fix(ng-update): do not throw if imports without named bindings are used

Currently if someone uses a namespace import or an import without named bindings in an Angular application, the `ng-update` schematics from Angular Material will fail due to missing safety checks before casting.

Fixes angular#11571

src/lib/schematics/update/material/typescript-specifiers.ts

@@ -27,6 +27,10 @@ export function isMaterialExportDeclaration(node: ts.Node) {
 
 /** Whether the declaration is part of Angular Material. */
 function isMaterialDeclaration(declaration: ts.ImportDeclaration | ts.ExportDeclaration) {
+  if (!declaration.moduleSpecifier) {
+    return false;
+  }
+
   const moduleSpecifier = declaration.moduleSpecifier.getText();
   return moduleSpecifier.indexOf(materialModuleSpecifier) !== -1 ||
       moduleSpecifier.indexOf(cdkModuleSpecifier) !== -1;

src/lib/schematics/update/rules/checkImportMiscRule.ts

@@ -12,26 +12,43 @@ import * as ts from 'typescript';
 import {isMaterialImportDeclaration} from '../material/typescript-specifiers';
 
 /**
- * Rule that walks through every identifier that is part of Angular Material and replaces the
- * outdated name with the new one.
+ * Rule that detects import declarations that refer to outdated identifiers from Angular Material
+ * or the CDK which cannot be updated automatically.
  */
 export class Rule extends Rules.TypedRule {
   applyWithProgram(sourceFile: ts.SourceFile, program: ts.Program): RuleFailure[] {
-    return this.applyWithWalker(new CheckImportMiscWalker(sourceFile, this.getOptions(), program));
+    return this.applyWithWalker(new Walker(sourceFile, this.getOptions(), program));
   }
 }
 
-export class CheckImportMiscWalker extends ProgramAwareRuleWalker {
-  visitImportDeclaration(declaration: ts.ImportDeclaration) {
-    if (isMaterialImportDeclaration(declaration)) {
-      declaration.importClause.namedBindings.forEachChild(n => {
-        let importName = n.getFirstToken() && n.getFirstToken().getText();
-        if (importName === 'SHOW_ANIMATION' || importName === 'HIDE_ANIMATION') {
-          this.addFailureAtNode(
-              n,
-              `Found deprecated symbol "${red(importName)}" which has been removed`);
-        }
-      });
+export class Walker extends ProgramAwareRuleWalker {
+
+  visitImportDeclaration(node: ts.ImportDeclaration) {
+    if (!isMaterialImportDeclaration(node) ||
+        !node.importClause ||
+        !node.importClause.namedBindings) {
+      return;
+    }
+
+    const namedBindings = node.importClause.namedBindings;
+
+    if (ts.isNamedImports(namedBindings)) {
+      this._checkAnimationConstants(namedBindings);
     }
   }
+
+  /**
+   * Checks for named imports that refer to the deleted animation constants.
+   * https://github.com/angular/material2/commit/9f3bf274c4f15f0b0fbd8ab7dbf1a453076e66d9
+   */
+  private _checkAnimationConstants(namedImports: ts.NamedImports) {
+    namedImports.elements.filter(element => ts.isIdentifier(element.name)).forEach(element => {
+      const importName = element.name.text;
+
+      if (importName === 'SHOW_ANIMATION' || importName === 'HIDE_ANIMATION') {
+        this.addFailureAtNode(element,
+            `Found deprecated symbol "${red(importName)}" which has been removed`);
+      }
+    });
+  }
 }