Fix single quote parsing, add tests

promql/lex_test.go

@@ -247,6 +247,15 @@ var tests = []struct {
 	{
 		input: `台北`,
 		fail:  true,
+	}, {
+		input: `{foo='bar'}`,
+		expected: []item{
+			{itemLeftBrace, 0, `{`},
+			{itemIdentifier, 1, `foo`},
+			{itemEQL, 4, `=`},
+			{itemString, 5, `'bar'`},
+			{itemRightBrace, 10, `}`},
+		},
 	}, {
 		input: `{foo="bar"}`,
 		expected: []item{
@@ -256,6 +265,15 @@ var tests = []struct {
 			{itemString, 5, `"bar"`},
 			{itemRightBrace, 10, `}`},
 		},
+	}, {
+		input: `{foo="bar\"bar"}`,
+		expected: []item{
+			{itemLeftBrace, 0, `{`},
+			{itemIdentifier, 1, `foo`},
+			{itemEQL, 4, `=`},
+			{itemString, 5, `"bar\"bar"`},
+			{itemRightBrace, 15, `}`},
+		},
 	}, {
 		input: `{NaN	!= "bar" }`,
 		expected: []item{

promql/parse.go

@@ -257,16 +257,10 @@ func (p *parser) alertStmt() *AlertStmt {
 	}
 
 	p.expect(itemSummary, ctx)
-	sum, err := strconv.Unquote(p.expect(itemString, ctx).val)
-	if err != nil {
-		p.error(err)
-	}
+	sum := trimOne(p.expect(itemString, ctx).val)
 
 	p.expect(itemDescription, ctx)
-	desc, err := strconv.Unquote(p.expect(itemString, ctx).val)
-	if err != nil {
-		p.error(err)
-	}
+	desc := trimOne(p.expect(itemString, ctx).val)
 
 	return &AlertStmt{
 		Name:        name.val,
@@ -663,10 +657,7 @@ func (p *parser) labelMatchers(operators ...itemType) metric.LabelMatchers {
 			p.errorf("operator must be one of %q, is %q", operators, op)
 		}
 
-		val, err := strconv.Unquote(p.expect(itemString, ctx).val)
-		if err != nil {
-			p.error(err)
-		}
+		val := trimOne(p.expect(itemString, ctx).val)
 
 		// Map the item to the respective match type.
 		var matchType metric.MatchType
@@ -887,3 +878,14 @@ func parseDuration(ds string) (time.Duration, error) {
 	}
 	return dur, nil
 }
+
+// trimOne removes the first and last character from a string.
+func trimOne(s string) string {
+	if len(s) > 0 {
+		s = s[1:]
+	}
+	if len(s) > 0 {
+		s = s[:len(s)-1]
+	}
+	return s
+}

promql/parse_test.go

@@ -497,22 +497,22 @@ var testExpr = []struct {
 			},
 		},
 	}, {
-		input: `foo:bar{a="b"}`,
+		input: `foo:bar{a="bc"}`,
 		expected: &VectorSelector{
 			Name:   "foo:bar",
 			Offset: 0,
 			LabelMatchers: metric.LabelMatchers{
-				{Type: metric.Equal, Name: "a", Value: "b"},
+				{Type: metric.Equal, Name: "a", Value: "bc"},
 				{Type: metric.Equal, Name: clientmodel.MetricNameLabel, Value: "foo:bar"},
 			},
 		},
 	}, {
-		input: `foo{NaN='b'}`,
+		input: `foo{NaN='bc'}`,
 		expected: &VectorSelector{
 			Name:   "foo",
 			Offset: 0,
 			LabelMatchers: metric.LabelMatchers{
-				{Type: metric.Equal, Name: "NaN", Value: "b"},
+				{Type: metric.Equal, Name: "NaN", Value: "bc"},
 				{Type: metric.Equal, Name: clientmodel.MetricNameLabel, Value: "foo"},
 			},
 		},