fix(cli/rt): Fix file URL to path conversion on Windows (#6920)

1 files changed, 15 insertions, 6 deletions

diff --git a/std/path/win32.ts b/std/path/win32.ts
index 0283f4b9c..eed1cbdb8 100644
--- a/std/path/win32.ts
+++ b/std/path/win32.ts
@@ -907,16 +907,25 @@ export function parse(path: string): ParsedPath {
 
 /** Converts a file URL to a path string.
  *
- *      fromFileUrl("file:///C:/Users/foo"); // "C:\\Users\\foo"
  *      fromFileUrl("file:///home/foo"); // "\\home\\foo"
- *
- * Note that non-file URLs are treated as file URLs and irrelevant components
- * are ignored.
+ *      fromFileUrl("file:///C:/Users/foo"); // "C:\\Users\\foo"
+ *      fromFileUrl("file://localhost/home/foo"); // "\\\\localhost\\home\\foo"
  */
 export function fromFileUrl(url: string | URL): string {
-  return decodeURIComponent(
-    (url instanceof URL ? url : new URL(url)).pathname
+  url = url instanceof URL ? url : new URL(url);
+  if (url.protocol != "file:") {
+    throw new TypeError("Must be a file URL.");
+  }
+  let path = decodeURIComponent(
+    url.pathname
       .replace(/^\/*([A-Za-z]:)(\/|$)/, "$1/")
       .replace(/\//g, "\\"),
   );
+  if (url.hostname != "") {
+    // Note: The `URL` implementation guarantees that the drive letter and
+    // hostname are mutually exclusive. Otherwise it would not have been valid
+    // to append the hostname and path like this.
+    path = `\\\\${url.hostname}${path}`;
+  }
+  return path;
 }