Add rye fetch --force to re-fetch a toolchain (#778)

CHANGELOG.md

@@ -16,6 +16,8 @@ _Unreleased_
 
 - When `uv` is used the prompt is now set to the project name.  #773
 
+- Allow `rye fetch --force` to force re-fetch a downloaded toolchain.  #778
+
 <!-- released start -->
 
 ## 0.26.0

docs/guide/commands/fetch.md

@@ -11,7 +11,8 @@ Fetch a specific version of Python:
 $ rye fetch 3.8.13
 Downloading [email protected]
 Checking checksum
-success: Downloaded [email protected]
+Unpacking
+Downloaded [email protected]
 ```
 
 To fetch the pinned version of Python you can leave out the argument:
@@ -20,7 +21,8 @@ To fetch the pinned version of Python you can leave out the argument:
 $ rye fetch
 Downloading [email protected]
 Checking checksum
-success: Downloaded [email protected]
+Unpacking
+Downloaded [email protected]
 ```
 
 ## Arguments
@@ -31,6 +33,8 @@ success: Downloaded [email protected]
 
 ## Options
 
+* `-f, --force`: Fetch the Python toolchain even if it is already installed.
+
 * `-v, --verbose`: Enables verbose diagnostics
 
 * `-q, --quiet`: Turns off all output

rye/src/bootstrap.rs

@@ -277,7 +277,7 @@ fn ensure_latest_self_toolchain(output: CommandOutput) -> Result<PythonVersion,
         }
         Ok(version)
     } else {
-        fetch(&SELF_PYTHON_TARGET_VERSION, output)
+        fetch(&SELF_PYTHON_TARGET_VERSION, output, false)
     }
 }
 
@@ -301,7 +301,7 @@ fn ensure_specific_self_toolchain(
                 toolchain_version
             );
         }
-        fetch(&toolchain_version.into(), output)
+        fetch(&toolchain_version.into(), output, false)
     } else {
         if output != CommandOutput::Quiet {
             echo!(
@@ -317,10 +317,11 @@ fn ensure_specific_self_toolchain(
 pub fn fetch(
     version: &PythonVersionRequest,
     output: CommandOutput,
+    force: bool,
 ) -> Result<PythonVersion, Error> {
     if let Ok(version) = PythonVersion::try_from(version.clone()) {
         let py_bin = get_toolchain_python_bin(&version)?;
-        if py_bin.is_file() {
+        if !force && py_bin.is_file() {
             if output == CommandOutput::Verbose {
                 echo!("Python version already downloaded. Skipping.");
             }
@@ -339,10 +340,17 @@ pub fn fetch(
         echo!("target dir: {}", target_dir.display());
     }
     if target_dir.is_dir() && target_py_bin.is_file() {
-        if output == CommandOutput::Verbose {
-            echo!("Python version already downloaded. Skipping.");
+        if !force {
+            if output == CommandOutput::Verbose {
+                echo!("Python version already downloaded. Skipping.");
+            }
+            return Ok(version);
+        }
+        if output != CommandOutput::Quiet {
+            echo!("Removing the existing Python version");
         }
-        return Ok(version);
+        fs::remove_dir_all(&target_dir)
+            .with_context(|| format!("failed to remove target folder {}", target_dir.display()))?;
     }
 
     fs::create_dir_all(&target_dir).path_context(&target_dir, "failed to create target folder")?;

rye/src/cli/fetch.rs

@@ -15,6 +15,9 @@ pub struct Args {
     ///
     /// If no version is provided, the requested version from local project or `.python-version` will be fetched.
     version: Option<String>,
+    /// Fetch the Python toolchain even if it is already installed.
+    #[arg(short, long)]
+    force: bool,
     /// Enables verbose diagnostics.
     #[arg(short, long)]
     verbose: bool,
@@ -40,6 +43,6 @@ pub fn execute(cmd: Args) -> Result<(), Error> {
         }
     };
 
-    fetch(&version, output).context("error while fetching Python installation")?;
+    fetch(&version, output, cmd.force).context("error while fetching Python installation")?;
     Ok(())
 }

rye/src/installer.rs

@@ -131,7 +131,7 @@ pub fn install(
     uninstall_helper(&target_venv_path, &shim_dir)?;
 
     // make sure we have a compatible python version
-    let py_ver = fetch(py_ver, output)?;
+    let py_ver = fetch(py_ver, output, false)?;
 
     create_virtualenv(
         output,

rye/src/sync.rs

@@ -147,7 +147,7 @@ pub fn sync(mut cmd: SyncOptions) -> Result<(), Error> {
 
     // make sure we have a compatible python version
     let py_ver =
-        fetch(&py_ver.into(), output).context("failed fetching toolchain ahead of sync")?;
+        fetch(&py_ver.into(), output, false).context("failed fetching toolchain ahead of sync")?;
 
     // kill the virtualenv if it's there and we need to get rid of it.
     if recreate && venv.is_dir() {

rye/tests/test_toolchain.rs

@@ -0,0 +1,38 @@
+use crate::common::{rye_cmd_snapshot, Space};
+
+mod common;
+
+#[test]
+fn test_fetch() {
+    let space = Space::new();
+    // Use a version not in use by other tests and will be supported for a long time.
+    let version = "[email protected]";
+
+    // Make sure the version is installed.
+    let status = space.rye_cmd().arg("fetch").arg(version).status().unwrap();
+    assert!(status.success());
+
+    // Fetching the same version again should be a no-op.
+    rye_cmd_snapshot!(space.rye_cmd().arg("fetch").arg(version).arg("--verbose"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    Python version already downloaded. Skipping.
+
+    ----- stderr -----
+    "###);
+
+    // Fetching the same version again with --force should re-download it.
+    rye_cmd_snapshot!(space.rye_cmd().arg("fetch").arg(version).arg("--force"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    Removing the existing Python version
+    Downloading [email protected]
+    Checking checksum
+    Unpacking
+    Downloaded [email protected]
+
+    ----- stderr -----
+    "###);
+}