textfield does not work "multiple" when "type=email"

[itagakishintaro]

What is affected?

Component

Description

When I use text-field (md-outlined-text-field or md-filled-text-field) with type="email" multiple="true",
I expect a list of zero email addresses (an empty string, or one which is entirely whitespace) is a valid value.
It is common in W3C standard html.
See
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/email#multiple
However, textfield does not work.

Maybe, the cause is below. This code does not care about "multiple".

material-web/textfield/internal/text-field.ts
line 600

 private renderInputOrTextarea() {
    const style = {direction: this.textDirection};
    const ariaLabel =
        (this as ARIAMixinStrict).ariaLabel || this.label || nothing;
    // lit-anaylzer `autocomplete` types are too strict
    // tslint:disable-next-line:no-any
    const autocomplete = this.autocomplete as any;

    if (this.type === 'textarea') {
      return html`
        <textarea
          class="input"
          style=${styleMap(style)}
          aria-describedby="description"
          aria-invalid=${this.hasError}
          aria-label=${ariaLabel}
          autocomplete=${autocomplete || nothing}
          ?disabled=${this.disabled}
          maxlength=${this.maxLength > -1 ? this.maxLength : nothing}
          minlength=${this.minLength > -1 ? this.minLength : nothing}
          placeholder=${this.placeholder || nothing}
          ?readonly=${this.readOnly}
          ?required=${this.required}
          rows=${this.rows}
          .value=${live(this.value)}
          @change=${this.handleChange}
          @focusin=${this.handleFocusin}
          @focusout=${this.handleFocusout}
          @input=${this.handleInput}
          @select=${this.redispatchEvent}
        ></textarea>
      `;
    }

Reproduction

https://lit.dev/playground/#project=W3sibmFtZSI6Im1hdGVyaWFsLWltcG9ydHMuanMiLCJjb250ZW50IjoiaW1wb3J0ICdAbWF0ZXJpYWwvd2ViL3RleHRmaWVsZC9vdXRsaW5lZC10ZXh0LWZpZWxkLmpzJztcbiJ9LHsibmFtZSI6ImluZGV4Lmh0bWwiLCJjb250ZW50IjoiPCFET0NUWVBFIGh0bWw-XG48c2NyaXB0IHR5cGU9XCJtb2R1bGVcIiBzcmM9XCIuL21hdGVyaWFsLWltcG9ydHMuanNcIj48L3NjcmlwdD5cblxuPGZvcm0-XG4gIDxtZC1vdXRsaW5lZC10ZXh0LWZpZWxkXG4gICAgaWQ9XCJtZW1iZXJzXCJcbiAgICBsYWJlbD1cIm11bHRpcGxlIGVtYWlsXCJcbiAgICB0eXBlPVwiZW1haWxcIlxuICAgIG11bHRpcGxlPVwidHJ1ZVwiXG4gID48L21kLW91dGxpbmVkLXRleHQtZmllbGQ-XG4gIDxpbnB1dCB0eXBlPVwic3VibWl0XCI-XG48L2Zvcm0-In0seyJuYW1lIjoicGFja2FnZS5qc29uIiwiY29udGVudCI6IntcbiAgXCJkZXBlbmRlbmNpZXNcIjoge1xuICAgIFwibGl0XCI6IFwiXjIuMC4wXCIsXG4gICAgXCJAbGl0L3JlYWN0aXZlLWVsZW1lbnRcIjogXCJeMS4wLjBcIixcbiAgICBcImxpdC1lbGVtZW50XCI6IFwiXjMuMC4wXCIsXG4gICAgXCJsaXQtaHRtbFwiOiBcIl4yLjAuMFwiXG4gIH1cbn0iLCJoaWRkZW4iOnRydWV9XQ

Workaround

I do not know.

Is this a regression?

No or unsure. This never worked, or I haven't tried before.

Affected versions

@material/[email protected]

Browser/OS/Node environment

Browser: Chrome 117.0.5938.149
OS: MacOS 13.4.1 (c)（22F770820d）
Node version: v20.5.0
npm version: 10.1.0