feat: add support for explicitly-specified extensionless scripts (#112)

Progress toward #90

We don't auto-discover them yet, but this adds all of the cases in terms of
doing the correct move operations. Also, we now detect shebang lines when
prepending the results comment and put them after the shebang line.

package.json

@@ -12,7 +12,7 @@
     "build": "rollup -c && babel jscodeshift-scripts --out-dir jscodeshift-scripts-dist",
     "lint": "eslint src test jscodeshift-scripts",
     "pretest": "npm run build",
-    "test": "mocha",
+    "test": "mocha test test/util",
     "semantic-release": "semantic-release pre && npm publish && semantic-release post"
   },
   "repository": {
@@ -44,7 +44,7 @@
     "babel-preset-es2015": "^6.13.0",
     "babel-register": "^6.11.6",
     "babelrc-rollup": "^3.0.0",
-    "decaffeinate": "^2.54.0",
+    "decaffeinate": "^2.54.2",
     "eslint": "^3.18.0",
     "eslint-plugin-babel": "^4.0.0",
     "jscodeshift": "^0.3.30",

src/config/getFilesToProcess.js

@@ -3,7 +3,7 @@ import { resolve } from 'path';
 
 import getFilesFromPathFile from './getFilesFromPathFile';
 import getFilesUnderPath from '../util/getFilesUnderPath';
-import { coffeePathPredicate, jsPathFor } from '../util/FilePaths';
+import { coffeePathPredicate, isExtensionless, jsPathFor } from '../util/FilePaths';
 import CLIError from '../util/CLIError';
 
 export default async function getFilesToProcess(config) {
@@ -35,9 +35,13 @@ function resolveFileFilter(filesToProcess, config) {
 }
 
 async function validateFilesToProcess(filesToProcess) {
-  for (let file of filesToProcess) {
-    if (await exists(jsPathFor(file))) {
-      throw new CLIError(`The file ${jsPathFor(file)} already exists.`);
+  for (let path of filesToProcess) {
+    if (isExtensionless(path)) {
+      continue;
+    }
+    let jsPath = jsPathFor(path);
+    if (await exists(jsPath)) {
+      throw new CLIError(`The file ${jsPath} already exists.`);
     }
   }
 }

src/convert.js

@@ -10,7 +10,7 @@ import makeDecaffeinateVerifyFn from './runner/makeDecaffeinateVerifyFn';
 import runWithProgressBar from './runner/runWithProgressBar';
 import CLIError from './util/CLIError';
 import execLive from './util/execLive';
-import { backupPathFor, jsPathFor } from './util/FilePaths';
+import { backupPathFor, decaffeinateOutPathFor, isExtensionless, jsPathFor } from './util/FilePaths';
 import getFilesUnderPath from './util/getFilesUnderPath';
 import isWorktreeEmpty from './util/isWorktreeEmpty';
 import makeCommit from './util/makeCommit';
@@ -20,6 +20,10 @@ export default async function convert(config) {
   await assertGitWorktreeClean();
 
   let coffeeFiles = await getFilesToProcess(config);
+  let coffeeFilesWithExtension = coffeeFiles.filter(p => !isExtensionless(p));
+  // Extensionless files are special because they don't change their name, so
+  // handle them separately in some cases.
+  let coffeeFilesWithoutExtension = coffeeFiles.filter(p => isExtensionless(p));
   let {decaffeinateArgs = [], decaffeinatePath} = config;
 
   if (!config.skipVerify) {
@@ -34,36 +38,34 @@ Re-run with the "check" command for more details.`);
     }
   }
 
-  async function runAsync(description, asyncFn) {
-    await runWithProgressBar(
-      description, coffeeFiles, async function(path) {
-        await asyncFn(path);
-        return {path};
-      });
-  }
-
-  await runAsync(
+  await runWithProgressBar(
     'Backing up files to .original.coffee...',
+    coffeeFiles,
     async function(coffeePath) {
       await copy(`${coffeePath}`, `${backupPathFor(coffeePath)}`);
     });
 
-  await runAsync(
+  await runWithProgressBar(
     'Renaming files from .coffee to .js...',
+    coffeeFilesWithExtension,
     async function(coffeePath) {
       await move(coffeePath, jsPathFor(coffeePath));
     });
 
   let shortDescription = getShortDescription(coffeeFiles);
   let renameCommitMsg =
     `decaffeinate: Rename ${shortDescription} from .coffee to .js`;
-  console.log(`Generating the first commit: "${renameCommitMsg}"...`);
-  await git().rm(coffeeFiles);
-  await git().raw(['add', '-f', ...coffeeFiles.map(p => jsPathFor(p))]);
-  await makeCommit(renameCommitMsg);
 
-  await runAsync(
+  if (coffeeFilesWithExtension.length > 0) {
+    console.log(`Generating the first commit: "${renameCommitMsg}"...`);
+    await git().rm(coffeeFilesWithExtension);
+    await git().raw(['add', '-f', ...coffeeFilesWithExtension.map(p => jsPathFor(p))]);
+    await makeCommit(renameCommitMsg);
+  }
+
+  await runWithProgressBar(
     'Moving files back...',
+    coffeeFilesWithExtension,
     async function(coffeePath) {
       await move(jsPathFor(coffeePath), coffeePath);
     });
@@ -74,12 +76,20 @@ Re-run with the "check" command for more details.`);
     makeCLIFn(path => `${decaffeinatePath} ${decaffeinateArgs.join(' ')} ${path}`)
   );
 
-  await runAsync(
+  await runWithProgressBar(
     'Deleting old files...',
+    coffeeFiles,
     async function(coffeePath) {
       await unlink(coffeePath);
     });
 
+  await runWithProgressBar(
+    'Setting proper extension for all files...',
+    coffeeFilesWithoutExtension,
+    async function(coffeePath) {
+      await move(decaffeinateOutPathFor(coffeePath), jsPathFor(coffeePath));
+    });
+
   let decaffeinateCommitMsg =
     `decaffeinate: Convert ${shortDescription} to JS`;
   console.log(`Generating the second commit: ${decaffeinateCommitMsg}...`);
@@ -265,6 +275,11 @@ ${ruleIds.map(ruleId => `    ${ruleId},`).join('\n')}
 
 async function prependToFile(path, prependText) {
   let contents = await readFile(path);
-  contents = prependText + contents;
+  let lines = contents.toString().split('\n');
+  if (lines[0] && lines[0].startsWith('#!')) {
+    contents = lines[0] + '\n' + prependText + lines.slice(1).join('\n');
+  } else {
+    contents = prependText + contents;
+  }
   await writeFile(path, contents);
 }

src/runner/runWithProgressBar.js

@@ -21,7 +21,7 @@ export default async function runWithProgressBar(
   let results;
   try {
     results = await runInParallel(files, asyncFn, numConcurrentProcesses, ({result}) => {
-      if (result.error) {
+      if (result && result.error) {
         if (!allowFailures) {
           throw new CLIError(`Error:\n${result.error}`);
         }

src/util/FilePaths.js

@@ -1,26 +1,52 @@
+import { basename, dirname, extname, join } from 'path';
+
 const COFFEE_EXTENSIONS = ['.coffee', '.litcoffee', '.coffee.md'];
 
+function extensionFor(path) {
+  if (path.endsWith('.coffee.md')) {
+    return '.coffee.md';
+  }
+  return extname(path);
+}
+
+function basePathFor(path) {
+  let extension = extensionFor(path);
+  return join(dirname(path), basename(path, extension));
+}
+
 export function coffeePathPredicate(path) {
   return COFFEE_EXTENSIONS.some(ext =>
-  path.endsWith(ext) && !path.endsWith(`.original${ext}`));
+    path.endsWith(ext) && !path.endsWith(`.original${ext}`));
+}
+
+export function isExtensionless(path) {
+  return extensionFor(path) === '';
 }
 
 export function backupPathFor(path) {
-  for (let ext of COFFEE_EXTENSIONS) {
-    if (path.endsWith(ext)) {
-      return path.slice(0, path.length - ext.length) + '.original' + ext;
-    }
-  }
-  return path + '.original';
+  let extension = extensionFor(path);
+  let basePath = basePathFor(path);
+  return basePath + '.original' + extension;
 }
 
+/**
+ * The resulting path where we should send the given input file. Note that when
+ * the input file is an extensionless script, we prefer to keep it extensionless
+ * (and decaffeinate handles the shebang line).
+ */
 export function jsPathFor(path) {
-  for (let ext of COFFEE_EXTENSIONS) {
-    if (path.endsWith(ext)) {
-      return path.slice(0, path.length - ext.length) + '.js';
-    }
+  if (isExtensionless(path)) {
+    return path;
+  } else {
+    return basePathFor(path) + '.js';
   }
-  return path + '.js';
+}
+
+/**
+ * The file generated by decaffeinate for the input file with this name.
+ */
+export function decaffeinateOutPathFor(path) {
+  return basePathFor(path) + '.js';
 }
 
 export function isLiterate(path) {

test/convert-test.js

@@ -191,7 +191,6 @@ console.log('This is a file');
     });
   });
 
-
   it('respects decaffeinate args', async function() {
     await runWithTemplateDir('decaffeinate-args-test', async function () {
       await initGitRepo();
@@ -209,6 +208,20 @@ module.exports = c;
     });
   });
 
+  it('allows converting extensionless scripts', async function() {
+    await runWithTemplateDir('extensionless-script', async function () {
+      await initGitRepo();
+      await runCliExpectSuccess('convert');
+      await assertFileContents('./runThing', `\
+#!/usr/bin/env node
+// TODO: This file was created by bulk-decaffeinate.
+// Sanity-check the conversion and remove this comment.
+
+console.log('Ran the thing!');
+`);
+    });
+  });
+
   it('runs eslint, applying fixes and disabling existing issues', async function() {
     await runWithTemplateDir('eslint-fix-test', async function() {
       await initGitRepo();

test/examples/extensionless-script/bulk-decaffeinate.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+  filesToProcess: ['./runThing'],
+};

test/examples/extensionless-script/runThing

@@ -0,0 +1,3 @@
+#!/usr/bin/env coffee
+
+console.log 'Ran the thing!'

test/util/FilePaths-test.js

@@ -0,0 +1,28 @@
+/* eslint-env mocha */
+import assert from 'assert';
+import * as FilePaths from '../../src/util/FilePaths';
+
+describe('FilePaths', () => {
+  it('generates correct backup paths', () => {
+    assert.equal(FilePaths.backupPathFor('./a/b/foo.coffee'), 'a/b/foo.original.coffee');
+    assert.equal(FilePaths.backupPathFor('foo.coffee'), 'foo.original.coffee');
+    assert.equal(FilePaths.backupPathFor('foo.coffee.md'), 'foo.original.coffee.md');
+    assert.equal(FilePaths.backupPathFor('foo.cjsx'), 'foo.original.cjsx');
+    assert.equal(FilePaths.backupPathFor('foo'), 'foo.original');
+  });
+
+  it('generates correct js paths', () => {
+    assert.equal(FilePaths.jsPathFor('./a/b/foo.coffee'), 'a/b/foo.js');
+    assert.equal(FilePaths.jsPathFor('foo.coffee'), 'foo.js');
+    assert.equal(FilePaths.jsPathFor('foo.coffee.md'), 'foo.js');
+    assert.equal(FilePaths.jsPathFor('foo.cjsx'), 'foo.js');
+    assert.equal(FilePaths.jsPathFor('foo'), 'foo');
+  });
+
+  it('generates correct decaffeinate out paths', () => {
+    assert.equal(FilePaths.decaffeinateOutPathFor('./a/b/foo.coffee'), 'a/b/foo.js');
+    assert.equal(FilePaths.decaffeinateOutPathFor('foo.coffee.md'), 'foo.js');
+    assert.equal(FilePaths.decaffeinateOutPathFor('foo.cjsx'), 'foo.js');
+    assert.equal(FilePaths.decaffeinateOutPathFor('foo'), 'foo.js');
+  });
+});