bug: backslashes in constant string attributes cannot be generated about templ HOT 7 CLOSED

Hey all, I'd like to take a crack at this one.

from templ.

I think we want to avoid making users use backticks. Someone should be able to copy/paste HTML without amendments into a templ file.

from templ.

Nice. I'd love a PR on it. Crack on mate! 😀

If you don't have time, just say, and I'll get to it.

from templ.

Please provide a reproducible example, with instructions of what to run, and explain what you expect to happen, and what is actually happening.

from templ.

so in the repo https://github.com/zmzlois/templ-repro I have provided two example, where regular expression is working in test.ts , but it will cause parsing failure in templ

from templ.

I understand the issue. This isn't related directly to regex but how we represent string attributes.

In HTML, this is a valid attribute: pattern="/^(https?|ftp):\/\/[^\s/$.?#].[^\s]*$/i"
Or a minimal reprod, this is valid HTML too: pattern="\s"

HTML spec states that an attribute value can contain anything except for a " or a &. So an unescaped \ is in-fact valid. But, we generate these strings directly to Go strings without escaping, where a backslash on it's own is invalid.

So I believe that the solution here, is to Go string escape constant string attributes(replace \ with \\). We shouldn't change the behaviour of expressions, since they are go strings, and follow go escaping rules.

from templ.

Question for the group here. If we start escaping constant string attributes I believe that will be a breaking change because someone previously could have done

templ input() {
    <input pattern="\\s" /> 
}

which would have resulted in <input pattern="\s">. With escaping this would become <input pattern="\\s">

I've got a branch here that demonstrates how to make the current state of the project generate the (https?|ftp):\/\/[^\s/$.?#].[^\s]* pattern from the start of this thread.

Do we want to avoid making users use a backtick string like this or is this an acceptable workaround?

from templ.