Cache update fails with numerous mods

[Bob-Z]

This bug happens on Linux. I didn't check on Windows.

When starting RoR with many (> 1000) new mods files, the update fails and there is no mods available in RoR's content selector.

To reproduce this: remove all files from "mods" directory. Start RoR: 0 mods available, this is correct ! Exit from RoR. Put more than 1000 mods files in "mods" directory. Start RoR: still 0 mods available.

I think we reach the maximum open file limit (which is 1024 on my system).
If I type "ulimit -n 4096" before running RoR, everything is working correctly.

Error in RoR.log:

15:21:31: FileNotFoundException: Cannot open file: mods.cache in create at /home/runner/.conan2/p/b/ogre393a60adbaf6f6/b/OgreMain/src/OgreFileSystem.cpp (line 431)
15:21:31: [RoR] Error writing JSON file 'mods.cache' (resource group 'Cache'), message: 'FileNotFoundException: Cannot open file: mods.cache in create at /home/runner/.conan2/p/b/ogre393a60adbaf6f6/b/OgreMain/src/OgreFileSystem.cpp (line 431)'
15:21:31: FileNotFoundException: Cannot open file: /home/bobz/.rigsofrods/cache/mods.cache in _openFileStream at /home/runner/.conan2/p/b/ogre393a60adbaf6f6/b/OgreMain/src/OgreFileSystem.cpp (line 388)
15:21:31: [RoR|ModCache] Error, cache file still invalid after check/update, content selector will be empty.
15:21:31: [RoR|ModCache] Cache loaded

[CuriousMike56]

This is definitely exclusive to Linux, I've never encountered this under Windows with over 2k files installed.

[ohlidalp]

If I type "ulimit -n 4096" before running RoR, everything is working correctly.

Thanks for the thorough investigation, I'm no Linux user so I wouldn't even know this command.

Unfortunately, this appears to be related to OGRE framework which we use for resource management. Our code examines the files strictly one-by-one, we never keep more than ~5 streams open (ZIP, thumbnail, document, cachefile...). To make things worse, we use an outdated OGRE (1.11.6) version so I can't even request support. This may also be related to the 3rd party ZIP archive library used by OGRE (zziplib for 1.11x, libz since 1.13).