Svelte trims content for <pre>

[lega911]

Describe the bug
Considering specs "pre" should display content as is, https://developer.mozilla.org/en-US/docs/Web/HTML/Element/pre
But Svelte trims content

To Reproduce
https://svelte.dev/repl/829574eb0d814385b6842c7a4ba000dc?version=3.38.3

[babakfp]

Check out this REPL
I don't know anything about Svelte core but if you are having this issue in your current project and you want to solve it quickly as possible, just check out the repl.
It seems that something is wrong with the first character(or group of character or a line) that goes into the <pre> tag maybe🤷‍♂️

[AviFS]

Check out this REPL

This is a perfect fix! I wonder why this isn't the default behavior, though. Does someone mind shedding some light on this? Bug or feature?

[Mlocik97]

it's interesting that simple empty span fix trimming. I saw already similiar bug with more ifs in row, where adding one space in code fixed padding by 200px.

[Conduitry]

Fixed in 3.46.4 - https://svelte.dev/repl/829574eb0d814385b6842c7a4ba000dc?version=3.46.4

[pablo-abc]

This took me a bit by surprise on my site (I updated too many packages at once so I didn't realise it was due to Svelte). My mistake since I was relying on the non-standard behaviour by doing this:

  <pre class="{`prism language-${lang}`}" tabindex="0">
    <code class=prism>{@html code}</code>
  </pre>

Switching to this solves it (and it is how it should be I guess?):

  <pre
    class="{`prism language-${lang}`}"
    tabindex="0"
  ><code class=prism>{@html code}</code></pre>

Only one detail. Svelte seems to be adding an extra whitespace when there's a new line at the beginning when this does not happen using plain HTML unless there's an explicit white space after the <pre> tag.