Ignore `<template>` in `vue/html-self-closing` rule

[Thomasan1999]

What rule do you want to change?
vue/html-self-closing

Does this change cause the rule to produce more or fewer warnings?
N/A

How will the change be implemented? (New option, new default behavior, etc.)?
Either by default or add an option to ignore <template> the same way <style> and <script> tags are ignored. Empty <template> tags don't make sense and should either be fully-removed from the Vue template by the engineer or left alone (if that's the way the engineer prefers it).

Please provide some example code that this change will affect:

<CustomComponent>
    <template #slotName></template>
</CustomComponent>

<template></template>

What does the rule currently do for this code?

<CustomComponent>
    <template #slotName />
</CustomComponent>

<template />

What will the rule do after it's changed?
It would leave the code unaffected.

Additional context
N/A

[FloEdelmann]

Hmm, I'm not sure why <template></template> should be a special case. What is the purpose?
Did you check whether the current options of the vue/html-self-closing rule are maybe already sufficient?

Note that there is the (recommended) vue/no-lone-template rule that disallows empty template elements anyway.

[Dimava]

This is a problem when you use autofix on save
I often make templates like

<script setup lang="ts">
</script>
<template>
</template>

and having it to self-close the <template> on save is annoying
I have to either fix that manually (which is annoying) or not to save (which is even more annoying)

As there is vue/no-lone-template empty <template></template> is considered invalid, so <template/> is obviously invalid, so autofixing unfinished <template></template> (which is already a warning) to invalid <template/> (which has to be unself-closed manually) makes no sense

[FloEdelmann]

I think that top-level block tags should just all be excluded in vue/html-self-closing. A pull request is welcome for this change.

However, I don't think that other <template> elements should then get any special treatment.

[Thomasan1999]

What about excluding <template> elements if vue/no-lone-template is turned on? So they're not conflicting each other.

[FloEdelmann]

No, rules should be independent, i.e. they should not be influenced by which other rules are enabled.

I still don't get why <template></template> should be a special case. "Autofix on save" does also apply to e.g. <div></div>.

[Dimava]

Something like exclude: string[] (or regex) would be fine

[Dimava]

Or excludeRoot: boolean as I don't think collapsing root items may ever make sense

[FloEdelmann]

As I said previously, top-level block tags should just all be excluded (without options). A pull request is welcome for this change.