feat: Implement --annotation-style parameter for uv pip compile (#1679)

## Summary

Hello there! The motivation for this feature is described here #1678 

## Test Plan

I've added unit tests and also tested this manually on my work project
by comparing it to the original `pip-compile` output - it looks much
like the `pip-compile` generated lock file.

crates/uv-resolver/src/lib.rs

@@ -4,7 +4,7 @@ pub use finder::{DistFinder, Reporter as FinderReporter};
 pub use manifest::Manifest;
 pub use options::{Options, OptionsBuilder};
 pub use prerelease_mode::PreReleaseMode;
-pub use resolution::{Diagnostic, DisplayResolutionGraph, ResolutionGraph};
+pub use resolution::{AnnotationStyle, Diagnostic, DisplayResolutionGraph, ResolutionGraph};
 pub use resolution_mode::ResolutionMode;
 pub use resolver::{
     BuildId, DefaultResolverProvider, InMemoryIndex, Reporter as ResolverReporter, Resolver,

crates/uv-resolver/src/resolution.rs

@@ -9,7 +9,6 @@ use petgraph::Direction;
 use pubgrub::range::Range;
 use pubgrub::solver::{Kind, State};
 use pubgrub::type_aliases::SelectedDependencies;
-
 use rustc_hash::FxHashMap;
 use url::Url;
 
@@ -23,9 +22,20 @@ use uv_normalize::{ExtraName, PackageName};
 use crate::pins::FilePins;
 use crate::pubgrub::{PubGrubDistribution, PubGrubPackage, PubGrubPriority};
 use crate::resolver::VersionsResponse;
-
 use crate::ResolveError;
 
+/// Indicate the style of annotation comments, used to indicate the dependencies that requested each
+/// package.
+#[derive(Debug, Default, Copy, Clone, PartialEq)]
+#[cfg_attr(feature = "clap", derive(clap::ValueEnum))]
+pub enum AnnotationStyle {
+    /// Render the annotations on a single, comma-separated line.
+    Line,
+    /// Render each annotation on its own line.
+    #[default]
+    Split,
+}
+
 /// A complete resolution graph in which every node represents a pinned package and every edge
 /// represents a dependency between two pinned packages.
 #[derive(Debug)]
@@ -256,11 +266,14 @@ pub struct DisplayResolutionGraph<'a> {
     /// Whether to include annotations in the output, to indicate which dependency or dependencies
     /// requested each package.
     include_annotations: bool,
+    /// The style of annotation comments, used to indicate the dependencies that requested each
+    /// package.
+    annotation_style: AnnotationStyle,
 }
 
 impl<'a> From<&'a ResolutionGraph> for DisplayResolutionGraph<'a> {
     fn from(resolution: &'a ResolutionGraph) -> Self {
-        Self::new(resolution, false, true)
+        Self::new(resolution, false, true, AnnotationStyle::default())
     }
 }
 
@@ -270,11 +283,13 @@ impl<'a> DisplayResolutionGraph<'a> {
         underlying: &'a ResolutionGraph,
         show_hashes: bool,
         include_annotations: bool,
+        annotation_style: AnnotationStyle,
     ) -> DisplayResolutionGraph<'a> {
         Self {
             resolution: underlying,
             show_hashes,
             include_annotations,
+            annotation_style,
         }
     }
 }
@@ -339,16 +354,13 @@ impl std::fmt::Display for DisplayResolutionGraph<'_> {
         // Print out the dependency graph.
         for (index, node) in nodes {
             // Display the node itself.
-            match node {
+            let mut line = match node {
-                Node::Distribution(_, dist) => {
+                Node::Distribution(_, dist) => format!("{}", dist.verbatim()),
-                    write!(f, "{}", dist.verbatim())?;
+                Node::Editable(_, editable) => format!("-e {}", editable.verbatim()),
-                }
+            };
-                Node::Editable(_, editable) => {
-                    write!(f, "-e {}", editable.verbatim())?;
-                }
-            }
 
             // Display the distribution hashes, if any.
+            let mut has_hashes = false;
             if self.show_hashes {
                 if let Some(hashes) = self
                     .resolution
@@ -358,13 +370,17 @@ impl std::fmt::Display for DisplayResolutionGraph<'_> {
                 {
                     for hash in hashes {
                         if let Some(hash) = hash.to_string() {
-                            writeln!(f, " \\")?;
+                            has_hashes = true;
-                            write!(f, "    --hash={hash}")?;
+                            line.push_str(" \\\n");
+                            line.push_str("    --hash=");
+                            line.push_str(&hash);
                         }
                     }
                 }
             }
-            writeln!(f)?;
+
+            // Determine the annotation comment and separator (between comment and requirement).
+            let mut annotation = None;
 
             if self.include_annotations {
                 // Display all dependencies.
@@ -376,21 +392,50 @@ impl std::fmt::Display for DisplayResolutionGraph<'_> {
                     .collect::<Vec<_>>();
                 edges.sort_unstable_by_key(|package| package.name());
 
-                match edges.len() {
+                match self.annotation_style {
-                    0 => {}
+                    AnnotationStyle::Line => {
-                    1 => {
+                        if !edges.is_empty() {
-                        for dependency in edges {
+                            let separator = if has_hashes { "\n    " } else { "  " };
-                            writeln!(f, "{}", format!("    # via {}", dependency.name()).green())?;
+                            let deps = edges
+                                .into_iter()
+                                .map(|dependency| dependency.name().to_string())
+                                .collect::<Vec<_>>()
+                                .join(", ");
+                            let comment = format!("# via {deps}").green().to_string();
+                            annotation = Some((separator, comment));
                         }
                     }
-                    _ => {
+                    AnnotationStyle::Split => match edges.as_slice() {
-                        writeln!(f, "{}", "    # via".green())?;
+                        [] => {}
-                        for dependency in edges {
+                        [edge] => {
-                            writeln!(f, "{}", format!("    #   {}", dependency.name()).green())?;
+                            let separator = "\n";
+                            let comment = format!("    # via {}", edge.name()).green().to_string();
+                            annotation = Some((separator, comment));
                         }
-                    }
+                        edges => {
+                            let separator = "\n";
+                            let deps = edges
+                                .iter()
+                                .map(|dependency| format!("    #   {}", dependency.name()))
+                                .collect::<Vec<_>>()
+                                .join("\n");
+                            let comment = format!("    # via\n{deps}").green().to_string();
+                            annotation = Some((separator, comment));
+                        }
+                    },
                 }
             }
+
+            if let Some((separator, comment)) = annotation {
+                // Assemble the line with the annotations and remove trailing whitespaces.
+                for line in format!("{line:24}{separator}{comment}").lines() {
+                    let line = line.trim_end();
+                    writeln!(f, "{line}")?;
+                }
+            } else {
+                // Write the line as is.
+                writeln!(f, "{line}")?;
+            }
         }
 
         Ok(())

crates/uv/src/commands/pip_compile.rs

@@ -28,8 +28,8 @@ use uv_installer::{Downloader, NoBinary};
 use uv_interpreter::{Interpreter, PythonVersion};
 use uv_normalize::{ExtraName, PackageName};
 use uv_resolver::{
-    DependencyMode, DisplayResolutionGraph, InMemoryIndex, Manifest, OptionsBuilder,
+    AnnotationStyle, DependencyMode, DisplayResolutionGraph, InMemoryIndex, Manifest,
-    PreReleaseMode, ResolutionMode, Resolver,
+    OptionsBuilder, PreReleaseMode, ResolutionMode, Resolver,
 };
 use uv_traits::{InFlight, NoBuild, SetupPyStrategy};
 use uv_warnings::warn_user;
@@ -62,6 +62,7 @@ pub(crate) async fn pip_compile(
     no_build: &NoBuild,
     python_version: Option<PythonVersion>,
     exclude_newer: Option<DateTime<Utc>>,
+    annotation_style: AnnotationStyle,
     cache: Cache,
     mut printer: Printer,
 ) -> Result<ExitStatus> {
@@ -391,7 +392,12 @@ pub(crate) async fn pip_compile(
     write!(
         writer,
         "{}",
-        DisplayResolutionGraph::new(&resolution, generate_hashes, include_annotations)
+        DisplayResolutionGraph::new(
+            &resolution,
+            generate_hashes,
+            include_annotations,
+            annotation_style
+        )
     )?;
 
     Ok(ExitStatus::Success)

crates/uv/src/compat/mod.rs

@@ -36,9 +36,6 @@ pub(crate) struct PipCompileCompatArgs {
     #[clap(long, hide = true)]
     resolver: Option<Resolver>,
 
-    #[clap(long, hide = true)]
-    annotation_style: Option<AnnotationStyle>,
-
     #[clap(long, hide = true)]
     max_rounds: Option<usize>,
 
@@ -144,21 +141,6 @@ impl CompatArgs for PipCompileCompatArgs {
             }
         }
 
-        if let Some(annotation_style) = self.annotation_style {
-            match annotation_style {
-                AnnotationStyle::Split => {
-                    warn_user!(
-                        "pip-compile's `--annotation-style=split` has no effect (uv always emits split annotations)."
-                    );
-                }
-                AnnotationStyle::Line => {
-                    return Err(anyhow!(
-                        "pip-compile's `--annotation-style=line` is unsupported (uv always emits split annotations)."
-                    ));
-                }
-            }
-        }
-
         if self.max_rounds.is_some() {
             return Err(anyhow!(
                 "pip-compile's `--max-rounds` is unsupported (uv always resolves until convergence)."
@@ -346,12 +328,6 @@ enum Resolver {
     Legacy,
 }
 
-#[derive(Debug, Copy, Clone, ValueEnum)]
-enum AnnotationStyle {
-    Line,
-    Split,
-}
-
 /// Arguments for `venv` compatibility.
 ///
 /// These represent a subset of the `virtualenv` interface that uv supports by default.

crates/uv/src/main.rs

@@ -19,7 +19,7 @@ use uv_client::Connectivity;
 use uv_installer::{NoBinary, Reinstall};
 use uv_interpreter::PythonVersion;
 use uv_normalize::{ExtraName, PackageName};
-use uv_resolver::{DependencyMode, PreReleaseMode, ResolutionMode};
+use uv_resolver::{AnnotationStyle, DependencyMode, PreReleaseMode, ResolutionMode};
 use uv_traits::{NoBuild, PackageNameSpecifier, SetupPyStrategy};
 
 use crate::commands::{extra_name_with_clap_error, ExitStatus, Upgrade};
@@ -354,6 +354,10 @@ struct PipCompileArgs {
     #[clap(long, hide = true)]
     emit_find_links: bool,
 
+    /// Choose the style of the annotation comments, which indicate the source of each package.
+    #[clap(long, default_value_t=AnnotationStyle::Split, value_enum)]
+    annotation_style: AnnotationStyle,
+
     #[command(flatten)]
     compat_args: compat::PipCompileCompatArgs,
 }
@@ -898,6 +902,7 @@ async fn run() -> Result<ExitStatus> {
                 &no_build,
                 args.python_version,
                 args.exclude_newer,
+                args.annotation_style,
                 cache,
                 printer,
             )

crates/uv/tests/common/mod.rs

@@ -266,7 +266,9 @@ pub fn run_and_format<'a>(
         // The optional leading +/- is for install logs, the optional next line is for lock files
         let windows_only_deps = [
             ("( [+-] )?colorama==\\d+(\\.[\\d+])+\n(    # via .*\n)?"),
+            ("( [+-] )?colorama==\\d+(\\.[\\d+])+\\s+(# via .*\n)?"),
             ("( [+-] )?tzdata==\\d+(\\.[\\d+])+\n(    # via .*\n)?"),
+            ("( [+-] )?tzdata==\\d+(\\.[\\d+])+\\s+(# via .*\n)?"),
         ];
         let mut removed_packages = 0;
         for windows_only_dep in windows_only_deps {

crates/uv/tests/pip_compile.rs

@@ -47,6 +47,33 @@ fn compile_requirements_in() -> Result<()> {
     Ok(())
 }
 
+/// Resolve a specific version of Django from a `requirements.in` file with a `--annotation-style=line` flag.
+#[test]
+fn compile_requirements_in_annotation_line() -> Result<()> {
+    let context = TestContext::new("3.12");
+    let requirements_in = context.temp_dir.child("requirements.in");
+    requirements_in.write_str("django==5.0b1")?;
+
+    uv_snapshot!(context
+        .compile()
+        .arg("--annotation-style=line")
+        .arg("requirements.in"), @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 2023-11-18T12:00:00Z --annotation-style=line requirements.in
+    asgiref==3.7.2            # via django
+    django==5.0b1
+    sqlparse==0.4.4           # via django
+
+    ----- stderr -----
+    Resolved 3 packages in [TIME]
+    "###);
+
+    Ok(())
+}
+
 /// Resolve a specific version of Django from a `requirements.in` file on stdin
 /// when passed a path of `-`.
 #[test]
@@ -550,6 +577,38 @@ fn compile_python_312() -> Result<()> {
     Ok(())
 }
 
+/// Resolve a specific version of Black at Python 3.12 with `--annotation-style=line`.
+#[test]
+fn compile_python_312_annotation_line() -> 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.compile()
+            .arg("--annotation-style=line")
+            .arg("requirements.in")
+            .arg("--python-version")
+            .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] --exclude-newer 2023-11-18T12:00:00Z --annotation-style=line requirements.in --python-version 3.12
+    black==23.10.1
+    click==8.1.7              # via black
+    mypy-extensions==1.0.0    # via black
+    packaging==23.2           # via black
+    pathspec==0.11.2          # via black
+    platformdirs==4.0.0       # via black
+
+    ----- stderr -----
+    Resolved 6 packages in [TIME]
+    "###
+    );
+
+    Ok(())
+}
+
 /// Resolve a specific version of Black at Python 3.12 without deps.
 #[test]
 fn compile_python_312_no_deps() -> Result<()> {
@@ -1426,6 +1485,53 @@ optional-dependencies.bar = [
     Ok(())
 }
 
+#[test]
+fn compile_pyproject_toml_all_extras_annotation_line() -> Result<()> {
+    let context = TestContext::new("3.12");
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"[build-system]
+requires = ["setuptools", "wheel"]
+
+[project]
+name = "project"
+dependencies = ["django==5.0b1"]
+optional-dependencies.foo = [
+    "anyio==4.0.0",
+]
+optional-dependencies.bar = [
+    "httpcore==0.18.0",
+]
+"#,
+    )?;
+
+    uv_snapshot!(context.compile()
+            .arg("--annotation-style=line")
+            .arg("pyproject.toml")
+            .arg("--all-extras"), @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 2023-11-18T12:00:00Z --annotation-style=line pyproject.toml --all-extras
+    anyio==4.0.0              # via httpcore
+    asgiref==3.7.2            # via django
+    certifi==2023.11.17       # via httpcore
+    django==5.0b1
+    h11==0.14.0               # via httpcore
+    httpcore==0.18.0
+    idna==3.4                 # via anyio
+    sniffio==1.3.0            # via anyio, httpcore
+    sqlparse==0.4.4           # via django
+
+    ----- stderr -----
+    Resolved 9 packages in [TIME]
+    "###
+    );
+
+    Ok(())
+}
+
 /// Resolve packages from all optional dependency groups in a `pyproject.toml` file.
 #[test]
 fn compile_does_not_allow_both_extra_and_all_extras() -> Result<()> {