Add support for specifying name@version in uv tool run (#4572)

Instead of requiring `uv tool run --from package==version command` we
support `uv tool run command@version` shorthand.

crates/uv-cli/src/lib.rs

@@ -1861,6 +1861,13 @@ pub enum ToolCommand {
 #[allow(clippy::struct_excessive_bools)]
 pub struct ToolRunArgs {
     /// The command to run.
+    ///
+    /// By default, the package to install is assumed to match the command name.
+    ///
+    /// The name of the command can include an exact version in the format `<package>@<version>`.
+    ///
+    /// If more complex version specification is desired or if the command is provided by a different
+    /// package, use `--from`.
     #[command(subcommand)]
     pub command: ExternalCommand,
 

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

@@ -1,7 +1,11 @@
+use std::borrow::Cow;
+use std::ffi::OsString;
 use std::path::PathBuf;
+use std::str::FromStr;
 
 use anyhow::{Context, Result};
 use itertools::Itertools;
+use pep440_rs::Version;
 use tokio::process::Command;
 use tracing::debug;
 
@@ -46,16 +50,13 @@ pub(crate) async fn run(
         return Err(anyhow::anyhow!("No tool command provided"));
     };
 
-    let from = if let Some(from) = from {
-        from
+    let (target, from) = if let Some(from) = from {
+        (Cow::Borrowed(target), Cow::Owned(from))
     } else {
-        let Some(target) = target.to_str() else {
-            return Err(anyhow::anyhow!("Tool command could not be parsed as UTF-8 string. Use `--from` to specify the package name."));
-        };
-        target.to_string()
+        parse_target(target)?
     };
 
-    let requirements = [RequirementsSource::from_package(from)]
+    let requirements = [RequirementsSource::from_package(from.to_string())]
         .into_iter()
         .chain(with.into_iter().map(RequirementsSource::from_package))
         .collect::<Vec<_>>();
@@ -109,7 +110,7 @@ pub(crate) async fn run(
     let command = target;
 
     // Construct the command
-    let mut process = Command::new(command);
+    let mut process = Command::new(command.as_ref());
     process.args(args);
 
     // Construct the `PATH` environment variable.
@@ -167,3 +168,33 @@ pub(crate) async fn run(
         Ok(ExitStatus::Failure)
     }
 }
+
+/// Parse a target into a command name and a requirement.
+fn parse_target(target: &OsString) -> Result<(Cow<OsString>, Cow<str>)> {
+    let Some(target_str) = target.to_str() else {
+        return Err(anyhow::anyhow!("Tool command could not be parsed as UTF-8 string. Use `--from` to specify the package name."));
+    };
+
+    // e.g. `uv`, no special handling
+    let Some((name, version)) = target_str.split_once('@') else {
+        return Ok((Cow::Borrowed(target), Cow::Borrowed(target_str)));
+    };
+
+    // e.g. `uv@`, warn and treat the whole thing as the command
+    if version.is_empty() {
+        debug!("Ignoring empty version request in command");
+        return Ok((Cow::Borrowed(target), Cow::Borrowed(target_str)));
+    }
+
+    // e.g. `uv@0.1.0`, convert to `uv==0.1.0`
+    if let Ok(version) = Version::from_str(version) {
+        return Ok((
+            Cow::Owned(OsString::from(name)),
+            Cow::Owned(format!("{name}=={version}")),
+        ));
+    }
+
+    // e.g. `uv@invalid`, warn and treat the whole thing as the command
+    debug!("Ignoring invalid version request `{}` in command", version);
+    Ok((Cow::Borrowed(target), Cow::Borrowed(target_str)))
+}

crates/uv/tests/tool_run.rs

@@ -53,3 +53,101 @@ fn tool_run_args() {
      + pytest==8.1.1
     "###);
 }
+
+#[test]
+fn tool_run_at_version() {
+    let context = TestContext::new("3.12");
+
+    uv_snapshot!(context.filters(), context.tool_run().arg("pytest@8.0.0").arg("--version"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    pytest 8.0.0
+
+    ----- stderr -----
+    warning: `uv tool run` is experimental and may change without warning.
+    Resolved 4 packages in [TIME]
+    Prepared 4 packages in [TIME]
+    Installed 4 packages in [TIME]
+     + iniconfig==2.0.0
+     + packaging==24.0
+     + pluggy==1.4.0
+     + pytest==8.0.0
+    "###);
+
+    // Empty versions are just treated as package and command names
+    uv_snapshot!(context.filters(), context.tool_run().arg("pytest@").arg("--version"), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    warning: `uv tool run` is experimental and may change without warning.
+    error: Failed to parse: `pytest@`
+      Caused by: Expected URL
+    pytest@
+           ^
+    "###);
+
+    // Invalid versions are just treated as package and command names
+    uv_snapshot!(context.filters(), context.tool_run().arg("pytest@invalid").arg("--version"), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    warning: `uv tool run` is experimental and may change without warning.
+    error: Distribution not found at: file://[TEMP_DIR]/invalid
+    "###);
+
+    let filters = context
+        .filters()
+        .into_iter()
+        .chain([(
+            // The error message is different on Windows
+            "Caused by: program not found",
+            "Caused by: No such file or directory (os error 2)",
+        )])
+        .collect::<Vec<_>>();
+
+    // When `--from` is used, `@` is not treated as a version request
+    uv_snapshot!(filters, context.tool_run().arg("--from").arg("pytest").arg("pytest@8.0.0").arg("--version"), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    warning: `uv tool run` is experimental and may change without warning.
+    Resolved 4 packages in [TIME]
+    Prepared 1 package in [TIME]
+    Installed 4 packages in [TIME]
+     + iniconfig==2.0.0
+     + packaging==24.0
+     + pluggy==1.4.0
+     + pytest==8.1.1
+    error: Failed to spawn: `pytest@8.0.0`
+      Caused by: No such file or directory (os error 2)
+    "###);
+}
+
+#[test]
+fn tool_run_from_version() {
+    let context = TestContext::new("3.12");
+
+    uv_snapshot!(context.filters(), context.tool_run().arg("--from").arg("pytest==8.0.0").arg("pytest").arg("--version"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    pytest 8.0.0
+
+    ----- stderr -----
+    warning: `uv tool run` is experimental and may change without warning.
+    Resolved 4 packages in [TIME]
+    Prepared 4 packages in [TIME]
+    Installed 4 packages in [TIME]
+     + iniconfig==2.0.0
+     + packaging==24.0
+     + pluggy==1.4.0
+     + pytest==8.0.0
+    "###);
+}