Preserve checking globals before declaration signature generation

tsc/internal/compiler/program.go

@@ -826,10 +826,16 @@ func (p *Program) GetSemanticDiagnostics(ctx context.Context, sourceFile *ast.So
 // GetSemanticDiagnosticsForIncremental includes newly discovered globals in each
 // file's cached diagnostics and leaves noEmit filtering to the builder.
 func (p *Program) GetSemanticDiagnosticsForIncremental(ctx context.Context, sourceFiles []*ast.SourceFile) map[*ast.SourceFile][]*ast.Diagnostic {
-	allDiags := p.collectCheckerDiagnosticsFromFiles(ctx, sourceFiles, func(ctx context.Context, c *checker.Checker, file *ast.SourceFile) []*ast.Diagnostic {
+	collect := func(ctx context.Context, c *checker.Checker, file *ast.SourceFile) []*ast.Diagnostic {
 		return p.getBindAndCheckDiagnosticsWithChecker(ctx, c, file, true /*includeDeferredGlobals*/)
-	})
+	}
 	result := make(map[*ast.SourceFile][]*ast.Diagnostic, len(sourceFiles))
+	if len(sourceFiles) == 1 {
+		file := sourceFiles[0]
+		result[file] = p.collectCheckerDiagnostics(ctx, file, collect)
+		return result
+	}
+	allDiags := p.collectCheckerDiagnosticsFromFiles(ctx, sourceFiles, collect)
 	for i, diags := range allDiags {
 		result[sourceFiles[i]] = filterAndSortDiagnostics(diags)
 	}

tsc/internal/execute/incremental/affectedfileshandler.go

@@ -22,14 +22,16 @@ func (c dtsMayChange) addFileToAffectedFilesPendingEmit(filePath tspath.PathKey,
 }
 
 type updatedSignature struct {
-	mu        sync.Mutex
-	signature string
-	kind      SignatureUpdateKind
+	mu                  sync.Mutex
+	signature           string
+	kind                SignatureUpdateKind
+	semanticDiagnostics *DiagnosticsOrBuildInfoDiagnosticsWithFileName
 }
 
 type affectedFilesHandler struct {
 	ctx                                    context.Context
 	program                                *Program
+	collectSemanticDiagnostics             bool
 	hasAllFilesExcludingDefaultLibraryFile atomic.Bool
 	updatedSignatures                      collections.SyncMap[tspath.PathKey, *updatedSignature]
 	dtsMayChange                           []dtsMayChange
@@ -101,6 +103,13 @@ func (h *affectedFilesHandler) updateShapeSignature(file *ast.SourceFile, useFil
 	// JSON files have no declaration output from which to compute a shape
 	// signature, so use the file version to conservatively invalidate dependents.
 	if !file.IsDeclarationFile && !ast.IsJsonSourceFile(file) && !useFileVersionAsSignature {
+		if h.collectSemanticDiagnostics && !h.program.snapshot.options.NoCheck.IsTrue() {
+			// Signature generation can discover globals before checking does. Keep the
+			// checking diagnostics first, without retaining incidental emit-only errors.
+			update.semanticDiagnostics = &DiagnosticsOrBuildInfoDiagnosticsWithFileName{
+				diagnostics: h.program.program.GetSemanticDiagnosticsForIncremental(h.ctx, core.SingleElementSlice(file))[file],
+			}
+		}
 		update.signature = h.computeDtsSignature(file)
 	}
 	// Default is to use file version as signature
@@ -347,6 +356,12 @@ func (h *affectedFilesHandler) updateSnapshot() {
 		h.program.snapshot.semanticDiagnosticsPerFile.Delete(file)
 		return true
 	})
+	h.updatedSignatures.Range(func(filePath tspath.PathKey, update *updatedSignature) bool {
+		if update.semanticDiagnostics != nil && h.filesToRemoveDiagnostics.Has(filePath) {
+			h.program.snapshot.semanticDiagnosticsPerFile.Store(filePath, update.semanticDiagnostics)
+		}
+		return true
+	})
 	for _, change := range h.dtsMayChange {
 		for filePath, emitKind := range change {
 			h.program.snapshot.addFileToAffectedFilesPendingEmit(filePath, emitKind)
@@ -356,12 +371,12 @@ func (h *affectedFilesHandler) updateSnapshot() {
 	h.program.snapshot.buildInfoEmitPending.Store(true)
 }
 
-func collectAllAffectedFiles(ctx context.Context, program *Program) {
+func collectAllAffectedFiles(ctx context.Context, program *Program, collectSemanticDiagnostics bool) {
 	if program.snapshot.changedFilesSet.Size() == 0 {
 		return
 	}
 
-	handler := affectedFilesHandler{ctx: ctx, program: program}
+	handler := affectedFilesHandler{ctx: ctx, program: program, collectSemanticDiagnostics: collectSemanticDiagnostics}
 	wg := core.NewWorkGroup(handler.program.program.SingleThreaded())
 	var result collections.SyncSet[*ast.SourceFile]
 	program.snapshot.changedFilesSet.Range(func(file tspath.PathKey) bool {

tsc/internal/execute/incremental/emitfileshandler.go

@@ -116,7 +116,7 @@ func (h *emitFilesHandler) emitBuildInfo(options compiler.EmitOptions, result *c
 
 func (h *emitFilesHandler) emitFilesIncremental(options compiler.EmitOptions) []*compiler.EmitResult {
 	// Get all affected files
-	collectAllAffectedFiles(h.ctx, h.program)
+	collectAllAffectedFiles(h.ctx, h.program, false /*collectSemanticDiagnostics*/)
 	if h.ctx.Err() != nil {
 		return nil
 	}

tsc/internal/execute/incremental/program.go

@@ -275,13 +275,15 @@ func (p *Program) Emit(ctx context.Context, options compiler.EmitOptions) *compi
 func (p *Program) collectSemanticDiagnosticsOfAffectedFiles(ctx context.Context, file *ast.SourceFile) {
 	if p.snapshot.canUseIncrementalState() {
 		// Get all affected files
-		collectAllAffectedFiles(ctx, p)
+		collectAllAffectedFiles(ctx, p, true /*collectSemanticDiagnostics*/)
 		if ctx.Err() != nil {
 			return
 		}
-
 		if p.snapshot.semanticDiagnosticsPerFile.Size() == len(p.program.GetSourceFiles()) {
-			// If we have all the files,
+			if p.snapshot.checkPending && !p.snapshot.options.NoCheck.IsTrue() {
+				p.snapshot.checkPending = false
+				p.snapshot.buildInfoEmitPending.Store(true)
+			}
 			return
 		}
 	}

tsc/internal/execute/tsctests/tsc_test.go

@@ -2326,12 +2326,10 @@ func TestTscIncremental(t *testing.T) {
 					edit: func(sys *TestSys) {
 						sys.appendFile("/home/src/workspaces/project/repro.ts", "\n// comment-only edit\n")
 					},
-					expectedDiff: "Like Strada, signature generation produces the missing-global diagnostic before semantic checking, so it is excluded from the file's semantic diagnostics.",
 				},
 				{
-					caption:      "no change",
-					edit:         noChange.edit,
-					expectedDiff: "Like Strada, the cached semantic diagnostics do not include the missing-global diagnostic produced during signature generation.",
+					caption: "no change",
+					edit:    noChange.edit,
 				},
 				{
 					caption: "delete build info to restore the semantic diagnostic",
@@ -2380,6 +2378,31 @@ func TestTscIncremental(t *testing.T) {
 				noChange,
 			},
 		},
+		{
+			subScenario: "global diagnostics survive build signature generation",
+			files: FileMap{
+				"/home/src/workspaces/project/tsconfig.json": `{"compilerOptions": {"noEmit": true, "incremental": true}}`,
+				"/home/src/workspaces/project/repro.ts":      `export function* values() { yield 1; }`,
+			},
+			commandLineArgs: []string{"--build"},
+			edits: []*tscEdit{
+				noChange,
+				{
+					caption: "add a comment",
+					edit: func(sys *TestSys) {
+						sys.appendFile("/home/src/workspaces/project/repro.ts", "\n// comment-only edit\n")
+					},
+				},
+				{
+					caption: "no change",
+					edit:    noChange.edit,
+				},
+				newTscEdit("remove the generator", func(sys *TestSys) {
+					sys.writeFileNoError("/home/src/workspaces/project/repro.ts", `export const value = 1;`)
+				}),
+				noChange,
+			},
+		},
 		{
 			subScenario: "reverse mapped declaration consumption",
 			files: FileMap{
@@ -2521,6 +2544,44 @@ func TestTscIncremental(t *testing.T) {
 		},
 	}
 
+	for _, checkers := range []int{1, 2} {
+		for _, build := range []bool{false, true} {
+			args := []string{}
+			if build {
+				args = []string{"--build"}
+			}
+			test := &tscInput{
+				subScenario: fmt.Sprintf("global diagnostics with declaration emit checkers %d build %t", checkers, build),
+				files: FileMap{
+					"/home/src/workspaces/project/tsconfig.json": fmt.Sprintf(`{"compilerOptions": {"declaration": true, "incremental": true, "checkers": %d}}`, checkers),
+					"/home/src/workspaces/project/generator.ts":  `export function* values() { yield 1; }`,
+					"/home/src/workspaces/project/index.ts":      `import { values } from "./generator"; export const get = values;`,
+				},
+				commandLineArgs: args,
+				edits: []*tscEdit{
+					newTscEdit("edit both modules without changing their types", func(sys *TestSys) {
+						sys.appendFile("/home/src/workspaces/project/generator.ts", "\n// generator comment\n")
+						sys.appendFile("/home/src/workspaces/project/index.ts", "\n// consumer comment\n")
+					}),
+					noChange,
+					newTscEdit("remove the generator", func(sys *TestSys) {
+						sys.writeFileNoError("/home/src/workspaces/project/generator.ts", `export function values() { return 1; }`)
+					}),
+					noChange,
+					newTscEdit("restore the generator", func(sys *TestSys) {
+						sys.writeFileNoError("/home/src/workspaces/project/generator.ts", `export function* values() { yield 2; }`)
+					}),
+					noChange,
+				},
+			}
+			watchTest := *test
+			watchTest.subScenario += " watch"
+			watchTest.commandLineArgs = append(args, "--watch")
+			watchTest.edits = core.Filter(test.edits, func(edit *tscEdit) bool { return edit != noChange })
+			testCases = append(testCases, test, &watchTest)
+		}
+	}
+
 	for _, test := range testCases {
 		test.run(t, "incremental")
 	}