[Varshith-Kali]

Summary

Fixes #4775.

When a Step Functions DefinitionString contains a validation error whose path crosses a JSON array (for example an ErrorEquals type error inside a Catch entry), E3601's _fix_message crashed and the cfn-lint dispatcher reported it as E1101. Worse, every other E3601 finding on that state machine was silently lost with the crash: a template with three real errors reported only the E1101.

Root cause

In src/cfnlint/rules/resources/stepfunctions/StateMachineDefinition.py, _fix_message built the message suffix with '/'.join(err.path). err.path is a jsonschema deque that holds integer indices for array positions, so the join raised TypeError: sequence item 3: expected str instance, int found for any path like States/T/Catch/0/ErrorEquals. This only affected the string form, because _fix_message runs only when the definition was parsed from DefinitionString (add_path_to_message=True).

Fix

Stringify each path element before joining: '/'.join(str(p) for p in err.path). Integer indices now render literally, so the suffix reads at 'States/T/Catch/0/ErrorEquals' and all findings surface as E3601.

Tests

• New regression test test_fix_message_with_array_index_in_path in test/unit/rules/resources/stepfunctions/test_state_machine_definition.py: a JSON-string DefinitionString with the issue's template-B shape (error inside Catch[0] plus a bad StartAt and an invalid state Type). It asserts all three E3601 findings surface, the path suffix renders with the array index, and no E1101 appears. Red/green verified: the test fails with TypeError on the unpatched code and passes with the fix.
• Full stepfunctions rule suite: 21/21 pass. ruff check and ruff format clean on both changed files.
• End-to-end check with the CLI on the issue's repro templates A and B: A reports E3601 'States.ALL' is not of type 'array' at 'States/T/Catch/0/ErrorEquals'; B reports that error plus the two previously hidden findings (StartAt target, invalid state Type); no E1101.

Known limits

None beyond the pre-existing behavior: message suffixes were already best-effort path annotations for the string form. The object form (Definition) was never affected and is unchanged.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.70%. Comparing base (16acc6f) to head (dbab1cb).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4782   +/-   ##
=======================================
  Coverage   94.70%   94.70%           
=======================================
  Files         439      439           
  Lines       15895    15895           
  Branches     3078     3078           
=======================================
  Hits        15053    15053           
  Misses        459      459           
  Partials      383      383           

Flag	Coverage Δ
unittests	94.70% <100.00%> (ø)

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