fix parsing comment tag with extra string

[ggmichaelgo]

What are you trying to solve?

#1755 introduced a bug in comment tag that prevents the tag from having extra string inside.

With the bug, this valid template fails to be parsed

{%comment}{% assign a = 1 %}
  {% if true %}
{%endcomment}{% endif %}

[peterzhu2118]

I'm confused about the example template. Is {%comment} valid opening for a comment? Is {%endcomment} a valid closing? What's the {% endif %} supposed to close?

[ggmichaelgo]

I'm confused about the example template. Is {%comment} valid opening for a comment? Is {%endcomment} a valid closing? What's the {% endif %} supposed to close?

{%endcomment}{% endif %} is the comment tag delimiter.

With Liquid 5.4.0, you can see how the comment tag used to get parsed.

require 'liquid'

template = Liquid::Template.parse("{%comment}{% assign a = 1 %}{%endcomment}{% endif %}")
pp template.root.nodelist[0]

[peterzhu2118]

I think this PR makes sense. However, I'm not a fan that this is valid Liquid syntax because it's confusing and hard to understand. Do we have a plan to deprecate or drop support for weird syntax like this?

[ggmichaelgo]

I agree that example Liquid template is awful to read, and I wish we could deprecate some Liquid syntaxes...
However, we can't deprecate this syntax pattern on Liquid because we can't break existing Shopify themes...