Merge pull request #31685 from uniqueiniquity/stopInvalidatingOnOpenFileSave

Stop invalidating module resolution cache when saving an open file

src/testRunner/unittests/tsserver/projects.ts

@@ -1341,6 +1341,26 @@ var x = 10;`
             }
         });
 
+        it("no project structure update on directory watch invoke on open file save", () => {
+            const projectRootPath = "/users/username/projects/project";
+            const file1: File = {
+                path: `${projectRootPath}/a.ts`,
+                content: "export const a = 10;"
+            };
+            const config: File = {
+                path: `${projectRootPath}/tsconfig.json`,
+                content: "{}"
+            };
+            const files = [file1, config];
+            const host = createServerHost(files);
+            const service = createProjectService(host);
+            service.openClientFile(file1.path);
+            checkNumberOfProjects(service, { configuredProjects: 1 });
+
+            host.modifyFile(file1.path, file1.content, { invokeFileDeleteCreateAsPartInsteadOfChange: true });
+            host.checkTimeoutQueueLength(0);
+        });
+
         it("handles delayed directory watch invoke on file creation", () => {
             const projectRootPath = "/users/username/projects/project";
             const fileB: File = {

src/testRunner/unittests/tsserver/resolutionCache.ts

@@ -975,5 +975,34 @@ export const x = 10;`
                 host.checkTimeoutQueueLength(0);
             });
         });
+
+        describe("avoid unnecessary invalidation", () => {
+            it("unnecessary lookup invalidation on save", () => {
+                const expectedNonRelativeDirectories = [`${projectLocation}/node_modules`, `${projectLocation}/src`];
+                const module1Name = "module1";
+                const module2Name = "module2";
+                const fileContent = `import { module1 } from "${module1Name}";import { module2 } from "${module2Name}";`;
+                const file1: File = {
+                    path: `${projectLocation}/src/file1.ts`,
+                    content: fileContent
+                };
+                const { module1, module2 } = getModules(`${projectLocation}/src/node_modules/module1/index.ts`, `${projectLocation}/node_modules/module2/index.ts`);
+                const files = [module1, module2, file1, configFile, libFile];
+                const host = createServerHost(files);
+                const resolutionTrace = createHostModuleResolutionTrace(host);
+                const service = createProjectService(host);
+                service.openClientFile(file1.path);
+                const project = service.configuredProjects.get(configFile.path)!;
+                (project as ResolutionCacheHost).maxNumberOfFilesToIterateForInvalidation = 1;
+                const expectedTrace = getExpectedNonRelativeModuleResolutionTrace(host, file1, module1, module1Name);
+                getExpectedNonRelativeModuleResolutionTrace(host, file1, module2, module2Name, expectedTrace);
+                verifyTrace(resolutionTrace, expectedTrace);
+                verifyWatchesWithConfigFile(host, files, file1, expectedNonRelativeDirectories);
+
+                // invoke callback to simulate saving
+                host.modifyFile(file1.path, file1.content, { invokeFileDeleteCreateAsPartInsteadOfChange: true });
+                host.checkTimeoutQueueLengthAndRun(0);
+            });
+        });
     });
 }

src/testRunner/unittests/tsserver/syntaxOperations.ts

@@ -60,13 +60,14 @@ describe("Test Suite 1", () => {
 
             const navBarResultUnitTest1 = navBarFull(session, unitTest1);
             host.deleteFile(unitTest1.path);
-            host.checkTimeoutQueueLengthAndRun(2);
-            checkProjectActualFiles(project, expectedFilesWithoutUnitTest1);
+            host.checkTimeoutQueueLengthAndRun(0);
+            checkProjectActualFiles(project, expectedFilesWithUnitTest1);
 
             session.executeCommandSeq<protocol.CloseRequest>({
                 command: protocol.CommandTypes.Close,
                 arguments: { file: unitTest1.path }
             });
+            host.checkTimeoutQueueLengthAndRun(2);
             checkProjectActualFiles(project, expectedFilesWithoutUnitTest1);
 
             const unitTest1WithChangedContent: File = {