[PATCH v2] mailmap: fix check-mailmap with full mailmap line

From: Jacob Keller <jacob.e.keller@intel.com>
Date: Feb 21, 2025, 23:47 UTC
Message-ID: <20250221-jk-fix-sendemail-mailinfo-v2-1-9aca7dc05dbb@gmail.com>

From: Jacob Keller <jacob.keller@gmail.com>

I recently had reported to me a crash from a coworker using the recently added sendemail mailmap support:

  3724814 Segmentation fault      (core dumped) git check-mailmap "bugs@company.xx"

This appears to happen because of the NULL pointer name passed into map_user(). Fix this by passing "" instead of NULL so that we have a valid pointer.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
---
Changes in v2:
- Just fix the NULL pointer dereference, leave mailmap resolution as-is
- Link to v1: https://lore.kernel.org/r/20250213-jk-fix-sendemail-mailinfo-v1-1-c0b06c215f21@gmail.com
---
 builtin/check-mailmap.c |  2 +-
 t/t4203-mailmap.sh      | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/builtin/check-mailmap.c b/builtin/check-mailmap.c
index df00b5ee13adb87881b8c1e92cac256e6ad319d1..be2cebe12152e38d3bb8cf12948823c8d710bdda 100644
--- a/builtin/check-mailmap.c
+++ b/builtin/check-mailmap.c
@@ -35,7 +35,7 @@ static void check_mailmap(struct string_list *mailmap, const char *contact)
 		mail = ident.mail_begin;
 		maillen = ident.mail_end - ident.mail_begin;
 	} else {
-		name = NULL;
+		name = "";
 		namelen = 0;
 		mail = contact;
 		maillen = strlen(contact);
diff --git a/t/t4203-mailmap.sh b/t/t4203-mailmap.sh
index 24214919312777b76e4d3b2b784bcb953583750a..4a6242ff99b59ea1a46eb14ca812c94e5e620162 100755
--- a/t/t4203-mailmap.sh
+++ b/t/t4203-mailmap.sh
@@ -113,6 +113,18 @@ test_expect_success 'check-mailmap --stdin simple address: no mapping' '
 	test_cmp expect actual
 '
 
+test_expect_success 'check-mailmap name and address: mapping' '
+	test_when_finished "rm .mailmap" &&
+	cat >.mailmap <<-EOF &&
+	Bug Reports <bugs-new@company.xx> Bugs <bugs@company.xx>
+	EOF
+	cat >expect <<-EOF &&
+	<bugs@company.xx>
+	EOF
+	git check-mailmap "bugs@company.xx" >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'No mailmap' '
 	cat >expect <<-EOF &&
 	$GIT_AUTHOR_NAME (1):

---
base-commit: b838bf1938926a7a900166136d995d86f8a00e24
change-id: 20250213-jk-fix-sendemail-mailinfo-32f027b1b9e7

Best regards,

-- 
Jacob Keller <jacob.keller@gmail.com>