Isolate per-run logging from the process root logger

[HarshRajSinghania]

Summary

Attach OpenEvolve log handlers to the openevolve package logger instead of the process root logger, and give each controller instance its own filtered handlers.

Motivation

Fixes #295. Parallel OpenEvolve runs in the same process were registering file and console handlers on the root logger, so each run duplicated the others' logs. Maintainer note on the issue: we should not take the global namespace.

Implementation

• _setup_logging now configures logging.getLogger("openevolve") with propagate=False.
• Each instance gets a short run id, its own file/console handlers, and a contextvars-based filter so concurrent tasks do not write to each other's handlers.
• Handlers are removed in _teardown_logging from the run() finally block.
• Log filenames include the run id.

Testing

export OPENAI_API_KEY=test-key-for-unit-tests
PYTHONPATH=. python -m unittest tests.test_logging_isolation -v

Result: 3 tests OK.

Note: worker processes still configure logging independently; this change targets same-process concurrent controllers, which is what #295 describes.

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❌ Harsh Raj Singhania
❌ HarshRajSinghania

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