From 16296d67918d675f894ba2b3f201e22b264b2a75 Mon Sep 17 00:00:00 2001
From: Zanie Blue <contact@zanie.dev>
Date: Thu, 13 Feb 2025 12:29:49 -0600
Subject: [PATCH] Allow `-p` to use complex Python version requests in `uv pip
 compile`

---
 crates/uv-cli/src/lib.rs              |  13 +-
 crates/uv/src/commands/pip/compile.rs |  67 +++++-
 crates/uv/src/lib.rs                  |   1 +
 crates/uv/src/settings.rs             |   3 +
 crates/uv/tests/it/pip_compile.rs     | 321 ++++++++++++++++++++++++++
 docs/reference/cli.md                 |   2 +-
 6 files changed, 403 insertions(+), 4 deletions(-)

diff --git a/crates/uv-cli/src/lib.rs b/crates/uv-cli/src/lib.rs
index 1d5e4739a9ca2..7c7de43816785 100644
--- a/crates/uv-cli/src/lib.rs
+++ b/crates/uv-cli/src/lib.rs
@@ -1170,9 +1170,20 @@ pub struct PipCompileArgs {
     ///
     /// If a patch version is omitted, the minimum patch version is assumed. For
     /// example, `3.8` is mapped to `3.8.0`.
-    #[arg(long, short, help_heading = "Python options")]
+    #[arg(long, help_heading = "Python options")]
     pub python_version: Option<PythonVersion>,
 
+    /// The Python interpreter or version to use for resolution.
+    ///
+    /// In previous versions of uv, `-p` was an alias for `--python-version` in `uv pip compile` but
+    /// an alias for `--python` in all other commands. This option is provided as a backwards
+    /// compatible shim, allowing `-p` to behave as `--python` without introducing a breaking
+    /// change.
+    ///
+    /// `UV_PYTHON` is respected, but overridden by `--python-version` or `--python`.
+    #[arg(short, hide = true, help_heading = "Python options")]
+    pub python_legacy: Option<String>,
+
     /// The platform for which requirements should be resolved.
     ///
     /// Represented as a "target triple", a string that describes the target platform in terms of
diff --git a/crates/uv/src/commands/pip/compile.rs b/crates/uv/src/commands/pip/compile.rs
index 0dc21a51273c5..2fc3c2709dd22 100644
--- a/crates/uv/src/commands/pip/compile.rs
+++ b/crates/uv/src/commands/pip/compile.rs
@@ -38,6 +38,7 @@ use uv_resolver::{
     InMemoryIndex, OptionsBuilder, PrereleaseMode, PythonRequirement, RequiresPython,
     ResolutionMode, ResolverEnvironment,
 };
+use uv_static::EnvVars;
 use uv_types::{BuildIsolation, EmptyInstalledPackages, HashStrategy};
 use uv_warnings::warn_user;
 
@@ -94,6 +95,7 @@ pub(crate) async fn pip_compile(
     annotation_style: AnnotationStyle,
     link_mode: LinkMode,
     python: Option<String>,
+    mut python_legacy: Option<String>,
     system: bool,
     python_preference: PythonPreference,
     concurrency: Concurrency,
@@ -103,6 +105,29 @@ pub(crate) async fn pip_compile(
     printer: Printer,
     preview: PreviewMode,
 ) -> Result<ExitStatus> {
+    // If the user requests both `-p` and `--python` or `--python-version`, error
+    if let Some(python_legacy) = python_legacy.as_ref() {
+        if let Some(python) = python.as_ref() {
+            return Err(anyhow!(
+                "Cannot specify both `-p` ({python_legacy}) and `--python` ({python}).",
+            ));
+        }
+        if let Some(python_version) = python_version.as_ref() {
+            return Err(anyhow!(
+                "Cannot specify both `-p` ({python_legacy}) and `--python-version` ({python_version}).",
+            ));
+        }
+    }
+
+    // Respect `UV_PYTHON` with legacy behavior
+    if python_legacy.is_none() && python_version.is_none() && python.is_none() {
+        if let Ok(python) = std::env::var(EnvVars::UV_PYTHON) {
+            if !python.is_empty() {
+                python_legacy = Some(python);
+            }
+        }
+    }
+
     // If the user requests `extras` but does not provide a valid source (e.g., a `pyproject.toml`),
     // return an error.
     if !extras.is_empty() && !requirements.iter().any(RequirementsSource::allows_extras) {
@@ -188,9 +213,30 @@ pub(crate) async fn pip_compile(
     let interpreter = if let Some(python) = python.as_ref() {
         let request = PythonRequest::parse(python);
         PythonInstallation::find(&request, environment_preference, python_preference, &cache)
+    } else if let Some(python_legacy) = python_legacy.as_ref() {
+        // `-p` uses backwards compatible behavior and does not fail if it cannot find the requested
+        // version; previously, this was short for `--python-version`
+        let request = PythonRequest::parse(python_legacy);
+        match request {
+            PythonRequest::Version(..) => PythonInstallation::find_best(
+                &request,
+                environment_preference,
+                python_preference,
+                &cache,
+            ),
+            // For queries _other_ than a version, we fail as we would if `--python` were used.
+            // There's no backwards compatibility concern here because `-p` / `--python-version`
+            // was restricted to Python versions.
+            _ => PythonInstallation::find(
+                &request,
+                environment_preference,
+                python_preference,
+                &cache,
+            ),
+        }
     } else {
-        // TODO(zanieb): The split here hints at a problem with the abstraction; we should be able to use
-        // `PythonInstallation::find(...)` here.
+        // TODO(zanieb): The split here hints at a problem with the request abstraction; we should
+        // be able to use `PythonInstallation::find(...)` here.
         let request = if let Some(version) = python_version.as_ref() {
             // TODO(zanieb): We should consolidate `VersionRequest` and `PythonVersion`
             PythonRequest::Version(VersionRequest::from(version))
@@ -227,6 +273,23 @@ pub(crate) async fn pip_compile(
         }
     }
 
+    if let Some(python_legacy) = python_legacy.as_ref() {
+        let request = PythonRequest::parse(&python_legacy);
+
+        // If the requested interpreter version does not match the interpreter we're using
+        if !no_build.is_none() && !request.satisfied(&interpreter, &cache) {
+            // Other cases should be unreachable, as we only use the legacy fallback for version
+            // requests
+            if let PythonRequest::Version(version) = request {
+                warn_user!(
+                    "The requested Python version {} is not available; {} will be used to build dependencies instead.",
+                    version,
+                    interpreter.python_version(),
+                );
+            }
+        }
+    }
+
     // Create the shared state.
     let state = SharedState::default();
 
diff --git a/crates/uv/src/lib.rs b/crates/uv/src/lib.rs
index 930c61121cdbe..ff83b3a2361f2 100644
--- a/crates/uv/src/lib.rs
+++ b/crates/uv/src/lib.rs
@@ -428,6 +428,7 @@ async fn run(mut cli: Cli) -> Result<ExitStatus> {
                 args.settings.annotation_style,
                 args.settings.link_mode,
                 args.settings.python,
+                args.python_legacy,
                 args.settings.system,
                 globals.python_preference,
                 globals.concurrency,
diff --git a/crates/uv/src/settings.rs b/crates/uv/src/settings.rs
index 91ba1eba2ebde..bba6e328715bd 100644
--- a/crates/uv/src/settings.rs
+++ b/crates/uv/src/settings.rs
@@ -1533,6 +1533,7 @@ pub(crate) struct PipCompileSettings {
     pub(crate) overrides_from_workspace: Vec<Requirement>,
     pub(crate) environments: SupportedEnvironments,
     pub(crate) refresh: Refresh,
+    pub(crate) python_legacy: Option<String>,
     pub(crate) settings: PipSettings,
 }
 
@@ -1572,6 +1573,7 @@ impl PipCompileSettings {
             no_binary,
             only_binary,
             python_version,
+            python_legacy,
             python_platform,
             universal,
             no_universal,
@@ -1641,6 +1643,7 @@ impl PipCompileSettings {
             overrides_from_workspace,
             environments,
             refresh: Refresh::from(refresh),
+            python_legacy,
             settings: PipSettings::combine(
                 PipOptions {
                     python: python.and_then(Maybe::into_option),
diff --git a/crates/uv/tests/it/pip_compile.rs b/crates/uv/tests/it/pip_compile.rs
index 53836facf568d..0906dfc2a8137 100644
--- a/crates/uv/tests/it/pip_compile.rs
+++ b/crates/uv/tests/it/pip_compile.rs
@@ -1309,6 +1309,89 @@ fn compile_python_312() -> Result<()> {
     "###
     );
 
+    // This should work with the short flag
+    uv_snapshot!(context.filters(), context.pip_compile()
+        .arg("requirements.in")
+        .arg("-p")
+        .arg("3.12"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in -p 3.12
+    black==23.10.1
+        # via -r requirements.in
+    click==8.1.7
+        # via black
+    mypy-extensions==1.0.0
+        # via black
+    packaging==24.0
+        # via black
+    pathspec==0.12.1
+        # via black
+    platformdirs==4.2.0
+        # via black
+
+    ----- stderr -----
+    Resolved 6 packages in [TIME]
+    "###
+    );
+
+    // And `--python`
+    uv_snapshot!(context.filters(), context.pip_compile()
+        .arg("requirements.in")
+        .arg("--python")
+        .arg("3.12"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in --python 3.12
+    black==23.10.1
+        # via -r requirements.in
+    click==8.1.7
+        # via black
+    mypy-extensions==1.0.0
+        # via black
+    packaging==24.0
+        # via black
+    pathspec==0.12.1
+        # via black
+    platformdirs==4.2.0
+        # via black
+
+    ----- stderr -----
+    Resolved 6 packages in [TIME]
+    "###
+    );
+
+    // And `UV_PYTHON`
+    uv_snapshot!(context.filters(), context.pip_compile()
+        .arg("requirements.in")
+        .env("UV_PYTHON", "3.12"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in
+    black==23.10.1
+        # via -r requirements.in
+    click==8.1.7
+        # via black
+    mypy-extensions==1.0.0
+        # via black
+    packaging==24.0
+        # via black
+    pathspec==0.12.1
+        # via black
+    platformdirs==4.2.0
+        # via black
+
+    ----- stderr -----
+    Resolved 6 packages in [TIME]
+    "###
+    );
+
     Ok(())
 }
 
@@ -1379,6 +1462,244 @@ fn compile_fallback_interpreter() -> Result<()> {
     "###
     );
 
+    // This should work for the short flag too
+    uv_snapshot!(context.filters(), context.pip_compile()
+            .arg("requirements.in")
+            .arg("-p")
+            .arg("3.12"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in -p 3.12
+    black==23.10.[X]
+        # via -r requirements.in
+    click==8.1.7
+        # via black
+    mypy-extensions==1.0.0
+        # via black
+    packaging==24.0
+        # via black
+    pathspec==0.12.1
+        # via black
+    platformdirs==4.2.0
+        # via black
+    tomli==2.0.1
+        # via black
+    typing-extensions==4.10.0
+        # via black
+
+    ----- stderr -----
+    Resolved 8 packages in [TIME]
+    "###
+    );
+
+    // And for `UV_PYTHON`
+    uv_snapshot!(context.filters(), context.pip_compile()
+            .arg("requirements.in")
+            .env(EnvVars::UV_PYTHON, "3.12"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in
+    black==23.10.[X]
+        # via -r requirements.in
+    click==8.1.7
+        # via black
+    mypy-extensions==1.0.0
+        # via black
+    packaging==24.0
+        # via black
+    pathspec==0.12.1
+        # via black
+    platformdirs==4.2.0
+        # via black
+    tomli==2.0.1
+        # via black
+    typing-extensions==4.10.0
+        # via black
+
+    ----- stderr -----
+    Resolved 8 packages in [TIME]
+    "###
+    );
+
+    // But fail for `--python`
+    uv_snapshot!(context.filters(), context.pip_compile()
+            .arg("requirements.in")
+            .arg("--python")
+            .arg("3.12"), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: No interpreter found for Python 3.12 in virtual environments, managed installations, or search path
+    "###
+    );
+
+    // The short flag also allows complex requests, like alternative implementations, but we should
+    // not fallback if that cannot be found
+    uv_snapshot!(context.filters(), context.pip_compile()
+        .arg("requirements.in")
+        .arg("-p")
+        .arg("pypy"), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: No interpreter found for PyPy in virtual environments, managed installations, or search path
+    "###
+    );
+
+    Ok(())
+}
+
+#[test]
+fn compile_python_conflicts() -> Result<()> {
+    let context = TestContext::new("3.12");
+    let requirements_in = context.temp_dir.child("requirements.in");
+    requirements_in.write_str("black==23.10.1")?;
+
+    uv_snapshot!(context.filters(), context.pip_compile()
+            .arg("requirements.in")
+            .arg("--python-version")
+            .arg("3.12")
+            .arg("-p")
+            .arg("3.12"), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: Cannot specify both `-p` (3.12) and `--python-version` (3.12).
+    "###
+    );
+
+    uv_snapshot!(context.filters(), context.pip_compile()
+            .arg("requirements.in")
+            .arg("--python")
+            .arg("3.12")
+            .arg("-p")
+            .arg("3.12"), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: Cannot specify both `-p` (3.12) and `--python` (3.12).
+    "###
+    );
+
+    // `UV_PYTHON` should  be usable with `-p`
+    uv_snapshot!(context.filters(), context.pip_compile()
+            .arg("requirements.in")
+            .arg("-p")
+            .arg("3.12")
+            .env("UV_PYTHON", "3.11"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in -p 3.12
+    black==23.10.1
+        # via -r requirements.in
+    click==8.1.7
+        # via black
+    mypy-extensions==1.0.0
+        # via black
+    packaging==24.0
+        # via black
+    pathspec==0.12.1
+        # via black
+    platformdirs==4.2.0
+        # via black
+
+    ----- stderr -----
+    Resolved 6 packages in [TIME]
+    "###
+    );
+
+    // `UV_PYTHON` should  be usable with `--python`
+    uv_snapshot!(context.filters(), context.pip_compile()
+            .arg("requirements.in")
+            .arg("--python")
+            .arg("3.12")
+            .env("UV_PYTHON", "3.11"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in --python 3.12
+    black==23.10.1
+        # via -r requirements.in
+    click==8.1.7
+        # via black
+    mypy-extensions==1.0.0
+        # via black
+    packaging==24.0
+        # via black
+    pathspec==0.12.1
+        # via black
+    platformdirs==4.2.0
+        # via black
+
+    ----- stderr -----
+    Resolved 6 packages in [TIME]
+    "###
+    );
+
+    // `UV_PYTHON` should  be usable with `--python-version`
+    uv_snapshot!(context.filters(), context.pip_compile()
+            .arg("requirements.in")
+            .arg("--python-version")
+            .arg("3.12")
+            .env("UV_PYTHON", "3.11"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in --python-version 3.12
+    black==23.10.1
+        # via -r requirements.in
+    click==8.1.7
+        # via black
+    mypy-extensions==1.0.0
+        # via black
+    packaging==24.0
+        # via black
+    pathspec==0.12.1
+        # via black
+    platformdirs==4.2.0
+        # via black
+
+    ----- stderr -----
+    Resolved 6 packages in [TIME]
+    "###
+    );
+
+    // `--python-legacy` is not available in long-form
+    uv_snapshot!(context.filters(), context.pip_compile()
+            .arg("requirements.in")
+            .arg("--python-legacy")
+            .arg("3.12"), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    error: unexpected argument '--python-legacy' found
+
+      tip: a similar argument exists: '--python'
+
+    Usage: uv pip compile --cache-dir [CACHE_DIR] --python <PYTHON> <SRC_FILE>...
+
+    For more information, try '--help'.
+    "###
+    );
+
     Ok(())
 }
 
diff --git a/docs/reference/cli.md b/docs/reference/cli.md
index 8d6be84c413b4..ab17a2654f3f6 100644
--- a/docs/reference/cli.md
+++ b/docs/reference/cli.md
@@ -5955,7 +5955,7 @@ uv pip compile [OPTIONS] <SRC_FILE>...
 
 <li><code>only-system</code>:  Only use system Python installations; never use managed Python installations</li>
 </ul>
-</dd><dt><code>--python-version</code>, <code>-p</code> <i>python-version</i></dt><dd><p>The Python version to use for resolution.</p>
+</dd><dt><code>--python-version</code> <i>python-version</i></dt><dd><p>The Python version to use for resolution.</p>
 
 <p>For example, <code>3.8</code> or <code>3.8.17</code>.</p>