Properly resolve referenced forms.

[geoffrey-eisenbarth]

Description

I would like to start off by thanking @scrhartley for their help with this PR.

When a non-GET htmx request is triggered on an element inside a form, htmx includes the other values in the form. However, it is currently including incorrect values when e.g. a <button form="referenced"> is inside a different form. This PR addresses that bug. Details are explained in the documentation change and the added test.

Corresponding issue: None

Testing

Using standard HTML behavior as a reference, consider the following:

<form id="externalForm" action="/test" method="post">
    <input type="text" name="t1" value="textValue">
    <input type="hidden" name="b1" value="inputValue">
</form>
<form action="/test2" method="post">
    <input type="text" name="t1" value="checkValue">
    <button id="submit" form="externalForm" formaction="/test3" formmethod="post" type="submit" name="b1" value="buttonValue">button</button>
</form>

clicking #submit will result in a request whose body contains t1=textValue&b1=inputValue&b1=buttonValue, which agrees with the new tests.

Checklist

• I have read the contribution guidelines
• I have targeted this PR against the correct branch (master for website changes, dev for
  source changes)
• This is either a bugfix, a documentation update, or a new feature that has been explicitly
  approved via an issue
• I ran the test suite locally (npm run test) and verified that it succeeded

[1cg]

would you mind extracting this to a local variable to avoid the complicated expression in the parameter position, w/ maybe a comment explaining the situation?

thank you, PR looks great love the tests!

[geoffrey-eisenbarth]

I addressed your request, but also there's been some discussion about a better way forward on #issues-and-pull-requests that I'm happy to implement (I am ironbeard on discord).

One thing that might need clarifying is the original intent of the sentence in the docs that this PR changes. Specifically, what kind of elements inside a form should also be sending form values on non-GET?

• <select hx-post=/foo>?
• <input type=text hx-post=/foo>?
• <input type=submit hx-post=/foo>?
• <div hx-post=/foo>?

Furthermore, personally I'm wondering why this is being limited to non-GET? Wouldn't we want to submit the entire form for e.g.

<form method=get action=/foo>
  <input name=bar value=baz>
  <button hx-get=/foo>Submit</button>
</form>

I'm actually not 100% on whether HTMX currently submits bar=baz in this situation or not (I haven't been able to find an associated test and I'm on mobile now), but the docs and the code appear to indicate that it won't. I will make sure to cover any of those situations with tests once I understand the specifics of that line in the docs.

In case it's helpful, here's the original PR of that line in the docs: a3c9cf6#diff-c7d06af83d22e155470d44a366cc1ba76cd5dc9da3405fc9e54a237174736b6aR962