Some questions regarding LSP integration

[Waqar Ahmed]

Hi,

Yes, that is more or less what clangd does.

> (so this will often fail)

Yes, if there is no compile_commands.json found. And there can be
multiple build dirs with multiple different compile_commands.json
lying around (Think about people working on porting kde software to
Qt6, they may have 2 build dirs one for Qt5 and one for Qt6, both
having different compile_commands). So, automating this will not work
for all scenarios. We currently have a solution in works which is:

Implementing basic CMake support. One of the features is to
automatically copy the compile_commands.json file to the root dir of
the project from the "active" build directory / cmake preset. This
will solve the problem for all cmake based projects.

>  According to the clangd documentation it's currently not possible to
tell clangd where the compile_commands.json file is. Correct ?

It is, but you don't want to do that usually, its very cumbersome as
you need to specify it as a command line arg.

On Thu, Feb 10, 2022 at 3:26 AM Alexander Neundorf <neundorf at kde.org> wrote:
>
> Hi,
>
> you may have noticed I'm catching up a bit...
>
> Do I understand correctly that kate starts clangd, and then when editing some
> source file foo.cpp, it asks clangd for information about foo.cpp.
>
> clangd then tries to "compile" foo.cpp by executing a compile command, which
> it tries to get from compile_commands.json.
> For a file /home/alex/src/Project/foo.cpp, clangd searches for
> compile_commands.json in /home/alex/src/Project/, /home/alex/src/, /home/
> alex/, /home/, / and /home/alex/src/Project/build/. Did I understand this
> correctly ? (so this will often fail)
>
> IIRC, in the project plugin, we know if a file is part of a project, and the
> project knows where the build and the source directories are.
> So kate could point clangd to the top level build directory of the source
> file. According to the clangd documentation it's currently not possible to
> tell clangd where the compile_commands.json file is. Correct ?
>
> Then, in the compile_commands.json file, the calls to the actual compile are
> listed, e.g. using g++. What does clangd do with them ? Simply skip the
> compile executable and "hope" that clang understands the rest of the command
> line ?
>
> Thanks
> Alex
>
>
>