Merge pull request #783 from cloudflare/issue-782

Fix false positive reports from promq/regexp
cloudflare · Nov 17, 2023 · 373e392 · 373e392
2 parents 8e456d8 + b13f7b9
commit 373e392
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diff --git a/docs/changelog.md b/docs/changelog.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## v0.49.2
+
+### Fixed
+
+- Fixed false positive reports from `promql/regexp` - #782.
+
 ## v0.49.1
 
 ### Fixed

diff --git a/internal/checks/promql_regexp.go b/internal/checks/promql_regexp.go
@@ -53,7 +53,15 @@ func (c RegexpCheck) Check(_ context.Context, _ string, rule parser.Rule, _ []di
 			var isUseful bool
 			var beginText, endText int
 			r, _ := syntax.Parse(re, syntax.Perl)
+			if r.Flags > 0 && r.Flags != syntax.Perl {
+				// If effective flags are different from default flags then we assume regexp is useful.
+				// It could be case sensitive match.
+				isUseful = true
+			}
 			for _, s := range r.Sub {
+				if s.Flags > 0 && s.Flags != syntax.Perl {
+					isUseful = true
+				}
 				// nolint: exhaustive
 				switch s.Op {
 				case syntax.OpBeginText:

diff --git a/internal/checks/promql_regexp_test.go b/internal/checks/promql_regexp_test.go
@@ -174,6 +174,13 @@ func TestRegexpCheck(t *testing.T) {
 				}
 			},
 		},
+		{
+			description: "regexp with a modifier",
+			content:     "- record: foo\n  expr: foo{job=~\"(?i)someone\"}\n",
+			checker:     newRegexpCheck,
+			prometheus:  noProm,
+			problems:    noProblems,
+		},
 	}
 	runTests(t, testCases)
 }