Some app extension questions

[Stephan Bergmann]

On 05/08/2021 12:38, Alexander Larsson wrote:
> On Thu, Aug 5, 2021 at 12:04 PM Stephan Bergmann <sbergman at redhat.com> wrote:
>> * <https://github.com/flathub/org.libreoffice.LibreOffice/pull/158> "Add
>> an org.libreoffice.LibreOffice.BundledExtension extension point"
>> introduces the extension point,
>>
>>>           }
>>>       ],
>>>       "add-extensions": {
>>> +        "org.libreoffice.LibreOffice.BundledExtension": {
>>> +            "directory": "libreoffice/share/extensions",
>>> +            "subdirectories": true,
>>> +            "no-autodownload": true,
>>> +            "autodelete": true
>>> +        },
>>>           "org.libreoffice.LibreOffice.Help": {
>>>               "directory": "libreoffice/help",
>>>               "bundle": true,
>>
>> I observe that without any extensions installed, the original content of
>> /app/libreoffice/share/extensions/, namely a package.txt file, is
>> present, but disappears once any extensions are installed (which each
>> add a subdirectory to /app/libreoffice/share/extensions/).  Is that a
>> bug, or a feature, or a misconfiguration in the json file?
> 
> Yeah, this is expected. Technically what happens is that
> /app/libreoffice/share/extensions is a read-only directory mounted
> into the app, and to add stuff there we need to create directories for
> the mountpoints. This happens by first mounting a tmpfs over this
> directory and then creating the mountpoints in that. This will hide
> the original content of the directory.

I see.  (Luckily, presence of that 
/app/libreoffice/share/extensions/package.txt file appears to be 
irrelevant after all.)

>> * Each extension flatpak must apparently have an id matching
>> org.libreoffice.LibreOffice.BundledExtension.XXX, where XXX must match
>> the directory /app/libreoffice/share/extensions/XXX/ into which the
>> extension's files go, and where XXX must not contain dots (or else I get
>> errors like
>>
>>> error: No extension point matching org.libreoffice.LibreOffice.BundledExtension.org.puimula.ooovoikko in app/org.libreoffice.LibreOffice/x86_64/test
> 
> Yeah, the ids are very sensitive for flatpak. So this is not doable.
> However there are some workaround you can use.
> For example, there is a merge-dirs key you can set in the extension
> point. Typically you set it so something like "lib" which will create
> a toplevel merged dir called "lib" next to all the extension dirs
> contain symlinks into all the files in the extensions that have a lib/
> subdirectory.
> 
> So, you could call the extension point
> org.libreoffice.LibreOffice.BundledExtension.ooovoikko, but with a
> subdirectory called extensions that has a directory called
> org.puimula.ooovoikko . Then if you say merged-dirs=extensions you
> would get a $extensionpoint/extensions/org.puimula.ooovoikko symlink.

I see.  I think I'll stick to my current design where that XXX is a 
short catchy name (like "Voikko") different from the corresponding 
LibreOffice extension <identifier>, and uniqueness needs to be set up 
through some other means (e.g., by having all those extension flatpaks 
be individual 
github.com/flathub/org.libreoffice.LibreOffice.BundledExtension.XXX 
repos).  (Esp. since, at least theoretically, those LibreOffice 
extension <identifier>s could contain arbitrary Unicode characters, 
posing potentially worse problems than just dot.)

>> *
>> <https://github.com/stbergmann/org.libreoffice.LibreOffice.BundledExtension.Voikko/>
>> is such an extension.  It needs two build-time modules, libvoikko and
>> foma, which for now I install to
>> /app/libreoffice/share/extensions/Voikko/build-deps/ (because everywhere
>> else appears to be read-only during the build) and then try to remove with
>>
>>>      "cleanup": [ "/libreoffice/share/extensions/Voikko/build-deps" ]
>>
>> But that cleanup does not seem to work the way I expect it, the
>> populated /libreoffice/share/extensions/Voikko/build-deps/ directory is
>> still present in the resulting flatpak.  Is there some better, ephemeral
>> place to install those build-time dependencies to, and/or how to fix the
>> cleanup?
> 
> I think it needs to be
> "cleanup": [ "/Voikko/build-deps" ]
> 
> but i'm not 100% sure.

That didn't work either, but

>     "cleanup-commands": [ "rm -r /app/libreoffice/share/extensions/Voikko/build-deps" ]

does.