fix(lambda): accept FunctionName as ARN / partial ARN / qualified name (#817)

[vieiralucas]

Summary

• Lambda's GetFunction (and every other op taking FunctionName) was using the literal path / body string as a state.functions map key. AWS accepts four equivalent forms — plain name, qualified name, full ARN, partial ARN — so the AWS Toolkit for VS Code (which calls GetFunction with the full ARN) listed zero functions.
• New resolve_function_name helper collapses every form, plus percent-encoded ARN segments emitted by AWS SDKs (arn%3Aaws%3Alambda%3A...), to the bare function name.
• Applied at dispatch only for FunctionName-bearing actions; Tag/EventSourceMapping/Layer/CodeSigningConfig/CapacityProvider/DurableExecution resources keep their original identifier. Also normalizes body-derived FunctionName in CreateFunction + CreateEventSourceMapping, and the IAM-action resource ARN so it doesn't double-wrap.

Fixes #817.

Test plan

• 13 new unit tests in service.rs covering the helper across plain / qualified / full ARN / partial ARN / percent-encoded / unknown-shape passthrough, plus three end-to-end dispatch tests for GetFunction and DeleteFunction via path with a full ARN.
• New E2E lambda_function_name_accepts_all_arn_forms exercising every form (plain qualifier, full ARN, qualified full ARN, partial ARN) and a delete-by-ARN through the AWS SDK.
• cargo test -p fakecloud-lambda --lib — 78 passing.
• cargo test -p fakecloud-e2e --test lambda — 7 passing (including the new test).
• cargo clippy --workspace --all-targets -- -D warnings clean.
• cargo fmt --all.

---

Summary by cubic

Accepts Lambda FunctionName as plain name, qualified name, full ARN, or partial ARN across all relevant ops. Fixes #817 where GetFunction with a full ARN returned 404 (e.g., from the AWS Toolkit for VS Code).

• Bug Fixes

  • Added a resolve_function_name helper to collapse all forms (including percent-encoded ARNs) to the bare name; tightened fallback to only single-colon inputs with valid names so foreign ARNs and multi-colon values pass through unchanged.
  • Applied at dispatch for all FunctionName-bearing actions; other resource types are unchanged. Normalizes body FunctionName in CreateFunction and CreateEventSourceMapping, and fixes IAM action resource ARN to avoid double-wrapping.
  • Expanded unit tests and added a new E2E covering all forms.

• Dependencies

  • Added percent-encoding for decoding encoded ARN segments.

^{Written for commit 298757e. Summary will update on new commits. Review in cubic}

[cubic-dev-ai]

1 issue found across 4 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="crates/fakecloud-lambda/src/service.rs">

<violation number="1" location="crates/fakecloud-lambda/src/service.rs:191">
P1: The generic `split_once(':')` fallback over-normalizes unknown identifiers (for example non-Lambda ARNs) to the text before the first colon, which can route requests to the wrong function instead of preserving the original identifier.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[codecov]

Codecov Report

❌ Patch coverage is 98.03922% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/fakecloud-lambda/src/service.rs	98.03%	4 Missing ⚠️

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[vieiralucas]

Closing as duplicate. Issue #817 was independently fixed and shipped via #822 (merged 13:23 UTC) using the same approach — normalize_function_name helper that strips full ARN, partial ARN, and qualifier suffix. No further action needed.