[Bug #220993; may also fix bug #479469] Fix flakiness when old
installations are present, by always unlinking the destination file
before copying to it. Without the unlink(), the copied file remains
owned by its previous UID, causing the subsequent chmod() to fail.
Bugfix candidate, though it may cause changes on platforms where
file ownership behaves differently.
diff --git a/Lib/distutils/file_util.py b/Lib/distutils/file_util.py
index 526e4cf..14772fb 100644
--- a/Lib/distutils/file_util.py
+++ b/Lib/distutils/file_util.py
@@ -36,6 +36,13 @@
raise DistutilsFileError, \
"could not open '%s': %s" % (src, errstr)
+ if os.path.exists(dst):
+ try:
+ os.unlink(dst)
+ except os.error, (errno, errstr):
+ raise DistutilsFileError, \
+ "could not delete '%s': %s" % (dst, errstr)
+
try:
fdst = open(dst, 'wb')
except os.error, (errno, errstr):