[api-extractor] API Extractor should treat ambient modules as it did before.

apps/api-extractor/src/analyzer/ExportAnalyzer.ts

@@ -259,11 +259,18 @@ export class ExportAnalyzer {
     importOrExportDeclaration: ts.ImportDeclaration | ts.ExportDeclaration | ts.ImportTypeNode,
     moduleSpecifier: string
   ): boolean {
-    const resolvedModule: ts.ResolvedModuleFull = this._getResolvedModule(
-      importOrExportDeclaration,
+    const resolvedModule: ts.ResolvedModuleFull | undefined = TypeScriptInternals.getResolvedModule(
+      importOrExportDeclaration.getSourceFile(),
       moduleSpecifier
     );
 
+    if (resolvedModule === undefined) {
+      // The TS compiler API `getResolvedModule` cannot resolve ambient modules. Thus, to match API Extractor's
+      // previous behavior, simply treat all ambient modules as external. This bug is tracked by
+      // https://github.com/microsoft/rushstack/issues/3335.
+      return true;
+    }
+
     // Either something like `jquery` or `@microsoft/api-extractor`.
     const packageName: string | undefined = resolvedModule.packageId?.name;
     if (packageName !== undefined && this._bundledPackageNames.has(packageName)) {
@@ -856,11 +863,23 @@ export class ExportAnalyzer {
     exportSymbol: ts.Symbol
   ): AstModule {
     const moduleSpecifier: string = this._getModuleSpecifier(importOrExportDeclaration);
-    const resolvedModule: ts.ResolvedModuleFull = this._getResolvedModule(
-      importOrExportDeclaration,
+    const resolvedModule: ts.ResolvedModuleFull | undefined = TypeScriptInternals.getResolvedModule(
+      importOrExportDeclaration.getSourceFile(),
       moduleSpecifier
     );
 
+    if (resolvedModule === undefined) {
+      // Encountered in https://github.com/microsoft/rushstack/issues/1914.
+      //
+      // It's also possible for this to occur with ambient modules. However, in practice this doesn't happen
+      // as API Extractor treats all ambient modules as external per the logic in `_isExternalModulePath`, and
+      // thus this code path is never reached for ambient modules.
+      throw new InternalError(
+        `getResolvedModule() could not resolve module name ${JSON.stringify(moduleSpecifier)}\n` +
+          SourceFileLocationFormatter.formatDeclaration(importOrExportDeclaration)
+      );
+    }
+
     // Map the filename back to the corresponding SourceFile. This circuitous approach is needed because
     // we have no way to access the compiler's internal resolveExternalModuleName() function
     const moduleSourceFile: ts.SourceFile | undefined = this._program.getSourceFile(
@@ -919,29 +938,6 @@ export class ExportAnalyzer {
     return astImport;
   }
 
-  private _getResolvedModule(
-    importOrExportDeclaration: ts.ImportDeclaration | ts.ExportDeclaration | ts.ImportTypeNode,
-    moduleSpecifier: string
-  ): ts.ResolvedModuleFull {
-    const resolvedModule: ts.ResolvedModuleFull | undefined = TypeScriptInternals.getResolvedModule(
-      importOrExportDeclaration.getSourceFile(),
-      moduleSpecifier
-    );
-
-    if (resolvedModule === undefined) {
-      // This should not happen, since getResolvedModule() specifically looks up names that the compiler
-      // found in export declarations for this source file
-      //
-      // Encountered in https://github.com/microsoft/rushstack/issues/1914
-      throw new InternalError(
-        `getResolvedModule() could not resolve module name ${JSON.stringify(moduleSpecifier)}\n` +
-          SourceFileLocationFormatter.formatDeclaration(importOrExportDeclaration)
-      );
-    }
-
-    return resolvedModule;
-  }
-
   private _getModuleSpecifier(
     importOrExportDeclaration: ts.ImportDeclaration | ts.ExportDeclaration | ts.ImportTypeNode
   ): string {

build-tests/api-extractor-scenarios/config/build-config.json

@@ -34,7 +34,6 @@
     "inconsistentReleaseTags",
     "internationalCharacters",
     "namedDefaultImport",
-    "pathMappings",
     "preapproved",
     "spanSorting",
     "typeOf",