WARN Response has no supported checksum. Not validating response payload. for simple S3 get

[couling]

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

This looks like a regression of #1606

Using github.com/aws/aws-sdk-go-v2/service/s3 v1.78.1 a simple getObject request causes a warning:

        result, err := client.GetObject(ctx, &s3.GetObjectInput{
		Bucket: &bucket,
		Key:    &key,
	})

SDK 2025/03/09 14:23:48 WARN Response has no supported checksum. Not validating response payload.

I understand that there is now a setting to turn of these warnings generally, but that's rather like cutting the wire to the warning light. Either this warning is a false positive and needs fixing, or else better instructions need to be given here whatever developer error causes the error.

Regression Issue

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

Expected Behavior

Be able to perform a simple get request without warnings by following the documentation

Current Behavior

Generates a warning

SDK 2025/03/09 14:23:48 WARN Response has no supported checksum. Not validating response payload.

Reproduction Steps

Follow instructions for a GetObject request in documentation.

Possible Solution

No response

Additional Information/Context

No response

AWS Go SDK V2 Module Versions Used

	github.com/aws/aws-sdk-go-v2/config v1.29.9
	github.com/aws/aws-sdk-go-v2/service/s3 v1.78.1

Compiler and Version used

go version go1.24.0 darwin/amd64

Operating System and version

MacOS 15

[jonathan-innis]

This warning appeared to start just firing randomly after we upgraded to the latest version of aws-sdk-go-v2 and called GetObject as well -- this strikes me as a regression since we didn't see this before -- agree that it's not entirely clear what this error means from the docs.

Seems like this might have something to do with the aws-sdk-go-v2 not supporting newer checksum algorithms that S3 supports?

[entigo-mart-erlenheim]

This warning is triggered for error responses. Make sure that the request actually correctly responds with the S3 object. Supposedly the warning for error responses is intentional and my ticket about this problem was closed #3020

[jonathan-innis]

This warning is triggered for error responses.

Sounds like from the issue that it's also triggered for 404s, which I think might be what our particular use-case is hitting. We are handling the 404 in the error responses but seems like the warning still gets logged.

Is the recommendation just to disable that warning log in the case where 404s are expected? I'm a little skeptical of how "safe" that is if that log is there for a reason and is intended to actually tell us something

[wty-Bryant]

#3034 should turn off the validation skip warning if no object is fetched in response intentionally or non-exist error is returned

[couling]

Just to clarify, I am getting this warning on successful [200] fetch of a json file from S3.

[lucix-aws]

We support every algorithm in Go now, that's not the issue. You're still going to get this on successful object reads if the object did not have a checksum to begin with. Post-integrity changes, S3 is tagging all objects w/ crc64s by default. Objects that existed before the integrity rollout did not get retconned checksums.

[Alvaro948]

Same issue, these are my dependencies

go 1.24.0

require (
	github.com/aws/aws-sdk-go-v2 v1.36.3
	github.com/aws/aws-sdk-go-v2/config v1.29.9
	github.com/aws/aws-sdk-go-v2/service/s3 v1.78.2