Implement full .hbs -> .gjs codemod

Hardcoded a bunch of thins to make it work with Discourse – the
chat plugin to be specific.

We have a bunch of custom resolver rules that needs to be ported
over to make this work.

The overall strategry should be generalizable. We have a bunch of
custom resolver logic that needs to be ported over, the average app
can probably try to share code with the Embroider resolver – or use
the Resolver from `@embroider/core` directly with `.resolver.json`.

See discourse/discourse#24260 for how this
code was used in context.

bin/ember-codemod-template-tag.ts

@@ -25,6 +25,7 @@ const argv = yargs(hideBin(process.argv))
 
 const codemodOptions: CodemodOptions = {
   appName: argv['app-name'] ?? 'example-app',
+  filename: 'nope',
   projectRoot: argv['root'] ?? process.cwd(),
 };
 

package.json

@@ -38,6 +38,7 @@
     "@codemod-utils/ast-javascript": "^1.2.0",
     "@codemod-utils/ast-template": "^1.1.0",
     "@codemod-utils/files": "^1.1.0",
+    "@glimmer/syntax": "^0.85.12",
     "change-case": "^5.1.2",
     "content-tag": "^1.1.2",
     "recast": "^0.23.4",

src/index.ts

@@ -1,12 +1,93 @@
-import { changeExtension } from './steps/change-extension.js';
-import { convertTests, createOptions } from './steps/index.js';
-import { removeHbsImport } from './steps/remove-import.js';
+import { execSync } from 'node:child_process';
+
+import { findFiles } from '@codemod-utils/files';
+
+import finalize from './steps/finalize.js';
+import { createOptions } from './steps/index.js';
+import inlineTemplate from './steps/inline-template.js';
+import renameJsToGjs from './steps/rename-js-to-gjs.js';
+import resolveImports from './steps/resolve-imports.js';
 import type { CodemodOptions } from './types/index.js';
 
 export function runCodemod(codemodOptions: CodemodOptions): void {
   const options = createOptions(codemodOptions);
 
-  convertTests(options);
-  changeExtension(options);
-  removeHbsImport(options);
+  const candidates = findFiles('**/*.hbs', {
+    ignoreList: ['**/templates/**/*.hbs'],
+    projectRoot: codemodOptions.projectRoot,
+  });
+
+  const converted: string[] = [];
+  const skipped: [string, string][] = [];
+
+  for (const candidate of candidates) {
+    const goodRef = execSync('git rev-parse HEAD', {
+      cwd: options.projectRoot,
+      encoding: 'utf8',
+    }).trim();
+
+    try {
+      console.log(`Converting ${candidate}`);
+
+      execSync(`git reset --hard ${goodRef}`, {
+        cwd: options.projectRoot,
+        encoding: 'utf8',
+        stdio: 'ignore',
+      });
+
+      options.filename = candidate;
+
+      renameJsToGjs(options);
+      resolveImports(options);
+      inlineTemplate(options);
+      finalize(options);
+
+      console.log(
+        execSync(`git show --color HEAD~`, {
+          cwd: options.projectRoot,
+          encoding: 'utf8',
+        }),
+      );
+
+      converted.push(candidate);
+    } catch (error: unknown) {
+      let reason = String(error);
+
+      if (error instanceof Error) {
+        reason = error.message;
+      }
+
+      reason = reason.trim();
+
+      console.warn(`Failed to convert ${candidate}: ${reason}`);
+
+      execSync(`git reset --hard ${goodRef}`, {
+        cwd: options.projectRoot,
+        stdio: 'ignore',
+      });
+
+      skipped.push([candidate, reason]);
+    }
+  }
+
+  if (converted.length) {
+    console.log('Successfully converted %d files:\n', converted.length);
+
+    for (const file of converted) {
+      console.log(`- ${file}`);
+    }
+
+    console.log('\n');
+  }
+
+  if (skipped.length) {
+    console.log('Skipped %d files:\n', skipped.length);
+
+    for (const [file, reason] of skipped) {
+      console.log(`- ${file}`);
+      console.log(`  ${reason}`);
+    }
+
+    console.log('\n');
+  }
 }

src/steps/create-options.ts

@@ -1,10 +1,11 @@
 import type { CodemodOptions, Options } from '../types/index.js';
 
 export function createOptions(codemodOptions: CodemodOptions): Options {
-  const { appName: appName, projectRoot } = codemodOptions;
+  const { appName, filename, projectRoot } = codemodOptions;
 
   return {
-    appName: appName,
+    appName,
+    filename,
     projectRoot,
   };
 }

src/steps/finalize.ts

@@ -0,0 +1,49 @@
+import { execSync } from 'node:child_process';
+import { unlinkSync } from 'node:fs';
+import path from 'node:path';
+
+import type { Options } from '../types/index.js';
+
+export default function finalize(options: Options): void {
+  const hbs = path.join(options.projectRoot, options.filename);
+
+  const gjs = path.join(
+    options.projectRoot,
+    options.filename.replace('.hbs', '.gjs'),
+  );
+
+  execSync(`yarn eslint --fix ${JSON.stringify(gjs)}`, {
+    cwd: options.projectRoot,
+  });
+
+  execSync(`yarn prettier --write ${JSON.stringify(gjs)}`, {
+    cwd: options.projectRoot,
+  });
+
+  execSync(`yarn ember-template-lint --fix ${JSON.stringify(hbs)}`, {
+    cwd: options.projectRoot,
+  });
+
+  execSync(`yarn prettier --write ${JSON.stringify(hbs)}`, {
+    cwd: options.projectRoot,
+  });
+
+  const label = path.basename(options.filename).replace('.hbs', '');
+  const convert = JSON.stringify(`DEV: convert chat/${label} -> gjs`);
+
+  execSync('git add .', { cwd: options.projectRoot });
+  execSync(`git commit -m ${convert}`, {
+    cwd: options.projectRoot,
+    stdio: 'ignore',
+  });
+
+  unlinkSync(hbs);
+
+  const cleanup = JSON.stringify(`DEV: cleanup chat/${label}`);
+
+  execSync('git add .', { cwd: options.projectRoot });
+  execSync(`git commit -m ${cleanup}`, {
+    cwd: options.projectRoot,
+    stdio: 'ignore',
+  });
+}

src/steps/inline-template.ts

@@ -0,0 +1,73 @@
+import { readFileSync, writeFileSync } from 'node:fs';
+import path from 'node:path';
+
+import { AST } from '@codemod-utils/ast-javascript';
+
+import type { Options } from '../types/index.js';
+
+export default function inlineTemplate(options: Options): void {
+  const hbs = path.join(options.projectRoot, options.filename);
+
+  const hbsSource = readFileSync(hbs, { encoding: 'utf8' });
+
+  const gjs = path.join(
+    options.projectRoot,
+    options.filename.replace('.hbs', '.gjs'),
+  );
+
+  const jsSource = readFileSync(gjs, { encoding: 'utf8' });
+
+  const traverse = AST.traverse(false);
+
+  let found = 0;
+
+  const ast = traverse(jsSource, {
+    visitClassDeclaration(path) {
+      if (
+        path.node.superClass?.type === 'Identifier' &&
+        path.node.superClass.name === 'Component'
+      ) {
+        found++;
+
+        path.node.body.body.push(
+          AST.builders.classProperty(
+            AST.builders.identifier('__template__'),
+            null,
+          ),
+        );
+      }
+
+      return false;
+    },
+  });
+
+  if (found === 0) {
+    throw new Error('cannot find class');
+  } else if (found > 1) {
+    throw new Error('too many classes?');
+  }
+
+  const jsPlaceholder = AST.print(ast);
+
+  const matches = [...jsPlaceholder.matchAll(/^\s*__template__;$/gm)];
+
+  if (matches.length === 0) {
+    throw new Error('cannot find placeholder');
+  } else if (matches.length > 1) {
+    throw new Error('too many placeholders?');
+  }
+
+  let templateTag = `\n`;
+
+  templateTag += `  <template>\n`;
+
+  for (const line of hbsSource.split('\n')) {
+    templateTag += `    ${line}\n`;
+  }
+
+  templateTag += `  </template>`;
+
+  const gjsSource = jsPlaceholder.replace(/^\s*__template__;$/m, templateTag);
+
+  writeFileSync(gjs, gjsSource, { encoding: 'utf8' });
+}

src/steps/rename-js-to-gjs.ts

@@ -0,0 +1,49 @@
+import { execSync } from 'node:child_process';
+import { existsSync, readFileSync, renameSync, writeFileSync } from 'node:fs';
+import path from 'node:path';
+
+import type { Options } from '../types/index.js';
+
+export default function renameJsToGjs(options: Options): void {
+  const src = path.join(
+    options.projectRoot,
+    options.filename.replace('.hbs', '.js'),
+  );
+
+  const dest = path.join(
+    options.projectRoot,
+    options.filename.replace('.hbs', '.gjs'),
+  );
+
+  if (existsSync(src)) {
+    if (readFileSync(src, { encoding: 'utf8' }).includes(`.extend(`)) {
+      throw new Error(
+        `It appears to be a classic class, convert it to native class first!`,
+      );
+    }
+
+    renameSync(src, dest);
+  } else {
+    if (options.filename.includes('/components/')) {
+      writeFileSync(
+        dest,
+        `import Component from "@glimmer/component";\n` +
+          `\n` +
+          `export default class extends Component {\n` +
+          `}\n`,
+        { encoding: 'utf8' },
+      );
+    } else {
+      throw new Error(`It does not appear to be a component!`);
+    }
+  }
+
+  const label = path.basename(options.filename).replace('.hbs', '');
+  const message = JSON.stringify(`DEV: mv chat/${label} -> gjs`);
+
+  execSync('git add .', { cwd: options.projectRoot });
+  execSync(`git commit -m ${message}`, {
+    cwd: options.projectRoot,
+    stdio: 'ignore',
+  });
+}