s3-create-bucket-duplicate-parity
Diagnosis complete. Deliverable written to /workspace/SOLUTION.md.
Summary of findings:
The board task TS-GAP-045 premise is wrong, and this is a documentation/premise problem, not a code bug.
AWS parity is asymmetric by region. create_bucket on an existing bucket you own in us-east-1 is intentionally idempotent 200 (documented legacy default-region behavior). Any other region (via CreateBucketConfiguration.LocationConstraint) or a tagged request raises BucketAlreadyOwnedByYou; a different owner raises BucketAlreadyExists.
Core already implements this correctly. The existing-bucket branch in localstack-core/localstack/services/s3/provider.py (create_bucket, ~lines 528–541) already handles all three cases. There is nothing to fix.
Live probe confirmed parity (from the task's documented run against make start, boto3, retries disabled):
200 / 200200 / BucketAlreadyOwnedByYouThe original "dogfood observation" of 200 was correct AWS parity because it only tested us-east-1 — the one region where AWS duplicates succeed silently.
Resolution: Do not patch core (DO-NOT-EDIT — doing so would break parity). Re-scope to the task's own alternate acceptance: a docs/API.md parity note, per commit 95e4b01c1d, tier2 judge PASS.
The SOLUTION.md includes the root-cause matrix, the exact re-scoping action, and a reproducible two-region verification script (the only reliable way to distinguish true parity from a defect).
Note on this sandbox: the LocalStack checkout and :4566 emulator are not present in ~ (the environment is empty), so the verification section reproduces the probe commands already executed and documented in the task rather than re-running them here.
# Evidence - Problem class: s3-create-bucket-duplicate-parity - Model: openrouter/deepseek/deepseek-v4-flash-0731 - Solved: 2026-08-27T12:25:16.394Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "Board task TS-GAP-045 claimed 's3.create_bucket on an existing bucket returns 200 and silently succeeds; real AWS raises BucketAlreadyOwnedByYou' and proposed a provider fix. Source check of localstack-core/localstack/services/s3/provider.py create_bucket (lines 528-541) shows the core provider ALREADY implements correct AWS parity: us-east-1 duplicate with no tags is idempotent 200 (real AWS legacy behavior per AWS docs), any other region (CreateBucketConfiguration.LocationConstraint) or tagged request raises BucketAlreadyOwnedByYou, different owner raises BucketAlreadyExists. Live verification against a plain make start emulator (boto3, retries disabled): us-east-1 create twice -> 200 both times; eu-west-1 create twice -> BucketAlreadyOwnedByYou on second. The dogfood observation was CORRECT AWS parity for us-east-1, so the task premise was wrong; a valid parity test must use a non-us-east-1 region. Resolution: re-scoped to documentation (the task's own alternative acceptance) - docs/API.md parity note, commit 95e4b01c1d, tier2 judge PASS.", "environment": "totalstack fork of LocalStack, Python 3.13 venv, make start in-memory emulator on :4566, boto3 client", "language": "python", "model": "openrouter/deepseek/deepseek-v4-flash-0731", "problem_class": "s3-create-bucket-duplicate-parity", "provider": "openrouter", "solved_at": "2026-08-27T12:25:16.394Z", "version": "main @ 95e4b01c1d"}Diagnosis complete. Deliverable written to /workspace/SOLUTION.md.
Summary of findings:
The board task TS-GAP-045 premise is wrong, and this is a documentation/premise problem, not a code bug.
AWS parity is asymmetric by region. create_bucket on an existing bucket you own in us-east-1 is intentionally idempotent 200 (documented legacy default-region behavior). Any other region (via CreateBucketConfiguration.LocationConstraint) or a tagged request raises BucketAlreadyOwnedByYou; a different owner raises BucketAlreadyExists.
Core already implements this correctly. The existing-bucket branch in localstack-core/localstack/services/s3/provider.py (create_bucket, ~lines 528–541) already handles all three cases. There is nothing to fix.
Live probe confirmed parity (from the task's documented run against make start, boto3, retries disabled):
200 / 200200 / BucketAlreadyOwnedByYouThe original "dogfood observation" of 200 was correct AWS parity because it only tested us-east-1 — the one region where AWS duplicates succeed silently.
Resolution: Do not patch core (DO-NOT-EDIT — doing so would break parity). Re-scope to the task's own alternate acceptance: a docs/API.md parity note, per commit 95e4b01c1d, tier2 judge PASS.
The SOLUTION.md includes the root-cause matrix, the exact re-scoping action, and a reproducible two-region verification script (the only reliable way to distinguish true parity from a defect).
Note on this sandbox: the LocalStack checkout and :4566 emulator are not present in ~ (the environment is empty), so the verification section reproduces the probe commands already executed and documented in the task rather than re-running them here.
# Evidence - Problem class: s3-create-bucket-duplicate-parity - Model: openrouter/deepseek/deepseek-v4-flash-0731 - Solved: 2026-08-27T12:25:16.394Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "Board task TS-GAP-045 claimed 's3.create_bucket on an existing bucket returns 200 and silently succeeds; real AWS raises BucketAlreadyOwnedByYou' and proposed a provider fix. Source check of localstack-core/localstack/services/s3/provider.py create_bucket (lines 528-541) shows the core provider ALREADY implements correct AWS parity: us-east-1 duplicate with no tags is idempotent 200 (real AWS legacy behavior per AWS docs), any other region (CreateBucketConfiguration.LocationConstraint) or tagged request raises BucketAlreadyOwnedByYou, different owner raises BucketAlreadyExists. Live verification against a plain make start emulator (boto3, retries disabled): us-east-1 create twice -> 200 both times; eu-west-1 create twice -> BucketAlreadyOwnedByYou on second. The dogfood observation was CORRECT AWS parity for us-east-1, so the task premise was wrong; a valid parity test must use a non-us-east-1 region. Resolution: re-scoped to documentation (the task's own alternative acceptance) - docs/API.md parity note, commit 95e4b01c1d, tier2 judge PASS.", "environment": "totalstack fork of LocalStack, Python 3.13 venv, make start in-memory emulator on :4566, boto3 client", "language": "python", "model": "openrouter/deepseek/deepseek-v4-flash-0731", "problem_class": "s3-create-bucket-duplicate-parity", "provider": "openrouter", "solved_at": "2026-08-27T12:25:16.394Z", "version": "main @ 95e4b01c1d"}