Correctly use ownMap from module resolution cache (#43986)

* Test showing the moduleResolutionCache reset issue with tsc --b --w

* Fix incorrect usage of ownMap by making it function returning ownMap instead of constant value

Author: sheetalkamat

src/compiler/moduleNameResolver.ts

@@ -504,7 +504,7 @@ namespace ts {
 
     /*@internal*/
     export interface CacheWithRedirects<T> {
-        ownMap: ESMap<string, T>;
+        getOwnMap: () => ESMap<string, T>;
         redirectsMap: ESMap<Path, ESMap<string, T>>;
         getOrCreateMapOfCacheRedirects(redirectedReference: ResolvedProjectReference | undefined): ESMap<string, T>;
         clear(): void;
@@ -517,14 +517,18 @@ namespace ts {
         let ownMap: ESMap<string, T> = new Map();
         const redirectsMap = new Map<Path, ESMap<string, T>>();
         return {
-            ownMap,
+            getOwnMap,
             redirectsMap,
             getOrCreateMapOfCacheRedirects,
             clear,
             setOwnOptions,
             setOwnMap
         };
 
+        function getOwnMap() {
+            return ownMap;
+        }
+
         function setOwnOptions(newOptions: CompilerOptions) {
             options = newOptions;
         }
@@ -586,10 +590,10 @@ namespace ts {
         if (directoryToModuleNameMap.redirectsMap.size === 0) {
             // The own map will be for projectCompilerOptions
             Debug.assert(!moduleNameToDirectoryMap || moduleNameToDirectoryMap.redirectsMap.size === 0);
-            Debug.assert(directoryToModuleNameMap.ownMap.size === 0);
-            Debug.assert(!moduleNameToDirectoryMap || moduleNameToDirectoryMap.ownMap.size === 0);
-            directoryToModuleNameMap.redirectsMap.set(options.configFile.path, directoryToModuleNameMap.ownMap);
-            moduleNameToDirectoryMap?.redirectsMap.set(options.configFile.path, moduleNameToDirectoryMap.ownMap);
+            Debug.assert(directoryToModuleNameMap.getOwnMap().size === 0);
+            Debug.assert(!moduleNameToDirectoryMap || moduleNameToDirectoryMap.getOwnMap().size === 0);
+            directoryToModuleNameMap.redirectsMap.set(options.configFile.path, directoryToModuleNameMap.getOwnMap());
+            moduleNameToDirectoryMap?.redirectsMap.set(options.configFile.path, moduleNameToDirectoryMap.getOwnMap());
         }
         else {
             // Set correct own map

src/testRunner/unittests/tsbuild/watchMode.ts

@@ -1020,4 +1020,59 @@ const a: string = "hello";`),
             ]
         });
     });
+
+    describe("unittests:: tsbuild:: watchMode:: module resolution different in referenced project", () => {
+        verifyTscWatch({
+            scenario: "moduleResolutionCache",
+            subScenario: "handles the cache correctly when two projects use different module resolution settings",
+            sys: () => createWatchedSystem(
+                [
+                    { path: `${projectRoot}/project1/index.ts`, content: `import { foo } from "file";` },
+                    { path: `${projectRoot}/project1/node_modules/file/index.d.ts`, content: "export const foo = 10;" },
+                    {
+                        path: `${projectRoot}/project1/tsconfig.json`,
+                        content: JSON.stringify({
+                            compilerOptions: { composite: true, types: ["foo", "bar"] },
+                            files: ["index.ts"]
+                        })
+                    },
+                    { path: `${projectRoot}/project2/index.ts`, content: `import { foo } from "file";` },
+                    { path: `${projectRoot}/project2/file.d.ts`, content: "export const foo = 10;" },
+                    {
+                        path: `${projectRoot}/project2/tsconfig.json`,
+                        content: JSON.stringify({
+                            compilerOptions: { composite: true, types: ["foo"], moduleResolution: "classic" },
+                            files: ["index.ts"]
+                        })
+                    },
+                    { path: `${projectRoot}/node_modules/@types/foo/index.d.ts`, content: "export const foo = 10;" },
+                    { path: `${projectRoot}/node_modules/@types/bar/index.d.ts`, content: "export const bar = 10;" },
+                    {
+                        path: `${projectRoot}/tsconfig.json`,
+                        content: JSON.stringify({
+                            files: [],
+                            references: [
+                                { path: "./project1" },
+                                { path: "./project2" }
+                            ]
+                        })
+                    },
+                    libFile
+                ],
+                { currentDirectory: projectRoot }
+            ),
+            commandLineArgs: ["--b", "-w", "-v"],
+            changes: [
+                {
+                    caption: "Append text",
+                    change: sys => sys.appendFile(`${projectRoot}/project1/index.ts`, "const bar = 10;"),
+                    timeouts: sys => {
+                        sys.checkTimeoutQueueLengthAndRun(1); // build project1
+                        sys.checkTimeoutQueueLengthAndRun(1); // Solution
+                        sys.checkTimeoutQueueLength(0);
+                    }
+                },
+            ]
+        });
+    });
 }