RaspberryPiFoundation · lizschwab · Jul 2, 2026
@@ -15,6 +15,7 @@ import {computeAriaLabel, getBeginStackLabel} from './block_aria_composer.js';
 import {BlockSvg} from './block_svg.js';
 import * as browserEvents from './browser_events.js';
 import * as bumpObjects from './bump_objects.js';
+import * as css from './css.js';
 import * as dialog from './dialog.js';
 import * as dropDownDiv from './dropdowndiv.js';
 import {EventType} from './events/type.js';
@@ -78,6 +79,11 @@ export abstract class FieldInput<T extends InputTypes> extends Field<
    */
   protected isTextValid_ = false;
 
+  /**
+   * The warning icon to display on invalid input
+   */
+  protected warningIcon: HTMLImageElement | null = null;
+
   /**
    * The intial value of the field when the user opened an editor to change its
    * value. When the editor is disposed, an event will be fired that uses this
@@ -195,6 +201,34 @@ export abstract class FieldInput<T extends InputTypes> extends Field<
     return this.fullBlockClickTarget_;
   }
 
+  /** Creates the DOM elements for the invalid input warning icon. */
+  private createWarningIcon(parent?: Element | null): HTMLImageElement | null {
+    const sourceBlock = this.sourceBlock_ as BlockSvg;
+    if (!sourceBlock) {
+      return null;
+    }
+
+    const bBox = this.getScaledBBox();
+    const bBoxHeight = bBox.bottom - bBox.top;
+    const e = document.createElement('img');
+    e.setAttribute('class', 'blocklyInputWarning');
+    e.setAttribute(
+      'src',
+      `${sourceBlock.workspace.options.pathToMedia}input-warning-icon.svg`,
+    );
+    e.setAttribute('x', `0`);
+    e.setAttribute('y', `0`);
+    e.setAttribute('height', `${bBoxHeight}px`);
+    e.setAttribute('width', `${bBoxHeight}px`);
+    e.setAttribute('float', 'inline-start');
+
+    if (parent) {
+      parent.appendChild(e);
+    }
+
+    return e;
+  }
+
   /**
    * Called by setValue if the text input is not valid. If the field is
    * currently being edited it reverts value of the field to the previous
@@ -312,21 +346,52 @@ export abstract class FieldInput<T extends InputTypes> extends Field<
    */
   protected override render_() {
     super.render_();
+    const block = this.getSourceBlock() as BlockSvg | null;
+    if (!block) throw new UnattachedFieldError();
+
     // This logic is done in render_ rather than doValueInvalid_ or
     // doValueUpdate_ so that the code is more centralized.
     if (this.isBeingEdited_) {
       const htmlInput = this.htmlInput_ as HTMLElement;
       if (!this.isTextValid_) {
         dom.addClass(htmlInput, 'blocklyInvalidInput');
         aria.setState(htmlInput, aria.State.INVALID, true);
+        // insert the icon
+        if (this.warningIcon && htmlInput) {
+          const bBox = this.getScaledBBox();
+          const hasBorder = !!this.borderRect_;
+          const xPadding = hasBorder
+            ? this.getConstants()!.FIELD_BORDER_RECT_X_PADDING
+            : (bBox.bottom - bBox.top) / 2;
+          dom.addClass(this.warningIcon, 'blocklyInputWarningInvalid');
+          htmlInput.setAttribute(
+            'width',
+            `${htmlInput.offsetWidth + this.warningIcon.width}px`,
+          );
+          // If we pad by the whole icon width, it looks too far from the
+          // text, and half the width looks too close.
+          const iconPadding = this.warningIcon.width / 1.5;
+          if (block.RTL) {
+            htmlInput.style.paddingRight = `${iconPadding}px`;
+          } else {
+            htmlInput.style.paddingLeft = `${iconPadding}px`;
+          }
+          this.size_.width = this.warningIcon.width;
+          const iconOffset = hasBorder
+            ? this.getConstants()!.FIELD_TEXT_HEIGHT -
+              this.getConstants()!.FIELD_BORDER_RECT_X_PADDING
+            : 0;
+          this.updateSize_(xPadding + iconOffset);
+        }
       } else {
         dom.removeClass(htmlInput, 'blocklyInvalidInput');
+        if (this.warningIcon) {
+          dom.removeClass(this.warningIcon, 'blocklyInputWarningInvalid');
+        }
         aria.setState(htmlInput, aria.State.INVALID, false);
       }
     }
 
-    const block = this.getSourceBlock() as BlockSvg | null;
-    if (!block) throw new UnattachedFieldError();
     // In general, do *not* let fields control the color of blocks. Having the
     // field control the color is unexpected, and could have performance
     // impacts.
@@ -462,6 +527,8 @@ export abstract class FieldInput<T extends InputTypes> extends Field<
       'spellcheck',
       this.spellcheck_ as AnyDuringMigration,
     );
+    this.warningIcon = this.createWarningIcon();
+
     const scale = this.workspace_!.getAbsoluteScale();
     const fontSize = this.getConstants()!.FIELD_TEXT_FONTSIZE * scale + 'pt';
     div!.style.fontSize = fontSize;
@@ -484,9 +551,15 @@ export abstract class FieldInput<T extends InputTypes> extends Field<
         div!.style.boxShadow =
           'rgba(255, 255, 255, 0.3) 0 0 0 ' + 4 * scale + 'px';
       }
+      // Adjust invalid input warning icon for full block style
+      const paddingX = (bBox.bottom - bBox.top) / 4;
+      this.warningIcon!.style.paddingLeft = `${paddingX}px`;
+      this.warningIcon!.style.paddingRight = `${paddingX}px`;
     }
     htmlInput.style.borderRadius = borderRadius;
-
+    if (this.warningIcon) {
+      div!.appendChild(this.warningIcon);
+    }
     div!.appendChild(htmlInput);
 
     htmlInput.value = htmlInput.defaultValue = this.getEditorText_(this.value_);
@@ -921,3 +994,13 @@ export interface FieldInputConfig extends FieldConfig {
 export type FieldInputValidator<T extends InputTypes> = FieldValidator<
   string | T
 >;
+
+css.register(`
+  .blocklyInputWarning {
+    display: none;
+    position: absolute;
+  }
+  .blocklyInputWarning.blocklyInputWarningInvalid {
+    display: inline;
+  }
+`);
@@ -569,6 +569,30 @@ suite('Number Fields', function () {
       assert.notInclude(label, 'dog');
       assert.include(label, '5');
     });
+    test('Invalid input has ARIA invalid state', function () {
+      this.field.setValue(5);
+      this.field.showEditor();
+
+      this.field.htmlInput_.value = 'a';
+      this.field.onHtmlInputChange(null);
+
+      // Move forward a few ticks to give the render_() a chance to run
+      this.clock.tick(16);
+      const ariaInvalid = this.field.htmlInput_.getAttribute('aria-invalid');
+      assert.equal(ariaInvalid, 'true');
+    });
+    test('Invalid input displays warning icon', function () {
+      this.field.setValue(5);
+      this.field.showEditor();
+
+      this.field.htmlInput_.value = 'a';
+      this.field.onHtmlInputChange(null);
+
+      // Move forward a few ticks to give the render_() a chance to run
+      this.clock.tick(16);
+      const warningIconDisplay = this.field.warningIcon.checkVisibility();
+      assert.isTrue(warningIconDisplay);
+    });
     suite('Full block fields', function () {
       setup(function () {
         this.workspace = Blockly.inject('blocklyDiv', {

@@ -224,6 +224,7 @@ suite('Text Input Fields', function () {
             FIELD_TEXT_FONTFAMILY: 'sans-serif',
           };
           field.clickTarget_ = document.createElement('div');
+          field.createWarningIcon = () => {};
           Blockly.common.setMainWorkspace(workspace);
           Blockly.WidgetDiv.createDom();
           this.stub = sinon.stub(field, 'resizeEditor_');
@@ -510,6 +511,29 @@ suite('Text Input Fields', function () {
           rightField.getFocusableElement(),
         );
       });
+      test('Invalid input displays warning icon', async function () {
+        const validator = function () {
+          return null;
+        };
+        const block = this.workspace.getBlockById('left_input_block');
+        const field = this.getFieldFromShadowBlock(block);
+        field.setValidator(validator);
+        const stub = sinon.stub(field, 'resizeEditor_');
+
+        Blockly.getFocusManager().focusNode(field);
+        field.showEditor();
+        // This must be called to avoid editor resize logic throwing an error.
+        await Blockly.renderManagement.finishQueuedRenders();
+
+        // Change the value of the field's input through its editor.
+        const fieldEditor = document.querySelector('.blocklyHtmlInput');
+        this.simulateTypingIntoInput(fieldEditor, 'a');
+
+        // Move forward a few ticks to give the render_() a chance to run
+        this.clock.tick(16);
+        const warningIconDisplay = field.warningIcon.checkVisibility();
+        assert.isTrue(warningIconDisplay);
+      });
     });
 
     // The block being tested uses full-block fields in Zelos.
@@ -645,5 +669,27 @@ suite('Text Input Fields', function () {
       const updatedLabel = this.focusableElement.getAttribute('aria-label');
       assert.isTrue(updatedLabel.includes('new value'));
     });
+    test('Invalid input has ARIA invalid state', async function () {
+      const validator = function () {
+        return null;
+      };
+      this.field.setValidator(validator);
+      const stub = sinon.stub(this.field, 'resizeEditor_');
+
+      Blockly.getFocusManager().focusNode(this.field);
+      this.field.showEditor();
+      // This must be called to avoid editor resize logic throwing an error.
+      await Blockly.renderManagement.finishQueuedRenders();
+
+      // Change the value of the field's input through its editor.
+      const fieldEditor = document.querySelector('.blocklyHtmlInput');
+      fieldEditor.value = 'a';
+      fieldEditor.dispatchEvent(new InputEvent('input'));
+
+      // Move forward a few ticks to give the render_() a chance to run
+      this.clock.tick(16);
+      const ariaInvalid = fieldEditor.getAttribute('aria-invalid');
+      assert.equal(ariaInvalid, 'true');
+    });
   });
 });