Version

3.0.5

Reproduction link

https://codesandbox.io/s/quizzical-hooks-1gbju?file=/src/components/Carousel.vue

Steps to reproduce

chidren

<template>
  <div>
    <slot></slot>
  </div>
</template>

<script>
import { inject, onMounted, defineComponent, getCurrentInstance } from "vue";
export default defineComponent({
  name: "ci",
  setup(_props) {
    const instance = getCurrentInstance();
    onMounted(() => {
      const { getChilrenItems } = inject("CAROUSEL");
      getChilrenItems(instance);
    });
    return {};
  },
});
</script>

parent

<template>
  <div>
    <slot></slot>
    <div>{{ items }}</div>
  </div>
</template>

<script>
import { ref, provide, defineComponent } from "vue";
export default defineComponent({
  name: "c",
  setup(_props) {
    const items = ref([]);
    function getChilrenItems(child) {
      items.value.push(child.proxy);
    }
    provide("CAROUSEL", { getChilrenItems });
    return { items };
  },
});
</script>

What is expected?

the variable was't empty in the template

What is actually happening?

[{},{},{},{}]

They are not empty, they are printed as empty. BTW, you should inject outside of onMounted()

Please, next time consider using the forum, the Discord server or StackOverflow for questions first. But feel free to come back and open an issue if it turns out to be a bug 🙂