clients/lsp-csharp.el: Implement go-to definition in metadata.

[razzmatazz]

This commit adds a handler for 'osmd://' uri when returned from
omnisharp-roslyn, parses the uri and issues corresponding 'o#/metadata'
request that is used to retrieve metadata source to display to the user.

The design is modelled after clients/lsp-clojure.el and lsp-java. I am not 100% about the directory: currently I save metadata .cs files under <project-dir>/.cache/lsp-csharp/metadata -- but maybe that needs to be a customizable variable or some other dir?

This PR is marked as draft as there is some changes pending to be merged into omnisharp-roslyn yet but open for review.

[razzmatazz]

Related omnisharp-roslyn PR is:

• LSP: Return custom schema (osmd:/) URIs for go to definition in LSP OmniSharp/omnisharp-roslyn#2079

[razzmatazz]

FYI @CsBigDataHub I have rebased this PR on the latest lsp-mode/master commit

[CsBigDataHub]

@razzmatazz Tested this PR and it works as intended.

I see few compilation warnings.

In lsp-csharp--omnisharp-metadata-uri-handler:
lsp-csharp.el:365:46: Warning: attempt to let-bind constant ‘:source-name’
lsp-csharp.el:365:59: Warning: attempt to let-bind constant ‘:source’
lsp-csharp.el:384:17: Warning: reference to free variable ‘source’

In end of data:
lsp-csharp.el:361:31: Warning: the function

again thanks for your work.

[jcs090218]

@razzmatazz Any progress on this? Can't wait to have this feature! 😄

[jcs090218]

The design is modelled after clients/lsp-clojure.el and lsp-java. I am not 100% about the directory: currently I save metadata .cs files under /.cache/lsp-csharp/metadata -- but maybe that needs to be a customizable variable or some other dir?

I think you might want to create a temporary buffer to display? Maybe

(with-current-buffer (get-buffer-create "*temp Metadata source name*")
  ;; Insert content here, etc.
  )

This way, it won't generate any file to user's disk.

[razzmatazz]

The design is modelled after clients/lsp-clojure.el and lsp-java. I am not 100% about the directory: currently I save metadata .cs files under /.cache/lsp-csharp/metadata -- but maybe that needs to be a customizable variable or some other dir?

I think you might want to create a temporary buffer to display? Maybe

(with-current-buffer (get-buffer-create "*temp Metadata source name*")
  ;; Insert content here, etc.
  )

This way, it won't generate any file to user's disk.

Hey @jcs090218. I remember temp buffers were not working for some reason, I think transitive ref find with xref was not working when buffer had no backing file.

[razzmatazz]

@razzmatazz Any progress on this? Can't wait to have this feature! 😄

It’s all on omnisharp-roslyn team. They don’t seem keen on merging my PR so this is in limbo :/

you may want to vouch on that PR by commenting, so maintainers would show it some attention:

• LSP: Return custom schema (osmd:/) URIs for go to definition in LSP OmniSharp/omnisharp-roslyn#2079

[jcs090218]

I remember temp buffers were not working for some reason, I think transitive ref find with xref was not working when buffer had no backing file.

Just to clarify, the temporary buffer refers to just a regular buffer but with invalid character (*) so it cannot be saved to disk. So you could create a buffer with name * [metadata] Source.cs * using the function get-buffer-create if it has not created.

you may want to vouch on that PR by commenting, so maintainers would show it some attention:

Definitely! Thanks for your hard work! 😄 👍

[razzmatazz]

cancelling in favor of #3096

sorry, omnisharp-roslyn is relucant to accept my patches and hacking my own LSP server is more fun :D