handle lower case drive letters on Windows

Ben Peart · gitster · commit 5a06a20e0c88 · 2018-07-12T12:11:05.000-07:00
On Windows, if a tool calls SetCurrentDirectory with a lower case drive
letter, the subsequent call to GetCurrentDirectory will return the same
lower case drive letter. Powershell, for example, does not normalize the
path. If that happens, test-drop-caches will error out as it does not
correctly to handle lower case drive letters.

Helped-by: Johannes Schindelin &lt;johannes.schindelin@gmx.de&gt;
Signed-off-by: Ben Peart &lt;Ben.Peart@microsoft.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/t/helper/test-drop-caches.c b/t/helper/test-drop-caches.c
@@ -16,8 +16,8 @@ static int cmd_sync(void)
 	if ((0 == dwRet) || (dwRet > MAX_PATH))
 		return error("Error getting current directory");
 
-	if ((Buffer[0] < 'A') || (Buffer[0] > 'Z'))
-		return error("Invalid drive letter '%c'", Buffer[0]);
+	if (!has_dos_drive_prefix(Buffer))
+		return error("'%s': invalid drive letter", Buffer);
 
 	szVolumeAccessPath[4] = Buffer[0];
 	hVolWrite = CreateFile(szVolumeAccessPath, GENERIC_READ | GENERIC_WRITE,
