Hello,
Creating AnalyzingSuggester in parallel sometimes fails with an IOException
"The file is already used by another process".
This is due to a flaw in FileSupport.CreateTempFile, most notably this:
if (File.Exists(fileName))
{
attempt++;
continue;
}
// Create the file
File.WriteAllText(fileName, string.Empty, new
UTF8Encoding(false) /* No BOM */);
If 2 or more threads execute File.Exists very close one after another, and the
file isn't found, the first call to File.WriteAllText will succeed and the
other ones will succeed as well since an existing file is simply overwritten.
Dependent code will attempt to use the file as if it were unique, which will
then trigger the exception mentioned above. Yes, it happens!
Consider replacing the File.WriteAllText call (which just creates an empty
file) with:
using (new FileStream(fileName, FileMode.CreateNew))
{
// do nothing
}
... which will fail if the file doesn't exist, and the exception will trigger
another attempt. This will work better as intended.
Happy new year,
Vincent Van Den Berghe
