Fix: device log detection uses mtime instead of filename set diff

[indigo1973]

When a device has been used before (log directory already exists), the
CANN driver creates the current process's .log file during
build_callable, before _snapshot_time runs. The original set-difference
approach captured this file in the snapshot, causing _wait_new_device_log
to spin for a full 15 s timeout. On first use of a device (no existing
log directory), the .log file is created later during _run_and_validate,
so the set-difference happened to work.

Switch to timestamp-based detection: _snapshot_time records the current
time, and _wait_new_device_log looks for any .log file whose mtime is
newer than that timestamp. This correctly detects the file regardless of
when it was created, as long as it is written to during the run.

[gemini-code-assist]

Code Review

This pull request refactors device log tracking to use timestamps instead of set-based comparisons. Reviewers identified an unused parameter in _snapshot_device_logs and suggested optimizing _wait_new_device_log to reduce redundant system calls and handle potential race conditions.

[indigo1973]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the device log detection logic in simpler_setup/scene_test.py by replacing the file-set snapshot approach with a timestamp-based baseline. The _wait_new_device_log function now identifies new logs by comparing their modification times against this baseline. Feedback suggests using nanosecond-precision timestamps (time.time_ns() and st_mtime_ns) instead of floating-point seconds to ensure more robust file detection and avoid precision issues.

[indigo1973]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the device log detection mechanism in simpler_setup/scene_test.py by transitioning from a file-set comparison approach to a timestamp-based approach. Specifically, it replaces the _snapshot_device_logs function with _snapshot_time to capture a baseline nanosecond timestamp and updates _wait_new_device_log to identify new logs by comparing their modification times against this baseline. I have no feedback to provide.