From cbb5738d00ca6e37a27d3d9b85420be49a570c88 Mon Sep 17 00:00:00 2001
From: Ben Ye <benye@amazon.com>
Date: Sun, 2 Feb 2025 23:22:44 -0800
Subject: [PATCH] generate equal empty string label matcher (#144)

---
 walk.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/walk.go b/walk.go
index f2ddcfe..ae83d19 100644
--- a/walk.go
+++ b/walk.go
@@ -494,7 +494,11 @@ func (s *PromQLSmith) walkLabelMatchers() []*labels.Matcher {
 			matchType := labels.MatchType(res)
 			switch matchType {
 			case labels.MatchEqual:
-				matcher = labels.MustNewMatcher(labels.MatchEqual, lbls[orders[i]].Name, lbls[orders[i]].Value)
+				val := lbls[orders[i]].Value
+				if s.rnd.Float64() > 0.9 {
+					val = ""
+				}
+				matcher = labels.MustNewMatcher(labels.MatchEqual, lbls[orders[i]].Name, val)
 			case labels.MatchNotEqual:
 				val := lbls[orders[i]].Value
 				if s.rnd.Float64() > 0.9 {