Bazel client, Windows: support "d:/" output root

Support drive roots as --output_user_root values,
so "d:\" and "d:/" will now work. However "d:"
doesn't work yet because that's shorthand for the
current working directory on "D:".

See https://github.com/bazelbuild/bazel/issues/2683

--
PiperOrigin-RevId: 150203657
MOS_MIGRATED_REVID=150203657

2 files changed, 4 insertions, 5 deletions

diff --git a/src/main/cpp/util/file_windows.cc b/src/main/cpp/util/file_windows.cc
index 5159917eb4..66c0197d47 100644
--- a/src/main/cpp/util/file_windows.cc
+++ b/src/main/cpp/util/file_windows.cc
@@ -1117,7 +1117,7 @@ static bool MakeDirectoriesW(const wstring& path) {
 bool MakeDirectories(const string& path, unsigned int mode) {
   // TODO(laszlocsomor): respect `mode` to the extent that it's possible on
   // Windows; it's currently ignored.
-  if (path.empty() || IsDevNull(path) || IsRootDirectory(path)) {
+  if (path.empty() || IsDevNull(path)) {
     return false;
   }
   wstring wpath;
diff --git a/src/test/cpp/util/file_windows_test.cc b/src/test/cpp/util/file_windows_test.cc
index 53116f8076..45e95384ae 100644
--- a/src/test/cpp/util/file_windows_test.cc
+++ b/src/test/cpp/util/file_windows_test.cc
@@ -38,7 +38,6 @@ using std::wstring;
 
 // Methods defined in file_windows.cc that are only visible for testing.
 bool AsWindowsPath(const string& path, wstring* result);
-bool AsWindowsPathWithUncPrefix(const string& path, wstring* wpath);
 void ResetMsysRootForTesting();
 string NormalizeWindowsPath(string path);
 
@@ -421,9 +420,9 @@ TEST_F(FileWindowsTest, TestMakeDirectories) {
   // Test that we can create come directories, can't create others.
   ASSERT_FALSE(MakeDirectories("", 0777));
   ASSERT_FALSE(MakeDirectories("/dev/null", 0777));
-  ASSERT_FALSE(MakeDirectories("c:/", 0777));
-  ASSERT_FALSE(MakeDirectories("c:\\", 0777));
-  ASSERT_FALSE(MakeDirectories("/", 0777));
+  ASSERT_TRUE(MakeDirectories("c:/", 0777));
+  ASSERT_TRUE(MakeDirectories("c:\\", 0777));
+  ASSERT_TRUE(MakeDirectories("/", 0777));
   ASSERT_TRUE(MakeDirectories("/foo", 0777));
   ASSERT_TRUE(MakeDirectories(".", 0777));
   ASSERT_TRUE(MakeDirectories(tmpdir, 0777));