Initialization of extension is very slow for large projects

[plevold]

Is there an existing issue for this?

• I have searched the existing issues

Description

Not really a bug and not really a feature, but more of an annoyance. In a somewhat recent update of Modern Fortran the extension started to have fortls(?) analyze all Fortran files each time a folder is opened. Fortls functionality is not available until this has been completed and for large projects this takes a very long time. See screencast below.

Screenshots

Expected Behaviour

Analyzing all source files is probably the right thing to do, but with the current performance I think it takes too long until fortls features are available. I would assume that in many situations, a large number of the files are actually unchanged since last time VSCode started. Maybe it would be possible to speed up the initialization by serializing the fortls data structure once initialized and then deserialize it the next time VSCode starts? This would require keeping track of which files has changed e.g. with modification timestamps or a hash of the content though.

Version of Modern Fortran

v3.4.2022112202

Version of Visual Studio Code

v1.73.1

Platform and Architecture

Linux

Additional Information

No response

[gnikit]

So what you're seeing there is an experimental initialisation process I added a while back that basically tries to generate all the .mod/.smod files for your linter. You should be able to disable this behaviour with fortran.linter.initialize set to false.

The only thing that really needs to happen is to figure out the dependency graph (what fpm does) and pass that to the linter. The problem is that fpm cannot be easily installed on systems + it's lacking this functionality currently.
For

1. see: FPM pip installation fpm#705
2. see: FPM Integration with Visual Studio Code - Discussion fpm#768 point 3.1

Serialising the dependency graph might be a good idea, but then you also have to take care of validating the cache's state which is not trivial.

[gnikit]

In general, the tools to do this exist. Either fortls, fpm or some other Python package, the problem is that they need a bit of polishing to accomplish this and more importantly I don't have much free time for this. I will see if I can squeeze some of that stuff into another proposal but for now I think attention is diverted to STF projects.

[plevold]

I see! When I turned off fortran.linter.initialize then the extension started quickly again 👍 I don't use any compiler linting (only fortls) for the moment so that works fine for me.

[gnikit]

Happy that worked out. BTW the initialisation stuff will be disabled by default in the official release. Same as the options under experimental. I have them on in the pre-release for users to give feedback. So thanks for taking the time to give feedback. I really appreciate it.