                     emit_index_url: flag(emit_index_url, no_emit_index_url),
                     emit_find_links: flag(emit_find_links, no_emit_find_links),
@@ -1499,6 +1502,7 @@ pub(crate) struct PipSettings {
     pub(crate) config_setting: ConfigSettings,
     pub(crate) python_version: Option<PythonVersion>,
     pub(crate) python_platform: Option<TargetTriple>,
+    pub(crate) universal: bool,
     pub(crate) exclude_newer: Option<ExcludeNewer>,
     pub(crate) no_emit_package: Vec<PackageName>,
     pub(crate) emit_index_url: bool,
@@ -1555,6 +1559,7 @@ impl PipSettings {
             config_settings,
             python_version,
             python_platform,
+            universal,
             exclude_newer,
             no_emit_package,
             emit_index_url,
@@ -1686,6 +1691,7 @@ impl PipSettings {
                 .unwrap_or_default(),
             python_version: args.python_version.combine(python_version),
             python_platform: args.python_platform.combine(python_platform),
+            universal: args.universal.combine(universal).unwrap_or_default(),
             exclude_newer: args.exclude_newer.combine(exclude_newer),
             no_emit_package: args
                 .no_emit_package

crates/uv/tests/pip_compile.rs

@@ -6324,6 +6324,100 @@ fn no_strip_markers_transitive_marker() -> Result<()> {
     Ok(())
 }
 
+/// Perform a universal resolution with a package that has a marker.
+#[test]
+fn universal() -> Result<()> {
+    let context = TestContext::new("3.12");
+    let requirements_in = context.temp_dir.child("requirements.in");
+    requirements_in.write_str(indoc::indoc! {r"
+        trio ; python_version > '3.11'
+        trio ; sys_platform == 'win32'
+    "})?;
+
+    uv_snapshot!(context.compile()
+            .arg("requirements.in")
+            .arg("--universal"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] --exclude-newer 2024-03-25T00:00:00Z requirements.in --universal
+    attrs==23.2.0 ; python_version > '3.11' or sys_platform == 'win32'
+        # via
+        #   outcome
+        #   trio
+    cffi==1.16.0 ; implementation_name != 'pypy' and os_name == 'nt' and (python_version > '3.11' or sys_platform == 'win32')
+        # via trio
+    idna==3.6 ; python_version > '3.11' or sys_platform == 'win32'
+        # via trio
+    outcome==1.3.0.post0 ; python_version > '3.11' or sys_platform == 'win32'
+        # via trio
+    pycparser==2.21 ; implementation_name != 'pypy' and os_name == 'nt' and (python_version > '3.11' or sys_platform == 'win32')
+        # via cffi
+    sniffio==1.3.1 ; python_version > '3.11' or sys_platform == 'win32'
+        # via trio
+    sortedcontainers==2.4.0 ; python_version > '3.11' or sys_platform == 'win32'
+        # via trio
+    trio==0.25.0 ; python_version > '3.11' or sys_platform == 'win32'
+        # via -r requirements.in
+
+    ----- stderr -----
+    Resolved 8 packages in [TIME]
+    "###
+    );
+
+    Ok(())
+}
+
+/// Perform a universal resolution with conflicting versions and markers.
+#[test]
+fn universal_conflicting() -> Result<()> {
+    let context = TestContext::new("3.12");
+    let requirements_in = context.temp_dir.child("requirements.in");
+    requirements_in.write_str(indoc::indoc! {r"
+        trio==0.25.0 ; sys_platform == 'darwin'
+        trio==0.10.0 ; sys_platform == 'win32'
+    "})?;
+
+    uv_snapshot!(context.compile()
+            .arg("requirements.in")
+            .arg("--universal"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] --exclude-newer 2024-03-25T00:00:00Z requirements.in --universal
+    async-generator==1.10 ; sys_platform == 'win32'
+        # via trio
+    attrs==23.2.0 ; sys_platform == 'darwin' or sys_platform == 'win32'
+        # via
+        #   outcome
+        #   trio
+    cffi==1.16.0 ; (implementation_name != 'pypy' and os_name == 'nt' and sys_platform == 'darwin') or (os_name == 'nt' and sys_platform == 'win32')
+        # via trio
+    idna==3.6 ; sys_platform == 'darwin' or sys_platform == 'win32'
+        # via trio
+    outcome==1.3.0.post0 ; sys_platform == 'darwin' or sys_platform == 'win32'
+        # via trio
+    pycparser==2.21 ; (implementation_name != 'pypy' and os_name == 'nt' and sys_platform == 'darwin') or (os_name == 'nt' and sys_platform == 'win32')
+        # via cffi
+    sniffio==1.3.1 ; sys_platform == 'darwin' or sys_platform == 'win32'
+        # via trio
+    sortedcontainers==2.4.0 ; sys_platform == 'darwin' or sys_platform == 'win32'
+        # via trio
+    trio==0.10.0 ; sys_platform == 'win32'
+        # via -r requirements.in
+    trio==0.25.0 ; sys_platform == 'darwin'
+        # via -r requirements.in
+
+    ----- stderr -----
+    Resolved 10 packages in [TIME]
+    "###
+    );
+
+    Ok(())
+}
+
 /// Resolve a package from a `requirements.in` file, with a `constraints.txt` file pinning one of
 /// its transitive dependencies to a specific version.
 #[test]

crates/uv/tests/show_settings.rs

@@ -140,6 +140,7 @@ fn resolve_uv_toml() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -269,6 +270,7 @@ fn resolve_uv_toml() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -399,6 +401,7 @@ fn resolve_uv_toml() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -561,6 +564,7 @@ fn resolve_pyproject_toml() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -669,6 +673,7 @@ fn resolve_pyproject_toml() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -809,6 +814,7 @@ fn resolve_pyproject_toml() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -986,6 +992,7 @@ fn resolve_index_url() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -1162,6 +1169,7 @@ fn resolve_index_url() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -1311,6 +1319,7 @@ fn resolve_find_links() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -1441,6 +1450,7 @@ fn resolve_top_level() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -1609,6 +1619,7 @@ fn resolve_top_level() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -1760,6 +1771,7 @@ fn resolve_top_level() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -1890,6 +1902,7 @@ fn resolve_user_configuration() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -2003,6 +2016,7 @@ fn resolve_user_configuration() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -2116,6 +2130,7 @@ fn resolve_user_configuration() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -2231,6 +2246,7 @@ fn resolve_user_configuration() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,
@@ -2371,6 +2387,7 @@ fn resolve_poetry_toml() -> anyhow::Result<()> {
             ),
             python_version: None,
             python_platform: None,
+            universal: false,
             exclude_newer: Some(
                 ExcludeNewer(
                     2024-03-25T00:00:00Z,

uv.schema.json

@@ -784,6 +784,12 @@
             "null"
           ]
         },
+        "universal": {
+          "type": [
+            "boolean",
+            "null"
+          ]
+        },
         "upgrade": {
           "type": [
             "boolean",