Fix failover validator coroutine leak when event loop is active

[matdev83]

Summary

• avoid instantiating the backend validation coroutine when the event loop is already running to prevent un-awaited coroutine warnings
• add tests covering both synchronous validation and the event-loop-running skip path

Testing

• python -m pytest (fails: environment is missing optional tooling such as vulture, bandit, and fixtures required by snapshot-based tests)

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Codex Task

Summary by CodeRabbit

• Bug Fixes

  • Improved backend validation logic to properly handle asynchronous operations across different system states, preventing execution conflicts and enhancing reliability.

• Tests

  • Added comprehensive test suite for failover route validation covering various scenarios and system state conditions to ensure consistent behavior.

[coderabbitai]

Walkthrough

The changes modify backend validation in the failover route validator to delay coroutine creation until the event loop state is confirmed. When the loop is running, the method returns early with a warning; otherwise, it constructs and executes the coroutine. New tests validate both scenarios and ensure no coroutine leakage.

Changes

Cohort / File(s)	Change Summary
Failover validation logic src/core/persistence.py	Modified ServiceProviderFailoverRouteValidator to defer coroutine creation until event loop state is verified; returns early with warning if loop is active, otherwise runs coroutine via asyncio.run()
Validation tests tests/unit/core/test_persistence_failover_validator.py	New test module covering backend validation when loop is inactive (mocks successful backend validation) and coroutine prevention when loop is active (validates no backend calls and no unawaited warnings)

Sequence Diagram(s)

sequenceDiagram
    participant Caller
    participant Validator
    participant EventLoop
    participant Coroutine as Coroutine<br/>(delayed)
    participant Backend

    rect rgba(240, 248, 255, 0.3)
    Note over Validator: Old Flow (creates eagerly)
    Caller->>Validator: validate()
    Validator->>Coroutine: create (always)
    Validator->>EventLoop: check running
    alt Loop active
        Validator-->>Caller: return with warning
        Coroutine--xCaller: (leaked, unawaited)
    else Loop inactive
        Validator->>Coroutine: await via asyncio.run()
        Coroutine->>Backend: validate_backend_and_model()
        Backend-->>Coroutine: result
        Validator-->>Caller: return result
    end
    end

    rect rgba(220, 240, 220, 0.3)
    Note over Validator: New Flow (creates conditionally)
    Caller->>Validator: validate()
    Validator->>EventLoop: check running
    alt Loop active
        Validator-->>Caller: return warning (no coroutine)
    else Loop inactive
        Validator->>Coroutine: create
        Validator->>Coroutine: await via asyncio.run()
        Coroutine->>Backend: validate_backend_and_model()
        Backend-->>Coroutine: result
        Validator-->>Caller: return result
    end
    end

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

• Changes involve conditional logic and event loop state management—requires careful verification of the control flow
• Test coverage is comprehensive but uses mock patterns that benefit from tracing through both scenarios
• Primary focus: verify coroutine creation is truly deferred and no resource leaks occur in the active-loop path

Poem

🐰 A hop and a skip through the event loop's domain,
Coroutines dance now with purpose, not bane!
We defer creation till certain we're clear,
No leaked, unawaited worries need we fear! ✨
thump thump with our feet at this test-covered cheer!

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Fix failover validator coroutine leak when event loop is active' directly and clearly summarizes the main change: preventing coroutine leakage in the failover validator when the event loop is running.

✨ 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 codex/find-and-fix-async/await-issues-rq37mg

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📜 Recent review details

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between c03159e and f684f37.

📒 Files selected for processing (2)

• src/core/persistence.py (1 hunks)
• tests/unit/core/test_persistence_failover_validator.py (1 hunks)

🧰 Additional context used

📓 Path-based instructions (2)

**/*.py

📄 CodeRabbit inference engine (AGENTS.md)

**/*.py: Avoid using emojis in Python code comments or docstrings
Follow PEP 8 and use type hints for all functions
Import order must be: standard library, third-party, then local imports, separated by blank lines
Naming conventions: snake_case for variables and functions; PascalCase for classes
Error handling: use specific exceptions and include meaningful error messages
Prefer f-strings for string formatting

Files:

• src/core/persistence.py
• tests/unit/core/test_persistence_failover_validator.py

src/**/*.py

📄 CodeRabbit inference engine (AGENTS.md)

src/**/*.py: Catch specific exceptions; avoid broad except Exception blocks
If a broad exception must be caught, log with exc_info=True and re-raise a specific custom exception
Use the most specific exception class from src.core.common.exceptions that accurately describes the error
Provide clear, helpful error messages and include relevant details in the details dictionary of custom exceptions

Files:

• src/core/persistence.py

🧬 Code graph analysis (2)

src/core/persistence.py (2)

src/core/services/backend_service.py (1)

• validate_backend_and_model (1229-1245)

src/core/interfaces/backend_service.py (1)

• validate_backend_and_model (44-55)

tests/unit/core/test_persistence_failover_validator.py (1)

src/core/persistence.py (4)

• ServiceProviderFailoverRouteValidator (217-315)
• validate (205-207)
• validate (213-214)
• validate (228-315)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (3)

• GitHub Check: test (3.10)
• GitHub Check: Analyze (python)
• GitHub Check: semgrep-cloud-platform/scan

🔇 Additional comments (4)

src/core/persistence.py (1)

275-276: LGTM! Coroutine leak fix is correct.

The coroutine is now created only after confirming the event loop is not running (due to the early return on line 273). This ensures no un-awaited coroutine warnings when the loop is active, directly addressing the PR objective.

tests/unit/core/test_persistence_failover_validator.py (3)

1-23: LGTM! Test infrastructure is well-structured.

The imports follow PEP 8 ordering, and the helper classes (_DummyProvider and _strict_supplier) provide clean test fixtures for the validator tests.

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26-38: LGTM! Test correctly verifies validation when loop is inactive.

The test properly asserts that validate_backend_and_model is awaited once and returns a valid result without warnings when the event loop is not running.

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41-58: LGTM! Excellent test coverage for coroutine leak prevention.

The test effectively verifies the fix by:

• Running in an async context (via @pytest.mark.asyncio) to ensure the event loop is active
• Using warnings.catch_warnings and gc.collect() to detect any un-awaited coroutine warnings
• Confirming the validator returns early with a warning without calling the backend service
• Asserting no "was never awaited" warnings are emitted

This directly validates the PR objective and provides strong regression protection.

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