RAR archives extracted in parallel fails

[svenclaesson]

Extracting RAR packages when Parallel = true results in several failed files
Example here (rar4). This file works fine when Parallel = false.

[gfs]

Thanks for the report and the example file. I'll try to get a fix out this week.

[gfs]

I can reproduce this. The tests have validated that the number of files extracted is correct, but it does appear that parallel extraction of RARs is resulting in incomplete files.

I looekd over our implementation and don't notice anything obviously wrong with the parallel implementation that would cause such an issue - so my suspicion is that the SharpCompress dependency's RarArchive implementation is not threadsafe. Taking a quick look at the code, we call OpenEntryStream, which calls the RarStream ctor, which then directly reads off the Archive's Stream, and does not appear to account for locking/thread safety. I suspect it is the side effects of moving the stream pointers that may be causing this behavior.

I am working on a PR to simply remove the parallelized implementation from the RarExtractor in RecursiveExtractor now.

[svenclaesson]

Thank you very much for your quick response and working on the fix!