Fix: restore sourceFileMayBeEmitted to emitter.go and add program context

Co-authored-by: sheetalkamat <8052792+sheetalkamat@users.noreply.github.com>

Author: Copilot

internal/checker/checker.go

@@ -22,7 +22,6 @@ import (
 	"github.com/microsoft/typescript-go/internal/jsnum"
 	"github.com/microsoft/typescript-go/internal/module"
 	"github.com/microsoft/typescript-go/internal/modulespecifiers"
-	"github.com/microsoft/typescript-go/internal/outputpaths"
 	"github.com/microsoft/typescript-go/internal/printer"
 	"github.com/microsoft/typescript-go/internal/scanner"
 	"github.com/microsoft/typescript-go/internal/stringutil"
@@ -14518,7 +14517,7 @@ func (c *Checker) resolveExternalModule(location *ast.Node, moduleReference stri
 						diagnostics.This_relative_import_path_is_unsafe_to_rewrite_because_it_looks_like_a_file_name_but_actually_resolves_to_0,
 						relativeToSourceFile,
 					)
-				} else if resolvedModule.ResolvedUsingTsExtension && !shouldRewrite && outputpaths.SourceFileMayBeEmitted(sourceFile, c.compilerOptions, false) {
+				} else if resolvedModule.ResolvedUsingTsExtension && !shouldRewrite && c.sourceFileMayBeEmitted(sourceFile) {
 					c.error(
 						errorNode,
 						diagnostics.This_import_uses_a_0_extension_to_resolve_to_an_input_TypeScript_file_but_will_not_be_rewritten_during_emit_because_it_is_not_a_relative_path,
@@ -30408,3 +30407,25 @@ func (c *Checker) GetEmitResolver(file *ast.SourceFile, skipDiagnostics bool) *e
 func (c *Checker) GetAliasedSymbol(symbol *ast.Symbol) *ast.Symbol {
 	return c.resolveAlias(symbol)
 }
+
+// sourceFileMayBeEmitted is a simplified version of the function in compiler/emitter.go
+// that handles the basic checks needed for import rewrite diagnostics
+func (c *Checker) sourceFileMayBeEmitted(sourceFile *ast.SourceFile) bool {
+	// Declaration files are not emitted
+	if sourceFile.IsDeclarationFile {
+		return false
+	}
+
+	// Source file from node_modules are not emitted
+	if strings.Contains(sourceFile.FileName(), "/node_modules/") {
+		return false
+	}
+
+	// Any non json file should be emitted
+	if !ast.IsJsonSourceFile(sourceFile) {
+		return true
+	}
+
+	// JSON files are generally not emitted
+	return false
+}

internal/compiler/emitter.go

@@ -2,6 +2,7 @@ package compiler
 
 import (
 	"encoding/base64"
+	"strings"
 
 	"github.com/microsoft/typescript-go/internal/ast"
 	"github.com/microsoft/typescript-go/internal/core"
@@ -296,6 +297,37 @@ func (e *emitter) getSourceMappingURL(mapOptions *core.CompilerOptions, sourceMa
 	return stringutil.EncodeURI(sourceMapFile)
 }
 
+func sourceFileMayBeEmitted(sourceFile *ast.SourceFile, host printer.EmitHost, forceDtsEmit bool) bool {
+	// !!! Js files are emitted only if option is enabled
+
+	// Declaration files are not emitted
+	if sourceFile.IsDeclarationFile {
+		return false
+	}
+
+	// !!! Source file from node_modules are not emitted. In Strada, this depends on module resolution and uses
+	// `sourceFilesFoundSearchingNodeModules` in `createProgram`. For now, we will just check for `/node_modules/` in
+	// the file name.
+	if strings.Contains(sourceFile.FileName(), "/node_modules/") {
+		return false
+	}
+
+	// forcing dts emit => file needs to be emitted
+	if forceDtsEmit {
+		return true
+	}
+
+	// !!! Source files from referenced projects are not emitted
+
+	// Any non json file should be emitted
+	if !ast.IsJsonSourceFile(sourceFile) {
+		return true
+	}
+
+	// !!! Should JSON input files be emitted
+	return false
+}
+
 func getSourceFilesToEmit(host printer.EmitHost, targetSourceFile *ast.SourceFile, forceDtsEmit bool) []*ast.SourceFile {
 	// !!! outFile not yet implemented, may be deprecated
 	var sourceFiles []*ast.SourceFile
@@ -305,7 +337,7 @@ func getSourceFilesToEmit(host printer.EmitHost, targetSourceFile *ast.SourceFil
 		sourceFiles = host.SourceFiles()
 	}
 	return core.Filter(sourceFiles, func(sourceFile *ast.SourceFile) bool {
-		return outputpaths.SourceFileMayBeEmitted(sourceFile, host.Options(), forceDtsEmit)
+		return sourceFileMayBeEmitted(sourceFile, host, forceDtsEmit)
 	})
 }
 

internal/compiler/program.go

@@ -710,8 +710,9 @@ func (p *Program) GetDefaultResolutionModeForFile(sourceFile ast.HasFileName) co
 func (p *Program) CommonSourceDirectory() string {
 	p.commonSourceDirectoryOnce.Do(func() {
 		var files []string
+		host := &emitHost{program: p}
 		for _, file := range p.files {
-			if outputpaths.SourceFileMayBeEmitted(file, p.Options(), false /*forceDtsEmit*/) {
+			if sourceFileMayBeEmitted(file, host, false /*forceDtsEmit*/) {
 				files = append(files, file.FileName())
 			}
 		}

internal/outputpaths/outputpaths.go

@@ -200,34 +200,4 @@ func getDeclarationEmitExtensionForPath(fileName string) string {
 	return tspath.ExtensionDts
 }
 
-// SourceFileMayBeEmitted checks if a source file may be emitted by the compiler
-func SourceFileMayBeEmitted(sourceFile *ast.SourceFile, options *core.CompilerOptions, forceDtsEmit bool) bool {
-	// !!! Js files are emitted only if option is enabled
 
-	// Declaration files are not emitted
-	if sourceFile.IsDeclarationFile {
-		return false
-	}
-
-	// !!! Source file from node_modules are not emitted. In Strada, this depends on module resolution and uses
-	// `sourceFilesFoundSearchingNodeModules` in `createProgram`. For now, we will just check for `/node_modules/` in
-	// the file name.
-	if strings.Contains(sourceFile.FileName(), "/node_modules/") {
-		return false
-	}
-
-	// forcing dts emit => file needs to be emitted
-	if forceDtsEmit {
-		return true
-	}
-
-	// !!! Source files from referenced projects are not emitted
-
-	// Any non json file should be emitted
-	if !ast.IsJsonSourceFile(sourceFile) {
-		return true
-	}
-
-	// !!! Should JSON input files be emitted
-	return false
-}