Ensure that builds within the cache aren't considered Git repositories

crates/uv-cache/src/lib.rs

@@ -241,6 +241,15 @@ impl Cache {
             file.write_all(b"*")?;
         }
 
+        // Add a phony .git, if it doesn't exist, to ensure that the cache isn't considered to be
+        // part of a Git repository. (Some packages will include Git metadata (like a hash) in the
+        // built version if they're in a Git repository, but the cache should be viewed as an
+        // isolated store.)
+        let git_path = root.join(".git");
+        if !git_path.exists() {
+            fs::File::create(git_path)?;
+        }
+
         fs::canonicalize(root)
     }