refactor(language-service): stop tracking lastKwownProgram in CompilerFactory (#41517)

With the work done in #41291, the compiler always tracks the last known
program, so there's no need to track the program in the compiler factory
anymore.

PR Close #41517

packages/language-service/ivy/compiler_factory.ts

@@ -10,10 +10,8 @@ import {CompilationTicket, freshCompilationTicket, incrementalFromCompilerTicket
 import {NgCompilerOptions} from '@angular/compiler-cli/src/ngtsc/core/api';
 import {TrackedIncrementalBuildStrategy} from '@angular/compiler-cli/src/ngtsc/incremental';
 import {ProgramDriver} from '@angular/compiler-cli/src/ngtsc/program_driver';
-import * as ts from 'typescript/lib/tsserverlibrary';
 
 import {LanguageServiceAdapter} from './adapters';
-import {isExternalTemplate} from './utils';
 
 /**
  * Manages the `NgCompiler` instance which backs the language service, updating or replacing it as
@@ -27,7 +25,6 @@ import {isExternalTemplate} from './utils';
 export class CompilerFactory {
   private readonly incrementalStrategy = new TrackedIncrementalBuildStrategy();
   private compiler: NgCompiler|null = null;
-  private lastKnownProgram: ts.Program|null = null;
 
   constructor(
       private readonly adapter: LanguageServiceAdapter,
@@ -39,7 +36,7 @@ export class CompilerFactory {
     const program = this.programStrategy.getProgram();
     const modifiedResourceFiles = this.adapter.getModifiedResourceFiles() ?? new Set();
 
-    if (this.compiler !== null && program === this.lastKnownProgram) {
+    if (this.compiler !== null && program === this.compiler.getCurrentProgram()) {
       if (modifiedResourceFiles.size > 0) {
         // Only resource files have changed since the last NgCompiler was created.
         const ticket = resourceChangeTicket(this.compiler, modifiedResourceFiles);
@@ -54,7 +51,7 @@ export class CompilerFactory {
     }
 
     let ticket: CompilationTicket;
-    if (this.compiler === null || this.lastKnownProgram === null) {
+    if (this.compiler === null) {
       ticket = freshCompilationTicket(
           program, this.options, this.incrementalStrategy, this.programStrategy,
           /* perfRecorder */ null, true, true);
@@ -64,11 +61,6 @@ export class CompilerFactory {
           modifiedResourceFiles, /* perfRecorder */ null);
     }
     this.compiler = NgCompiler.fromTicket(ticket, this.adapter);
-    this.lastKnownProgram = program;
     return this.compiler;
   }
-
-  registerLastKnownProgram() {
-    this.lastKnownProgram = this.programStrategy.getProgram();
-  }
 }

packages/language-service/ivy/language_service.ts

@@ -266,7 +266,6 @@ export class LanguageService {
         return undefined;
       }
       const result = builder.getCompletionEntrySymbol(entryName);
-      this.compilerFactory.registerLastKnownProgram();
       return result;
     });
   }
@@ -360,8 +359,6 @@ export class LanguageService {
   private withCompilerAndPerfTracing<T>(phase: PerfPhase, p: (compiler: NgCompiler) => T): T {
     const compiler = this.compilerFactory.getOrCreate();
     const result = compiler.perfRecorder.inPhase(phase, () => p(compiler));
-    this.compilerFactory.registerLastKnownProgram();
-
     const logger = this.project.projectService.logger;
     if (logger.hasLevel(ts.server.LogLevel.verbose)) {
       logger.perftrc(`LanguageService#${PerfPhase[phase]}: ${

packages/language-service/ivy/test/legacy/language_service_spec.ts

@@ -207,7 +207,7 @@ describe('language service adapter', () => {
 });
 
 function getLastKnownProgram(ngLS: LanguageService): ts.Program {
-  const program = ngLS['compilerFactory']['lastKnownProgram'];
+  const program = ngLS['compilerFactory']['compiler']?.getCurrentProgram();
   expect(program).toBeDefined();
   return program!;
 }

packages/language-service/ivy/testing/src/project.ts

@@ -158,8 +158,6 @@ export class Project {
       const ngDiagnostics = ngCompiler.getDiagnosticsForFile(sf, OptimizeFor.WholeProgram);
       expect(ngDiagnostics.map(diag => diag.messageText)).toEqual([]);
     }
-
-    this.ngLS.compilerFactory.registerLastKnownProgram();
   }
 
   expectNoTemplateDiagnostics(projectFileName: string, className: string): void {
@@ -172,7 +170,6 @@ export class Project {
     const component = getClassOrError(sf, className);
 
     const diags = this.getTemplateTypeChecker().getDiagnosticsForComponent(component);
-    this.ngLS.compilerFactory.registerLastKnownProgram();
     expect(diags.map(diag => diag.messageText)).toEqual([]);
   }