fix(language_server): use the first Span of the message as the primary Diagnostic range

[Sysix]

This PR aligns the main label/span with oxlint.
oxlint will use the first available span as the error. The LSP should use this span for the red line.

let a: {
  b?: {
    c: number;
  };
} = {};

for(var i = 0; i < 10; i--){}
console.log(a?.b?.c!);

Note that file.ts:7:16 means the line/column number and is linkable.

  ⚠ eslint(for-direction): The update clause in this loop moves the variable in the wrong direction
   ╭─[for_direction.ts:7:16]
 6 │ 
 7 │ for(var i = 0; i < 10; i--){}
   ·                ───┬──  ─┬─
   ·                   │     ╰── with this update
   ·                   ╰── This test moves in the wrong direction
 8 │ console.log(a?.b?.c!);
   ╰────
  help: Use while loop for intended infinite loop

  ⚠ typescript-eslint(no-non-null-asserted-optional-chain): Optional chain expressions can return undefined by design: using a non-null assertion is unsafe and wrong.
   ╭─[for_direction.ts:8:20]
 7 │ for(var i = 0; i < 10; i--){}
 8 │ console.log(a?.b?.c!);
   ·                 ┬  ┬
   ·                 │  ╰── non-null assertion made after optional chain
   ·                 ╰── optional chain used
 9 │ 
   ╰────
  help: Remove the non-null assertion.

https://github.com/oxc-project/oxc/blob/main/crates/oxc_language_server/fixtures/linter/issue_9958/issue.ts

Main:

This PR:

[Sysix]

• refactor(linter/language_server): move all lsp relevant code to oxc_language_server crate #14430
• refactor(linter/language_server): oxc_linter::TsgoLinter::run_source returns Message #14429
• refactor(linter/language_server): oxc_linter::Runtime::run_source returns Message #14428
• fix(language_server): use the first Span of the message as the primary Diagnostic range #14057 👈 (View in Graphite)
• main

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[codspeed-hq]

CodSpeed Performance Report

Merging #14057 will not alter performance

_{Comparing 09-23-fix_language_server_build_releated_spans_from_0_instead_of_max_lsp_int_ (493082c) with main (83e7824)¹}

Summary

✅ 4 untouched
⏩ 33 skipped²

Footnotes

1. No successful run was found on main (493082c) during the generation of this report, so 83e7824 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

2. 33 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[Copilot]

Pull Request Overview

Align LSP diagnostics to use the first span/label as the primary diagnostic range, matching oxlint’s behavior.

• Use the first SpanPositionMessage as the diagnostic range instead of deriving it from related information
• Derive Default for SpanPosition and re-export SpanPositionMessage under the language_server feature
• Remove LSP_MAX_INT and update snapshots to reflect new primary/related message ranges

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
crates/oxc_linter/src/lsp.rs	Adds #[must_use] to with_message and derives Default for SpanPosition to support default fallbacks.
crates/oxc_linter/src/lib.rs	Re-exports SpanPositionMessage for language_server feature consumers.
crates/oxc_language_server/src/linter/error_with_position.rs	Computes Diagnostic.range from the first label; removes LSP_MAX_INT and cmp_range logic; adjusts imports.
crates/oxc_language_server/src/main.rs	Removes unused LSP_MAX_INT constant and its documentation comments.
crates/oxc_language_server/src/snapshots/fixtures_linter_issue_9958@issue.ts.snap	Updates expected ranges/messages to reflect using the first span as primary.

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[camc314]

Merge activity

• Oct 8, 10:11 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Oct 8, 10:11 AM UTC: camc314 added this pull request to the Graphite merge queue.
• Oct 8, 10:15 AM UTC: Merged by the Graphite merge queue.

[camc314]

can you double check this is correct? I think it should be:

Suggested change

	let start = labels.first().map(SpanPositionMessage::start).cloned().unwrap_or_default();
	let end = labels.first().map(SpanPositionMessage::end).cloned().unwrap_or_default();
	let (start, end) = labels
	.iter()
	.find(|span| span.primary())
	.or_else(|| labels.first())
	.map(|span| ((SpanPositionMessage::start(span), SpanPositionMessage::end(span))));

The reasoning, is that some rules - e.g. react/exhaustive deps, mark the primary span (out of the two), and this is where the red line should be

[camc314]

oh these aren't spans, and don't have a primary(), method on them.