VFS problem with user.cfg on Windows

[Itms]

I encountered this problem on the alpha16 rcs: my config changes were not remembered.

After a quick research I found out that a file mods/user/config/user.cfg was created in my My Games/ folder (see GameDataPaths). This file was identical to my %appdata/0ad/config/user.cfg but none of the two files was modified by the game.

This only happens for a non-development copy. The reason is the code in GameSetup.cpp, at line 405 a "user" mod is created and at line 465 the use of My Games/ folder is forced with higher priority.

I know issues with VFS are already investigated but I wanted to log this issue somewhere for information.

I solved the problem by removing all the contents of mods/ in My Games/. I can't remember if I touched the files in there nor when.

[leper]

Was it mods/user/user.cfg or mods/user/config/user.cfg?

[Itms]

Sorry, it was actually mods/user/config/user.cfg. I correct the ticket.

[sanderd17]

Another problem noted with user.cfg on IRC: ​http://irclogs.wildfiregames.com/2016-04-25-QuakeNet-%230ad.log

The user.cfg wasn't created when setting the language, but it was created when changing another setting.

[Vladislav Belov]

Replying to sanderd17:

Another problem noted with user.cfg on IRC: ​http://irclogs.wildfiregames.com/2016-04-25-QuakeNet-%230ad.log

The user.cfg wasn't created when setting the language, but it was created when changing another setting.

Fixed in r18960 (refs #4146).

[Vladislav Belov]

What was the problem? What did you try to save (options, languages, etc)?

[wraitii]

Thanks Stan for noticing. This is fixed by ​Phab:D2781.

[wraitii]

Moved to ​Phab:D3217 I ain't fixing this for A24, somewhat likely to introduce weirdness.

[wraitii]

In 25104:

Make real directory paths on the VFS predictable.

Partial revert/fix of rP13167 and rP13472.

Before this diff, it was possible for a mod containing a cache/ or a config/ folder to get written to incorrectly.
The issue is VFS can map multiple directories to one 'virtual' path, for reading mods. However, writing data is problematic: which path to choose?
The only viable solution is to use a path relative to the highest priority directory encountered in the VFS path, or write paths could be 'hijacked' by lower-priority mods.

This fixes these issues by:

• Adding a new lookup mode ('Real-path') that explicitly picks the real path relative to the highest-priority subdirectory in the VFS Path.
• Preventing overwriting a real directory with a lower priority one in general.
• Revert rP8082's GetRealPath change, re-introducing the function as GetOriginalPath.

This also cleans up some duplication that led to empty mod folders in the user mod path, and cleans up loading the 'user' mod.

Note that the new 'realpath' lookup can still be somewhat complex with many mount points at various hierarchy levels, but it is at least predictable/deterministic without having to be careful about populating order.

Fixes #2553

Differential Revision: ​https://code.wildfiregames.com/D3217

[wraitii]

In 25107:

Make real directory paths on the VFS predictable (retry)

This is the same commit as rP25104, reverted in rP25105. Noted issues were fixed.

Partial revert/fix of rP13167 and rP13472.

Before this diff, it was possible for a mod containing a cache/ or a config/ folder to get written to incorrectly.
The issue is VFS can map multiple directories to one 'virtual' path, for reading mods. However, writing data is problematic: which path to choose?
The only viable solution is to use a path relative to the highest priority directory encountered in the VFS path, or write paths could be 'hijacked' by lower-priority mods.

This fixes these issues by:

• Adding a new lookup mode ('Real-path') that explicitly picks the real path relative to the highest-priority subdirectory in the VFS Path.
• Preventing overwriting a real directory with a lower priority one in general.
• Revert rP8082's GetRealPath change, re-introducing the function as GetOriginalPath.

This also cleans up some duplication that led to empty mod folders in the user mod path, and cleans up loading the 'user' mod.
It also makes it explicit that a directory must be passed to Mount().

Note that the new 'realpath' lookup can still be somewhat complex with many mount points at various hierarchy levels, but it is at least predictable/deterministic without having to be careful about populating order.

Fixes #2553

Differential Revision: ​https://code.wildfiregames.com/D3728