HLS version 0.8.0 frequently stuck when saving files

[poscat0x04]

Your environment

Output of haskell-language-server --probe-tools or haskell-language-server-wrapper --probe-tools:

haskell-language-server version: 0.8.0.0 (GHC: 8.10.3) (PATH: /nix/store/px0cwk7xl79yq4b1pvkwaxfkwaswhis1-haskell-language-server-0.8.0.0/bin/haskell-language-server)
Tool versions found on the $PATH
cabal:		3.2.0.0
stack:		Not found
ghc:		8.10.3

Which lsp-client do you use:
vscode
Describe your project (alternative: link to the project):
cabal project
Contents of hie.yaml:
implicit hie

Steps to reproduce

I'm not sure how to reproduce this issue reliably, but it seems that this issue comes up a lot more frequently when I'm editing a file that has errors (type errors/parse errors, etc.) in it.

Expected behaviour

HLS should not stuck

Include debug information

Execute in the root of your project the command haskell-language-server --debug . and paste the logs here:

Debug output:

<paste your logs here>

Paste the logs from the lsp-client, e.g. for VS Code

LSP logs:

<paste your logs here>

[poscat0x04]

update: I can reliably reproduce this issue just by commenting out code

[jneira]

@poscat0x04 that definitely can help to debug the issue, please, could you give the instructions to reproduce it (linking to the source code if possible)?

[poscat0x04]

Oh right, sorry. To reproduce:

1. Open any Haskell file
2. type {-
3. type enter
4. type -}
5. save file
6. delete the lines containing comments you just entered
7. save file
8. repeat 2-7 for a few times, HLS will then stuck

[konn]

I have encountered this bug these days, too.
I suspect Eval plugin's comment parser, but no evidence.
If so, it can be addressed by using getParsedModuelWithComments instead of the custom comment parser to detect doctests.

[berberman]

I could repro following above steps.

[Ailrun]

That probably comes from Eval plugin. @poscat0x04 and @berberman, could you check whether your log messages contain something like "Parser error" or so?

[konn]

If there is no other people to do with, I will try to rewrite doctest parser in Eval Plugin with getParsedModuleWithComments to see how this can affect this issue.