Skip missing interpreters during discovery

This feels kind of obvious, but the query code never checked if the requested interpreter exists so we would fail with an IO error and stop discovery which does not feel quite right

crates/uv-toolchain/src/discovery.rs

@@ -438,6 +438,10 @@ fn should_stop_discovery(err: &Error) -> bool {
                 trace!("Skipping bad interpreter at {}", path.display());
                 false
             }
+            InterpreterError::NotFound(path) => {
+                trace!("Skipping missing interpreter at {}", path.display());
+                false
+            }
         },
         _ => true,
     }

crates/uv-toolchain/src/interpreter.rs

@@ -456,6 +456,8 @@ impl ExternallyManaged {
 pub enum Error {
     #[error("Failed to query Python interpreter")]
     Io(#[from] io::Error),
+    #[error("Python interpreter not found at `{0}`")]
+    NotFound(PathBuf),
     #[error("Failed to query Python interpreter at `{path}`")]
     SpawnFailed {
         path: PathBuf,
@@ -645,7 +647,14 @@ impl InterpreterInfo {
 
         // We check the timestamp of the canonicalized executable to check if an underlying
         // interpreter has been modified
-        let modified = Timestamp::from_path(uv_fs::canonicalize_executable(executable)?)?;
+        let modified =
+            Timestamp::from_path(uv_fs::canonicalize_executable(executable).map_err(|err| {
+                if err.kind() == io::ErrorKind::NotFound {
+                    Error::NotFound(executable.to_path_buf())
+                } else {
+                    err.into()
+                }
+            })?)?;
 
         // Read from the cache.
         if cache

crates/uv/tests/pip_compile.rs

@@ -129,33 +129,19 @@ fn missing_venv() -> Result<()> {
     context.temp_dir.child("requirements.in").touch()?;
     fs_err::remove_dir_all(context.temp_dir.child(".venv").path())?;
 
-    if cfg!(windows) {
-        uv_snapshot!(context.filters(), context.compile()
-                .arg("requirements.in"), @r###"
-        success: false
-        exit_code: 2
-        ----- stdout -----
-
-        ----- stderr -----
-        warning: Requirements file requirements.in does not contain any dependencies
-        error: failed to canonicalize path `[VENV]/Scripts/python.exe`
-          Caused by: The system cannot find the path specified. (os error 3)
-        "###
-        );
-    } else {
-        uv_snapshot!(context.filters(), context.compile()
-                .arg("requirements.in"), @r###"
-        success: false
-        exit_code: 2
-        ----- stdout -----
-
-        ----- stderr -----
-        warning: Requirements file requirements.in does not contain any dependencies
-        error: failed to canonicalize path `[VENV]/bin/python3`
-          Caused by: No such file or directory (os error 2)
-        "###
-        );
-    }
+    uv_snapshot!(context.filters(), context.compile()
+            .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 2024-03-25T00:00:00Z requirements.in
+
+    ----- stderr -----
+    warning: Requirements file requirements.in does not contain any dependencies
+    Resolved 0 packages in [TIME]
+    "###
+    );
 
     context
         .temp_dir

crates/uv/tests/pip_sync.rs

@@ -127,8 +127,7 @@ fn missing_venv() -> Result<()> {
         ----- stdout -----
 
         ----- stderr -----
-        error: failed to canonicalize path `[VENV]/bin/python3`
-          Caused by: No such file or directory (os error 2)
+        error: No Python interpreters found in virtual environments
         "###);
     }