Port of #51626 and #51689 to release-4.9 (#51627)

* When fsEvent for change is repeated

* When trying to check if program is uptodate, read the files from disk to determine the version instead of delaying so that new program is not created if file contents have not changed

* Test for empty string change

* Fix empty string for file versioning

Author: sheetalkamat

src/compiler/tsbuildPublic.ts

@@ -292,7 +292,7 @@ namespace ts {
         // State of the solution
         const baseCompilerOptions = getCompilerOptionsOfBuildOptions(options);
         const compilerHost = createCompilerHostFromProgramHost(host, () => state.projectCompilerOptions) as CompilerHost & ReadBuildProgramHost;
-        setGetSourceFileAsHashVersioned(compilerHost, host);
+        setGetSourceFileAsHashVersioned(compilerHost);
         compilerHost.getParsedCommandLine = fileName => parseConfigFile(state, fileName as ResolvedConfigFileName, toResolvedConfigFilePath(state, fileName as ResolvedConfigFileName));
         compilerHost.resolveModuleNames = maybeBind(host, host.resolveModuleNames);
         compilerHost.resolveTypeReferenceDirectives = maybeBind(host, host.resolveTypeReferenceDirectives);
@@ -1655,7 +1655,7 @@ namespace ts {
                     if (!buildInfoVersionMap) buildInfoVersionMap = getBuildInfoFileVersionMap(buildInfoProgram, buildInfoPath!, host);
                     version = buildInfoVersionMap.get(toPath(state, inputFile));
                     const text = version ? state.readFileWithCache(inputFile) : undefined;
-                    currentVersion = text && (host.createHash || generateDjb2Hash)(text);
+                    currentVersion = text !== undefined ? (host.createHash || generateDjb2Hash)(text) : undefined;
                     if (version && version === currentVersion) pseudoInputUpToDate = true;
                 }
 

src/compiler/watch.ts

@@ -595,12 +595,13 @@ namespace ts {
     export function createCompilerHostFromProgramHost(host: ProgramHost<any>, getCompilerOptions: () => CompilerOptions, directoryStructureHost: DirectoryStructureHost = host): CompilerHost {
         const useCaseSensitiveFileNames = host.useCaseSensitiveFileNames();
         const hostGetNewLine = memoize(() => host.getNewLine());
-        return {
+        const compilerHost: CompilerHost = {
             getSourceFile: (fileName, languageVersionOrOptions, onError) => {
                 let text: string | undefined;
                 try {
                     performance.mark("beforeIORead");
-                    text = host.readFile(fileName, getCompilerOptions().charset);
+                    const encoding = getCompilerOptions().charset;
+                    text = !encoding ? compilerHost.readFile(fileName) : host.readFile(fileName, encoding);
                     performance.mark("afterIORead");
                     performance.measure("I/O Read", "beforeIORead", "afterIORead");
                 }
@@ -632,6 +633,7 @@ namespace ts {
             disableUseFileVersionAsSignature: host.disableUseFileVersionAsSignature,
             storeFilesChangingSignatureDuringEmit: host.storeFilesChangingSignatureDuringEmit,
         };
+        return compilerHost;
 
         function writeFile(fileName: string, text: string, writeByteOrderMark: boolean, onError: (message: string) => void) {
             try {
@@ -659,9 +661,9 @@ namespace ts {
         }
     }
 
-    export function setGetSourceFileAsHashVersioned(compilerHost: CompilerHost, host: { createHash?(data: string): string; }) {
+    export function setGetSourceFileAsHashVersioned(compilerHost: CompilerHost) {
         const originalGetSourceFile = compilerHost.getSourceFile;
-        const computeHash = maybeBind(host, host.createHash) || generateDjb2Hash;
+        const computeHash = maybeBind(compilerHost, compilerHost.createHash) || generateDjb2Hash;
         compilerHost.getSourceFile = (...args) => {
             const result = originalGetSourceFile.call(compilerHost, ...args);
             if (result) {

src/compiler/watchPublic.ts

@@ -28,7 +28,7 @@ namespace ts {
         host.createHash = maybeBind(system, system.createHash);
         host.disableUseFileVersionAsSignature = system.disableUseFileVersionAsSignature;
         host.storeFilesChangingSignatureDuringEmit = system.storeFilesChangingSignatureDuringEmit;
-        setGetSourceFileAsHashVersioned(host, system);
+        setGetSourceFileAsHashVersioned(host);
         changeCompilerHostLikeToUseCache(host, fileName => toPath(fileName, host.getCurrentDirectory(), host.getCanonicalFileName));
         return host;
     }
@@ -330,7 +330,7 @@ namespace ts {
         }
 
         const compilerHost = createCompilerHostFromProgramHost(host, () => compilerOptions, directoryStructureHost) as CompilerHost & ResolutionCacheHost;
-        setGetSourceFileAsHashVersioned(compilerHost, host);
+        setGetSourceFileAsHashVersioned(compilerHost);
         // Members for CompilerHost
         const getNewSourceFile = compilerHost.getSourceFile;
         compilerHost.getSourceFile = (fileName, ...args) => getVersionedSourceFileByPath(fileName, toPath(fileName), ...args);
@@ -452,9 +452,9 @@ namespace ts {
             const hasInvalidatedResolutions = resolutionCache.createHasInvalidatedResolutions(customHasInvalidatedResolutions);
             const {
                 originalReadFile, originalFileExists, originalDirectoryExists,
-                originalCreateDirectory, originalWriteFile,
+                originalCreateDirectory, originalWriteFile, readFileWithCache,
             } = changeCompilerHostLikeToUseCache(compilerHost, toPath);
-            if (isProgramUptoDate(getCurrentProgram(), rootFileNames, compilerOptions, getSourceVersion, fileName => compilerHost.fileExists(fileName), hasInvalidatedResolutions, hasChangedAutomaticTypeDirectiveNames, getParsedCommandLine, projectReferences)) {
+            if (isProgramUptoDate(getCurrentProgram(), rootFileNames, compilerOptions, path => getSourceVersion(path, readFileWithCache), fileName => compilerHost.fileExists(fileName), hasInvalidatedResolutions, hasChangedAutomaticTypeDirectiveNames, getParsedCommandLine, projectReferences)) {
                 if (hasChangedConfigFileParsingErrors) {
                     if (reportFileChangeDetectedOnCreateProgram) {
                         reportWatchDiagnostic(Diagnostics.File_change_detected_Starting_incremental_compilation);
@@ -609,9 +609,13 @@ namespace ts {
             }
         }
 
-        function getSourceVersion(path: Path): string | undefined {
+        function getSourceVersion(path: Path, readFileWithCache: (fileName: string) => string | undefined): string | undefined {
             const hostSourceFile = sourceFilesCache.get(path);
-            return !hostSourceFile || !hostSourceFile.version ? undefined : hostSourceFile.version;
+            if (!hostSourceFile) return undefined;
+            if (hostSourceFile.version) return hostSourceFile.version;
+            // Read file and get new version
+            const text = readFileWithCache(path);
+            return text !== undefined ? (compilerHost.createHash || generateDjb2Hash)(text) : undefined;
         }
 
         function onReleaseOldSourceFile(oldSourceFile: SourceFile, _oldOptions: CompilerOptions, hasSourceFileByPath: boolean) {

src/harness/virtualFileSystemWithWatch.ts

@@ -730,7 +730,7 @@ interface Array<T> { length: number; [n: number]: T; }`
             }
         }
 
-        private invokeFsWatches(fullPath: string, eventName: "rename" | "change", modifiedTime: Date | undefined, useTildeSuffix: boolean | undefined) {
+        invokeFsWatches(fullPath: string, eventName: "rename" | "change", modifiedTime: Date | undefined, useTildeSuffix: boolean | undefined) {
             this.invokeFsWatchesCallbacks(fullPath, eventName, modifiedTime, fullPath, useTildeSuffix);
             this.invokeFsWatchesCallbacks(getDirectoryPath(fullPath), eventName, modifiedTime, fullPath, useTildeSuffix);
             this.invokeRecursiveFsWatches(fullPath, eventName, modifiedTime, /*entryFullPath*/ undefined, useTildeSuffix);

src/testRunner/unittests/tscWatch/watchEnvironment.ts

@@ -687,5 +687,37 @@ namespace ts.tscWatch {
                 ]
             });
         });
+
+        verifyTscWatch({
+            scenario,
+            subScenario: "fsEvent for change is repeated",
+            commandLineArgs: ["-w", "main.ts", "--extendedDiagnostics"],
+            sys: () => createWatchedSystem({
+                "/user/username/projects/project/main.ts": `let a: string = "Hello"`,
+                [libFile.path]: libFile.content,
+            }, { currentDirectory: "/user/username/projects/project" }),
+            changes: [
+                {
+                    caption: "change main.ts",
+                    change: sys => replaceFileText(sys, "/user/username/projects/project/main.ts", "Hello", "Hello World"),
+                    timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+                },
+                {
+                    caption: "receive another change event without modifying the file",
+                    change: sys => sys.invokeFsWatches("/user/username/projects/project/main.ts", "change", /*modifiedTime*/ undefined, /*useTildeSuffix*/ undefined),
+                    timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+                },
+                {
+                    caption: "change main.ts to empty text",
+                    change: sys => sys.writeFile("/user/username/projects/project/main.ts", ""),
+                    timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+                },
+                {
+                    caption: "receive another change event without modifying the file",
+                    change: sys => sys.invokeFsWatches("/user/username/projects/project/main.ts", "change", /*modifiedTime*/ undefined, /*useTildeSuffix*/ undefined),
+                    timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+                }
+            ]
+        });
     });
 }

tests/baselines/reference/tsbuildWatch/noEmit/does-not-go-in-loop-when-watching-when-no-files-are-emitted-with-incremental.js

@@ -132,25 +132,11 @@ Output::
 >> Screen clear
 [12:00:36 AM] File change detected. Starting incremental compilation...
 
-[[90m12:00:37 AM[0m] Project 'tsconfig.json' is out of date because output 'tsconfig.tsbuildinfo' is older than input 'a.js'
+[[90m12:00:37 AM[0m] Project 'tsconfig.json' is up to date but needs to update timestamps of output files that are older than input files
 
-[[90m12:00:38 AM[0m] Building project '/user/username/projects/myproject/tsconfig.json'...
+[[90m12:00:38 AM[0m] Found 0 errors. Watching for file changes.
 
-[12:00:39 AM] Found 0 errors. Watching for file changes.
-
-
-
-Program root files: ["/user/username/projects/myproject/a.js","/user/username/projects/myproject/b.ts"]
-Program options: {"allowJs":true,"noEmit":true,"watch":true,"incremental":true,"configFilePath":"/user/username/projects/myproject/tsconfig.json"}
-Program structureReused: Not
-Program files::
-/a/lib/lib.d.ts
-/user/username/projects/myproject/a.js
-/user/username/projects/myproject/b.ts
-
-Semantic diagnostics in builder refreshed for::
 
-No shapes updated in the builder::
 
 PolledWatches::
 
@@ -178,13 +164,13 @@ const x = 10;
 
 Output::
 >> Screen clear
-[[90m12:00:43 AM[0m] File change detected. Starting incremental compilation...
+[[90m12:00:42 AM[0m] File change detected. Starting incremental compilation...
 
-[[90m12:00:44 AM[0m] Project 'tsconfig.json' is out of date because output 'tsconfig.tsbuildinfo' is older than input 'a.js'
+[[90m12:00:43 AM[0m] Project 'tsconfig.json' is out of date because output 'tsconfig.tsbuildinfo' is older than input 'a.js'
 
-[[90m12:00:45 AM[0m] Building project '/user/username/projects/myproject/tsconfig.json'...
+[[90m12:00:44 AM[0m] Building project '/user/username/projects/myproject/tsconfig.json'...
 
-[[90m12:00:53 AM[0m] Found 0 errors. Watching for file changes.
+[[90m12:00:52 AM[0m] Found 0 errors. Watching for file changes.
 
 
 

tests/baselines/reference/tscWatch/emitAndErrorUpdates/assumeChangesOnlyAffectDirectDependencies/with-noEmitOnError-with-incremental.js

@@ -179,30 +179,6 @@ Input::
 //// [/user/username/projects/noEmitOnError/src/main.ts] file written with same contents
 
 Output::
->> Screen clear
-[12:00:43 AM] File change detected. Starting incremental compilation...
-
-src/main.ts:4:1 - error TS1005: ',' expected.
-
-4 ;
-  ~
-
-[12:00:44 AM] Found 1 error. Watching for file changes.
-
-
-
-Program root files: ["/user/username/projects/noEmitOnError/shared/types/db.ts","/user/username/projects/noEmitOnError/src/main.ts","/user/username/projects/noEmitOnError/src/other.ts"]
-Program options: {"outDir":"/user/username/projects/noEmitOnError/dev-build","noEmitOnError":true,"watch":true,"assumeChangesOnlyAffectDirectDependencies":true,"incremental":true,"configFilePath":"/user/username/projects/noEmitOnError/tsconfig.json"}
-Program structureReused: Completely
-Program files::
-/a/lib/lib.d.ts
-/user/username/projects/noEmitOnError/shared/types/db.ts
-/user/username/projects/noEmitOnError/src/main.ts
-/user/username/projects/noEmitOnError/src/other.ts
-
-Semantic diagnostics in builder refreshed for::
-
-No shapes updated in the builder::
 
 PolledWatches::
 /user/username/projects/noemitonerror/node_modules/@types:
@@ -239,9 +215,9 @@ const a = {
 
 Output::
 >> Screen clear
-[[90m12:00:48 AM[0m] File change detected. Starting incremental compilation...
+[[90m12:00:46 AM[0m] File change detected. Starting incremental compilation...
 
-[[90m12:01:06 AM[0m] Found 0 errors. Watching for file changes.
+[[90m12:01:04 AM[0m] Found 0 errors. Watching for file changes.
 
 
 
@@ -370,14 +346,14 @@ const a: string = 10;
 
 Output::
 >> Screen clear
-[[90m12:01:13 AM[0m] File change detected. Starting incremental compilation...
+[[90m12:01:11 AM[0m] File change detected. Starting incremental compilation...
 
 src/main.ts:2:7 - error TS2322: Type 'number' is not assignable to type 'string'.
 
 2 const a: string = 10;
         ~
 
-[[90m12:01:17 AM[0m] Found 1 error. Watching for file changes.
+[[90m12:01:15 AM[0m] Found 1 error. Watching for file changes.
 
 
 
@@ -501,30 +477,6 @@ Input::
 //// [/user/username/projects/noEmitOnError/src/main.ts] file written with same contents
 
 Output::
->> Screen clear
-[12:01:25 AM] File change detected. Starting incremental compilation...
-
-src/main.ts:2:7 - error TS2322: Type 'number' is not assignable to type 'string'.
-
-2 const a: string = 10;
-        ~
-
-[12:01:26 AM] Found 1 error. Watching for file changes.
-
-
-
-Program root files: ["/user/username/projects/noEmitOnError/shared/types/db.ts","/user/username/projects/noEmitOnError/src/main.ts","/user/username/projects/noEmitOnError/src/other.ts"]
-Program options: {"outDir":"/user/username/projects/noEmitOnError/dev-build","noEmitOnError":true,"watch":true,"assumeChangesOnlyAffectDirectDependencies":true,"incremental":true,"configFilePath":"/user/username/projects/noEmitOnError/tsconfig.json"}
-Program structureReused: Completely
-Program files::
-/a/lib/lib.d.ts
-/user/username/projects/noEmitOnError/shared/types/db.ts
-/user/username/projects/noEmitOnError/src/main.ts
-/user/username/projects/noEmitOnError/src/other.ts
-
-Semantic diagnostics in builder refreshed for::
-
-No shapes updated in the builder::
 
 PolledWatches::
 /user/username/projects/noemitonerror/node_modules/@types:
@@ -559,9 +511,9 @@ const a: string = "hello";
 
 Output::
 >> Screen clear
-[[90m12:01:30 AM[0m] File change detected. Starting incremental compilation...
+[[90m12:01:26 AM[0m] File change detected. Starting incremental compilation...
 
-[[90m12:01:37 AM[0m] Found 0 errors. Watching for file changes.
+[[90m12:01:33 AM[0m] Found 0 errors. Watching for file changes.
 
 
 
@@ -673,25 +625,6 @@ Input::
 //// [/user/username/projects/noEmitOnError/src/main.ts] file written with same contents
 
 Output::
->> Screen clear
-[12:01:44 AM] File change detected. Starting incremental compilation...
-
-[12:01:45 AM] Found 0 errors. Watching for file changes.
-
-
-
-Program root files: ["/user/username/projects/noEmitOnError/shared/types/db.ts","/user/username/projects/noEmitOnError/src/main.ts","/user/username/projects/noEmitOnError/src/other.ts"]
-Program options: {"outDir":"/user/username/projects/noEmitOnError/dev-build","noEmitOnError":true,"watch":true,"assumeChangesOnlyAffectDirectDependencies":true,"incremental":true,"configFilePath":"/user/username/projects/noEmitOnError/tsconfig.json"}
-Program structureReused: Completely
-Program files::
-/a/lib/lib.d.ts
-/user/username/projects/noEmitOnError/shared/types/db.ts
-/user/username/projects/noEmitOnError/src/main.ts
-/user/username/projects/noEmitOnError/src/other.ts
-
-Semantic diagnostics in builder refreshed for::
-
-No shapes updated in the builder::
 
 PolledWatches::
 /user/username/projects/noemitonerror/node_modules/@types: