Merge remote-tracking branch 'github/master' into changing_unwrap_ref

# Conflicts:
#	packages/reactivity/src/ref.ts
#	packages/runtime-core/__tests__/apiTemplateRef.spec.ts
#	packages/runtime-core/src/apiWatch.ts

Author: pikax

.circleci/config.yml

@@ -1,37 +1,63 @@
 version: 2
-jobs:
-  build:
-    docker:
-      - image: vuejs/ci
 
-    working_directory: ~/repo
+defaults: &defaults
+  docker:
+    - image: vuejs/ci
+
+step_restore_cache: &restore_cache
+  restore_cache:
+    keys:
+    - v1-dependencies-{{ checksum "yarn.lock" }}-1
+    - v1-dependencies-
+
+step_install_deps: &install_deps
+  run:
+    name: Install Dependencies
+    command: yarn --frozen-lockfile
+
+step_save_cache: &save_cache
+  save_cache:
+    paths:
+      - node_modules
+      - packages/compiler-core/node_modules
+      - packages/compiler-sfc/node_modules
+      - packages/vue/node_modules
+      - ~/.cache/yarn
+    key: v1-dependencies-{{ checksum "yarn.lock" }}-1
 
+jobs:
+  test:
+    <<: *defaults
     steps:
       - checkout
+      - *restore_cache
+      - *install_deps
+      - *save_cache
+      - run: yarn ls-lint
+      - run: yarn test --ci --runInBand
+
+  test-dts:
+    <<: *defaults
+    steps:
+      - checkout
+      - *restore_cache
+      - *install_deps
+      - *save_cache
+      - run: yarn test-dts
 
-      - restore_cache:
-          keys:
-          - v1-dependencies-{{ checksum "yarn.lock" }}
-          - v1-dependencies-
-
-      - run:
-          name: Install Dependencies
-          command: yarn --frozen-lockfile
-
-      - save_cache:
-          paths:
-            - node_modules
-            - ~/.cache/yarn
-          key: v1-dependencies-{{ checksum "yarn.lock" }}
-
-      - run:
-          name: Run Tests
-          command: yarn test --ci --runInBand
-
-      - run:
-          name: Test d.ts
-          command: yarn test-dts
-
-      - run:
-          name: Check size
-          command: yarn size
+  check-size:
+    <<: *defaults
+    steps:
+      - checkout
+      - *restore_cache
+      - *install_deps
+      - *save_cache
+      - run: yarn size
+
+workflows:
+  version: 2
+  ci:
+    jobs:
+      - test
+      - test-dts
+      - check-size

.github/FUNDING.yml

@@ -0,0 +1,2 @@
+open_collective: vuejs
+patreon: evanyou

.github/contributing.md

@@ -19,10 +19,12 @@ Hi! I'm really excited that you are interested in contributing to Vue.js. Before
 - Checkout a topic branch from a base branch, e.g. `master`, and merge back against that branch.
 
 - If adding a new feature:
+
   - Add accompanying test case.
   - Provide a convincing reason to add this feature. Ideally, you should open a suggestion issue first and have it approved before working on it.
 
 - If fixing bug:
+
   - If you are resolving a special issue, add `(fix #xxxx[,#xxxx])` (#xxxx is the issue id) in your PR title for a better release log, e.g. `update entities encoding/decoding (fix #3899)`.
   - Provide a detailed description of the bug in the PR. Live demo preferred.
   - Add appropriate test coverage if applicable. You can check the coverage of your code addition by running `yarn test --coverage`.
@@ -41,7 +43,7 @@ You will need [Node.js](http://nodejs.org) **version 10+**, and [Yarn](https://y
 
 After cloning the repo, run:
 
-``` bash
+```bash
 $ yarn # install the dependencies of the project
 ```
 
@@ -60,46 +62,72 @@ The `build` script builds all public packages (packages without `private: true`
 
 Packages to build can be specified with fuzzy matching:
 
-``` bash
+```bash
 # build runtime-core only
 yarn build runtime-core
 
 # build all packages matching "runtime"
 yarn build runtime --all
 ```
 
+#### Build Formats
+
 By default, each package will be built in multiple distribution formats as specified in the `buildOptions.formats` field in its `package.json`. These can be overwritten via the `-f` flag. The following formats are supported:
 
-- **`global`**: for direct use via `<script>` in the browser. The global variable exposed is specified via the `buildOptions.name` field in a package's `package.json`.
-- **`esm-bundler`**: for use with bundlers like `webpack`, `rollup` and `parcel`.
-- **`esm`**: for usage via native ES modules imports (in browser via `<script type="module">`, or via Node.js native ES modules support in the future)
-- **`cjs`**: for use in Node.js via `require()`.
+- **`global`**:
+
+  - For direct use via `<script>` in the browser. The global variable exposed is specified via the `buildOptions.name` field in a package's `package.json`.
+  - Note: global builds are not [UMD](https://github.com/umdjs/umd) builds. Instead they are built as [IIFEs](https://developer.mozilla.org/en-US/docs/Glossary/IIFE).
+
+- **`esm-bundler`**:
+
+  - Leaves prod/dev branches with `process.env.NODE_ENV` guards (to be replaced by bundler)
+  - Does not ship a minified build (to be done together with the rest of the code after bundling)
+  - For use with bundlers like `webpack`, `rollup` and `parcel`.
+  - Imports dependencies (e.g. `@vue/runtime-core`, `@vue/runtime-compiler`)
+    - Imported dependencies are also `esm-bundler` builds and will in turn import their dependencies (e.g. `@vue/runtime-core` imports `@vue/reactivity`)
+    - This means you **can** install/import these deps without ending up with different instances of these dependencies
+
+- **`esm`**:
+
+  - For usage via native ES modules imports (in browser via `<script type="module">`, or via Node.js native ES modules support in the future)
+  - Inlines all dependencies - i.e. it's a single ES module with no imports from other files
+    - This means you **must** import everything from this file and this file only to ensure you are getting the same instance of code.
+  - Hard-coded prod/dev branches, and the prod build is pre-minified (you will have to use different paths/aliases for dev/prod)
+
+- **`cjs`**:
+  - For use in Node.js server-side rendering via `require()`.
+  - The dev/prod files are pre-built, but are dynamically required based on `process.env.NODE_ENV` in `index.js`, which is the default entry when you do `require('vue')`.
 
 For example, to build `runtime-core` with the global build only:
 
-``` bash
+```bash
 yarn build runtime-core -f global
 ```
 
 Multiple formats can be specified as a comma-separated list:
 
-``` bash
+```bash
 yarn build runtime-core -f esm,cjs
 ```
 
+#### Build with Source Maps
+
+Use the `--sourcemap` or `-s` flag to build with source maps. Note this will make the build much slower.
+
 #### Build with Type Declarations
 
-The `--types` flag will generate type declarations during the build and in addition:
+The `--types` or `-t` flag will generate type declarations during the build and in addition:
 
-- Roll the declarations into a single `.dts` file for each package;
+- Roll the declarations into a single `.d.ts` file for each package;
 - Generate an API report in `<projectRoot>/temp/<packageName>.api.md`. This report contains potential warnings emitted by [api-extractor](https://api-extractor.com/).
-- Generate an API model json in `<projectRoot>/temp/<packageName>.api.md`. This file can be used to generate a Markdown version of the exported APIs.
+- Generate an API model json in `<projectRoot>/temp/<packageName>.api.json`. This file can be used to generate a Markdown version of the exported APIs.
 
 ### `yarn dev`
 
 The `dev` script bundles a target package (default: `vue`) in a specified format (default: `global`) in dev mode and watches for changes. This is useful when you want to load up a build in an HTML page for quick debugging:
 
-``` bash
+```bash
 $ yarn dev
 
 > rollup v1.19.4
@@ -110,11 +138,13 @@ $ yarn dev
 
 - The `dev` script supports specifying build format via the `-f` flag just like the `build` script.
 
+- The `dev` script also supports the `-s` flag for generating source maps, but it will make rebuilds slower.
+
 ### `yarn test`
 
 The `yarn test` script simply calls the `jest` binary, so all [Jest CLI Options](https://jestjs.io/docs/en/cli) can be used. Some examples:
 
-``` bash
+```bash
 # run all tests
 $ yarn test
 
@@ -149,32 +179,33 @@ This repository employs a [monorepo](https://en.wikipedia.org/wiki/Monorepo) set
 
 - `compiler-dom`: Compiler with additional plugins specifically targeting the browser.
 
+- `compiler-ssr`: Compiler that produces render functions optimized for server-side rendering.
+
 - `template-explorer`: A development tool for debugging compiler output. You can run `yarn dev template-explorer` and open its `index.html` to get a repl of template compilation based on current source code.
 
   A [live version](https://vue-next-template-explorer.netlify.com) of the template explorer is also available, which can be used for providing reproductions for compiler bugs. You can also pick the deployment for a specific commit from the [deploy logs](https://app.netlify.com/sites/vue-next-template-explorer/deploys).
 
-- `shared`: **Private.** Platform-agnostic internal utilities shared across multiple packages. This package is private and not published.
+- `shared`: Internal utilities shared across multiple packages (especially environment-agnostic utils used by both runtime and compiler packages).
 
 - `vue`: The public facing "full build" which includes both the runtime AND the compiler.
 
 ### Importing Packages
 
 The packages can import each other directly using their package names. Note that when importing a package, the name listed in its `package.json` should be used. Most of the time the `@vue/` prefix is needed:
 
-``` js
+```js
 import { h } from '@vue/runtime-core'
 ```
 
 This is made possible via several configurations:
 
 - For TypeScript, `compilerOptions.path` in `tsconfig.json`
-- For Jest, `moduleNameMapping` in `jest.config.js`
+- For Jest, `moduleNameMapper` in `jest.config.js`
 - For plain Node.js, they are linked using [Yarn Workspaces](https://yarnpkg.com/blog/2017/08/02/introducing-workspaces/).
 
 ### Package Dependencies
 
 ```
-
                                     +---------------------+
                                     |                     |
                                     |  @vue/compiler-sfc  |

.github/issue-template.md

@@ -0,0 +1,16 @@
+<!--
+IMPORTANT: Please use the following link to create a new issue:
+
+  https://new-issue.vuejs.org/?repo=vuejs/vue-next
+
+If your issue was not created using the app above, it will be closed immediately.
+
+中文用户请注意：
+请使用上面的链接来创建新的 issue。如果不是用上述工具创建的 issue 会被自动关闭。
+-->
+
+<!--
+Love vuejs? Please consider supporting us via Patreon or OpenCollective:
+👉  https://www.patreon.com/evanyou
+👉  https://opencollective.com/vuejs/donate
+-->

.ls-lint.yml

@@ -0,0 +1,7 @@
+ls:
+  packages/*/{src,__tests__}:
+    .js: kebab-case
+    .ts: camelCase | PascalCase
+    .d.ts: camelCase
+    .spec.ts: camelCase | PascalCase
+    .mock.ts: camelCase