HLS corrupts eventlog

[TeofilC]

I am seeing this message in my stderr when running HLS with -la:

haskell-language-server: Event size exceeds EVENT_PAYLOAD_SIZE_MAX, bail out

Your environment

Which OS do you use? NixOS

Which version of GHC do you use and how did you install it? 9.12.4 via haskell.nix

How is your project built (alternative: link to the project)? cabal

Which LSP client (editor/plugin) do you use?

Which version of HLS do you use and how did you install it? 2.14.0

Have you configured HLS in any way (especially: a hie.yaml file)? nah

Steps to reproduce

Run HLS with -la on a big project and notice this message in the logs:

Expected behaviour

Don't corrupt the eventlog

Actual behaviour

haskell-language-server: Event size exceeds EVENT_PAYLOAD_SIZE_MAX, bail out

This then corrupts the eventlog

Debug information

[fendor]

Hi! Thank you for the bug report!

Is this something we do, or is this a GHC bug?

[TeofilC]

I'm not really sure. I think it's probably a HLS bug (or at least triggered from something in HLS rather than something in GHC).

ghc-events inc shows a lot of messages like this:

55483552328: cap 0: binary message OT..c1......GetFileExists
55483558500: cap 0: binary message OT..c1..............File/home/teo/.cache/hie-bios/dist-haskell-language-server-39960683fbcbc2c0565e868121a65cf3/build/x86_64-linux/ghc-9.12.4/hls-graph-2.14.0.0/build/autogen/GHC/Unit/Home/ModInfo.lhs
55483560073: cap 0: binary message OT..c1..............ModeRunDependenciesChanged
55483873139: cap 0: binary message OT..e1......GetFileExists
55483918063: cap 0: binary message OT..Z1..............diagnostics

The only call to eventlog functions I could find is traceMarkerIO in ghcide/src/Development/IDE/Core/Compile.hs:1559

These might be coming from opentelemetry, which uses the eventlog I think.

So I think one of those two is probably to blame.

[soulomoon]

yes, through opentelemetry, eventlog is being used to trace the rules' builds event in the rules system. e.g. beginSpan in the codebase