Config and/or state files in read-only file systems cause crashes and prevent logging.

[TheSast]

Describe the bug
Lazygit crashes after prompting for making a repo, before entering the TUI, if it cannot write to$XDG_CONFIG_HOME/lazygit/state.yml and it is not possible to log the issue using lazy --debug if $XDG_CONFIG_HOME/lazygit/development.log is also not able to be written to.
Both of those are inevitable to happen if the lazygit config folder is in a read-only file system.

To Reproduce
This is not the only way it can happen but it is how I specifically encountered the issue.
Steps to reproduce the an instance of the behavior:

0. Install home-manager, back up your lazygit config folder and run home-manager init.
1. Open $HOME/.config/home-manager/home.nix with a text editor.
2. Add home.file.".config/lazygit/config.yml".text = ""; inside it's configuration.
3. Run home-manager switch
4. Run lazygit inside a git repository

Expected behavior
For program state files to respect $XDG_STATE_HOME as mentioned in #2794 with the expected default of $HOME/.local/state.
The XDG Base Directory Specification can be found here

Version info:
This issue happens in the current lazygit nix package for nix stable 23.05 (which is lazygit 0.38.2) and on a build from the current latest commit of this repository b92c294.
I have prepended the output of the lazygit --version command to the stderr output of lazygit of both builds.

Stderr Output:
commit=, build date=, build source=nix, version=0.38.2, os=linux, arch=amd64, git version=2.40.1

2023/07/31 21:16:03 An error occurred! Please create an issue at: https://github.com/jesseduffield/lazygit/issues

*fs.PathError open /home/u/.config/lazygit/state.yml: read-only file system
github.com/jesseduffield/lazygit/pkg/app/app.go:54 (0xab73dc)
github.com/jesseduffield/lazygit/pkg/app/entry_point.go:146 (0xab92da)
github.com/jesseduffield/lazygit/main.go:23 (0xabaebe)
runtime/internal/atomic/types.go:194 (0x439767)
runtime/asm_amd64.s:1598 (0x469b01)

commit=, build date=, build source=unknown, version=unversioned, os=linux, arch=amd64, git version=2.40.1

2023/07/31 21:31:33 An error occurred! Please create an issue at: https://github.com/jesseduffield/lazygit/issues

*fs.PathError open /home/u/.config/lazygit/state.yml: read-only file system
/home/u/go/pkg/mod/github.com/jesseduffield/[email protected]/pkg/app/app.go:55 (0xad7e9c)
	Run: newErr := errors.Wrap(err, 0)
/home/u/go/pkg/mod/github.com/jesseduffield/[email protected]/pkg/app/entry_point.go:151 (0xad9fa6)
	Start: Run(appConfig, common, appTypes.NewStartArgs(cliArgs.FilterPath, parsedGitArg, integrationTest))
/home/u/go/pkg/mod/github.com/jesseduffield/[email protected]/main.go:23 (0xadb85e)
	main: app.Start(ldFlagsBuildInfo, nil)
/nix/store/fp9k417pvah7d6ibbnz2x2llzframbk4-go-1.20.6/share/go/src/runtime/internal/atomic/types.go:194 (0x439767)
	(*Uint32).Load: return Load(&u.value)
/nix/store/fp9k417pvah7d6ibbnz2x2llzframbk4-go-1.20.6/share/go/src/runtime/asm_amd64.s:1598 (0x469b01)
	goexit: BYTE	$0x90	// NOP

[TheSast]

Similar to #818 with same changes necessary for resolution.

[stefanhaller]

I can't reproduce this with a read-only config folder (i.e. chmod 555 "~/Library/Application Support/lazygit" on Mac). Lazygit starts normally, and displays the "Thanks for using lazygit" message every time, because it can't record that it did so in state.yml. It seems that you really need a read-only file system to trigger the crash, but I'm too lazy to set one up to try that.

There's code in app_config.go that checks for permission errors when writing the state file and silently ignores those. My guess is that the os.IsPermission function doesn't check for EROFS, so we might consider including that check ourselves at that point.

[stefanhaller]

@TheSast This should be fixed by #2936, could you test that PR please?

[TheSast]

Tested that fork. It is a partial fix to what was mentioned in this issue.

1. It does fix the error only for when state.yml is absent from the config folder, it yelds same error as before if present, I assume it tries to move it to the new location, this means the fix for that works as intended for home-manager users, since they probably wouldn't declare state.
2. The log files are still written in the config folder making it impossible to check them for info.

But while testing I also encountered a similar issue for config.yml, lazygit will refuse to launch if it can't write config.yml.
Assuming it only tries to write to it if it's absent this won't be an issue for any home-manager users (like in my case or #818), since the folder is read-only only if it's declared, but one would have no reason declare it without the config file, but it may be possible that someone sets XDG_CONFIG_HOME to point to a read-only file system manually or through other means, which would make this behavior (and the state.yml migration behavior) an issue.

If it is possible, I'd suggest:

1. (As you mentioned previously) specifically checking for read-only file systems (both for the config and state directories) and skipping any writing logic for those cases.
2. Flag to specify where to write the log file (with - or no argument resulting in it going to stdout)

[stefanhaller]

Thanks for testing!

1. It does fix the error only for when state.yml is absent from the config folder, it yelds same error as before if present, I assume it tries to move it to the new location,

No, it writes to the file again in the same location where it found it. Which means that for existing users it will continue to save state.yml in the same folder as config.yml, forever. I don't think that's a problem, since state.yml is only created by lazygit, so if it exists in the config folder, that folder must be writeable.

We did consider moving files to the new locations, but decided against it in #2936.

2. The log files are still written in the config folder making it impossible to check them for info.

Ah, I missed this one. Log files shouldn't be saved into the config folder. According to the XDG spec they should probably go to XDG_STATE_HOME. @horriblename, could you add that change to #2936? It looks like this will just be a one-line change to the LogPath() function at the end of app_config.go.

But while testing I also encountered a similar issue for config.yml, lazygit will refuse to launch if it can't write config.yml.

Again, only on a read-only file system. I can't reproduce with a folder that doesn't have write permissions.

But anyway, since this is a slightly unrelated problem, I think it should be fixed in a different PR (if at all). It doesn't seem like a serious issue to me.

To sum it up, with the additional change of writing log files to XDG_STATE_HOME we're good in my opinion.

[horriblename]

According to the XDG spec they should probably go to XDG_STATE_HOME. @horriblename, could you add that change to #2936?

log files belong in XDG_CACHE_HOME I think. Logs aren't part of the app state after all.

I can add it in #2936 but would probably be better to split it off in another PR, what do you think?

[TheSast]

Just for reference: https://specifications.freedesktop.org/basedir-spec/0.8/ar01s03.html

The $XDG_STATE_HOME contains state data that should persist between (application) restarts, but that is not important or portable enough to the user that it should be stored in $XDG_DATA_HOME. It may contain:

• actions history (logs, history, recently used files, …)

[horriblename]

seems reasonable to put it in XDG_STATE_HOME, will do that later in #2936