Change 676132 had a related patch set uploaded (by Wikitrent; author: Wikitrent):

[mediawiki/extensions/SecurePoll@master] Convert SecurePoll VotePage to OOUI

https://gerrit.wikimedia.org/r/676132

Change 676132 merged by jenkins-bot:

[mediawiki/extensions/SecurePoll@master] Convert SecurePoll VotePage to OOUI

https://gerrit.wikimedia.org/r/676132

Change 677639 had a related patch set uploaded (by Tchanders; author: Tchanders):

[mediawiki/extensions/SecurePoll@master] Wrap VotePage error message in HTMLSnippet

https://gerrit.wikimedia.org/r/677639

The new patch fixes a bug that appears when the vote page is submitted with an error:

We're outputting escaped HTML as a result of the error being built as a string and passed to OOUI\Element as text content:

// In class Ballot

public function getForm( $prevStatus = false ) {
    // ...
    $formStatus = new \OOUI\Element( [
        'content' => $this->formatStatus( $prevStatus ),
    ] );
    // ...
}

public function formatStatus( $status ) {
    return $status->sp_getHTML( $this->usedErrorIds );
}

// In class BallotStatus

public function sp_getHTML( $usedIds ) {
	// ...
	$s = '<ul class="securepoll-error-box">';
	// Then more HTML string building...
	$s .= "</ul>\n";

	return $s;
}

A quick fix is to wrap it in an HTMLSnippet in Ballot::getForm. A better long-term fix would be to use an error message widget for the error: T279570

Change 677639 merged by jenkins-bot:

[mediawiki/extensions/SecurePoll@master] Wrap VotePage error message in HTMLSnippet

https://gerrit.wikimedia.org/r/677639

I tested a few different types of election, including Range voting (plurality) with comment and Range voting (histogram range) with comment.

I could submit a vote and it was recorded correctly in the database.

I tested with and without javascript.

I tested the validation error messages. They mostly have not changed, apart from Range votes as shown below.

Before:

After:

Test Environment: https://vote.wikimedia.beta.wmflabs.org SecurePoll 2.0.0 (bd806ca) 07:21, 13 April 2021.
Test browser: Firefox 78