fix: reslice error log to remove nil values

retry.go

@@ -157,7 +157,7 @@ func Do(retryableFunc RetryableFunc, opts ...Option) error {
 				}
 				n++
 				errorLog[n] = config.context.Err()
-				return errorLog
+				return errorLog[:lenWithoutNil(errorLog)]
 			}
 
 		} else {
@@ -175,7 +175,7 @@ func Do(retryableFunc RetryableFunc, opts ...Option) error {
 	if config.lastErrorOnly {
 		return errorLog[lastErrIndex]
 	}
-	return errorLog
+	return errorLog[:lenWithoutNil(errorLog)]
 }
 
 func newDefaultRetryConfig() *Config {
@@ -243,7 +243,7 @@ when you need unwrap all erros, you should use `WrappedErrors()` instead
 added in version 4.2.0
 */
 func (e Error) Unwrap() error {
-	return e[len(e)-1]
+	return e[lenWithoutNil(e)-1]
 }
 
 func lenWithoutNil(e Error) (count int) {

retry_test.go

@@ -31,6 +31,7 @@ func TestDoAllFailed(t *testing.T) {
 #8: test
 #9: test
 #10: test`
+	assert.Len(t, err, 10)
 	assert.Equal(t, expectedErrorFormat, err.Error(), "retry error format")
 	assert.Equal(t, uint(45), retrySum, "right count of retry")
 }
@@ -68,6 +69,7 @@ func TestRetryIf(t *testing.T) {
 #1: test
 #2: test
 #3: special`
+	assert.Len(t, err, 3)
 	assert.Equal(t, expectedErrorFormat, err.Error(), "retry error format")
 	assert.Equal(t, uint(2), retryCount, "right count of retry")
 
@@ -163,16 +165,17 @@ func TestLastErrorOnly(t *testing.T) {
 
 func TestUnrecoverableError(t *testing.T) {
 	attempts := 0
-	expectedErr := errors.New("error")
+	testErr := errors.New("error")
+	expectedErr := Error{testErr}
 	err := Do(
 		func() error {
 			attempts++
-			return Unrecoverable(expectedErr)
+			return Unrecoverable(testErr)
 		},
 		Attempts(2),
-		LastErrorOnly(true),
 	)
 	assert.Equal(t, expectedErr, err)
+	assert.Equal(t, testErr, errors.Unwrap(err))
 	assert.Equal(t, 1, attempts, "unrecoverable error broke the loop")
 }
 
@@ -366,6 +369,7 @@ func TestContext(t *testing.T) {
 #1: test
 #2: test
 #3: context canceled`
+		assert.Len(t, err, 3)
 		assert.Equal(t, expectedErrorFormat, err.Error(), "retry error format")
 		assert.Equal(t, 2, retrySum, "called at most once")
 	})