fix(compiler): make sure language service use updated compiler options

src/compiler/ts-compiler.spec.ts

@@ -329,6 +329,14 @@ describe('TsCompiler', () => {
     beforeEach(() => {
       // @ts-expect-error testing purpose
       compiler._projectVersion = 1
+      /**
+       * This is to ensure that `compilerOptions` value and `_parsedTsConfig.fileNames` are always like
+       * when compiler instance is created since here we only create compiler instance once for all the tests below.
+       */
+      // @ts-expect-error testing purpose.
+      compiler._compilerOptions = { ...compiler._initialCompilerOptions }
+      // @ts-expect-error testing purpose.
+      compiler._parsedTsConfig.fileNames = []
       fileContentCache.clear()
       fileVersionCache.clear()
     })
@@ -360,6 +368,29 @@ describe('TsCompiler', () => {
       expect(compiler._projectVersion).toEqual(2)
     })
 
+    test('should increase project version if processing file is in compiler file list', () => {
+      // @ts-expect-error testing purpose
+      compiler._parsedTsConfig.fileNames.push(fileName)
+      fileContentCache.set(fileName, fileContent)
+      fileVersionCache.set(fileName, 1)
+      // @ts-expect-error testing purpose
+      compiler._fileContentCache = fileContentCache
+      // @ts-expect-error testing purpose
+      compiler._fileVersionCache = fileVersionCache
+      // @ts-expect-error testing purpose
+      compiler._compilerOptions = {
+        // @ts-expect-error testing purpose
+        ...compiler._compilerOptions,
+        module: ModuleKind.AMD,
+      }
+
+      // @ts-expect-error testing purpose
+      compiler._updateMemoryCache(fileContent, fileName)
+
+      // @ts-expect-error testing purpose
+      expect(compiler._projectVersion).toEqual(2)
+    })
+
     test('should increase project version if processing file version is 0', () => {
       fileContentCache.set(fileName, fileContent)
       fileVersionCache.set(fileName, 0)

src/compiler/ts-compiler.ts

@@ -32,6 +32,7 @@ import type {
   TsJestCompileOptions,
   TTypeScript,
 } from '../types'
+import { stringify } from '../utils/json'
 import { rootLogger } from '../utils/logger'
 import { Errors, interpolate } from '../utils/messages'
 
@@ -405,6 +406,9 @@ export class TsCompiler implements TsCompilerInstance {
         shouldIncrementProjectVersion = true
       }
     }
+    if (stringify(this._compilerOptions) !== stringify(this._initialCompilerOptions)) {
+      shouldIncrementProjectVersion = true
+    }
 
     if (shouldIncrementProjectVersion) this._projectVersion++
   }