Represent language service diagnostics using the pull model

Protocol v3.17 added support for pull-model diagnostics which are modeled as a “report” that is either a full set of diagnostics for a document (and related documents) or “unchanged”

We can convert these to the push model by pulling the diagnostics like we were doing before and inspecting the report before pushing diagnostics to the client

Author: thecrypticace

packages/tailwindcss-language-server/src/lsp/diagnosticsProvider.ts

@@ -9,10 +9,13 @@ export async function provideDiagnostics(
 ) {
   if (!state.enabled) return
   let doc = await service.open(document.uri)
-  let diagnostics = await doc?.diagnostics()
+  let report = await doc?.diagnostics()
+
+  // No need to send diagnostics if the document is unchanged
+  if (report.kind === 'unchanged') return
 
   state.editor?.connection.sendDiagnostics({
     uri: document.uri,
-    diagnostics: diagnostics ?? [],
+    diagnostics: report?.items ?? [],
   })
 }

packages/tailwindcss-language-service/src/codeActions/codeActionProvider.ts

@@ -5,8 +5,8 @@ import { doValidate } from '../diagnostics/diagnosticsProvider'
 import { rangesEqual } from '../util/rangesEqual'
 import {
   type DiagnosticKind,
-  isInvalidApplyDiagnostic,
   type AugmentedDiagnostic,
+  isInvalidApplyDiagnostic,
   isCssConflictDiagnostic,
   isInvalidConfigPathDiagnostic,
   isInvalidTailwindDirectiveDiagnostic,
@@ -26,7 +26,8 @@ async function getDiagnosticsFromCodeActionParams(
   only?: DiagnosticKind[],
 ): Promise<AugmentedDiagnostic[]> {
   if (!document) return []
-  let diagnostics = await doValidate(state, document, only)
+  let report = await doValidate(state, document, only)
+  let diagnostics = report.items as AugmentedDiagnostic[]
 
   return params.context.diagnostics
     .map((diagnostic) => {

packages/tailwindcss-language-service/src/diagnostics/diagnosticsProvider.ts

@@ -1,6 +1,10 @@
 import type { TextDocument } from 'vscode-languageserver-textdocument'
+import {
+  DocumentDiagnosticReportKind,
+  type FullDocumentDiagnosticReport,
+} from 'vscode-languageserver'
 import type { State } from '../util/state'
-import { DiagnosticKind, type AugmentedDiagnostic } from './types'
+import { DiagnosticKind } from './types'
 import { getCssConflictDiagnostics } from './getCssConflictDiagnostics'
 import { getInvalidApplyDiagnostics } from './getInvalidApplyDiagnostics'
 import { getInvalidScreenDiagnostics } from './getInvalidScreenDiagnostics'
@@ -25,10 +29,10 @@ export async function doValidate(
     DiagnosticKind.RecommendedVariantOrder,
     DiagnosticKind.UsedBlocklistedClass,
   ],
-): Promise<AugmentedDiagnostic[]> {
-  const settings = await state.editor.getConfiguration(document.uri)
+): Promise<FullDocumentDiagnosticReport> {
+  let settings = await state.editor.getConfiguration(document.uri)
 
-  return settings.tailwindCSS.validate
+  let items = settings.tailwindCSS.validate
     ? [
         ...(only.includes(DiagnosticKind.CssConflict)
           ? await getCssConflictDiagnostics(state, document, settings)
@@ -59,4 +63,9 @@ export async function doValidate(
           : []),
       ]
     : []
+
+  return {
+    kind: DocumentDiagnosticReportKind.Full,
+    items,
+  }
 }

packages/tailwindcss-language-service/src/service.ts

@@ -12,9 +12,10 @@ import {
   type DocumentLink,
   type Hover,
   type ColorPresentation,
+  type DocumentDiagnosticReport,
 } from 'vscode-languageserver'
 import type { State } from './util/state'
-import type { AugmentedDiagnostic, DiagnosticKind } from './diagnostics/types'
+import type { DiagnosticKind } from './diagnostics/types'
 import type { FileSystem } from './fs'
 import picomatch from 'picomatch'
 import { doHover } from './hoverProvider'
@@ -39,7 +40,7 @@ export interface LanguageDocument {
   documentLinks(): Promise<DocumentLink[]>
   documentColors(): Promise<ColorInformation[]>
   codeLenses(): Promise<CodeLens[]>
-  diagnostics(kinds?: DiagnosticKind[]): Promise<AugmentedDiagnostic[]>
+  diagnostics(kinds?: DiagnosticKind[]): Promise<DocumentDiagnosticReport>
   codeActions(range: Range, context: CodeActionContext): Promise<CodeAction[]>
   completions(position: Position, ctx?: CompletionContext): Promise<CompletionList | null>
   resolveCompletion(item: CompletionItem): Promise<CompletionItem>
@@ -150,7 +151,10 @@ async function createLanguageDocument(
 
     async diagnostics(kinds?: DiagnosticKind[]) {
       if (!state.enabled || !settings.tailwindCSS.validate) {
-        return []
+        return {
+          kind: 'full',
+          items: [],
+        }
       }
 
       return doValidate(state, doc, kinds)