Avoid crashing in PollingFileWatcher

[BrennanConroy]

There is a race we haven't observed before where the test could finish and cleanup the temporary files it creates but the PollingFileWatcher is in the middle of scanning for changes.

This change will observe the exception and just not look at that directory during the current poll.

The active test run was aborted. Reason: Test host process crashed : Unhandled exception. System.IO.DirectoryNotFoundException: Could not find a part of the path 'C:\Users\runner\AppData\Local\Temp\FileWatcherTests-5a01a8c78ee044dfb358a585c3696b83'.
   at System.IO.Enumeration.FileSystemEnumerator`1.CreateDirectoryHandle(String path, Boolean ignoreNotFound)
   at System.IO.Enumeration.FileSystemEnumerator`1.Init()
   at System.IO.Enumeration.FileSystemEnumerator`1..ctor(String directory, Boolean isNormalized, EnumerationOptions options)
   at System.IO.Enumeration.FileSystemEnumerable`1..ctor(String directory, FindTransform transform, EnumerationOptions options, Boolean isNormalized)
   at System.IO.Enumeration.FileSystemEnumerableFactory.FileSystemInfos(String directory, String expression, EnumerationOptions options, Boolean isNormalized)
   at System.IO.DirectoryInfo.InternalEnumerateInfos(String path, String searchPattern, SearchTarget searchTarget, EnumerationOptions options)
   at Microsoft.DotNet.Watcher.Internal.PollingFileWatcher.ForeachEntityInDirectory(DirectoryInfo dirInfo, Action`1 fileAction) in /_/src/Tools/dotnet-watch/src/Internal/FileWatcher/PollingFileWatcher.cs:line 191
   at Microsoft.DotNet.Watcher.Internal.PollingFileWatcher.CheckForChangedFiles() in /_/src/Tools/dotnet-watch/src/Internal/FileWatcher/PollingFileWatcher.cs:line 105
   at Microsoft.DotNet.Watcher.Internal.PollingFileWatcher.PollingLoop() in /_/src/Tools/dotnet-watch/src/Internal/FileWatcher/PollingFileWatcher.cs:line 85
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Threading.ThreadHelper.ThreadStart()

[pranavkm]

Do you think the ForeachEntityInDirectory needs a similar treatment vis-a-vis files being deleted?

[BrennanConroy]

? This is in ForeachEntityInDirectory

[pranavkm]

Ahh, I meant for this: https://github.com/dotnet/aspnetcore/pull/21544/files#diff-f043a2280759c2b01c8f9cec3cbc060dR204?

[BrennanConroy]

I don't think so? It has a catch for FileNotFoundException and is using the already resolved FileSystemInfo object, so should be pretty safe.

[Pilchie]

👀

[Pilchie]

There are 12 quarantined dotnet-watch tests. Possible that others of them are related to this?

[BrennanConroy]

There are 12 quarantined dotnet-watch tests. Possible that others of them are related to this?

I know I put some of them in quarantine when I enabled them to run on Helix. It's probably time for some of them to leave. I do see that there are a couple semi recent failures, but they don't look related.