Error displaying hover on self-written module/function documentation

[H12]

Environment

• Elixir & Erlang versions (elixir --version): Elixir 1.14.3 & Erlang 25.2.2
• Elixir Language Server version: 0.15.1
• Operating system: MacOS 13.3.1
• Editor or IDE name (e.g. Emacs/VSCode): VSCode & NeoVim (Reproduced in both)
• Editor Plugin/LSP Client name and version: ElixirLS: Elixir support and debugger (VSCode), elixir-ls (NeoVim lsp config)

Current behavior

When I attempt to display a hover window for functions/module documentation in my project, the operation fails. Doing the same for externally defined documentation works as-expected, however.

In VSCode, I see the following error:

[Error - 9:03:47 AM] Request textDocument/hover failed.
  Message: an exception was raised:
    ** (CaseClauseError) no case clause matching: nil
        (elixir_sense 2.0.0) lib/elixir_sense/providers/docs.ex:58: ElixirSense.Providers.Docs.mod_fun_docs/9
        (elixir_sense 2.0.0) lib/elixir_sense.ex:74: ElixirSense.docs/3
        (language_server 0.15.1) lib/language_server/providers/hover.ex:24: ElixirLS.LanguageServer.Providers.Hover.hover/4
        (language_server 0.15.1) lib/language_server/server.ex:834: anonymous fn/3 in ElixirLS.LanguageServer.Server.handle_request_async/2
  Code: -32000 
[Error - 9:03:47 AM] Process #PID<0.420.0> raised an exception
** (CaseClauseError) no case clause matching: nil
    (elixir_sense 2.0.0) lib/elixir_sense/providers/docs.ex:58: ElixirSense.Providers.Docs.mod_fun_docs/9
    (elixir_sense 2.0.0) lib/elixir_sense.ex:74: ElixirSense.docs/3
    (language_server 0.15.1) lib/language_server/providers/hover.ex:24: ElixirLS.LanguageServer.Providers.Hover.hover/4
    (language_server 0.15.1) lib/language_server/server.ex:834: anonymous fn/3 in ElixirLS.LanguageServer.Server.handle_request_async/2

In NeoVim, this is what I see:

[ERROR][2023-07-06 09:04:48] ...lsp/handlers.lua:535	"Process #PID<0.393.0> raised an exception
** (CaseClauseError) no case clause matching: nil
    (elixir_sense 2.0.0) lib/elixir_sense/providers/docs.ex:58: ElixirSense.Providers.Docs.mod_fun_docs/9
    (elixir_sense 2.0.0) lib/elixir_sense.ex:74: ElixirSense.docs/3
    (language_server 0.15.1) lib/language_server/providers/hover.ex:24: ElixirLS.LanguageServer.Providers.Hover.hover/4
    (language_server 0.15.1) lib/language_server/server.ex:834: anonymous fn/3 in ElixirLS.LanguageServer.Server.handle_request_async/2"

I was able to reproduce in both editors by generating a new default mix project (e.g. mix new lsp_test) and attempting to trigger hover documentation for LspTest.hello/0 via shift+K in both VSCode and NeoVim.

Expected behavior

Hover documentation displays properly.

[lukaszsamson]

That's a known (and harmless) issue.

[H12]

Not sure exactly what changed by the issue appeared to resolve itself. I wonder if the PLT simply hadn't fully generated?

🤷🏻

[lukaszsamson]

Reopening for visibility

[jacksonludwig]

maybe caused by this commit 303dafb

[lukaszsamson]

maybe caused by this commit 303dafb

No. It was never supported and didn't crash by accident. Refactor to CodeFragment API exposed the crash

[jacksonludwig]

maybe caused by this commit 303dafb

No. It was never supported and didn't crash by accident. Refactor to CodeFragment API exposed the crash

Thanks for the info. But I'm confused when you say that it was never supported, as if this is expected behavior for an error to be thrown.

EDIT: Okay I think I understand: the LSP does not/no longer supports querying for hover info on these types of values.

[lukaszsamson]

It’s a feature that was never implemented. elixir_sense currently only provides docs from compiled modules that have doc chunks. For current file it used to return some dummy string and now it returns nil that is not handled. I plan to implement doc extraction from the current file for the next release

[lukaszsamson]

Partially addressed in elixir-lsp/elixir_sense#253

[lukaszsamson]

The crash is fixed now. ElixirLS will return stub documentation on hover for current file. Providing full documentation is tracked in elixir-lsp/elixir_sense#261

[lukaszsamson]

Full local documentation will be released in v0.20