fix(51017): Make lineText in the references response opt-out

src/server/protocol.ts

@@ -1158,12 +1158,14 @@ namespace ts.server.protocol {
     }
 
     export interface ReferencesResponseItem extends FileSpanWithContext {
-        /** Text of line containing the reference.  Including this
-         *  with the response avoids latency of editor loading files
-         * to show text of reference line (the server already has
-         * loaded the referencing files).
+        /**
+         * Text of line containing the reference. Including this
+         * with the response avoids latency of editor loading files
+         * to show text of reference line (the server already has loaded the referencing files).
+         *
+         * If {@link UserPreferences.disableLineTextInReferences} is enabled, the property won't be filled
          */
-        lineText: string;
+        lineText?: string;
 
         /**
          * True if reference is a write location, false otherwise.
@@ -3478,6 +3480,11 @@ namespace ts.server.protocol {
         readonly includeInlayFunctionLikeReturnTypeHints?: boolean;
         readonly includeInlayEnumMemberValueHints?: boolean;
         readonly autoImportFileExcludePatterns?: string[];
+
+        /**
+         * Indicates whether {@link ReferencesResponseItem.lineText} is supported.
+         */
+        readonly disableLineTextInReferences?: boolean;
     }
 
     export interface CompilerOptions {

src/server/session.ts

@@ -1807,6 +1807,7 @@ namespace ts.server {
 
             if (!simplifiedResult) return references;
 
+            const preferences = this.getPreferences(file);
             const defaultProject = this.getDefaultProject(args);
             const scriptInfo = defaultProject.getScriptInfoForNormalizedPath(file)!;
             const nameInfo = defaultProject.getLanguageService().getQuickInfoAtPosition(file, position);
@@ -1815,14 +1816,15 @@ namespace ts.server {
             const symbolStartOffset = nameSpan ? scriptInfo.positionToLineOffset(nameSpan.start).offset : 0;
             const symbolName = nameSpan ? scriptInfo.getSnapshot().getText(nameSpan.start, textSpanEnd(nameSpan)) : "";
             const refs: readonly protocol.ReferencesResponseItem[] = flatMap(references, referencedSymbol => {
-                return referencedSymbol.references.map(entry => referenceEntryToReferencesResponseItem(this.projectService, entry));
+                return referencedSymbol.references.map(entry => referenceEntryToReferencesResponseItem(this.projectService, entry, preferences));
             });
             return { refs, symbolName, symbolStartOffset, symbolDisplayString };
         }
 
         private getFileReferences(args: protocol.FileRequestArgs, simplifiedResult: boolean): protocol.FileReferencesResponseBody | readonly ReferenceEntry[] {
             const projects = this.getProjects(args);
             const fileName = args.file;
+            const preferences = this.getPreferences(toNormalizedPath(fileName));
 
             const references: ReferenceEntry[] = [];
             const seen = createDocumentSpanSet();
@@ -1842,7 +1844,7 @@ namespace ts.server {
             });
 
             if (!simplifiedResult) return references;
-            const refs = references.map(entry => referenceEntryToReferencesResponseItem(this.projectService, entry));
+            const refs = references.map(entry => referenceEntryToReferencesResponseItem(this.projectService, entry, preferences));
             return {
                 refs,
                 symbolName: `"${args.file}"`
@@ -3516,11 +3518,10 @@ namespace ts.server {
         return text;
     }
 
-    function referenceEntryToReferencesResponseItem(projectService: ProjectService, { fileName, textSpan, contextSpan, isWriteAccess, isDefinition }: ReferencedSymbolEntry): protocol.ReferencesResponseItem {
+    function referenceEntryToReferencesResponseItem(projectService: ProjectService, { fileName, textSpan, contextSpan, isWriteAccess, isDefinition }: ReferencedSymbolEntry, { disableLineTextInReferences }: protocol.UserPreferences): protocol.ReferencesResponseItem {
         const scriptInfo = Debug.checkDefined(projectService.getScriptInfo(fileName));
         const span = toProtocolTextSpanWithContext(textSpan, contextSpan, scriptInfo);
-        const lineSpan = scriptInfo.lineToTextSpan(span.start.line - 1);
-        const lineText = scriptInfo.getSnapshot().getText(lineSpan.start, textSpanEnd(lineSpan)).replace(/\r|\n/g, "");
+        const lineText = disableLineTextInReferences ? undefined : getLineText(scriptInfo, span);
         return {
             file: fileName,
             ...span,
@@ -3530,6 +3531,11 @@ namespace ts.server {
         };
     }
 
+    function getLineText(scriptInfo: ScriptInfo, span: protocol.TextSpanWithContext) {
+        const lineSpan = scriptInfo.lineToTextSpan(span.start.line - 1);
+        return scriptInfo.getSnapshot().getText(lineSpan.start, textSpanEnd(lineSpan)).replace(/\r|\n/g, "");
+    }
+
     function isCompletionEntryData(data: any): data is CompletionEntryData {
         return data === undefined || data && typeof data === "object"
             && typeof data.exportName === "string"

src/testRunner/unittests/tsserver/getFileReferences.ts

@@ -54,5 +54,28 @@ namespace ts.projectSystem {
 
             assert.deepEqual(response, expectResponse);
         });
+
+        it("should skip lineText from file references", () => {
+            const session = makeSampleSession();
+            session.getProjectService().setHostConfiguration({ preferences: { disableLineTextInReferences: true } });
+
+            const response = executeSessionRequest<protocol.FileReferencesRequest, protocol.FileReferencesResponse>(
+                session,
+                protocol.CommandTypes.FileReferences,
+                { file: aTs.path },
+            );
+
+            const expectResponse: protocol.FileReferencesResponseBody = {
+                refs: [
+                    makeReferenceItem({ file: bTs, text: "./a", lineText: undefined, contextText: importA, isWriteAccess: false }),
+                    makeReferenceItem({ file: cTs, text: "./a", lineText: undefined, contextText: importCurlyFromA, isWriteAccess: false }),
+                    makeReferenceItem({ file: dTs, text: "/project/a", lineText: undefined, contextText: importAFromA, isWriteAccess: false }),
+                    makeReferenceItem({ file: dTs, text: "./a", lineText: undefined, contextText: typeofImportA, isWriteAccess: false }),
+                ],
+                symbolName: `"${aTs.path}"`,
+            };
+
+            assert.deepEqual(response, expectResponse);
+        });
     });
 }

src/testRunner/unittests/tsserver/helpers.ts

@@ -810,7 +810,7 @@ namespace ts.projectSystem {
     export interface MakeReferenceItem extends DocumentSpanFromSubstring {
         isDefinition?: boolean;
         isWriteAccess?: boolean;
-        lineText: string;
+        lineText?: string;
     }
 
     export function makeReferenceItem({ isDefinition, isWriteAccess, lineText, ...rest }: MakeReferenceItem): protocol.ReferencesResponseItem {

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -7982,12 +7982,14 @@ declare namespace ts.server.protocol {
         command: CommandTypes.References;
     }
     interface ReferencesResponseItem extends FileSpanWithContext {
-        /** Text of line containing the reference.  Including this
-         *  with the response avoids latency of editor loading files
-         * to show text of reference line (the server already has
-         * loaded the referencing files).
+        /**
+         * Text of line containing the reference. Including this
+         * with the response avoids latency of editor loading files
+         * to show text of reference line (the server already has loaded the referencing files).
+         *
+         * If {@link UserPreferences.disableLineTextInReferences} is enabled, the property won't be filled
          */
-        lineText: string;
+        lineText?: string;
         /**
          * True if reference is a write location, false otherwise.
          */
@@ -9833,6 +9835,10 @@ declare namespace ts.server.protocol {
         readonly includeInlayFunctionLikeReturnTypeHints?: boolean;
         readonly includeInlayEnumMemberValueHints?: boolean;
         readonly autoImportFileExcludePatterns?: string[];
+        /**
+         * Indicates whether {@link ReferencesResponseItem.lineText} is supported.
+         */
+        readonly disableLineTextInReferences?: boolean;
     }
     interface CompilerOptions {
         allowJs?: boolean;