[cfe] Normalize repo dir

Uri.base, Platform.script and dart:io operations use the drive letter capitalization of the current working directory, but git, alas, does not. This normalizes the computeRepoDir to match that of Uri.base, thus avoiding spurious errors on Windows.

Change-Id: If4324874fa9b5c73c679c1b67a9481371ce8808d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/421161
Commit-Queue: Johnni Winther <[email protected]>
Reviewed-by: Jens Johansen <[email protected]>

Author: johnniwinther

pkg/front_end/test/utils/io_utils.dart

@@ -35,6 +35,20 @@ String computeRepoDir() {
   if (!new Directory(dirPath).existsSync()) {
     throw "The path returned by git ($dirPath) does not actually exist.";
   }
+  if (dirPath.length > 1 && dirPath[1] == ':') {
+    // Absolute Windows path. Normalize drive letter to match Uri.base.
+    if (Uri.base.path.length < 3 ||
+        Uri.base.path[0] != '/' ||
+        Uri.base.path[2] != ':') {
+      throw "Expected Uri.base=${Uri.base} to be an absolute file path.";
+    }
+    bool isLowerCase = Uri.base.path[1] == Uri.base.path[1].toLowerCase();
+    if (isLowerCase) {
+      dirPath = dirPath[0].toLowerCase() + dirPath.substring(1);
+    } else {
+      dirPath = dirPath[0].toUpperCase() + dirPath.substring(1);
+    }
+  }
   return dirPath;
 }