adapter-static: Placing media before srcset in a <source> tag will prevent srcset from being crawled

Describe the bug

If the attributes in a <source> tag appear like so <source media="(max-width: 400px)" srcset="/myimage.jpg"> the srcset won’t be crawled and the image won’t be downloaded.

When arranged like this <source srcset="/myimage.jpg" media="(max-width: 400px)"> it works as expected.

Reproduction

Add a <source> tag as mentioned above and run a SvelteKit build with adapter-static configured. Images will not be downloaded as expected.

Logs

No response

System Info

System:
    OS: Linux 5.10 Alpine Linux
    CPU: (6) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
    Memory: 4.01 GB / 7.77 GB
    Container: Yes
    Shell: 1.31.1 - /bin/ash
  Binaries:
    Node: 14.18.1 - /usr/local/bin/node
    Yarn: 1.22.15 - /usr/local/bin/yarn
    npm: 6.14.15 - /usr/local/bin/npm
  npmPackages:
    @sveltejs/adapter-static: ^1.0.0-next.21 => 1.0.0-next.21
    @sveltejs/kit: next => 1.0.0-next.183
    svelte: ^3.43.1 => 3.43.2

Severity

serious, but I can work around it

Additional Information

No response

[Conduitry]

I’ve wondered whether it would be a good idea to give up on regexes here and just use something like parse5 to parse the HTML and walk the AST ourselves to find stuff more robustly. If this only ever happens at build time, I guess I see less of a cost to doing this with a bigger slower library.

[Rich-Harris]

fixed by https://github.com/sveltejs/kit/pull/3288