fix incorrect handling of nil slices in HaveExactElements (fixes #771)

matchers/have_exact_elements.go

@@ -30,15 +30,18 @@ func (matcher *HaveExactElementsMatcher) Match(actual interface{}) (success bool
 
 	lenMatchers := len(matchers)
 	lenValues := len(values)
+	success = true
 
 	for i := 0; i < lenMatchers || i < lenValues; i++ {
 		if i >= lenMatchers {
 			matcher.extraIndex = i
+			success = false
 			continue
 		}
 
 		if i >= lenValues {
 			matcher.missingIndex = i
+			success = false
 			return
 		}
 
@@ -49,15 +52,17 @@ func (matcher *HaveExactElementsMatcher) Match(actual interface{}) (success bool
 				index:   i,
 				failure: err.Error(),
 			})
+			success = false
 		} else if !match {
 			matcher.mismatchFailures = append(matcher.mismatchFailures, mismatchFailure{
 				index:   i,
 				failure: elemMatcher.FailureMessage(values[i]),
 			})
+			success = false
 		}
 	}
 
-	return matcher.missingIndex+matcher.extraIndex+len(matcher.mismatchFailures) == 0, nil
+	return success, nil
 }
 
 func (matcher *HaveExactElementsMatcher) FailureMessage(actual interface{}) (message string) {

matchers/have_exact_elements_test.go

@@ -76,6 +76,16 @@ var _ = Describe("HaveExactElements", func() {
 		})
 	})
 
+	When("passed nil", func() {
+		It("should fail correctly", func() {
+			failures := InterceptGomegaFailures(func() {
+				var expected []any
+				Expect([]string{"one"}).Should(HaveExactElements(expected...))
+			})
+			Expect(failures).Should(HaveLen(1))
+		})
+	})
+
 	Describe("Failure Message", func() {
 		When("actual contains extra elements", func() {
 			It("should print the starting index of the extra elements", func() {