Fix thread safety race in UsbDrives property#383
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The try/catch wrapped the entire while loop, so a ManagementException or similar hardware error from GetDrives permanently stopped drive detection for the session. Move the try/catch inside the loop so each scan cycle is isolated: exceptions are logged and the loop retries after the normal 3-second sleep. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- Use ex.ToString() instead of ex.Message so stack trace and inner exceptions are preserved in the log. - Return _usbDrives.ToList() inside the lock so callers enumerate a snapshot rather than the live list, closing a pre-existing race where the background thread could mutate the list during enumeration. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
…lures Silent logging masked the error for users with persistently faulty hardware. Restore the outer try/catch with ErrorReport.ReportNonFatalException so those users still receive feedback. Keep the ToList() snapshot fix in UsbDrives. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
rmunn
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Jul 2, 2026
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This is a decent solution to solve the immediate problem. A more effective solution would involve rewriting the class to use thread-safe collections like ConcurrentDictionary (there's no ConcurrentList, but since in this case order doesn't matter, it can be simulated by using a dictionary where the keys and values are the same). But making a copy before returning it is definitely enough for our use case: we don't need the list of USB drives to be updated "live" when someone plugs a new drive in, because if the drive doesn't show up, we can exit and reenter the dialog and then the drive will appear.
So this is fine as-is, and rewriting to use a thread-safe collection isn't truly needed.
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The `UsbDrives` property returned the live `List` reference while holding the lock, but callers (e.g. `SyncStartModel`) enumerated the result after the lock was released. The background scan thread can concurrently call `Clear()`/`AddRange()` during that enumeration, causing `InvalidOperationException: Collection was modified during enumeration`.
Return `_usbDrives.ToList()` inside the lock so callers get a snapshot.
(This is a pre-existing issue unrelated to #261, which was already addressed in #272.)
Devin review: https://app.devin.ai/review/sillsdev/chorus/pull/383
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