From 910a1de4c56e8651ce5e6fecbcfd08f51d45a875 Mon Sep 17 00:00:00 2001
From: Nelson Elhage <nelhage@nelhage.com>
Date: Thu, 26 Dec 2019 22:30:09 -0500
Subject: [PATCH] Fix some parser bugs around mixing [ and (

---
 server/query.go      | 22 +++++++++++++++-------
 server/query_test.go | 22 ++++++++++++++++++++--
 2 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/server/query.go b/server/query.go
index 8a52129b6..333ddffc9 100644
--- a/server/query.go
+++ b/server/query.go
@@ -12,7 +12,7 @@ import (
 	pb "github.com/livegrep/livegrep/src/proto/go_proto"
 )
 
-var pieceRE = regexp.MustCompile(`\(|(?:^([a-zA-Z0-9-_]+):|\\.)| `)
+var pieceRE = regexp.MustCompile(`\[|\(|(?:^([a-zA-Z0-9-_]+):|\\.)| `)
 
 var knownTags = map[string]bool{
 	"file":        true,
@@ -79,16 +79,24 @@ func ParseQuery(query string, globalRegex bool) (pb.Query, error) {
 				term = ""
 				inRegex = globalRegex
 			}
-		} else if match == "(" {
+		} else if match == "(" || match == "[" {
 			if !(inRegex || justGotSpace) {
-				term += "("
+				term += match
 			} else {
-				// A parenthesis. Nothing is special until the
-				// end of a balanced set of parenthesis
+				// A parenthesis or a bracket. Consume
+				// until the end of a balanced set.
 				p := 1
 				i := 0
 				esc := false
 				var w bytes.Buffer
+				var open, close rune
+				switch match {
+				case "(":
+					open, close = '(', ')'
+				case "[":
+					open, close = '[', ']'
+				}
+
 				for i < len(q) {
 					// We decode runes ourselves instead
 					// of using range because exiting the
@@ -101,9 +109,9 @@ func ParseQuery(query string, globalRegex bool) (pb.Query, error) {
 						esc = false
 					case r == '\\':
 						esc = true
-					case r == '(':
+					case r == open:
 						p++
-					case r == ')':
+					case r == close:
 						p--
 					}
 					w.WriteRune(r)
diff --git a/server/query_test.go b/server/query_test.go
index 8cba455c9..960556080 100644
--- a/server/query_test.go
+++ b/server/query_test.go
@@ -1,6 +1,7 @@
 package server
 
 import (
+	"encoding/json"
 	"reflect"
 	"testing"
 
@@ -153,6 +154,21 @@ func TestParseQuery(t *testing.T) {
 			pb.Query{Line: `a\(b`, File: "c", FoldCase: false},
 			true,
 		},
+		{
+			`[(] file:\.c`,
+			pb.Query{Line: `[(]`, File: "\\.c", FoldCase: true},
+			true,
+		},
+		{
+			`[ ] file:\.c`,
+			pb.Query{Line: `[ ]`, File: "\\.c", FoldCase: true},
+			true,
+		},
+		{
+			`[ \]] file:\.c`,
+			pb.Query{Line: `[ \]]`, File: "\\.c", FoldCase: true},
+			true,
+		},
 
 		// literal parse mode
 		{
@@ -200,8 +216,10 @@ func TestParseQuery(t *testing.T) {
 	for _, tc := range cases {
 		parsed, err := ParseQuery(tc.in, tc.regex)
 		if !reflect.DeepEqual(tc.out, parsed) {
-			t.Errorf("error parsing %q: expected %#v got %#v",
-				tc.in, tc.out, parsed)
+			got, _ := json.MarshalIndent(parsed, "", "  ")
+			want, _ := json.MarshalIndent(tc.out, "", "  ")
+			t.Errorf("error parsing %q: expected:\n%s\ngot:\n%s",
+				tc.in, want, got)
 		}
 		if err != nil {
 			t.Errorf("parse(%v) error=%v", tc.in, err)