From e69bbfa2947ee733a2b76f1dc28ceaf415368f2a Mon Sep 17 00:00:00 2001 From: Ayush Chandekar Date: Wed, 16 Jul 2025 17:13:28 +0530 Subject: commit: avoid scanning trailing comments when 'core.commentChar' is "auto" When core.commentChar is set to "auto", Git selects a comment character by scanning the commit message contents and avoiding any character already present in the message. If the message still contains old conflict comments (starting with a comment character), Git assumes that character is in use and chooses a different one. As a result, those existing comment lines are no longer recognized as comments and end up being included in the final commit message. To avoid this, skip scanning the trailing comment block when selecting the comment character. This allows Git to safely reuse the original character when appropriate, keeping the commit message clean and free of leftover conflict information. Background: The "auto" value for core.commentchar was introduced in the commit 84c9dc2c5a (commit: allow core.commentChar=auto for character auto selection, 2014-05-17) but did not exhibit this issue at that time. The bug was introduced in commit a6c2654f83 (rebase -m: fix --signoff with conflicts, 2024-04-18) where Git started writing conflict comments to the file at 'rebase_path_message()'. Mentored-by: Christian Couder Mentored-by: Ghanshyam Thakkar Signed-off-by: Ayush Chandekar Signed-off-by: Junio C Hamano --- builtin/commit.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'builtin/commit.c') diff --git a/builtin/commit.c b/builtin/commit.c index fba0dded64..63e7158e98 100644 --- a/builtin/commit.c +++ b/builtin/commit.c @@ -688,6 +688,10 @@ static void adjust_comment_line_char(const struct strbuf *sb) char candidates[] = "#;@!$%^&|:"; char *candidate; const char *p; + size_t cutoff; + + /* Ignore comment chars in trailing comments (e.g., Conflicts:) */ + cutoff = sb->len - ignored_log_message_bytes(sb->buf, sb->len); if (!memchr(sb->buf, candidates[0], sb->len)) { free(comment_line_str_to_free); @@ -700,7 +704,7 @@ static void adjust_comment_line_char(const struct strbuf *sb) candidate = strchr(candidates, *p); if (candidate) *candidate = ' '; - for (p = sb->buf; *p; p++) { + for (p = sb->buf; p + 1 < sb->buf + cutoff; p++) { if ((p[0] == '\n' || p[0] == '\r') && p[1]) { candidate = strchr(candidates, p[1]); if (candidate) -- cgit v1.2.3