Streamline stage1 template compilation

CHANGELOG.md

@@ -1,5 +1,18 @@
 # Embroider Changelog
 
+# main
+
+## `@embroider/core`, `@embroider/compat`, `@embroidre/webpack`
+
+- BREAKING: drop support for Ember < 3.28.
+
+## `@ember/addon-dev`
+
+- BREAKING: `@embroider/addon-template/template-transform-plugin` is removed
+  because `babel-plugin-ember-template-compilation >= 2.0.0-alpha.2` directly
+  supports source-to-source transformation (and it offers new capabilities to
+  AST transform authors that we would like to be available everywhere).
+
 # Release 2022-10-06.0
 
 ## `@embroider/core` 1.8.3 -> 1.9.0 minor

PORTING-ADDONS-TO-V2.md

@@ -216,7 +216,7 @@ Now that we've separated the test-app and docs app concerns from the addon, we c
    `yarn add --dev @embroider/addon-dev rollup @rollup/plugin-babel @babel/core @babel/plugin-proposal-class-properties @babel/plugin-proposal-decorators`
 
 6. Grab the [example babel config](https://github.com/embroider-build/embroider/blob/main/packages/addon-dev/sample-babel.config.json) and save it as `addon/babel.config.json`
-   - If you addon requires template transforms in order to publish to a shareable format. Apply transforms using the `@embroider/addon-dev/template-transform-plugin`. View how to use this in the [example babel.config.js](https://github.com/embroider-build/embroider/blob/main/packages/addon-dev/sample-babel.config.js)
+   - If you addon requires template transforms in order to publish to a shareable format. Apply transforms using the `babel-plugin-ember-template-compilation`. View how to use this in the [example babel.config.js](https://github.com/embroider-build/embroider/blob/main/packages/addon-dev/sample-babel.config.js)
 7. Grab the [example rollup config](https://github.com/embroider-build/embroider/blob/main/packages/addon-dev/sample-rollup.config.js) and save it as `addon/rollup.config.js`.
 8. Identify your **app reexports**. This is the list of modules from your addon that get reexported by files in the `addon/app` directory.
 9. Delete the `addon/app` directory. You aren't going to need it anymore.

packages/addon-dev/package.json

@@ -14,7 +14,6 @@
   },
   "exports": {
     "./template-colocation-plugin": "./src/template-colocation-plugin.js",
-    "./template-transform-plugin": "./src/template-transform-plugin.js",
     "./rollup": "./src/rollup.js"
   },
   "files": [

packages/addon-dev/sample-babel.config.js

@@ -3,17 +3,15 @@
 // be done during the addon build.
 const someAstTransformPlugin = require('./some-ast-transform-plugin');
 
-// The `@embroider/addon-dev/template-transform-plugin` has the following options:
-// `options.astTransforms` - an array of functions or paths to preprocess the GlimmerAST
-// `options.compilerPath` - Optional: Defaults to `ember-source/dist/ember-template-compiler`
-
 module.exports = {
   plugins: [
     '@embroider/addon-dev/template-colocation-plugin',
     [
-      '@embroider/addon-dev/template-transform-plugin',
+      'babel-plugin-ember-template-compilation',
       {
-        astTransforms: [
+        targetFormat: 'hbs',
+        compilerPath: 'ember-source/dist/ember-template-compiler',
+        transforms: [
           someAstTransformPlugin,
           './path/to/another-template-transform-plugin',
         ],

packages/compat/src/hbs-to-js-broccoli-plugin.ts

@@ -0,0 +1,36 @@
+import type { Node } from 'broccoli-node-api';
+import Filter from 'broccoli-persistent-filter';
+import { hbsToJS } from '@embroider/core';
+import { join } from 'path';
+
+export default class TemplateCompileTree extends Filter {
+  constructor(inputTree: Node) {
+    super(inputTree, {
+      name: `embroider-template-compile-stage1`,
+      persist: true,
+      extensions: ['hbs', 'handlebars'],
+    });
+  }
+
+  getDestFilePath(relativePath: string, entry: Parameters<Filter['getDestFilePath']>[1]) {
+    if (this.isDirectory(relativePath, entry)) {
+      return null;
+    }
+    for (let ext of ['hbs', 'handlebars']) {
+      if (relativePath.slice(-ext.length - 1) === '.' + ext) {
+        // we deliberately don't chop off the .hbs before appending .js, because if
+        // the user has both .js` and .hbs` side-by-side we don't want our new file
+        // to collide with theirs.
+        return relativePath + '.js';
+      }
+    }
+    return null;
+  }
+
+  processString(source: string, relativePath: string) {
+    return hbsToJS(source, relativePath);
+  }
+  baseDir() {
+    return join(__dirname, '..');
+  }
+}