diff --git a/config.c b/config.c
index a30cb5c07d..40799a1dba 100644
--- a/config.c
+++ b/config.c
@@ -824,11 +824,11 @@ static int git_default_core_config(const char *var, const char *value)
 		return git_config_string(&editor_program, var, value);
 
 	if (!strcmp(var, "core.commentchar")) {
-		const char *comment;
-		int ret = git_config_string(&comment, var, value);
-		if (!ret)
-			comment_line_char = comment[0];
-		return ret;
+		if (!value)
+			return config_error_nonbool(var);
+		else
+			comment_line_char = value[0];
+		return 0;
 	}
 
 	if (!strcmp(var, "core.askpass"))