fix(stepfunctions): fix execution overwrite, IsPresent null, catcher short-circuit

[vieiralucas]

Summary

• Guard succeed_execution/fail_execution against overwriting terminal states (e.g., ABORTED by StopExecution) — background interpreter no longer clobbers stopped executions
• Fix IsPresent to correctly return true for fields explicitly set to null — checks parent object instead of relying on resolve_path which returns Value::Null for both missing and null
• Fix find_catcher to skip malformed catchers (missing Next) instead of aborting the entire search via ? operator
• Add warning log when Wait state has no valid Seconds/SecondsPath/Timestamp/TimestampPath

Addresses unresolved Cubic findings from PRs #241, #244, #242.

Test plan

• cargo clippy -p fakecloud-stepfunctions -- -D warnings passes
• All 41 unit tests pass (2 new: test_is_present_with_null_value, test_find_catcher_skips_malformed_and_finds_next)

---

Summary by cubic

Fixes in fakecloud-stepfunctions: stop overwriting terminal executions by guarding before add_event, treat explicit nulls as present for IsPresent (including array indices; reject malformed segments like foo[0]extra), skip catchers without Next, and warn when Wait lacks valid Seconds/SecondsPath/Timestamp/TimestampPath. Prevents clobbered ABORTED runs and addresses Cubic findings from #241, #242, and #244.

^{Written for commit 5aad2bf. Summary will update on new commits.}

[cubic-dev-ai]

2 issues found across 3 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-stepfunctions/src/choice.rs">

<violation number="1" location="crates/fakecloud-stepfunctions/src/choice.rs:240">
P2: The new `IsPresent` existence check regresses JsonPath support by not handling array-index segments (e.g. `$.items[0]`), so existing fields can be treated as missing.</violation>
</file>

<file name="crates/fakecloud-stepfunctions/src/interpreter.rs">

<violation number="1" location="crates/fakecloud-stepfunctions/src/interpreter.rs:1539">
P1: The terminal-status guard runs after writing the terminal history event, so aborted/stopped executions can still record `ExecutionSucceeded`/`ExecutionFailed` events. Move the guard before `add_event` to avoid inconsistent history.</violation>
</file>

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

[cubic-dev-ai]

1 issue found across 2 files (changes from recent commits).

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-stepfunctions/src/choice.rs">

<violation number="1" location="crates/fakecloud-stepfunctions/src/choice.rs:255">
P1: Array index parsing assumes a trailing `]` and can panic or mis-parse malformed JsonPath segments.</violation>
</file>

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

[cubic-dev-ai]

1 issue found across 1 file (changes from recent commits).

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-stepfunctions/src/choice.rs">

<violation number="1" location="crates/fakecloud-stepfunctions/src/choice.rs:260">
P2: Array-index path parsing now accepts malformed segments with trailing characters after `]`, which can make invalid JsonPath expressions evaluate as existing fields.</violation>
</file>

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