Fix error encountered running in helix

[forivall]

I manually applied this fix and the lsp works now. Single character fix to add a missing ?.

[changeset-bot]

🦋 Changeset detected

Latest commit: 2230bf8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
graphql-language-service-server	Patch

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[trevor-scheer]

@forivall change seems reasonable to me, but can you share a reproduction that demonstrates the issue?

[forivall]

Here's my reproduction repository: https://github.com/forivall/gql-config-repro-workspace/tree/89204bd11c78655db950237db8264e205f624d90

setup: npm install -g graphql-language-service-cli and helix editor. helix has graphql-lsp support out of the box.

to reproduce, i first watch the helix logs via tail -f ~/.cache/helix/*.log | rg --max-columns 10000 graphql-language-service

and then run hx -vvv test-files/1.ts

Among the log lines, i will see

2026-04-17T09:52:55.949 helix_lsp::transport [INFO] graphql-language-service <- {"jsonrpc":"2.0","method":"window/logMessage","params":{"type":1,"message":"TypeError: Cannot read properties of undefined (reading 'length')"}}

and the error will not appear.

The expected behaviour, which is how it works when i apply my fix, is to show this error:

(the files for the above repo were adapted from the tests for graphql-codegen)

[dimaMachina]

Could you improve type for settings?

[forivall]

Done.

[dimaMachina]

Suggested change

	? this._settings?.load?.rootDir
	? this._settings.load.rootDir

[forivall]

Done

[codecov]

Codecov Report

❌ Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 63.96%. Comparing base (8f25b38) to head (2230bf8).
⚠️ Report is 42 commits behind head on main.

Files with missing lines	Patch %	Lines
...ql-language-service-server/src/MessageProcessor.ts	33.33%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4123   +/-   ##
=======================================
  Coverage   63.96%   63.96%           
=======================================
  Files          35       35           
  Lines        3086     3086           
  Branches      949      934   -15     
=======================================
  Hits         1974     1974           
  Misses       1107     1107           
  Partials        5        5           

Files with missing lines	Coverage Δ
...ql-language-service-server/src/MessageProcessor.ts	89.22% <33.33%> (ø)

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