fix: make auto-width and text-align usable in custom slot

packages/grid/src/vaadin-grid-column-mixin.js

@@ -487,7 +487,7 @@ export const ColumnBaseMixin = (superClass) =>
 
     /** @private */
     _textAlignChanged(textAlign) {
-      if (textAlign === undefined) {
+      if (textAlign === undefined || this._grid === undefined) {
         return;
       }
       if (['start', 'end', 'center'].indexOf(textAlign) === -1) {

packages/grid/src/vaadin-grid-mixin.js

@@ -339,7 +339,10 @@ export const GridMixin = (superClass) =>
         return 0;
       }
 
-      const columnWidth = Math.max(this.__getIntrinsicWidth(col), this.__getDistributedWidth(col.parentElement, col));
+      const columnWidth = Math.max(
+        this.__getIntrinsicWidth(col),
+        this.__getDistributedWidth((col.assignedSlot || col).parentElement, col),
+      );
 
       // We're processing a regular grid-column and not a grid-column-group
       if (!innerColumn) {

packages/grid/test/grid-wrapper.test.js

@@ -0,0 +1,56 @@
+import { expect } from '@esm-bundle/chai';
+import { fixtureSync } from '@vaadin/testing-helpers';
+import sinon from 'sinon';
+import '../vaadin-grid.js';
+import '../vaadin-grid-column-group.js';
+import '../vaadin-grid-column.js';
+import { html, PolymerElement } from '@polymer/polymer/polymer-element.js';
+import { flushGrid } from './helpers.js';
+
+class GridWrapper extends PolymerElement {
+  static get template() {
+    return html`
+      <vaadin-grid id="grid">
+        <vaadin-grid-column-group>
+          <slot name="group"></slot>
+        </vaadin-grid-column-group>
+        <slot></slot>
+      </vaadin-grid>
+    `;
+  }
+}
+
+customElements.define('grid-wrapper', GridWrapper);
+
+describe('columns slotted in custom element', () => {
+  let spy;
+  beforeEach(() => {
+    spy = sinon.spy(console, 'error');
+  });
+
+  afterEach(() => {
+    spy.restore();
+  });
+
+  it('should not throw if column with auto-width is defined', () => {
+    fixtureSync('<grid-wrapper><vaadin-grid-column path="name" auto-width></vaadin-grid-column></grid-wrapper>');
+
+    expect(spy.called).to.be.false;
+  });
+
+  it('should not throw if column inside group with auto-width is defined', () => {
+    fixtureSync(
+      '<grid-wrapper><vaadin-grid-column slot="group" path="name" auto-width></vaadin-grid-column></grid-wrapper>',
+    );
+    expect(spy.called).to.be.false;
+  });
+
+  it('should not throw if column with text-align is defined', () => {
+    fixtureSync(
+      '<grid-wrapper-delayed><vaadin-grid-column text-align="end"></vaadin-grid-column></grid-wrapper-delayed>',
+    );
+    // Delaying the definition of the custom-element so internal <vaadin-grid> is not yet defined
+    customElements.define('grid-wrapper-delayed', class extends GridWrapper {});
+    expect(spy.called).to.be.false;
+  });
+});