fix(lambda): accept ARN, partial ARN, qualified names in URL paths

[vieiralucas]

Summary

Closes #817.

The VS Code AWS Toolkit calls GetFunction with a fully-qualified function ARN. Real AWS Lambda accepts ARN, partial ARN (ACCOUNT:function:NAME), and name:qualifier in any URL slot that names a function. fakecloud was looking up the raw URL segment in the in-memory map keyed by short name, so every toolkit request returned 404 and the Lambda explorer in the IDE showed nothing.

• New normalize_function_name helper strips full ARN, partial ARN, and trailing :qualifier down to the bare name. Percent-decodes first since SDKs URL-encode : in path segments (arn%3A...).
• Applied at dispatch: handle() normalizes the resource name for every action that takes a FunctionName (Get/Delete/Invoke/aliases/concurrency/URL config/event invoke config/recursion config/versions/policy/scaling). Layer and event-source-mapping routes are untouched.

Test plan

• 8 unit tests for the normalizer (bare name, qualifier strip, full ARN, qualified full ARN, partial ARN, malformed ARN passthrough, empty, percent-encoded ARN)
• 3 unit tests exercising LambdaService::handle end-to-end with full ARN, partial ARN, and name:qualifier
• 1 e2e test via aws-sdk-lambda calling GetFunction with all three forms — same code path the VS Code toolkit hits
• cargo clippy --workspace --all-targets -- -D warnings clean
• cargo fmt --all clean
• VS Code AWS Toolkit smoke test against running fakecloud (manual, post-merge)

---

Summary by cubic

Accept full ARNs, partial ARNs, and name:qualifier in Lambda function URL paths to match AWS behavior. This fixes GetFunction 404s from the VS Code AWS Toolkit so functions appear in the IDE.

• Bug Fixes

  • Added a normalizer that percent-decodes and strips full/partial ARNs and trailing qualifiers to the bare function name.
  • Applied at dispatch to all actions that take FunctionName, including runtime management and durable-executions routes; layer and event-source-mapping routes are unchanged.

• Dependencies

  • Added percent-encoding for URL-decoding path segments.

^{Written for commit 55daeeb. 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:67">
P2: Add the missing function-name actions to action_takes_function_name; otherwise runtime-management-config and durable-executions routes still won't accept ARN/qualified names and will continue to 404 on those endpoints.</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 96.51163% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/fakecloud-lambda/src/service.rs	96.51%	6 Missing ⚠️

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