Locate failing with "not in environment"

[ulugbekna]

Problem

Go-to-def, go-to-declaration stop working after the first time going to the file of interest.

How to reproduce:

1. open src/import.ml in vscode_ocaml_platform project.
2. trigger go-to-def on Ocaml_version module name line 210. This opens .../ocaml_version.ml
3. switch back to file src/import.ml
4. trigger again go-to-def on Ocaml_version → locate fails with message “not in environment: Ocaml_version”

Interesting observations:

• I thought whether opening ocaml_version.ml is causing this problem, so I put code in ocaml_lsp_server.ml (ocaml-lsp project) that would ignore the notification textDocument/didOpen if the file name is ocaml_version.ml . Indeed! After adding this code, I don’t observe this problem, so opening the file must be causing the problem.

  • either olsp opens a file and that triggers some problem in environments
  • or merlin is getting incorrect environment when a file is opened

• ocaml-lsp/ocaml-lsp-server/vendor/merlin/src/analysis/locate.ml

  Line 765 in 2cca06f

  match Env_lookup.in_namespaces nss ident env with

  is the first place that’s causing the error. Env_lookup.in_namespaces nss ident env returns None. The function that it invokes is Env.find_module_by_name that uses Location.(!input_name) that's equal to import.ml on the first run of go-to-def and ocaml_version.ml on the second run. Changing it on Query_commands.dispatch as such Location.(input_name := (Mpipeline.final_config pipeline).Mconfig.query.filename); before the main pattern match doesn't help.

• Invoking go-to-def on some other symbol in import.ml and coming back to Ocaml_version symbol and then doing go-to-def seems to fix it.

---

Something similar was reported here before - ocamllabs/vscode-ocaml-platform#970
The error message isn't exactly the same however

[ulugbekna]

Hi Ulysse, do you have any ideas why this may be happening or where I should look? @voodoos

[voodoos]

I would guess a configuration issue ?
Maybe OCaml-LSP doesn't refresh the configuration when coming back to the initial file ?
(I will try to reproduce when I find some time.)

[ulugbekna]

Fixed in #904