Refactor the assets resolution of the script setup

[HcySunYang]

Close: #3543

with <script setup>, Assets(components/directives) will be tried to resolve from the setup state, this leads to naming conflicts between assets and ordinary variables, e.g.

<template>
  <div v-focus/>
</template>

<script setup>
const focus = ref(0);
</script>

The constant focus in setup will overwrite the globally registered directive with the same name. This is because the above code will be compiled as:

export function render(_ctx, _cache, $props, $setup) {
  return _withDirectives((_openBlock(), _createBlock('div', null, null, 512 /* NEED_PATCH */)), [
    // Will no longer perform asset resolution
    [$setup["focus"]]
  ])
}

with $setup["focus"], it will no longer perform asset resolution.

My idea is that in order to avoid name conflicts, we should always perform asset resolution, which makes globally registered assets have a higher priority, and at the same time, use setup state as a fallback. E.g.

export function render(_ctx, _cache, $props, $setup) {
  const _directive_focus = _resolveDirective(
    // resolve globally registered assets
    "focus",
    // warnMissing
    false,
    // fallback, when the asset resolution fails, use the fallback instead
    $setup["focus"]
  )

  return _withDirectives((_openBlock(), _createBlock('div', null, null, 512 /* NEED_PATCH */)), [
    [_directive_focus]
  ])
}

This behavior also applies to components resolution. And it only takes effect when there is a state with the same name in the setup result, without breaking anything.

[yyx990803]

I don't think we should prioritize global asset registrations over local variable resolutions. Local resolution should always have higher priority.

To reduce the potential shadowing of directives (which is way less obvious and more likely than components), I reverted it to require the variable to have a v prefix (RFC updates soon) in d35e0b1.