var: avoid a segmentation fault when HOME is unset

The code introduced in 576a37f (var: add attributes files locations, 2023-06-27) paid careful attention to use `xstrdup()` for pointers known never to be `NULL`, and `xstrdup_or_null()` otherwise. One spot was missed, though: `git_attr_global_file()` can return `NULL`, when the `HOME` variable is not set (and neither `XDG_CONFIG_HOME`), a scenario not too uncommon in certain server scenarios. Fix this, and add a test case to avoid future regressions. Signed-off-by: Johannes Schindelin <[email protected]>
dscho · Sep 3, 2023 · 6ad63c8 · 6ad63c8
1 parent 43c8a30
commit 6ad63c8
Show file tree

Hide file tree

Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/builtin/var.c b/builtin/var.c
@@ -66,7 +66,7 @@ static char *git_attr_val_system(int ident_flag UNUSED)
 
 static char *git_attr_val_global(int ident_flag UNUSED)
 {
-	char *file = xstrdup(git_attr_global_file());
+	char *file = xstrdup_or_null(git_attr_global_file());
 	if (file) {
 		normalize_path_copy(file, file);
 		return file;

diff --git a/t/t0007-git-var.sh b/t/t0007-git-var.sh
@@ -268,4 +268,13 @@ test_expect_success 'listing and asking for variables are exclusive' '
 	test_must_fail git var -l GIT_COMMITTER_IDENT
 '
 
+test_expect_success '`git var -l` works even without HOME' '
+	(
+		XDG_CONFIG_HOME= &&
+		export XDG_CONFIG_HOME &&
+		unset HOME &&
+		git var -l
+	)
+'
+
 test_done