preserveWhitespace strips prefix space

[bwbroersma]

Describe the bug
The compiler option preserveWhitespace: true strips prefix space:

<h1> Hello {name}!</h1>

To Reproduce
See this repo. With minimal changes from the svelte/template. This is my output with missing prefix space.

Expected behavior
Keep the prefix whitespace in the SSR.

Information about your Svelte project:
svelte-3.21.0 & rollup.

[bwbroersma]

I'm trying to make near-byte-perfect SSR output because we might be involved in the Creative Commons static site generator of the Licenses (the deeds and legalcode). Because this is quite a project (with many languages), I wanted to verify the Svelte (Sapper) output with the current situation (both compared to the code live and in the repo).

Because both comments and whitespace is not working like expected: whitespace is stripped in this case:

<div>
    <div>
        <p> Some text </p>
    </div>
</div>

to

<div><div><p>Some text </p></div>

however, there is a 'trick':

<div><!---->
    <div><!---->
        <p><!----> Some text </p>
    </div><!---->
</div>

this will the desired output:

<div>
    <div>
        <p> Some text </p>
    </div>
</div>

and it is what I'm currently doing in a PoC to get the compare working.

The main function involved in stripping whitespace is remove_whitespace_children not checking preserveWhitespace.

This ssr trim function is involved in stripping leading & trailing whitespace in a component, without checking preserveWhitespace.

I also had issues with tags like select and option which are in elements_without_text meaning all spaces are skipped, also without checking preserveWhitespace.

I think the option preserveWhitespace should preserve all whitespace: newlines, prefix spaces, spaces in select tags, etc.
I would love to hear some feedback how people are thinking about this.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[frederikhors]

Can we please disable this stupid bot?

[Conduitry]

This should be fixed in 3.46.4.