#2138 Removing a file from a solid archive changes its compression method

[Alex Alabuzhev]

1. Compress some files into a solid archive using LZMA method.
2. Open the archive, check properties of the files to make sure that LZMA is used.
3. Remove any file from the archive.
4. Check properties of the files again, now compression method is suddenly LZMA2 everywhere.

7-Zip 18.05.
Reproducible in 7zFM.exe and Far Manager (using both 7-Zip and arclite plugins), so presumably it's a 7z.dll issue.

[Igor Pavlov]

Not a BUG.
The archive could be created at another powerful computer with 128 GB of RAM with big LZMA dectionary.
So 7-Zip don't follow old method, and it uses default method.
It's more safe way.

[Alex Alabuzhev]

Thank you for your response.

The archive could be created at another powerful computer

That definitely makes sense. However, there are some drawbacks too - not every unpacker supports LZMA2 and change of the compression method might render the archive "broken" for them and cause troubles for the user.
Please see this topic for an example https://forum.farmanager.com/viewtopic.php?f=4&t=11264

[Vladimir Surguchev]

Why not old (LZMA) method with default parameters?

[Alex Alabuzhev]

(I wonder why I can freely create a ticket here but adding a comment to it requires moderaton)