From e3498121b4700f5a9dce9bf6d72af4bc411e262d Mon Sep 17 00:00:00 2001
From: Micha Reiser <micha@reiser.io>
Date: Wed, 24 Dec 2025 16:36:18 +0100
Subject: [PATCH] [ty] Fix module resolution on network drives (#22173)

---
 crates/ruff_db/src/system/os.rs | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/crates/ruff_db/src/system/os.rs b/crates/ruff_db/src/system/os.rs
index 92513b72d8..f553dff1be 100644
--- a/crates/ruff_db/src/system/os.rs
+++ b/crates/ruff_db/src/system/os.rs
@@ -275,16 +275,16 @@ impl OsSystem {
     /// instead of at least one system call for each component between `path` and `prefix`.
     ///
     /// However, using `canonicalize` to resolve the path's casing doesn't work in two cases:
-    /// * if `path` is a symlink because `canonicalize` then returns the symlink's target and not the symlink's source path.
-    /// * on Windows: If `path` is a mapped network drive because `canonicalize` then returns the UNC path
-    ///   (e.g. `Z:\` is mapped to `\\server\share` and `canonicalize` then returns `\\?\UNC\server\share`).
+    /// * if `path` is a symlink, `canonicalize` returns the symlink's target and not the symlink's source path.
+    /// * on Windows: If `path` is a mapped network drive, `canonicalize` returns the UNC path
+    ///   (e.g. `Z:\` is mapped to `\\server\share` and `canonicalize` returns `\\?\UNC\server\share`).
     ///
     /// Symlinks and mapped network drives should be rare enough that this fast path is worth trying first,
     /// even if it comes at a cost for those rare use cases.
     fn path_exists_case_sensitive_fast(&self, path: &SystemPath) -> Option<bool> {
         // This is a more forgiving version of `dunce::simplified` that removes all `\\?\` prefixes on Windows.
         // We use this more forgiving version because we don't intend on using either path for anything other than comparison
-        // and the prefix is only relevant when passing the path to other programs and its longer than 200 something
+        // and the prefix is only relevant when passing the path to other programs and it's longer than 200 something
         // characters.
         fn simplify_ignore_verbatim(path: &SystemPath) -> &SystemPath {
             if cfg!(windows) {
@@ -298,9 +298,7 @@ impl OsSystem {
             }
         }
 
-        let simplified = simplify_ignore_verbatim(path);
-
-        let Ok(canonicalized) = simplified.as_std_path().canonicalize() else {
+        let Ok(canonicalized) = path.as_std_path().canonicalize() else {
             // The path doesn't exist or can't be accessed. The path doesn't exist.
             return Some(false);
         };
@@ -309,12 +307,13 @@ impl OsSystem {
             // The original path is valid UTF8 but the canonicalized path isn't. This definitely suggests
             // that a symlink is involved. Fall back to the slow path.
             tracing::debug!(
-                "Falling back to the slow case-sensitive path existence check because the canonicalized path of `{simplified}` is not valid UTF-8"
+                "Falling back to the slow case-sensitive path existence check because the canonicalized path of `{path}` is not valid UTF-8"
             );
             return None;
         };
 
         let simplified_canonicalized = simplify_ignore_verbatim(&canonicalized);
+        let simplified = simplify_ignore_verbatim(path);
 
         // Test if the paths differ by anything other than casing. If so, that suggests that
         // `path` pointed to a symlink (or some other none reversible path normalization happened).