sequencer: add newline before adding footers

When encountering a commit message that does not end in a newline,
sequencer does not complete the line before determining if a blank line
should be added.  This causes the "(cherry picked..." and sign-off lines
to sometimes appear on the same line as the last line of the commit
message.

This behavior was introduced by commit 967dfd4 ("sequencer: use
trailer's trailer layout", 2016-11-29). However, a revert of that commit
would not resolve this issue completely: prior to that commit, a
conforming footer was deemed to be non-conforming by
has_conforming_footer() if there was no terminating newline, resulting
in both conforming and non-conforming footers being treated the same
when they should not be.

Resolve this issue, both for conforming and non-conforming footers, and
in both do_pick_commit() and append_signoff(), by always adding a
newline to the commit message if it does not end in one before checking
the footer for conformity.

Reported-by: Brian Norris <[email protected]>
Signed-off-by: Jonathan Tan <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: jonathantanmy

sequencer.c

@@ -698,6 +698,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 			strbuf_addstr(&msgbuf, skip_blank_lines(p + 2));
 
 		if (opts->record_origin) {
+			strbuf_complete_line(&msgbuf);
 			if (!has_conforming_footer(&msgbuf, NULL, 0))
 				strbuf_addch(&msgbuf, '\n');
 			strbuf_addstr(&msgbuf, cherry_picked_prefix);
@@ -1362,6 +1363,9 @@ void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
 				getenv("GIT_COMMITTER_EMAIL")));
 	strbuf_addch(&sob, '\n');
 
+	if (!ignore_footer)
+		strbuf_complete_line(msgbuf);
+
 	/*
 	 * If the whole message buffer is equal to the sob, pretend that we
 	 * found a conforming footer with a matching sob
@@ -1382,13 +1386,6 @@ void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
 			 * the title and body to be filled in by the user.
 			 */
 			append_newlines = "\n\n";
-		} else if (msgbuf->buf[len - 1] != '\n') {
-			/*
-			 * Incomplete line.  Complete the line and add a
-			 * blank one so that there is an empty line between
-			 * the message body and the sob.
-			 */
-			append_newlines = "\n\n";
 		} else if (len == 1) {
 			/*
 			 * Buffer contains a single newline.  Add another

t/t3511-cherry-pick-x.sh

@@ -208,6 +208,50 @@ test_expect_success 'cherry-pick -x -s adds sob even when trailing sob exists fo
 	test_cmp expect actual
 '
 
+test_expect_success 'cherry-pick -x handles commits with no NL at end of message' '
+	pristine_detach initial &&
+	printf "title\n\nSigned-off-by: A <[email protected]>" >msg &&
+	sha1=$(git commit-tree -p initial mesg-with-footer^{tree} <msg) &&
+	git cherry-pick -x $sha1 &&
+	git log -1 --pretty=format:%B >actual &&
+
+	printf "\n(cherry picked from commit %s)\n" $sha1 >>msg &&
+	test_cmp msg actual
+'
+
+test_expect_success 'cherry-pick -x handles commits with no footer and no NL at end of message' '
+	pristine_detach initial &&
+	printf "title\n\nnot a footer" >msg &&
+	sha1=$(git commit-tree -p initial mesg-with-footer^{tree} <msg) &&
+	git cherry-pick -x $sha1 &&
+	git log -1 --pretty=format:%B >actual &&
+
+	printf "\n\n(cherry picked from commit %s)\n" $sha1 >>msg &&
+	test_cmp msg actual
+'
+
+test_expect_success 'cherry-pick -s handles commits with no NL at end of message' '
+	pristine_detach initial &&
+	printf "title\n\nSigned-off-by: A <[email protected]>" >msg &&
+	sha1=$(git commit-tree -p initial mesg-with-footer^{tree} <msg) &&
+	git cherry-pick -s $sha1 &&
+	git log -1 --pretty=format:%B >actual &&
+
+	printf "\nSigned-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>\n" >>msg &&
+	test_cmp msg actual
+'
+
+test_expect_success 'cherry-pick -s handles commits with no footer and no NL at end of message' '
+	pristine_detach initial &&
+	printf "title\n\nnot a footer" >msg &&
+	sha1=$(git commit-tree -p initial mesg-with-footer^{tree} <msg) &&
+	git cherry-pick -s $sha1 &&
+	git log -1 --pretty=format:%B >actual &&
+
+	printf "\n\nSigned-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>\n" >>msg &&
+	test_cmp msg actual
+'
+
 test_expect_success 'cherry-pick -x treats "(cherry picked from..." line as part of footer' '
 	pristine_detach initial &&
 	sha1=$(git rev-parse mesg-with-cherry-footer^0) &&