Re: diffs in changelogs

Joe Perches
2015-06-12T03:13:05Z

On Thu, 2015-06-11 at 13:40 -0700, Andrew Morton wrote:
> People often put diff snippets in changelogs. This causes problems
> when one tries to apply a file containing both the changelog and the
> diff because patch(1) tries to apply the diff which it found in the
> changelog.
That
> eg, something like
>
> git show d24a6e1087030b6da | patch -p1
>
> will go haywire.
>
> So can we please have a checkpatch test warning people away from doing
> this?
>
>
> patch(1) seems to be really promiscuous in its detection of a patch. I
> haven't had much success searching for "^--- " and similar. What works
> best for me is searching for "^[whitespace]@@ -".

I don't think that's a good test.
Coccinelle uses @@

And how did that commit actually get applied?

I tried applying it to a new branch checked out at
ce2b3f595e1c56639085645e0130426e443008c0, it fails.

Anyway, maybe:
---
scripts/checkpatch.pl | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 69c4716..2d87e37 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2399,6 +2399,18 @@ sub process {
$in_commit_log = 1;
}

+# Check if the commit log has a diff which confuse patch
+
+ print("icl: <$in_commit_log> line: <$line>\n");
+ if ($in_commit_log &&
+ (($line =~ m@^\s+diff\b.*a/[\w/]+@ &&
+ $line =~ m@^\s+diff\b.*a/([\w/]+)\s+b/$1\b@) ||
+ $line =~ m@^\s*(?:\-\-\-\s+a/|\+\+\+\s+b/)@ ||
+ $line =~ m/^\s*\@\@ \-\d+,\d+ \+\d+,\d+ \@\@/)) {
+ ERROR("DIFF_IN_COMMIT_MSG",
+ "It seems a diff exists in the commit message. This can confuse patch\n" . $herecurr);
+ }
+
# Check if there is UTF-8 in a commit log when a mail header has explicitly
# declined it, i.e defined some charset where it is missing.
if ($in_header_lines &&