MissingNullHandler triggered on subflow output variables #67

[RubenHalman]

✅ PR Summary: Improve MissingNullHandler Rule Logic

#67

This PR improves the MissingNullHandler rule to avoid false positives in subflows and flows where the result of a Get Records operation is not used within the same flow.

🔧 Changes Made

• ✅ Added logic to skip null-check enforcement when the result of a recordLookup:
  • Is only passed to an output variable, and
  • Is not used in any downstream flow element (e.g., Assignment, Decision, etc.)
• ✅ Corrected reference matching by using startsWith(...) to detect field-level usage like GetAnAccount.Name
• ✅ Preserved original behavior:
  • Flows that use lookup results without a null-check still trigger violations
  • Flows that include proper IsNull == false checks are not flagged

✅ Outcomes

• 🔒 Eliminates false positives for safe subflow output-only use cases
• ✅ All existing tests continue to pass
• 🧪 Added a new test case: No_Missing_Null_Handler.test.ts to validate lookup results that are never used internally

[RubenHalman]

This downstream check can perhaps be included in the compiler, or a helper class?