Subject: [PATCH 2/2] format-patch: escape "From " lines recognized by mailsplit

From: Eric Wong <[email-masked]>
Date: Sun, 24 Jul 2016 03:15:43 +0000

Users have mistakenly copied "From " lines into commit messages
in the past, and will certainly make the same mistakes in the
future.  Since not everyone uses mboxrd, yet, we should at least
prevent miss-split mails by always escaping "From " lines based
on the check used by mailsplit.

mailsplit will not perform unescaping by default, yet, as it
could cause further invocations of format-patch from old
versions of git to generate bad output.  Propagating the mboxo
escaping is preferable to miss-split patches.  Unescaping may
still be performed via "--mboxrd".

ref: https://public-inbox.org/git/[email-masked]/T/#u

Signed-off-by: Eric Wong <[email-masked]>
---
 pretty.c                | 16 +++++++++++++---
 t/t4014-format-patch.sh | 14 ++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/pretty.c b/pretty.c
index 9fa42c2..898c0a3 100644
--- a/pretty.c
+++ b/pretty.c
@@ -10,6 +10,7 @@
 #include "color.h"
 #include "reflog-walk.h"
 #include "gpg-interface.h"
+#include "mailinfo.h"
 
 static char *user_format;
 static struct cmt_fmt_map {
@@ -1745,9 +1746,18 @@ void pp_remainder(struct pretty_print_context *pp,
 			strbuf_add_tabexpand(sb, pp->expand_tabs_in_log,
 					     line, linelen);
 		else {
-			if (pp->fmt == CMIT_FMT_MBOXRD &&
-					is_mboxrd_from(line, linelen))
-				strbuf_addch(sb, '>');
+			switch (pp->fmt) {
+			case CMIT_FMT_EMAIL:
+				if (is_from_line(line, linelen))
+					strbuf_addch(sb, '>');
+				break;
+			case CMIT_FMT_MBOXRD:
+				if (is_mboxrd_from(line, linelen))
+					strbuf_addch(sb, '>');
+				break;
+			default:
+				break;
+			}
 
 			strbuf_add(sb, line, linelen);
 		}
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index 1206c48..8fa3982 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -1606,4 +1606,18 @@ test_expect_success 'format-patch --pretty=mboxrd' '
 	test_cmp expect actual
 '
 
+test_expect_success 'format-patch From escaping' '
+	cat >msg <<-INPUT_END &&
+	somebody pasted format-patch output into a body
+
+	From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+	INPUT_END
+
+	C=$(git commit-tree HEAD^^{tree} -p HEAD <msg) &&
+	git format-patch --stdout -1 $C~1..$C >patch &&
+	git grep -h --no-index \
+		">From 0000000000000000000000000000000000000000 " \
+		patch
+'
+
 test_done
-- 
EW