fix(table): throw error when missing row defs (#7751)

* fix(table): throw error when missing row defs

* nit: change conditional

Author: andrewseguin

src/cdk/table/table-errors.ts

@@ -12,29 +12,38 @@
  * @docs-private
  */
 export function getTableUnknownColumnError(id: string) {
-  return Error(`cdk-table: Could not find column with id "${id}".`);
+  return Error(`Could not find column with id "${id}".`);
 }
 
 /**
  * Returns an error to be thrown when two column definitions have the same name.
  * @docs-private
  */
 export function getTableDuplicateColumnNameError(name: string) {
-  return Error(`cdk-table: Duplicate column definition name provided: "${name}".`);
+  return Error(`Duplicate column definition name provided: "${name}".`);
 }
 
 /**
  * Returns an error to be thrown when there are multiple rows that are missing a when function.
  * @docs-private
  */
 export function getTableMultipleDefaultRowDefsError() {
-  return Error(`cdk-table: There can only be one default row without a when predicate function.`);
+  return Error(`There can only be one default row without a when predicate function.`);
 }
 
 /**
  * Returns an error to be thrown when there are no matching row defs for a particular set of data.
  * @docs-private
  */
 export function getTableMissingMatchingRowDefError() {
-  return Error(`cdk-table: Could not find a matching row definition for the provided row data.`);
+  return Error(`Could not find a matching row definition for the provided row data.`);
+}
+
+/**
+ * Returns an error to be thrown when there is no row definitions present in the content.
+ * @docs-private
+ */
+export function getTableMissingRowDefsError() {
+  return Error('Missing definitions for header and row, ' +
+      'cannot determine which columns should be rendered.');
 }

src/cdk/table/table.spec.ts

@@ -10,6 +10,7 @@ import {map} from 'rxjs/operators/map';
 import {
   getTableDuplicateColumnNameError,
   getTableMissingMatchingRowDefError,
+  getTableMissingRowDefsError,
   getTableMultipleDefaultRowDefsError,
   getTableUnknownColumnError
 } from './table-errors';
@@ -39,6 +40,7 @@ describe('CdkTable', () => {
         WhenRowCdkTableApp,
         WhenRowWithoutDefaultCdkTableApp,
         WhenRowMultipleDefaultsCdkTableApp,
+        MissingRowDefsCdkTableApp,
         BooleanRowCdkTableApp
       ],
     }).compileComponents();
@@ -158,6 +160,11 @@ describe('CdkTable', () => {
         .toThrowError(getTableUnknownColumnError('column_a').message);
   });
 
+  it('should throw an error if the row definitions are missing', () => {
+    expect(() => TestBed.createComponent(MissingRowDefsCdkTableApp).detectChanges())
+        .toThrowError(getTableMissingRowDefsError().message);
+  });
+
   it('should not throw an error if columns are undefined on initialization', () => {
     const undefinedColumnsFixture = TestBed.createComponent(UndefinedColumnsCdkTableApp);
     undefinedColumnsFixture.detectChanges();
@@ -998,6 +1005,20 @@ class MissingColumnDefCdkTableApp {
   dataSource: FakeDataSource = new FakeDataSource();
 }
 
+@Component({
+  template: `
+    <cdk-table [dataSource]="dataSource">
+      <ng-container cdkColumnDef="column_a">
+        <cdk-header-cell *cdkHeaderCellDef> Column A</cdk-header-cell>
+        <cdk-cell *cdkCellDef="let row"> {{row.a}}</cdk-cell>
+      </ng-container>
+    </cdk-table>
+  `
+})
+class MissingRowDefsCdkTableApp {
+  dataSource: FakeDataSource = new FakeDataSource();
+}
+
 @Component({
   template: `
     <cdk-table [dataSource]="dataSource">

src/cdk/table/table.ts

@@ -39,6 +39,7 @@ import {CdkCellDef, CdkColumnDef, CdkHeaderCellDef} from './cell';
 import {
   getTableDuplicateColumnNameError,
   getTableMissingMatchingRowDefError,
+  getTableMissingRowDefsError,
   getTableMultipleDefaultRowDefsError,
   getTableUnknownColumnError
 } from './table-errors';
@@ -182,6 +183,10 @@ export class CdkTable<T> implements CollectionViewer {
   }
 
   ngAfterContentInit() {
+    if (!this._headerDef && !this._rowDefs.length) {
+      throw getTableMissingRowDefsError();
+    }
+
     this._cacheColumnDefsByName();
     this._columnDefs.changes.subscribe(() => this._cacheColumnDefsByName());
     this._renderHeaderRow();