Take another approach

Signed-off-by: gotjosh <josue.abreu@gmail.com>

pkg/labels/parse.go

@@ -120,18 +120,14 @@ func ParseMatcher(s string) (_ *Matcher, err error) {
 		return nil, errors.Errorf("bad matcher format: %s", s)
 	}
 
-	rawValue := ms[3]
-	if len(rawValue) == 0 {
-		return nil, errors.Errorf("matcher value is not present: %s", s)
-	}
-
 	var (
+		rawValue            = ms[3]
 		value               strings.Builder
 		escaped             bool
 		expectTrailingQuote bool
 	)
 
-	if rawValue[0] == '"' {
+	if strings.HasPrefix(rawValue, "\"") {
 		rawValue = strings.TrimPrefix(rawValue, "\"")
 		expectTrailingQuote = true
 	}

pkg/labels/parse_test.go

@@ -191,7 +191,10 @@ func TestMatchers(t *testing.T) {
 		},
 		{
 			input: `job=`,
-			err:   `matcher value is not present: job=`,
+			want: func() []*Matcher {
+				m, _ := NewMatcher(MatchEqual, "job", "")
+				return []*Matcher{m}
+			}(),
 		},
 		{
 			input: `job="value`,