Needs --filesytem=/tmp

[Waqar144]

Following up from https://github.com/flathub/org.kde.kate/pull/24

I don't really understand why we need to have /tmp shared? Is this for getting the output of applications that are run outside the Flatpak?

The reason is that Kate invokes processes on the host and then passes the temporary file as an argument.

E.g.,

The new formatter plugin (v23.04) will

• format a file using for example clangd and read the stdout
• write the stdout into a temporary file
• use git to diff the document before formatting with the temporary file
• applies the diff on top of document

Similarly, the project plugin stores the ctag index into a temporary file. This file is passed as an argument to the ctags process.

We use QTemporaryFile to create and manage temporary files.

@travier

[travier]

So as I mentioned in https://github.com/flathub/org.kde.kate/pull/24#issuecomment-1467779235, I think it would be really great if Kate could use something like xdg-run/kate instead of /tmp for temporary files.

[Waqar144]

@travier I tried once more to make sure I wasn't getting anything wrong.

The thing is we want a path that is accessible by both the host and flatpak. If we use $XDG_RUNTIME_DIR/kate, host processes fail to access the temporary files we create. There might be a way to convert xdg-run/kate to a proper host path but I am not sure if that would be a reliable way and most likely that wouldn't be an acceptable solution as it requires us changing + ensuring all the scenarios work.

In contrast, /tmp just works. So I think this is the simplest solution that will work for now.

[travier]

Did you make sure to grant the Kate Flatpak access to xdg-run/kate when testing this? This path should be accessible both outside and inside the Flatpak.

Edit: I've just tried it and it needs to be created outside before the Flatpak startup to be accessible inside:

$ cd $XDG_RUNTIME_DIR
$ mkdir kate
$ touch kate/foo
$ flatpak run --filesystem=xdg-run/kate --command=bash org.kde.kcalc
$ ls $XDG_RUNTIME_DIR/kate
foo

[travier]

OK, so that makes it not a viable solution

[travier]

/tmp it is 😢

[Waqar144]

I tried to create a directory when launching up by running mkdir, the directory does get created but it is not usable during that session. On the next session it works.