Version

3.0.6

Reproduction link

[APP: git@github.com:fatbone008/vue3-test-demo.git Lib: git@github.com:fatbone008/vue3-test-lib.git](APP: git@github.com:fatbone008/vue3-test-demo.git Lib: git@github.com:fatbone008/vue3-test-lib.git)

Steps to reproduce

1. In vue3-testing-lib, run lib command to build testing component lib.
2. In vue3-testing-demo, run npm install path/to/lib, install testing lib above by file mode through npm, and import its component(Testing.vue) into Helloworld.vue as a component.
3. npm run serve to start the demo project.
4. check the lib component through vue-devtool, the provide is exist but injected variable is undefined. and there is warning in console: [Vue warn]: inject() can only be used inside setup() or functional components.

What is expected?

The inject variable in setup of lib component is available to detect provide correctly, rather than undefined, and there is no vue warning in console.

What is actually happening?

[Vue warn]: inject() can only be used inside setup() or functional components. But inject() are not used in places other than in setup()

The customized lib component injected variable in setup function can not receive provide. It seems that inject function can not get currentInstance when debugging in the vue source code.

This happen either by using vue-cli 4.5.x or rollup.js. here is my rollup.config.js

import esbuild from "rollup-plugin-esbuild";
import vue from "rollup-plugin-vue"; // 处理vue文件

export default {
    input: 'src/components/index.js',
    external: ["vue"],
    plugins: [resolve({ extensions: [".vue"] }), vue(), esbuild()],
    output: {
        file: 'dist/bundle.js',
        format: 'es'
    }
};

and the component in bundle also warning me that inject() can only be used inside setup() or functional components. But my inject indeed used in setup() function. And my custom component work well in the lib project without packing. Is this bundle problem? Do I need some sort of plugin for vue 3 compose API specially?

I cannot point out the problem you encountered unless you provide a minimal and runnable reproduction. But it seems that you have encountered a multi-instance problem, you can check out these two:

https://github.com/vuejs/vue-next/issues/1870 https://github.com/vuejs/vue-next/issues/2108

I've provide two project to reproduce, May be I should put merge them into one. And thanks for you proposal. I would check the two issues.