Merge branch 'es/grep-require-name-when-needed' into maint

More parameter validation.

* es/grep-require-name-when-needed:
  grep: fail if call could output and name is null

Author: gitster

grep.c

@@ -1780,6 +1780,10 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 	enum grep_context ctx = GREP_CONTEXT_HEAD;
 	xdemitconf_t xecfg;
 
+	if (!opt->status_only && gs->name == NULL)
+		BUG("grep call which could print a name requires "
+		    "grep_source.name be non-NULL");
+
 	if (!opt->output)
 		opt->output = std_output;