Marking a track as a favourite starts an extraction #677

Pressing the heart on the now-playing block submits the job form and starts a split.

Why

The composer is <form id="job-form">. A <button> inside a form with no explicit type is a submit button, and the heart has never had one:

<button class="daw-fav-btn" id="fav-btn" aria-label="Toggle favorite" ...>

It was harmless for as long as it lived in the footer, outside the form. The top bar rework moved the now-playing block up into the composer, which put the heart inside the form without changing anything about the heart itself. That is why nothing looked suspicious on the day it broke: the diff that caused it does not touch the button.

It is the only button inside the form without a type. Every other one, including the three dots and the mode buttons, carries type="button".

Reproducing

Open a track in a window wider than 1460px, so the now-playing block is on screen, and press the heart. The track is favourited and an extraction starts.

Constraints for whoever fixes it

The one-line fix is type="button". The part worth spending longer on is that this will happen again: the composer is a form and it is where controls keep being added, and the failure is silent, because the button does its own job perfectly well while also doing this one. A guard that covers the next control added to that bar is worth more than one that covers the heart.