Merge pull request #27805 from Microsoft/jjh/fixbuildercache

Windows: Fix builder cache bug
Upstream-commit: 9e206b551288c5197a2523ad0f887341972d75c8
Component: engine

components/engine/builder/tarsum.go

@@ -63,7 +63,7 @@ func (c *tarSumContext) Stat(path string) (string, FileInfo, error) {
 	sum := path
 	// Use the checksum of the followed path(not the possible symlink) because
 	// this is the file that is actually copied.
-	if tsInfo := c.sums.GetFile(rel); tsInfo != nil {
+	if tsInfo := c.sums.GetFile(filepath.ToSlash(rel)); tsInfo != nil {
 		sum = tsInfo.Sum()
 	}
 	fi := &HashedFileInfo{PathFileInfo{st, fullpath, filepath.Base(cleanpath)}, sum}