Multi-root workspace support ?

[lljr]

https://github.com/Microsoft/vscode-extension-samples/tree/main/basic-multi-root-samples multi-root support. Now, #778 (reply in thread) shows an example of trying to set this up. I have had no success doing this for a React project. Given my very limited Elisp knowledge, does #893 solve multi-root support? If so, is there an easy way to set this up? I've failed to find an example in the repo that teaches how to do so.

Thanks in advance :).

[joaotavora]

Hi @lljr. It's possible that #893 indeed solves it. But you are right, we are missing an example in the README.md that demonstrates how it is used. If a simple example can derive from this discussion it would be great.

I'm not a user of multi-root projects myself, but my understanding is that if you setup an Emacs project.el project x so that:

• (project-root x) returns the "primary" root
• (project-external-roots x) returns a list of the secondary(?) roots

... then invoking M-x eglot inside that project ("inside" meaning project-current will return x) will cause the primary and secondary root information will be sent to the LSP server:

• in the workspaceFolders argument of the initialize client-to-server request
• as the response to the workspace/workspaceFolders server-to-client request

@dgutov is the project.el specialist and maintainer. @nemethf also has some knowledge in this deparment, I gather.

[nemethf]

I'm not aware of any user-level documentation of project.el, but from the NEWS.md:

Eglot now advertises `project-root` and `project-external-roots` as
workspace-folders.  (Configuring `tags-table-list` sets the external
roots of a simple git project.)

[joaotavora]

Right, I forgot about that. That's minimal documentation, but the sentence in parenthesis is very mysterious :-)

[lljr]

Hi @nemethf @joaotavora . Should I see in the :workspaceFolders arg, in the client-to-server request, the same paths I added to tags-table-list? If so, that's not the case... I only see the path for project-root and not the ones I added to tags-table-list.

EDIT: However, this works, at least for webpack resolved modules . After I add the "sub-root" folders as said in

Eglot now advertises `project-root` and `project-external-roots` as
workspace-folders.  (Configuring `tags-table-list` sets the external
roots of a simple git project.)

specifically, tags-table-list. I get auto completion from the configured webpack modules, not just the relative path for the imported variable or function. When I start Emacs without setting the "sub-root" directories via tags-table-list I don't get auto-completion for webpack resolved modules. I get completion to the variable or function in it's relative path. This is due to the way my repo is setup with Next.js, which you can get a clearer idea by quickly reading: https://stackoverflow.com/a/61838859.

That said, perhaps it's a bug that I don't see the extra directories in :workspaceFolders arg in the client-server request?

Now, it would be nice that this could all be done automagically :). Maybe through some user-defined setter that binds a string file.extension to a variable and tells Eglot to set its directory as "sub-root" of a given project and adds them to the :workspaceFolders arg.

EDIT 2: I guess it may not be a bug. I launched the elisp debugger and called eglot (M-x eglot) and when it stopped at 01699c8#diff-d6c5a55ddb4dd8dca075c4e0d48c851460ead14c77f333c66b02ccc7d1c2aff0R727, the value of dirs is the same value I see in :workspaceFolders arg in the client-server request. To reiterate, this is after I set tags-table-list to the "sub-root" folders I need. Keep in mind I double checked by eval'ing tags-table-list and I do see the paths I need in tags-table-list.

To all this, it's still a bit confusing how all these vars work because in project.el the docstring for project-vc-external-roots-function says

"Function that returns a list of external roots.

It should return a list of directory roots that contain source
files related to the current buffer.

The directory names should be absolute.  Used in the VC project
backend implementation of `project-external-roots'."

this talks about directory roots but the docstring for tags-table-list says

Documentation:
List of file names of tags tables to search.
An element that is a directory means the file "TAGS" in that directory.

which imply that tags-table-list should be set to the absolute path including the file, and if no element with file is included, means that "TAGS" is in the directory, which is not necessarily in this case (it's jsconfig.json).

[lljr]

As @nemethf, adding the "sub-root" dirs to tags-table-list solves the problem. Hopefully more is added to this feature in the future.

[lljr]

@joaotavora this stopped working with the latest commit in master. I use to be able to do (setq tags-table-list '("~/src/proj/path2/file.json" "~/src/proj/path1/file.json)) and I would see the paths in workspaceFolders server-client response. Has something changed since then?

What I think should be added is a way to set the files in a variable that indicate another "workspaceFolder". For example, in Typescript lang server the existance of a jsconfig.json or tsconfig.json inside a directory below the root indicate a "sub-root".

[joaotavora]

Please write a full recipe starting with emacs -Q that explains exactly what you want to do. A full but minimal recipe, containing the server used, a simple project, and all the things that you do. Only then can I help you. For example I don't understand what you mean by "see the paths in workspaceFolders server-client response."

Also, what "latest commit in master" are you referring to? The latest commit is about clojure-lsp: I doubt that has any bearing to your problem, which seems to be about workspaces? If you could bisect and come up with the actual commit where this stopped working it would be helpful. (and verify that it is indeed worked with the commit before).

[joaotavora]

Perhaps pinging @nemethf can help as he added this functionality. I can't think of any Eglot commit that has touched this code.

[lljr]

@joaotavora thaks for the quick response. I will get to you later

[nemethf]

Perhaps pinging @nemethf can help as he added this functionality.

Maybe I can help when I see the full recipe. Nevertheless, it's worth checking the return value of project-external-roots.

[quotuva]

FWIW, for jdtls I use:

(push `((java-mode java-ts-mode) "jdtls" "--jvm-arg=-javaagent:/home/user/lombok.jar"
	:initializationOptions
	,(lambda (server)
	   `(:workspaceFolders ,(vconcat (mapcar (lambda (o) (plist-get o :uri)) (eglot-workspace-folders server))))))
      eglot-server-programs)

and comment this line in eglot.el, to work around eclipse-jdtls/eclipse.jdt.ls#1245

EDIT (by @joaotavora): Commenting this line in eglot.el is not needed apparently.

EDIT2: This is indeed down to a bug in the jdtls server. Go here to support its fix eclipse-jdtls/eclipse.jdt.ls#1245 (I'd say it shouldn't be terribly hard).

[joaotavora]

OK. Also, I've confirmed that eglot-workspace-folders already returns a vector. So are you sure your hand-rolled vconcat is needed?

[quotuva]

Yes, I checked again; probably because of mapcar returning a list: json-serialize (wrong-type-argument symbolp "file:///first item in tags-table-list").

[joaotavora]

But what is the mapcar doing there anyway?

[joaotavora]

Maybe is it because jdtls wants just a vector of strings in that place? Then replace the elt with (plist-get i :uri), I'd say.

Has jdtls been made aware of this problem?

[quotuva]

jdtls wants just a vector of strings in that place?

Exactly.

Then replace the elt with (plist-get i :uri)

Yes, that's better.

Has jdtls been made aware of this problem?

Yes, the issue I'd mentioned above; it also has a link to the code.