Merge branch 'maint-1.6.0' into maint-1.6.1

* maint-1.6.0:
  grep: fix segfault when "git grep '('" is given
  Documentation: fix a grammatical error in api-builtin.txt
  builtin-merge: fix a typo in an error message

1 files changed, 6 insertions, 2 deletions

diff --git a/grep.c b/grep.c
index 600f69f2fe..704facf996 100644
--- a/grep.c
+++ b/grep.c
@@ -54,6 +54,8 @@ static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 	struct grep_expr *x;
 
 	p = *list;
+	if (!p)
+		return NULL;
 	switch (p->token) {
 	case GREP_PATTERN: /* atom */
 	case GREP_PATTERN_HEAD:
@@ -66,8 +68,6 @@ static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 	case GREP_OPEN_PAREN:
 		*list = p->next;
 		x = compile_pattern_or(list);
-		if (!x)
-			return NULL;
 		if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 			die("unmatched parenthesis");
 		*list = (*list)->next;
@@ -83,6 +83,8 @@ static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 	struct grep_expr *x;
 
 	p = *list;
+	if (!p)
+		return NULL;
 	switch (p->token) {
 	case GREP_NOT:
 		if (!p->next)
@@ -368,6 +370,8 @@ static int match_expr_eval(struct grep_opt *o,
 {
 	int h = 0;
 
+	if (!x)
+		die("Not a valid grep expression");
 	switch (x->node) {
 	case GREP_NODE_ATOM:
 		h = match_one_pattern(o, x->u.atom, bol, eol, ctx);