Incorrect extension of the extracted file

[IchinichiQ]

When trying to extract the .gz archive, the "System.ArgumentOutOfRangeException" error appears inside dll, and the .tar archive with the same name in the same folder appears. I attached the .gz archive, it's from a PSP game. It can be unpacked with the desktop version of 7zip. _0000ESS1.obj.gz

[IchinichiQ]

Oh, looks like that ".tar archive" isn't tar archive, it is the file that is contained in the .gz archive, but it has the wrong extension. The real extension of this file is .obj and just renaming helps. Removing the double extension from the original archive doesn't help. 7zip itself extracts the file from the .gz archive with the correct extension.

[squid-box]

I haven't had a look at the code yet, but can you tell me what format this .obj extension is meant to be?

GZip will only zip a single file, hence confined formats like .tar.gz exists (tar combines a set of files into one file, and that file is then compressed with GZip.

I'm not familiar with the .obj format, and if SevenZipSharp can't determine the format it will default to assuming it's a .tar file.

[IchinichiQ]

This file contains the game script, but it doesn't matter.

It turns out that this bug happens to any archive that was created with the argument "-n", which doesn't save the original file name. When unpacking such archives, the file is assigned an archive name.

I attached a text file archived with that argument. test.txt.gz