Merge branch 'cb/log-follow-with-combined' into maint

"git log -c --follow $path" segfaulted upon hitting the commit that
renamed the $path being followed.

* cb/log-follow-with-combined:
  fix segfault with git log -c --follow

combine-diff.c

@@ -1305,6 +1305,7 @@ void diff_tree_combined(const unsigned char *sha1,
 	int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
 
 	diffopts = *opt;
+	diff_tree_setup_paths(diffopts.pathspec.raw, &diffopts);
 	diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 	DIFF_OPT_SET(&diffopts, RECURSIVE);
 	DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
@@ -1375,6 +1376,8 @@ void diff_tree_combined(const unsigned char *sha1,
 		paths = paths->next;
 		free(tmp);
 	}
+
+	diff_tree_release_paths(&diffopts);
 }
 
 void diff_tree_combined_merge(const struct commit *commit, int dense,

t/t4202-log.sh

@@ -530,6 +530,20 @@ test_expect_success 'show added path under "--follow -M"' '
 	)
 '
 
+test_expect_success 'git log -c --follow' '
+	test_create_repo follow-c &&
+	(
+		cd follow-c &&
+		test_commit initial file original &&
+		git rm file &&
+		test_commit rename file2 original &&
+		git reset --hard initial &&
+		test_commit modify file foo &&
+		git merge -m merge rename &&
+		git log -c --follow file2
+	)
+'
+
 cat >expect <<\EOF
 *   commit COMMIT_OBJECT_NAME
 |\  Merge: MERGE_PARENTS