bug: S3 PutObject returns InternalError on buckets with Suspended versioning (Pro v2026.3.1)

[lorenzo-attuned]

Current Behavior

s3.PutObject returns 500 InternalError for any key on a bucket where versioning is in Suspended state. The error message is:

exception while calling s3.PutObject: '<key>'

No Python traceback is emitted in the LocalStack logs — only the single-line error above.

Expected Behavior

PutObject should succeed on buckets with Suspended versioning, writing objects without version IDs (matching AWS behavior).

Steps To Reproduce

# Create bucket
awslocal s3 mb s3://test-versioning-bug

# Enable versioning
awslocal s3api put-bucket-versioning --bucket test-versioning-bug \
  --versioning-configuration Status=Enabled

# PutObject works while Enabled
echo "hello" | awslocal s3 cp - s3://test-versioning-bug/test.txt
# => SUCCESS

# Suspend versioning
awslocal s3api put-bucket-versioning --bucket test-versioning-bug \
  --versioning-configuration Status=Suspended

# PutObject now fails — every time, for any key
echo "hello" | awslocal s3 cp - s3://test-versioning-bug/test.txt
# => An error occurred (InternalError) when calling the PutObject operation:
#    exception while calling s3.PutObject: 'test.txt'

Key Observations

Bucket state	PutObject works?
Versioning never enabled	✅ Yes
Versioning Enabled	✅ Yes
Versioning Suspended (was Enabled)	❌ InternalError

The file is actually written to disk (visible in /var/lib/localstack/state/s3/<bucket>/) with a version ID suffix, but the response generation throws an exception.

How We Hit This

AWS CDK s3.Bucket({ versioned: false }) on a bucket that previously had versioned: true causes CloudFormation to issue PutBucketVersioning(Status=Suspended) — not delete and recreate the bucket. After this stack update, all PutObject calls to that bucket fail permanently.

Workaround: delete and recreate the bucket (or the entire CloudFormation stack).

Environment

• LocalStack: Pro v2026.3.1.dev166
• OS: macOS (Darwin 25.4.0, Apple Silicon / OrbStack)
• Started via: docker-compose with localstack/localstack:latest