Support `uv run -m foo` to run a module (#7754)

## Summary

This is another attempt using `module: bool` instead of `module:
Option<String>` following #7322.
The original PR can't be reopened after a force-push to the branch, I've
created this new PR.

Resolves #6638

crates/uv-cli/src/lib.rs

@@ -2469,6 +2469,12 @@ pub struct RunArgs {
     #[arg(long, overrides_with("dev"))]
     pub no_dev: bool,
 
+    /// Run a Python module.
+    ///
+    /// Equivalent to `python -m <module>`.
+    #[arg(short, long)]
+    pub module: bool,
+
     /// Omit non-development dependencies.
     ///
     /// The project itself will also be omitted.
@@ -2495,7 +2501,7 @@ pub struct RunArgs {
     #[arg(long)]
     pub with: Vec<String>,
 
-    /// Run with the given packages installed as editables
+    /// Run with the given packages installed as editables.
     ///
     /// When used in a project, these dependencies will be layered on top of
     /// the project environment in a separate, ephemeral environment. These

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

@@ -832,6 +832,9 @@ pub(crate) enum RunCommand {
     Python(Vec<OsString>),
     /// Execute a `python` script.
     PythonScript(PathBuf, Vec<OsString>),
+    /// Search `sys.path` for the named module and execute its contents as the `__main__` module.
+    /// Equivalent to `python -m module`.
+    PythonModule(OsString, Vec<OsString>),
     /// Execute a `pythonw` script (Windows only).
     PythonGuiScript(PathBuf, Vec<OsString>),
     /// Execute a Python package containing a `__main__.py` file.
@@ -856,6 +859,7 @@ impl RunCommand {
             | Self::PythonPackage(..)
             | Self::PythonZipapp(..)
             | Self::Empty => Cow::Borrowed("python"),
+            Self::PythonModule(..) => Cow::Borrowed("python -m"),
             Self::PythonGuiScript(..) => Cow::Borrowed("pythonw"),
             Self::PythonStdin(_) => Cow::Borrowed("python -c"),
             Self::External(executable, _) => executable.to_string_lossy(),
@@ -878,6 +882,13 @@ impl RunCommand {
                 process.args(args);
                 process
             }
+            Self::PythonModule(module, args) => {
+                let mut process = Command::new(interpreter.sys_executable());
+                process.arg("-m");
+                process.arg(module);
+                process.args(args);
+                process
+            }
             Self::PythonGuiScript(target, args) => {
                 let python_executable = interpreter.sys_executable();
 
@@ -944,6 +955,14 @@ impl std::fmt::Display for RunCommand {
                 }
                 Ok(())
             }
+            Self::PythonModule(module, args) => {
+                write!(f, "python -m")?;
+                write!(f, " {}", module.to_string_lossy())?;
+                for arg in args {
+                    write!(f, " {}", arg.to_string_lossy())?;
+                }
+                Ok(())
+            }
             Self::PythonGuiScript(target, args) => {
                 write!(f, "pythonw {}", target.display())?;
                 for arg in args {
@@ -970,17 +989,18 @@ impl std::fmt::Display for RunCommand {
     }
 }
 
-impl TryFrom<&ExternalCommand> for RunCommand {
-    type Error = std::io::Error;
-
-    fn try_from(command: &ExternalCommand) -> Result<Self, Self::Error> {
+impl RunCommand {
+    pub(crate) fn from_args(command: &ExternalCommand, module: bool) -> anyhow::Result<Self> {
         let (target, args) = command.split();
-
         let Some(target) = target else {
             return Ok(Self::Empty);
         };
 
-        let target_path = PathBuf::from(&target);
+        if module {
+            return Ok(Self::PythonModule(target.clone(), args.to_vec()));
+        }
+
+        let target_path = PathBuf::from(target);
         let metadata = target_path.metadata();
         let is_file = metadata.as_ref().map_or(false, std::fs::Metadata::is_file);
         let is_dir = metadata.as_ref().map_or(false, std::fs::Metadata::is_dir);

crates/uv/src/lib.rs

@@ -131,8 +131,11 @@ async fn run(cli: Cli) -> Result<ExitStatus> {
 
     // Parse the external command, if necessary.
     let run_command = if let Commands::Project(command) = &*cli.command {
-        if let ProjectCommand::Run(uv_cli::RunArgs { command, .. }) = &**command {
-            Some(RunCommand::try_from(command)?)
+        if let ProjectCommand::Run(uv_cli::RunArgs {
+            command, module, ..
+        }) = &**command
+        {
+            Some(RunCommand::from_args(command, *module)?)
         } else {
             None
         }

crates/uv/src/settings.rs

@@ -245,6 +245,7 @@ impl RunSettings {
             no_all_extras,
             dev,
             no_dev,
+            module: _,
             only_dev,
             no_editable,
             command: _,

crates/uv/tests/run.rs

@@ -1830,6 +1830,43 @@ fn run_zipapp() -> Result<()> {
     Ok(())
 }
 
+/// Run a module equivalent to `python -m foo`.
+#[test]
+fn run_module() {
+    let context = TestContext::new("3.12");
+
+    uv_snapshot!(context.filters(), context.run().arg("-m").arg("__hello__"), @r#"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    Hello world!
+
+    ----- stderr -----
+    "#);
+
+    uv_snapshot!(context.filters(), context.run().arg("-m").arg("http.server").arg("-h"), @r#"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    usage: server.py [-h] [--cgi] [-b ADDRESS] [-d DIRECTORY] [-p VERSION] [port]
+
+    positional arguments:
+      port                  bind to this port (default: 8000)
+
+    options:
+      -h, --help            show this help message and exit
+      --cgi                 run as CGI server
+      -b ADDRESS, --bind ADDRESS
+                            bind to this address (default: all interfaces)
+      -d DIRECTORY, --directory DIRECTORY
+                            serve this directory (default: current directory)
+      -p VERSION, --protocol VERSION
+                            conform to this HTTP version (default: HTTP/1.0)
+
+    ----- stderr -----
+    "#);
+}
+
 /// When the `pyproject.toml` file is invalid.
 #[test]
 fn run_project_toml_error() -> Result<()> {

docs/reference/cli.md

@@ -217,6 +217,10 @@ uv run [OPTIONS] <COMMAND>
 
 <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>
 
+</dd><dt><code>--module</code>, <code>-m</code></dt><dd><p>Run a Python module.</p>
+
+<p>Equivalent to <code>python -m &lt;module&gt;</code>.</p>
+
 </dd><dt><code>--native-tls</code></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>
@@ -380,7 +384,7 @@ uv run [OPTIONS] <COMMAND>
 
 <p>When used in a project, these dependencies will be layered on top of the project environment in a separate, ephemeral environment. These dependencies are allowed to conflict with those specified by the project.</p>
 
-</dd><dt><code>--with-editable</code> <i>with-editable</i></dt><dd><p>Run with the given packages installed as editables</p>
+</dd><dt><code>--with-editable</code> <i>with-editable</i></dt><dd><p>Run with the given packages installed as editables.</p>
 
 <p>When used in a project, these dependencies will be layered on top of the project environment in a separate, ephemeral environment. These dependencies are allowed to conflict with those specified by the project.</p>