fix: go 1.21 adding goroutine ID to creator+location (#685)

tested on go1.21rc2 as of today's latest

gleak/goroutine/goroutine.go

@@ -33,6 +33,7 @@ import (
 //   - "copystack"
 //   - "preempted"
 //   - ("???" ... something IS severely broken.)
+//
 // In case a goroutine is in waiting state, the State field instead starts with
 // one of the following strings, never showing a lonely "waiting" string, but
 // rather one of the reasons for waiting:
@@ -176,6 +177,9 @@ func findCreator(backtrace string) (creator, location string) {
 	}
 	location = strings.TrimSpace(details[1][:offsetpos])
 	creator = details[0]
+	if offsetpos := strings.LastIndex(creator, " in goroutine "); offsetpos >= 0 {
+		creator = creator[:offsetpos]
+	}
 	return
 }
 

gleak/ignoring_creator_test.go

@@ -27,9 +27,11 @@ var _ = Describe("IgnoringCreator matcher", func() {
 	It("matches a creator function by full name", func() {
 		type T struct{}
 		pkg := reflect.TypeOf(T{}).PkgPath()
-		m := IgnoringCreator(pkg + ".creator")
+		ignore := pkg + ".creator"
+		m := IgnoringCreator(ignore)
 		g := creator()
-		Expect(m.Match(g)).To(BeTrue(), "creator %v", g.String())
+		Expect(m.Match(g)).To(BeTrue(), "creator: %v\ntried to ignore: %s",
+			g.String(), ignore)
 		Expect(m.Match(goroutine.Current())).To(BeFalse())
 	})