Textareas being formatted by HTMLFormatter

[APB9785]

Environment

• Elixir version (elixir -v): 1.15.5
• Phoenix version (mix deps): 1.7.7
• Phoenix LiveView version (mix deps): 0.19.5
• Operating system: OS X 12.6.6
• Browsers you attempted to reproduce this bug on (the more the merrier): Firefox
• Does the problem persist after removing "assets/node_modules" and trying again? Yes/no: Yes

Actual behavior

HTMLFormatter is adding a newline between <textarea> tags, which adds unexpected whitespace to the rendered output

iex(1)> Phoenix.LiveView.HTMLFormatter.format("<textarea class=\"test\"></textarea>", heex_line_length: 10)
"<textarea class=\"test\">\n</textarea>\n"

The tag phx-no-format has no effect. The newline is still added even when that attr is included.

Expected behavior

iex(1)> Phoenix.LiveView.HTMLFormatter.format("<textarea class=\"test\"></textarea>", heex_line_length: 10)
"<textarea class=\"test\"></textarea>\n"

[leandrocp]

For extra context, this assertion fails (just added it for testing):

      assert_formatter_doesnt_change(
        """
        <textarea></textarea>
        """,
        line_length: 5
      )

But seems like it shouldn't. And the root cause is the check buffer != [] here

phoenix_live_view/lib/phoenix_live_view/html_formatter.ex

Line 482 in 1626c38

if (tag_name in ["pre", "textarea"] or contains_special_attrs?(attrs)) and buffer != [] do

Idk why only nom-empty elements are preserved, but all tests pass removing that check, including the assert above.

[josevalim]

@leandrocp please send a PR with tests. I think your changes are good.

[leandrocp]

@josevalim thanks. @APB9785 will push a PR soon.