Revert "retry: always include last operation error on timeout or context cancel (#181)"

This reverts commit 8801700.

Author: cenkalti

CHANGELOG.md

@@ -5,15 +5,6 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [6.0.0] - 2026-02-21
-
-### Changed
-
-- `Retry` now returns `errors.Join(context.Cause(ctx), lastErr)` when the context is cancelled, instead of returning only the context error. This ensures the last operation error is always available to the caller.
-- `Retry` now returns `errors.Join(context.DeadlineExceeded, lastErr)` when `WithMaxElapsedTime` is exceeded, instead of returning only the operation error. This makes timeout behaviour consistent regardless of whether the deadline comes from the context or `WithMaxElapsedTime`. (#181)
-
-See [`ExampleRetry_outcomes`](example_test.go) for how to inspect the different error outcomes.
-
 ## [5.0.0] - 2024-12-19
 
 ### Added

example_test.go

@@ -7,7 +7,6 @@ import (
 	"log"
 	"net/http"
 	"strconv"
-	"time"
 
 	"github.com/cenkalti/backoff/v5"
 )
@@ -55,44 +54,6 @@ func ExampleRetry() {
 	// Output: hello
 }
 
-func ExampleRetry_outcomes() {
-	operation := func() (string, error) {
-		resp, err := http.Get("http://httpbin.org/get")
-		if err != nil {
-			return "", err
-		}
-		defer resp.Body.Close()
-		return "ok", nil
-	}
-
-	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
-	defer cancel()
-
-	result, err := backoff.Retry(ctx, operation,
-		backoff.WithMaxElapsedTime(10*time.Second),
-		backoff.WithMaxTries(5),
-	)
-
-	switch {
-	case err == nil:
-		// Operation succeeded.
-		fmt.Println(result)
-
-	case errors.Is(err, context.Canceled):
-		// Context was cancelled by the caller.
-		fmt.Println("cancelled:", err)
-
-	case errors.Is(err, context.DeadlineExceeded):
-		// Either the context deadline or WithMaxElapsedTime was reached.
-		// err contains both the timeout signal and the last operation error.
-		fmt.Println("timed out:", err)
-
-	default:
-		// Retries exhausted (MaxTries or backoff stopped) or Permanent error.
-		fmt.Println("retries exhausted:", err)
-	}
-}
-
 func ExampleTicker() {
 	// An operation that may fail.
 	operation := func() (string, error) {

retry.go

@@ -102,7 +102,7 @@ func Retry[T any](ctx context.Context, operation Operation[T], opts ...RetryOpti
 
 		// Stop retrying if context is cancelled.
 		if cerr := context.Cause(ctx); cerr != nil {
-			return res, errors.Join(cerr, err)
+			return res, cerr
 		}
 
 		// Calculate next backoff duration.
@@ -120,7 +120,7 @@ func Retry[T any](ctx context.Context, operation Operation[T], opts ...RetryOpti
 
 		// Stop retrying if maximum elapsed time exceeded.
 		if args.MaxElapsedTime > 0 && time.Since(startedAt)+next > args.MaxElapsedTime {
-			return res, errors.Join(context.DeadlineExceeded, err)
+			return res, err
 		}
 
 		// Notify on error if a notifier function is provided.
@@ -133,7 +133,7 @@ func Retry[T any](ctx context.Context, operation Operation[T], opts ...RetryOpti
 		select {
 		case <-args.Timer.C():
 		case <-ctx.Done():
-			return res, errors.Join(context.Cause(ctx), err)
+			return res, context.Cause(ctx)
 		}
 	}
 }

retry_test.go

@@ -121,50 +121,6 @@ func TestRetryContext(t *testing.T) {
 	}
 }
 
-// https://github.com/cenkalti/backoff/issues/181
-func TestRetryContextErrorIncludesOperationError(t *testing.T) {
-	opErr := errors.New("operation error")
-	ctxErr := errors.New("context error")
-
-	ctx, cancel := context.WithCancelCause(context.Background())
-	defer cancel(nil)
-
-	i := 0
-	f := func() (bool, error) {
-		i++
-		if i == 2 {
-			cancel(ctxErr)
-		}
-		return false, opErr
-	}
-
-	_, err := Retry(ctx, f, WithBackOff(NewConstantBackOff(time.Millisecond)), withTimer(&testTimer{}))
-	if !errors.Is(err, ctxErr) {
-		t.Errorf("context error not in result: %v", err)
-	}
-	if !errors.Is(err, opErr) {
-		t.Errorf("operation error not in result: %v", err)
-	}
-}
-
-// https://github.com/cenkalti/backoff/issues/181
-func TestRetryMaxElapsedTimeErrorIncludesOperationError(t *testing.T) {
-	opErr := errors.New("operation error")
-
-	_, err := Retry(
-		context.Background(),
-		func() (bool, error) { return false, opErr },
-		WithMaxElapsedTime(time.Millisecond),
-		withTimer(&testTimer{}),
-	)
-	if !errors.Is(err, context.DeadlineExceeded) {
-		t.Errorf("DeadlineExceeded not in result: %v", err)
-	}
-	if !errors.Is(err, opErr) {
-		t.Errorf("operation error not in result: %v", err)
-	}
-}
-
 func TestRetryPermanent(t *testing.T) {
 	ensureRetries := func(test string, shouldRetry bool, f func() (int, error), expectRes int) {
 		numRetries := -1