Cannot set unlimited retries with `o.MaxAttempts = 0` despite developer guide claims that you can

[injust]

Acknowledgements

• I have searched (https://github.com/aws/aws-sdk/issues?q=is%3Aissue) for past instances of this issue
• I have verified all of my SDK modules are up-to-date (you can perform a bulk update with go get -u github.com/aws/aws-sdk-go-v2/...)

Describe the bug

When using the retry package, the docs say that you can do this to set MaxAttempts:

customRetry := retry.NewStandard(func(o *retry.StandardOptions) {
    o.MaxAttempts = 5
})

My understanding is that setting MaxAttempts to 0 will result in unlimited attempts.

However, setting o.MaxAttempts = 0 is a no-op and retrying will still stop after the default of 3 attempts.

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

Setting o.MaxAttempts = 0 will result in unlimted retries

Current Behavior

Retrying still stops after the default of 3 attempts

Reproduction Steps

package main

import (
	"context"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/aws/retry"
	"github.com/aws/aws-sdk-go-v2/config"
)

func main() {
	retryer := retry.NewStandard(func(o *retry.StandardOptions) {
		o.MaxAttempts = 0
	})

	cfg, err := config.LoadDefaultConfig(context.TODO(),
		config.WithRetryer(func() aws.Retryer {
			return retryer
		}),
	)
}

Possible Solution

No response

Additional Information/Context

Setting MaxAttempts like this worked to get unlimited retries:

cfg, err := config.LoadDefaultConfig(context.TODO(),
	config.WithRetryer(func() aws.Retryer {
		return retry.AddWithMaxAttempts(retryer, 0)
	}),
)

AWS Go SDK V2 Module Versions Used

module foo

go 1.25.1

require (
	github.com/aws/aws-sdk-go-v2 v1.39.0 // indirect
	github.com/aws/aws-sdk-go-v2/config v1.31.8 // indirect
	github.com/aws/aws-sdk-go-v2/credentials v1.18.12 // indirect
	github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.18.7 // indirect
	github.com/aws/aws-sdk-go-v2/internal/configsources v1.4.7 // indirect
	github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.7.7 // indirect
	github.com/aws/aws-sdk-go-v2/internal/ini v1.8.3 // indirect
	github.com/aws/aws-sdk-go-v2/service/ec2 v1.253.0 // indirect
	github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.13.1 // indirect
	github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.13.7 // indirect
	github.com/aws/aws-sdk-go-v2/service/sso v1.29.3 // indirect
	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.34.4 // indirect
	github.com/aws/aws-sdk-go-v2/service/sts v1.38.4 // indirect
	github.com/aws/smithy-go v1.23.0 // indirect
)

Compiler and Version used

go version go1.25.1 linux/amd64

Operating System and version

Ubuntu 24.04.3 LTS

[lucix-aws]

My understanding is that setting MaxAttempts to 0 will result in unlimited attempts.

Do we have documentation that says this somewhere? This has never been the intended behavior as far as I know.

[lucix-aws]

FWIW we really do not recommend you uncap the attempt limit (or set a high one). You're ultimately paying for those requests and if you get into a scenario where you're retrying endlessly you may end up with a runaway billing cycle.

[injust]

Do we have documentation that says this somewhere? This has never been the intended behavior as far as I know.

https://docs.aws.amazon.com/sdk-for-go/v2/developer-guide/configure-retries-timeouts.html says:

Setting max attempts to zero will allow the SDK to retry all retryable errors until the request succeeds, or a non-retryable error is returned.

Right before that, it specifically mentions using retry.AddWithMaxAttempts to do this:

You use retry.AddWithMaxAttempts to wrap an aws.Retryer implementation to set the max number attempts to your desired value.

But I'd expect o.MaxAttempts = 0 to function identically.

[injust]

FWIW we really do not recommend you uncap the attempt limit (or set a high one). You're ultimately paying for those requests and if you get into a scenario where you're retrying endlessly you may end up with a runaway billing cycle.

Thanks for the warning. But that's what service quotas are for, right? 😆

Jokes aside, this is for a rather esoteric use case, and I think I know what I'm doing.

[lucix-aws]

The documentation is definitely incorrect here, we'll get that updated. The code explicitly defaults to the 3 if the caller sets 0. That's not something we can really change, since the SDK has millions of users and some are likely setting it to 0 without realizing, it is all but guaranteed we will break someone out there by doing so.

Is setting MaxAttempts to max int32 enough? The SDK doesn't support a way to make it truly infinite [EDIT: it can be made infinite if the retryer implementation of MaxAttempts() actually returns 0, see below]