refactor(error): migrate make_error call sites to typed error codes (Issue #230)

[kcenon]

Closes #230

Summary

• Migrated all make_error/error_info call sites across 32 files to use messaging_error_category typed error codes via make_typed_error_code()
• Replaced #include <kcenon/messaging/error/error_codes.h> with #include <kcenon/messaging/error/messaging_error_category.h> in all migrated files
• Updated message_serializer.h to use messaging-specific error codes (message_serialization_failed, message_deserialization_failed, invalid_payload, not_supported) instead of generic common::error_codes
• Updated test_message_bus.cpp to use messaging_error_category type alias for error code assertions
• Fixed thread_pool_executor::worker_count() to return total workers (active + idle) instead of only active workers

Scope

Files Modified (32 total + 4 test fixes)

Core (5 files): message.cpp, message_bus.cpp, message_broker.cpp, message_queue.cpp, topic_router.cpp
Patterns (4 files): request_reply.cpp, event_streaming.cpp, message_pipeline.cpp, pub_sub.cpp
Backends (2 files): standalone_backend.cpp, integration_backend.cpp
Adapters (4 files): http_transport.h/.cpp, websocket_transport.h/.cpp
Task (11 files): task.cpp, scheduler.cpp, cron_parser.cpp, worker_pool.cpp, monitor.cpp, memory_result_backend.cpp, task_queue.cpp, task_system.cpp, task_client.cpp, task_context.cpp, async_result.cpp
Headers (5 files): message_serializer.h, event_bridge.h, executor_adapter.h, task_event_bridge.h, task_handler.h
Tests (4 files): test_message_bus.cpp, test_result_backend.cpp, test_async_result.cpp, test_worker_pool.cpp

Not migrated (intentional)

• Call sites using common::error::codes::common_errors::* (e.g., invalid_argument, not_found) remain unchanged as they represent genuine common system errors, not messaging-specific errors

Migration Pattern

// Before
return common::make_error<T>(error::code_name, "message", "source");
return common::error_info(error::code_name, "message");

// After
return common::Result<T>::err(make_typed_error_code(messaging_error_category::code_name));

Test Plan

• CI build passes on all platforms (12/12 checks pass)
• All existing unit tests pass (error code numeric values are identical)
• No remaining messaging/error/error_codes.h includes in migrated files

[kcenon]

CI/CD Failure Analysis

Analysis Time: 2026-02-14
Attempt: #1

Failed Workflows

Workflow	Job	Step	Status
CI	windows-2022 / msvc	Run tests	Failed

Root Cause Analysis

Primary Error: Test assertions checking error message strings fail after migrating to typed error codes.

The migration from make_error<T>(code, "Custom message") to Result<T>::err(make_typed_error_code(messaging_error_category::code)) changes how error messages are generated. Previously, each call site provided a custom string. Now, the error category provides standardized messages via its message(int code) method.

Failed Tests (5):

Test	File	Issue
MemoryResultBackendTest.WaitForResultFailure	test_result_backend.cpp:216	message.find("Something went wrong") fails
MemoryResultBackendTest.WaitForResultTimeout	test_result_backend.cpp:231	message.find("Timeout") fails
AsyncResultTest.GetResult_InvalidHandle	test_async_result.cpp:156	Error message equality check fails
WorkerPoolTest.TaskTimeoutErrorMessage	test_worker_pool.cpp:911	message.find("timed out") fails
StandaloneBackendTest.ZeroThreads	test_standalone_backend.cpp:163	Possibly pre-existing

Proposed Fix

Update test assertions to match new typed error code messages from messaging_error_category::message(), or change assertions to verify error codes instead of message strings.

Next Steps

• Read failing test files and corresponding source changes
• Update test assertions to match new error messages
• Push fix and monitor CI

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Automated failure analysis - Attempt #1

[kcenon]

CI/CD Failure Analysis - Attempt #2

Previous Attempt Result: 4/5 test failures fixed, 1 remaining
Previous Fix Applied: Updated error message assertions in test_result_backend.cpp, test_async_result.cpp, test_worker_pool.cpp

New Failure Analysis

Workflow	Job	Step	Previous Status	Current Status
Build & Test	windows-2022 / msvc	Run tests	5 failures	1 failure

What Changed

Previous Fix:

• Updated 4 test assertions to match new typed error code messages

Remaining Failure:

• StandaloneBackendTest.ZeroThreads - unrelated to error code migration

Root Cause

Error:

Expected: (executor->worker_count()) > (0), actual: 0 vs 0

Analysis:
thread_pool_executor::worker_count() was calling pool_->get_active_worker_count() which only returns workers currently executing tasks. Since the ZeroThreads test doesn't submit any tasks after initialization, all workers are idle. On Windows MSVC, the timing is such that get_active_worker_count() correctly returns 0.

The fix sums get_active_worker_count() + get_idle_worker_count() to return the total worker count, which is what the test expects.

Fix Applied

Issue	Solution	Files Affected
worker_count() returns 0 when no tasks are running	Sum active + idle workers for total count	src/impl/backends/standalone_backend.cpp

Commits

1. c2dd7a49 - refactor(error): migrate make_error call sites to typed error codes
2. 17199406 - fix(test): update error message assertions for typed error codes
3. 48a18cdd - fix(backend): return total worker count instead of only active workers

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Automated failure analysis - Attempt #2 of 3