feat: add MaxRetries and MaxSleep options to customize retry behavior

leaks_test.go

@@ -36,7 +36,7 @@ var _ = TestingT(testing.TB(nil))
 // testOptions passes a shorter max sleep time, used so tests don't wait
 // ~1 second in cases where we expect Find to error out.
 func testOptions() Option {
-	return maxSleep(time.Millisecond)
+	return MaxSleep(time.Millisecond)
 }
 
 func TestFind(t *testing.T) {
@@ -74,6 +74,41 @@ func TestFindRetry(t *testing.T) {
 	require.NoError(t, Find(), "Find should retry while background goroutine ends")
 }
 
+func TestFindMaxRetries(t *testing.T) {
+	t.Run("zero retries does not retry and fails immediately", func(t *testing.T) {
+		bg := startBlockedG()
+		defer bg.unblock()
+
+		start := time.Now()
+		err := Find(MaxRetries(0))
+		require.Error(t, err, "Should find leaks without retrying")
+		assert.Less(t, time.Since(start), 50*time.Millisecond, "Should return immediately with 0 retries")
+	})
+
+	t.Run("custom retries allows delayed goroutine exit", func(t *testing.T) {
+		bg := startBlockedG()
+		go func() {
+			time.Sleep(5 * time.Millisecond)
+			bg.unblock()
+		}()
+
+		err := Find(MaxRetries(20), MaxSleep(5*time.Millisecond))
+		require.NoError(t, err, "Find should retry and succeed when goroutine finishes")
+	})
+}
+
+func TestFindMaxSleep(t *testing.T) {
+	t.Run("shorter max sleep fails faster", func(t *testing.T) {
+		bg := startBlockedG()
+		defer bg.unblock()
+
+		start := time.Now()
+		err := Find(MaxRetries(5), MaxSleep(time.Millisecond))
+		require.Error(t, err)
+		assert.Less(t, time.Since(start), 100*time.Millisecond, "Find should return quickly with short max sleep")
+	})
+}
+
 type fakeT struct {
 	errors []string
 }
@@ -103,6 +138,15 @@ func TestVerifyNone(t *testing.T) {
 		}))
 		require.True(t, cleanupCalled, "expect cleanup registered callback to be called")
 	})
+
+	t.Run("VerifyNone with MaxRetries and MaxSleep", func(t *testing.T) {
+		ft := &fakeT{}
+		bg := startBlockedG()
+		defer bg.unblock()
+
+		VerifyNone(ft, MaxRetries(1), MaxSleep(time.Millisecond))
+		require.NotEmpty(t, ft.errors, "Expect errors from VerifyNone with custom MaxRetries and MaxSleep")
+	})
 }
 
 func TestIgnoreCurrent(t *testing.T) {

options.go

@@ -126,12 +126,29 @@ func RunOnFailure() Option {
 	})
 }
 
-func maxSleep(d time.Duration) Option {
+// MaxRetries sets the maximum retry attempts when looking for extra goroutines.
+// When looking for leaking goroutines, goleak will retry until all goroutines
+// terminate or until the maximum retry attempts are exhausted.
+// If not configured, defaults to 20.
+func MaxRetries(n int) Option {
+	return optionFunc(func(opts *opts) {
+		opts.maxRetries = n
+	})
+}
+
+// MaxSleep sets the maximum sleep duration in-between each retry attempt.
+// The sleep duration grows in an exponential backoff, up to the maximum specified here.
+// If not configured, defaults to 100 milliseconds.
+func MaxSleep(d time.Duration) Option {
 	return optionFunc(func(opts *opts) {
 		opts.maxSleep = d
 	})
 }
 
+func maxSleep(d time.Duration) Option {
+	return MaxSleep(d)
+}
+
 func addFilter(f func(stack.Stack) bool) Option {
 	return optionFunc(func(opts *opts) {
 		opts.filters = append(opts.filters, f)
@@ -170,9 +187,12 @@ func (o *opts) retry(i int) bool {
 		return false
 	}
 
-	d := time.Duration(int(time.Microsecond) << uint(i))
-	if d > o.maxSleep {
-		d = o.maxSleep
+	d := o.maxSleep
+	if i < 40 {
+		d = time.Duration(int(time.Microsecond) << uint(i))
+		if d > o.maxSleep {
+			d = o.maxSleep
+		}
 	}
 	time.Sleep(d)
 	return true

options_test.go

@@ -111,14 +111,29 @@ func TestOptionsIgnoreAnyFunction(t *testing.T) {
 	}
 }
 
-func TestOptionsRetry(t *testing.T) {
+func TestMaxRetriesAndMaxSleep(t *testing.T) {
 	opts := buildOpts()
-	opts.maxRetries = 50 // initial attempt + 50 retries = 11
-	opts.maxSleep = time.Millisecond
+	assert.Equal(t, _defaultRetries, opts.maxRetries)
+	assert.Equal(t, 100*time.Millisecond, opts.maxSleep)
+
+	opts = buildOpts(MaxRetries(50), MaxSleep(time.Millisecond))
+	assert.Equal(t, 50, opts.maxRetries)
+	assert.Equal(t, time.Millisecond, opts.maxSleep)
+}
+
+func TestOptionsRetry(t *testing.T) {
+	opts := buildOpts(MaxRetries(50), MaxSleep(time.Millisecond))
 
 	for i := 0; i < 50; i++ {
-		assert.True(t, opts.retry(i), "Attempt %v/51 should allow retrying", i)
+		assert.True(t, opts.retry(i), "Attempt %v/50 should allow retrying", i)
 	}
-	assert.False(t, opts.retry(51), "Attempt 51/51 should not allow retrying")
-	assert.False(t, opts.retry(52), "Attempt 52/51 should not allow retrying")
+	assert.False(t, opts.retry(50), "Attempt 50/50 should not allow retrying")
+	assert.False(t, opts.retry(51), "Attempt 51/50 should not allow retrying")
+	assert.False(t, opts.retry(52), "Attempt 52/50 should not allow retrying")
+}
+
+func TestOptionsRetryLargeAttempt(t *testing.T) {
+	opts := buildOpts(MaxRetries(100), MaxSleep(time.Millisecond))
+	assert.True(t, opts.retry(65), "Attempt 65 should not overflow")
+	assert.False(t, opts.retry(100), "Attempt 100 should not allow retrying")
 }