[jonahgabriel]

Summary

Remove listener/consumer lifecycle code from omnibase_core to enforce the architectural invariant: "infra owns Kafka plumbing, core provides contracts + publish-only abstractions."

This resolves the competing subscription systems between:

• omnibase_core: MixinEventBus listener management (REMOVED)
• omnibase_infra: EventBusSubcontractWiring (KEPT - canonical approach)

Changes

Removed Files (5 files, -4,368 lines)

File	Reason
mixin_event_listener.py	100% listener code
model_event_bus_listener_handle.py	Listener handle model
protocol_event_bus_listener.py	Orphaned protocol
test_mixin_event_listener.py	30 listener tests
test_model_event_bus_listener_handle.py	62 listener tests

Refactored

• mixin_event_bus.py: 40% reduction (1977 → 1200 lines)
  • ❌ Removed: start_event_listener, stop_event_listener, _event_listener_loop
  • ❌ Removed: get_event_patterns, get_completion_event_type, bind_contract_path
  • ❌ Removed: _create_event_handler, _event_to_input_state, _get_input_state_class
  • ✅ Kept: publish_event, publish_completion_event, apublish_completion_event
  • ✅ Kept: bind_event_bus, bind_registry, bind_node_name

Updated

File	Change
model_service_effect.py	Removed stop_event_listener() fallback
test_mixin_event_bus.py	25 listener tests removed, 53 publish tests kept
conftest.py	Removed dead listener thread cleanup code
mixin_tool_execution.py	Updated docstrings
Various __init__.py	Updated exports

Added (CI Guard)

File	Purpose
scripts/validation/validate-no-listener-apis.py	Prevents listener reintroduction
.pre-commit-config.yaml	Hook: validate-no-listener-apis

Inventory Evidence

Production references verified:

• ✅ No production code calls start_event_listener()
• ✅ model_service_effect.py only had shutdown fallback (now removed)
• ✅ All consumers of listener APIs were tests (now deleted)

Test Plan

• mypy passes on modified files
• 53 publish-related tests pass
• All pre-commit hooks pass (44 checks)
• Import smoke tests pass
• Full CI test suite

Breaking Changes

⚠️ Breaking: MixinEventListener and related APIs removed.

Migration: Use EventBusSubcontractWiring in omnibase_infra for Kafka consumer lifecycle management.

References

• Linear: OMN-1747
• Invariant: contract declares subscriptions ⇒ infra wiring runs ⇒ no core listener code needed

Summary by CodeRabbit

• Refactor

  • Event bus is now publish-only; listener/consumer lifecycle and related public APIs have been removed.

• Chores

  • Added a pre-commit validation hook to prevent reintroduction of deprecated listener APIs.

• Tests

  • Removed numerous listener-related unit tests.

• Documentation

  • Bumped package version to 0.10.0 and updated changelog.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR removes event-listener functionality, converting the event bus to publish-only; deletes listener-related classes and tests; adds a pre-commit validation hook and script preventing reintroduction of listener APIs; and bumps version to 0.10.0.

Changes

Cohort / File(s)	Summary
Pre-commit validation setup \.pre-commit-config\.yaml, scripts/validation/validate-no-listener-apis.py	Adds a pre-commit hook and a validation script that scans src/omnibase_core Python files for forbidden listener API patterns (start_event_listener, stop_event_listener, _event_listener_loop, ModelEventBusListenerHandle and imports), with an opt-out header comment.
Listener implementation removals src/omnibase_core/mixins/mixin_event_listener.py, src/omnibase_core/models/event_bus/model_event_bus_listener_handle.py, src/omnibase_core/protocols/event_bus/protocol_event_bus_listener.py	Removes the MixinEventListener, ModelEventBusListenerHandle model, and ProtocolEventBusListener protocol — deleting subscription/lifecycle logic, thread-handling model, and listener interface.
Event bus refactor (publish-only) src/omnibase_core/mixins/mixin_event_bus.py, src/omnibase_core/mixins/__init__.py	Refactors MixinEventBus to publish-only: removes subscribe/unsubscribe and listener lifecycle methods/exports, retains publish methods and binding helpers; removes MixinEventListener export.
Public API cleanup src/omnibase_core/models/event_bus/__init__.py, src/omnibase_core/protocols/event_bus/__init__.py	Removes exports of ModelEventBusListenerHandle and ProtocolEventBusListener from package-level all.
Docs and minor behavior updates src/omnibase_core/mixins/mixin_tool_execution.py, src/omnibase_core/models/services/model_service_effect.py	Updated docstrings to reflect publish-only semantics and removed fallback to stop_event_listener() in cleanup logic.
Tests and test harness changes tests/unit/mixins/test_mixin_event_listener.py, tests/unit/models/event_bus/test_model_event_bus_listener_handle.py, tests/unit/mixins/test_mixin_event_bus.py, tests/conftest.py	Deletes listener-focused test suites and many event-listener tests; simplifies conftest.py cleanup by removing thread-joining logic and leaving a direct gc.collect().
Release/version changes pyproject.toml, src/omnibase_core/__init__.py, CHANGELOG.md	Bumps project and package version to 0.10.0 and documents breaking change: removal of listener APIs and addition of pre-commit guard.

Sequence Diagram(s)

sequenceDiagram
    autonumber
    participant Dev as Developer
    participant Git as Git
    participant Hook as Pre-commit Hook (ONEX Validation)
    participant Script as validate-no-listener-apis.py
    participant FS as Repository Files

    Dev->>Git: git commit
    Git->>Hook: run configured hooks
    Hook->>Script: invoke via poetry
    Script->>FS: scan `src/omnibase_core` python files
    alt forbidden patterns found
        Script->>Hook: return non-zero / report violations
        Hook->>Git: block commit (fail)
        Git->>Dev: show validation failures
    else no violations
        Script->>Hook: return success
        Hook->>Git: allow commit to proceed
        Git->>Dev: commit succeeds
    end

Loading

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~55 minutes

Possibly related PRs

• refactor(mixins): separate MixinEventBus data from behavior (OMN-1081) #266 — Direct overlap with listener-surface changes (adds/removes listener methods, listener handle and protocol); strong file-level overlap.
• Audit non-standard folder structures #82 — Prior modifications to mixin_event_listener implementation; touches the same listener logic and related helper functions.
• feat(registry): add capability metadata and registry services (OMN-1156) #295 — Changes to mixin_event_bus.py bindings and imports; related to the event-bus refactor in this PR.

Poem

🐰
I thumped my foot where listeners lay,
Now messages hop a publish-way,
A tiny guard checks every line—
No sneaky listeners can entwine. 🥕

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically summarizes the main change: removal of listener management from MixinEventBus, with issue reference OMN-1747.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch jonah/omn-1747-cleanup-remove-listener-management-from-mixineventbus

---

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[coderabbitai]

Actionable comments posted: 0

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

src/omnibase_core/mixins/mixin_event_bus.py (1)

1064-1121: ⚠️ Potential issue | 🟠 Major

dispose_event_bus_resources can raise when runtime state was never bound.

_event_bus_runtime_state raises ModelOnexError if the state is missing, which breaks the method’s “idempotent and safe to call multiple times” contract for unbound instances. Consider using _ensure_runtime_state() (or guarding on state presence) to avoid raising during cleanup.

🔧 Suggested fix

-            try:
-                self._event_bus_runtime_state.reset()
-            except (AttributeError, RuntimeError) as e:
+            try:
+                self._ensure_runtime_state().reset()
+            except (ModelOnexError, RuntimeError) as e:
                 cleanup_errors.append(f"Failed to reset runtime state: {e!r}")
                 emit_log_event(
                     LogLevel.ERROR,
                     f"MIXIN_DISPOSE: Failed to reset runtime state: {e!r}",
                     ModelLogData(node_name=self.get_node_name()),
                 )

🧹 Nitpick comments (2)

src/omnibase_core/models/services/model_service_effect.py (1)

115-120: Guard dispose_event_bus_resources with a callable check.
hasattr only verifies presence; a non-callable attribute (e.g., overridden to None) would raise during shutdown. Consider resolving once and checking callable for resilience.

Suggested fix

-        if hasattr(self, "dispose_event_bus_resources"):
-            self.dispose_event_bus_resources()
+        dispose = getattr(self, "dispose_event_bus_resources", None)
+        if callable(dispose):
+            dispose()

scripts/validation/validate-no-listener-apis.py (1)

2-39: Trim the module docstring to 3–6 lines.

It’s currently far longer than the project standard; move the usage/details into argparse help or a README section.

💡 Proposed docstring trim

-"""
-ONEX Listener API Prevention Validation.
-
-OMN-1747: Listener/consumer lifecycle management was removed from omnibase_core.
-This pre-commit hook prevents these APIs from being reintroduced.
-
-For Kafka consumer management, use EventBusSubcontractWiring in omnibase_infra.
-
-Detected Patterns:
-1. def start_event_listener( - Listener start method
-2. def stop_event_listener( - Listener stop method
-3. def _event_listener_loop( - Internal listener loop
-4. class ModelEventBusListenerHandle - Listener handle model
-5. from ... import ... ModelEventBusListenerHandle - Imports of listener handle
-
-Usage:
-    # Check specific files (pre-commit mode)
-    poetry run python scripts/validation/validate-no-listener-apis.py <file1> [file2] ...
-
-    # Check entire src/ directory (default)
-    poetry run python scripts/validation/validate-no-listener-apis.py
-
-    # Check specific directory
-    poetry run python scripts/validation/validate-no-listener-apis.py src/omnibase_core/
-
-    To allow listener APIs in specific files (rare cases), add comment:
-    # listener-api-ok: reason for exception
-
-Rationale:
-    - omnibase_core must remain transport-agnostic (ADR-005)
-    - Listener lifecycle creates tight coupling to Kafka implementation
-    - Consumer management belongs in omnibase_infra via EventBusSubcontractWiring
-    - Core should only define protocols, not implementations
-
-Reference:
-    - OMN-1747: Remove listener management from omnibase_core
-    - docs/architecture/adr/ADR-005-core-infra-dependency-boundary.md
-"""
+"""
+ONEX listener API prevention validator.
+
+OMN-1747 blocks reintroduction of listener lifecycle APIs in omnibase_core.
+Use EventBusSubcontractWiring in omnibase_infra for consumer management.
+See ADR-005 for the core/infra boundary.
+"""

As per coding guidelines: Module docstrings must be concise (3-6 lines max for simple modules); follow PEP 257 with module docstring first, then from __future__ import annotations.