[BUG] Issue with conditional tags

[blanklob]

Hey there I have an issue with conditional tags the vscode extension reports an error but theme check deosn't thanks, here is a loom about the issue.

https://www.loom.com/share/1471e9b27acf4ab6896e354699c9ffe8

[charlespwd]

Yeah so this is caused because we don't have a way to parse IF tags as HTML tag names.

Unfortunately, I don't have a fix for this because I believe it would make the syntax ambiguous. For the prettier plugin to work (and our LiquidHTML parser, which powers the next version of theme check), we kind of need to be slightly more specific about what we accept.

You have a couple of options:

1. Dangling open/close nodes inside if statements are OK

{% if cond %}
  <some-wrapper with-some-props>
{% else %}
  <some-other-wrapper with-some-other-props>
{% endif %}

{% if cond %}
  </some-wrapper>
{% else %}
  </some-other-wrapper>
{% endif %}

2. Name and props as variables

{% liquid
  if cond
    assign wrapper = 'some-wrapper'
    assign props = '...'
  else
    assign wrapper = 'some-other-wrapper'
    assign props = '...'
  endif
%}
<{{ wrapper }} {{ props }}>

</{{ wrapper }}>

Known issues that don't work:

<{% if cond %}wrapper props{% else %}other other-props{% endif %}>

</{% if cond %}wrapper{% else %}other{% endif %}>

Mostly because our LiquidHTML HTMLElement nodes are something like this type:

interface HTMLElement {
  name: (LiquidVariableOutput | TextNode)[]
  attributes: (HTMLAttribute | LiquidNode)[]
}

[blanklob]

Thanks!