Add `--marker` flag to `uv add` (#12012)

## Summary

Add a `--marker` flag to `uv add` which applies a marker to all given
requirements.

Example:

```
$ uv-debug add --marker "platform_machine == 'x86_64'" \
    "anyio>=2.31.0" \
    "iniconfig>=2; sys_platform != 'win32'" \
    "numpy>1.19; sys_platform == 'win32'"
```

```toml
[project]
name = "project"
version = "0.1.0"
requires-python = ">=3.12.0"
dependencies = [
    "anyio>=2.31.0 ; platform_machine == 'x86_64'",
    "iniconfig>=2 ; platform_machine == 'x86_64' and sys_platform != 'win32'",
    "numpy>1.19 ; platform_machine == 'x86_64' and sys_platform == 'win32'",
]
```

Fixes https://github.com/astral-sh/uv/issues/11987


## Test Plan

Added snapshot tests

---------

Co-authored-by: konstin <konstin@mailbox.org>

crates/uv-cli/src/lib.rs

@@ -16,7 +16,7 @@ use uv_configuration::{
 };
 use uv_distribution_types::{Index, IndexUrl, Origin, PipExtraIndex, PipFindLinks, PipIndex};
 use uv_normalize::{ExtraName, GroupName, PackageName};
-use uv_pep508::Requirement;
+use uv_pep508::{MarkerTree, Requirement};
 use uv_pypi_types::VerbatimParsedUrl;
 use uv_python::{PythonDownloads, PythonPreference, PythonVersion};
 use uv_resolver::{AnnotationStyle, ExcludeNewer, ForkStrategy, PrereleaseMode, ResolutionMode};
@@ -3272,6 +3272,10 @@ pub struct AddArgs {
     #[arg(long, short, alias = "requirement", group = "sources", value_parser = parse_file_path)]
     pub requirements: Vec<PathBuf>,
 
+    /// Apply this marker to all added packages.
+    #[arg(long, short, value_parser = MarkerTree::from_str)]
+    pub marker: Option<MarkerTree>,
+
     /// Add the requirements to the development dependency group.
     ///
     /// This option is an alias for `--group dev`.

crates/uv/src/commands/project/add.rs

@@ -26,7 +26,7 @@ use uv_fs::Simplified;
 use uv_git::GIT_STORE;
 use uv_git_types::GitReference;
 use uv_normalize::{PackageName, DEV_DEPENDENCIES};
-use uv_pep508::{ExtraName, Requirement, UnnamedRequirement, VersionOrUrl};
+use uv_pep508::{ExtraName, MarkerTree, Requirement, UnnamedRequirement, VersionOrUrl};
 use uv_pypi_types::{redact_credentials, ParsedUrl, RequirementSource, VerbatimParsedUrl};
 use uv_python::{Interpreter, PythonDownloads, PythonEnvironment, PythonPreference, PythonRequest};
 use uv_requirements::{NamedRequirementsResolver, RequirementsSource, RequirementsSpecification};
@@ -64,6 +64,7 @@ pub(crate) async fn add(
     active: Option<bool>,
     no_sync: bool,
     requirements: Vec<RequirementsSource>,
+    marker: Option<MarkerTree>,
     editable: Option<bool>,
     dependency_type: DependencyType,
     raw_sources: bool,
@@ -274,6 +275,7 @@ pub(crate) async fn add(
                     rev.as_deref(),
                     tag.as_deref(),
                     branch.as_deref(),
+                    marker,
                 )
             })
             .partition_map(|requirement| match requirement {
@@ -896,10 +898,17 @@ fn augment_requirement(
     rev: Option<&str>,
     tag: Option<&str>,
     branch: Option<&str>,
+    marker: Option<MarkerTree>,
 ) -> UnresolvedRequirement {
     match requirement {
-        UnresolvedRequirement::Named(requirement) => {
+        UnresolvedRequirement::Named(mut requirement) => {
             UnresolvedRequirement::Named(uv_pypi_types::Requirement {
+                marker: marker
+                    .map(|marker| {
+                        requirement.marker.and(marker);
+                        requirement.marker
+                    })
+                    .unwrap_or(requirement.marker),
                 source: match requirement.source {
                     RequirementSource::Git {
                         git,
@@ -926,8 +935,14 @@ fn augment_requirement(
                 ..requirement
             })
         }
-        UnresolvedRequirement::Unnamed(requirement) => {
+        UnresolvedRequirement::Unnamed(mut requirement) => {
             UnresolvedRequirement::Unnamed(UnnamedRequirement {
+                marker: marker
+                    .map(|marker| {
+                        requirement.marker.and(marker);
+                        requirement.marker
+                    })
+                    .unwrap_or(requirement.marker),
                 url: match requirement.url.parsed_url {
                     ParsedUrl::Git(mut git) => {
                         let reference = if let Some(rev) = rev {

crates/uv/src/lib.rs

@@ -1647,6 +1647,7 @@ async fn run_project(
                 args.active,
                 args.no_sync,
                 requirements,
+                args.marker,
                 args.editable,
                 args.dependency_type,
                 args.raw_sources,

crates/uv/src/settings.rs

@@ -31,7 +31,7 @@ use uv_configuration::{
 use uv_distribution_types::{DependencyMetadata, Index, IndexLocations, IndexUrl};
 use uv_install_wheel::LinkMode;
 use uv_normalize::PackageName;
-use uv_pep508::{ExtraName, RequirementOrigin};
+use uv_pep508::{ExtraName, MarkerTree, RequirementOrigin};
 use uv_pypi_types::{Requirement, SupportedEnvironments};
 use uv_python::{Prefix, PythonDownloads, PythonPreference, PythonVersion, Target};
 use uv_resolver::{
@@ -1167,6 +1167,7 @@ pub(crate) struct AddSettings {
     pub(crate) no_sync: bool,
     pub(crate) packages: Vec<String>,
     pub(crate) requirements: Vec<PathBuf>,
+    pub(crate) marker: Option<MarkerTree>,
     pub(crate) dependency_type: DependencyType,
     pub(crate) editable: Option<bool>,
     pub(crate) extras: Vec<ExtraName>,
@@ -1190,6 +1191,7 @@ impl AddSettings {
         let AddArgs {
             packages,
             requirements,
+            marker,
             dev,
             optional,
             group,
@@ -1280,6 +1282,7 @@ impl AddSettings {
             no_sync,
             packages,
             requirements,
+            marker,
             dependency_type,
             raw_sources,
             rev,

crates/uv/tests/it/edit.rs

@@ -4736,6 +4736,95 @@ fn add_requirements_file() -> Result<()> {
     Ok(())
 }
 
+/// Add requirements from a file with a marker flag.
+///
+/// We test that:
+/// * Adding requirements from a file applies the marker to all of them
+/// * We combine the marker with existing markers
+/// * We only sync the packages applicable under this marker
+#[test]
+fn add_requirements_file_with_marker_flag() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let requirements_win_txt = context.temp_dir.child("requirements.win.txt");
+    requirements_win_txt.write_str("anyio>=2.31.0\niniconfig>=2; sys_platform != 'fantasy_os'\nnumpy>1.9; sys_platform == 'fantasy_os'")?;
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    let base_pyproject_toml = indoc! {r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = []
+    "#};
+    pyproject_toml.write_str(base_pyproject_toml)?;
+
+    // Add dependencies with a marker that does not apply for the current target.
+    uv_snapshot!(context.filters(), context.add().arg("-r").arg("requirements.win.txt").arg("-m").arg("python_version == '3.11'"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 1 package in [TIME]
+    Audited in [TIME]
+    ");
+    let edited_pyproject_toml = context.read("pyproject.toml");
+
+    // TODO(konsti): We should output `python_version == '3.12'` instead of lowering to
+    // `python_full_version`.
+    assert_snapshot!(
+        edited_pyproject_toml, @r#"
+    [project]
+    name = "project"
+    version = "0.1.0"
+    requires-python = ">=3.12"
+    dependencies = [
+        "anyio>=2.31.0 ; python_full_version == '3.11.*'",
+        "iniconfig>=2 ; python_full_version == '3.11.*' and sys_platform != 'fantasy_os'",
+        "numpy>1.9 ; python_full_version == '3.11.*' and sys_platform == 'fantasy_os'",
+    ]
+    "#
+    );
+
+    // Reset the project.
+    pyproject_toml.write_str(base_pyproject_toml)?;
+    fs_err::remove_file(context.temp_dir.join("uv.lock"))?;
+
+    // Add dependencies with a marker that applies for the current target.
+    uv_snapshot!(context.filters(), context.add().arg("-r").arg("requirements.win.txt").arg("-m").arg("python_version == '3.12'"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 6 packages in [TIME]
+    Prepared 4 packages in [TIME]
+    Installed 4 packages in [TIME]
+     + anyio==4.3.0
+     + idna==3.6
+     + iniconfig==2.0.0
+     + sniffio==1.3.1
+    ");
+    let edited_pyproject_toml = context.read("pyproject.toml");
+
+    assert_snapshot!(
+        edited_pyproject_toml, @r#"
+    [project]
+    name = "project"
+    version = "0.1.0"
+    requires-python = ">=3.12"
+    dependencies = [
+        "anyio>=2.31.0 ; python_full_version == '3.12.*'",
+        "iniconfig>=2 ; python_full_version == '3.12.*' and sys_platform != 'fantasy_os'",
+        "numpy>1.9 ; python_full_version == '3.12.*' and sys_platform == 'fantasy_os'",
+    ]
+    "#
+    );
+
+    Ok(())
+}
+
 /// Add a requirement to a dependency group.
 #[test]
 fn add_group() -> Result<()> {

docs/reference/cli.md

@@ -951,6 +951,8 @@ uv add [OPTIONS] <PACKAGES|--requirements <REQUIREMENTS>>
 <p>Requires that the lockfile is up-to-date. If the lockfile is missing or needs to be updated, uv will exit with an error.</p>
 
 <p>May also be set with the <code>UV_LOCKED</code> environment variable.</p>
+</dd><dt id="uv-add--marker"><a href="#uv-add--marker"><code>--marker</code></a>, <code>-m</code> <i>marker</i></dt><dd><p>Apply this marker to all added packages</p>
+
 </dd><dt id="uv-add--native-tls"><a href="#uv-add--native-tls"><code>--native-tls</code></a></dt><dd><p>Whether to load TLS certificates from the platform&#8217;s native certificate store.</p>
 
 <p>By default, uv loads certificates from the bundled <code>webpki-roots</code> crate. The <code>webpki-roots</code> are a reliable set of trust roots from Mozilla, and including them in uv improves portability and performance (especially on macOS).</p>