Flush stderr on Windows

While on Linux stderr is unbuffered, it is buffered on Windows. Always
flush stderr on Windows to ensure any error messages appear in the right
order to ease diagnosing.

Change-Id: I37300e384ecd3a51a321a48818f0114d6f3357a0

1 files changed, 4 insertions, 0 deletions

diff --git a/repo b/repo
index 13ccd2ba..3ae38360 100755
--- a/repo
+++ b/repo
@@ -144,6 +144,10 @@ def _print(*objects, **kwargs):
   out = kwargs.get('file', sys.stdout)
   out.write(sep.join(objects) + end)
 
+  # On Windows stderr is buffered, so flush to maintain the order of error messages.
+  if out == sys.stderr and platform.system() == "Windows":
+    out.flush()
+
 
 # Python version check
 ver = sys.version_info