patchwork-bot: Ignore empty context lines

It seems that there is some mismatch in diff output (or storage?) between
git and patchwork under conditions I haven't figured out (MUA or MTA
whitespace stripping?): patchwork appears to ignore empty context lines
(i.e. a line that is only a single space). As a result, the patchwork
hash will not match, and commits will not be identified in patchwork.

As an example of a commit in upstream that patchwork-bot cannot locate
in patchwork due to a different hash, due to the differing empty context
lines:

$ MSGID=20210911102818.3804-1-len.baker@gmx.com
$ wget -qO- https://patchwork.kernel.org/project/linux-hardening/patch/$MSGID/raw/ | \
	grep '^ $' | wc -l
0

$ SHA=f11ee2ad25b22c2ee587045dd6999434375532f7
$ git diff ${SHA}~..${SHA} | \
	grep '^ $' | wc -l
2

Teaching patchwork-bot to ignore empty context lines allows pwhashes to
match in these cases, which lets those patches get located again.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Link: https://lore.kernel.org/r/20211202233836.2024510-2-keescook@chromium.org

1 files changed, 3 insertions, 1 deletions

diff --git a/git-patchwork-bot.py b/git-patchwork-bot.py
index 2ebe5b4..4e10385 100755
--- a/git-patchwork-bot.py
+++ b/git-patchwork-bot.py
@@ -528,7 +528,9 @@ def get_patchwork_hash(diff):
             line_nos = list(map(fn, hunk_match.groups()))
             line = '@@ -%d +%d @@' % tuple(line_nos)
         elif line[0] in prefixes:
-            # if we have a +, - or context line, leave as-is
+            # if we have a +, - or context line, leave as-is, except blank lines
+            if line == ' ':
+                continue
             pass
         else:
             # other lines are ignored