Populate if emit was skipped correctly as part of emit result

src/compiler/declarationEmitter.ts

@@ -1608,12 +1608,14 @@ namespace ts {
     /* @internal */
     export function writeDeclarationFile(declarationFilePath: string, sourceFile: SourceFile, host: EmitHost, resolver: EmitResolver, diagnostics: Diagnostic[]) {
         let emitDeclarationResult = emitDeclarations(host, resolver, diagnostics, declarationFilePath, sourceFile);
-        if (!emitDeclarationResult.reportedDeclarationError && !host.isDeclarationEmitBlocked(declarationFilePath, sourceFile)) {
+        let emitSkipped = emitDeclarationResult.reportedDeclarationError || host.isDeclarationEmitBlocked(declarationFilePath, sourceFile);
+        if (!emitSkipped) {
             let declarationOutput = emitDeclarationResult.referencePathsOutput
                 + getDeclarationOutput(emitDeclarationResult.synchronousDeclarationOutput, emitDeclarationResult.moduleElementDeclarationEmitInfo);
             let compilerOptions = host.getCompilerOptions();
             writeFile(host, diagnostics, declarationFilePath, declarationOutput, compilerOptions.emitBOM);
         }
+        return emitSkipped;
 
         function getDeclarationOutput(synchronousDeclarationOutput: string, moduleElementDeclarationEmitInfo: ModuleElementDeclarationEmitInfo[]) {
             let appliedSyncOutputPos = 0;

src/compiler/emitter.ts

@@ -323,27 +323,28 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
         let modulekind = compilerOptions.module ? compilerOptions.module : languageVersion === ScriptTarget.ES6 ? ModuleKind.ES6 : ModuleKind.None;
         let sourceMapDataList: SourceMapData[] = compilerOptions.sourceMap || compilerOptions.inlineSourceMap ? [] : undefined;
         let diagnostics: Diagnostic[] = [];
+        let emitSkipped = false;
         let newLine = host.getNewLine();
 
         if (targetSourceFile === undefined) {
             forEach(host.getSourceFiles(), sourceFile => {
                 if (shouldEmitToOwnFile(sourceFile, compilerOptions)) {
-                    emitFile(getEmitFileNames(sourceFile, host), sourceFile);
+                    emitSkipped = emitFile(getEmitFileNames(sourceFile, host), sourceFile) || emitSkipped;
                 }
             });
 
             if (compilerOptions.outFile || compilerOptions.out) {
-                emitFile(getBundledEmitFileNames(compilerOptions));
+                emitSkipped = emitFile(getBundledEmitFileNames(compilerOptions)) || emitSkipped;
             }
         }
         else {
             // targetSourceFile is specified (e.g calling emitter from language service or calling getSemanticDiagnostic from language service)
             if (shouldEmitToOwnFile(targetSourceFile, compilerOptions)) {
-                emitFile(getEmitFileNames(targetSourceFile, host), targetSourceFile);
+                emitSkipped = emitFile(getEmitFileNames(targetSourceFile, host), targetSourceFile) || emitSkipped;
             }
             else if (!isDeclarationFile(targetSourceFile) &&
                 (compilerOptions.outFile || compilerOptions.out)) {
-                emitFile(getBundledEmitFileNames(compilerOptions));
+                emitSkipped = emitFile(getBundledEmitFileNames(compilerOptions)) || emitSkipped;
             }
         }
 
@@ -351,7 +352,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
         diagnostics = sortAndDeduplicateDiagnostics(diagnostics);
 
         return {
-            emitSkipped: false,
+            emitSkipped,
             diagnostics,
             sourceMaps: sourceMapDataList
         };
@@ -7597,13 +7598,16 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
 
         function emitFile({ jsFilePath, sourceMapFilePath, declarationFilePath}: { jsFilePath: string, sourceMapFilePath: string, declarationFilePath: string }, sourceFile?: SourceFile) {
             // Make sure not to write js File and source map file if any of them cannot be written
-            if (!host.isEmitBlocked(jsFilePath) && (!sourceMapFilePath || !host.isEmitBlocked(sourceMapFilePath))) {
+            let emitSkipped = host.isEmitBlocked(jsFilePath) || (sourceMapFilePath && host.isEmitBlocked(sourceMapFilePath));
+            if (!emitSkipped) {
                 emitJavaScript(jsFilePath, sourceMapFilePath, sourceFile);
             }
 
             if (compilerOptions.declaration) {
-                writeDeclarationFile(declarationFilePath, sourceFile, host, resolver, diagnostics);
+                emitSkipped = writeDeclarationFile(declarationFilePath, sourceFile, host, resolver, diagnostics) || emitSkipped;
             }
+
+            return emitSkipped;
         }
     }
 }

src/compiler/program.ts

@@ -293,7 +293,7 @@ namespace ts {
                           program.getSemanticDiagnostics(sourceFile, cancellationToken));
 
         if (program.getCompilerOptions().declaration) {
-            diagnostics.concat(program.getDeclarationDiagnostics(sourceFile, cancellationToken));
+            diagnostics = diagnostics.concat(program.getDeclarationDiagnostics(sourceFile, cancellationToken));
         }
 
         return sortAndDeduplicateDiagnostics(diagnostics);

src/harness/harness.ts

@@ -1121,7 +1121,7 @@ namespace Harness {
 
                 let emitResult = program.emit();
 
-                let errors = ts.getPreEmitDiagnostics(program).concat(emitResult.diagnostics);
+                let errors = ts.getPreEmitDiagnostics(program);
                 this.lastErrors = errors;
 
                 let result = new CompilerResult(fileOutputs, errors, program, Harness.IO.getCurrentDirectory(), emitResult.sourceMaps);
@@ -1666,7 +1666,7 @@ namespace Harness {
             let encoded_actual =  Utils.encodeString(actual);
             if (expected != encoded_actual) {
                 // Overwrite & issue error
-                let errMsg = "The baseline file " + relativeFileName + " has changed.\nExpected:\n" + expected + "\nActual:\n" + encoded_actual;
+                let errMsg = "The baseline file " + relativeFileName + " has changed.";
                 throw new Error(errMsg);
             }
         }

tests/baselines/reference/compileOnSaveWorksWhenEmitBlockingErrorOnOtherFile.baseline

@@ -0,0 +1,8 @@
+EmitSkipped: true
+Diagnostics:
+  Cannot write file 'tests/cases/fourslash/b.js' which is one of the input files.
+
+EmitSkipped: false
+FileName : tests/cases/fourslash/a.js
+function foo2() { return 30; } // no error - should emit a.js
+

tests/baselines/reference/getEmitOutputWithEmitterErrors.baseline

@@ -1,4 +1,6 @@
-EmitSkipped: false
+EmitSkipped: true
+Diagnostics:
+  Exported variable 'foo' has or is using private name 'C'.
 FileName : tests/cases/fourslash/inputFile.js
 var M;
 (function (M) {

tests/baselines/reference/getEmitOutputWithEmitterErrors2.baseline

@@ -1,4 +1,6 @@
-EmitSkipped: false
+EmitSkipped: true
+Diagnostics:
+  Exported variable 'foo' has or is using private name 'C'.
 FileName : tests/cases/fourslash/inputFile.js
 define(["require", "exports"], function (require, exports) {
     var C = (function () {

tests/baselines/reference/getEmitOutputWithSemanticErrors2.baseline

@@ -1,4 +1,6 @@
-EmitSkipped: false
+EmitSkipped: true
+Diagnostics:
+  Type 'string' is not assignable to type 'number'.
 FileName : tests/cases/fourslash/inputFile.js
 var x = "hello world";
 

tests/baselines/reference/getEmitOutputWithSemanticErrorsForMultipleFiles2.baseline

@@ -1,4 +1,6 @@
-EmitSkipped: false
+EmitSkipped: true
+Diagnostics:
+  Type 'string' is not assignable to type 'boolean'.
 FileName : out.js
 // File to emit, does not contain semantic errors, but --out is passed
 // expected to not generate declarations because of the semantic errors in the other file

tests/cases/fourslash/compileOnSaveWorksWhenEmitBlockingErrorOnOtherFile.ts

@@ -0,0 +1,13 @@
+/// <reference path="fourslash.ts" />
+
+// @BaselineFile: compileOnSaveWorksWhenEmitBlockingErrorOnOtherFile.baseline
+// @jsExtensions: js
+// @Filename: b.js
+// @emitThisFile: true
+////function foo() { } // This has error because js file cannot be overwritten - emitSkipped should be true
+
+// @Filename: a.ts
+// @emitThisFile: true
+////function foo2() { return 30; } // no error - should emit a.js
+
+verify.baselineGetEmitOutput();