test(grpc): Add race condition regression tests from PR #7 with analysis

Adds test/race_condition_test.dart (293 lines, 3 tests) from PR #7 to provide
regression coverage for the race condition fixes applied in commit dedce7a.

SOURCE:
  • Original PR: #7
  • Feature Branch: https://github.com/open-runtime/grpc-dart/tree/hiro/race_condition_fix
  • Original Commits:
    - e8b9ad8 (main fixes)
    - 4371c8d (test coverage)
  • Author: hiro@pieces
  • Date: September 1, 2025

TEST COVERAGE:
  1. "Should handle serialization error without crashing when stream closes concurrently"
     - Simulates serialization failure + concurrent client disconnect
     - Validates no "Cannot add event after closing" exception
     - Result: ✅ PASSING

  2. "Stress test - multiple concurrent disconnections during serialization errors"
     - Runs 10 concurrent iterations with random timing
     - Tests different disconnect methods
     - Result: ✅ PASSING

  3. "Reproduce exact 'Cannot add event after closing' scenario"
     - Attempts exact production scenario
     - Shows error is handled gracefully
     - Result: ✅ PASSING (error properly handled)

MODIFICATIONS:
  • Removed unused import: package:grpc/src/server/handler.dart
  • Removed unused variable: gotError
  • Fixed type annotations (changed int/bool to var)
  • Result: No lint issues, all tests passing

VERIFICATION:
  • Total test suite: 172 tests (169 + 3 new)
  • All tests passing
  • No analyzer errors
  • Production-ready

PR #7 ANALYSIS:
  • Added PR_7_ANALYSIS.md (672 lines) documenting:
    - Complete diff analysis between PR branch and aot_monorepo_compat
    - Why PR #7 cannot be merged directly (removes v5.0.0 + ServerInterceptor)
    - Review comments from mark-at-pieces about Sentry logging
    - Recommendation to close PR #7 (superseded by our work)
    - Decision matrix and risk analysis

RELATED:
  • PR #7: #7
  • Fixes applied: dedce7a
  • Documentation: e8b6d52

Author: tsavo-at-pieces