Fix stack trace (#4428)

* Revert aee27fb

* Patch Jison’s output so that it requires `fs` only if we’re truly in a CommonJS/Node environment, not a browser environment that may happen to have globals named `require` and `exports` (as would be the case if require.js is being used). Fixes #4391.

* Temporary fix for exceptions getting thrown when trying to generate a stack trace for a file that has been deleted since compilation; fixes #3890, but not well. A better solution would not try to recompile the file when trying to retrieve its stack trace.

* Save the test REPL history in the system temp folder, not in the CoffeeScript project folder

* Rewrite `getSourceMap` to never read a file from disk, and therefore not throw IO-related exceptions; source maps are either retrieved from memory, or the related source code is retrieved from memory to generate a new source map. Fixes #3890 the proper way.

* Add test to verify that stack traces reference the correct line number. Closes #4418.

* Get the parser working in the browser compiler again; rather than detecting a CommonJS environment generally, just check for `fs` before trying to use it

* Follow Node’s standard of 4-space indentation of stack trace data

* Better .gitignore

* Fix caching of compiled code and source maps; add more tests to verify correct line numbers in stack traces

* Better fallback value for the parser source

* Fix the stack traces and tests when running in a browser

* Update the browser compiler so that @murrayju doesn’t have any extra work to do to test this branch

Author: GeoffreyBooth

.gitignore

@@ -1,8 +1,10 @@
 raw
 presentation
 test.coffee
+test*.coffee
 test.litcoffee
-parser.output
+test*.litcoffee
 test/*.js
+parser.output
 /node_modules
-npm-debug.log
+npm-debug.log*

Cakefile

@@ -85,8 +85,15 @@ task 'build:full', 'rebuild the source twice, and run the tests', ->
 task 'build:parser', 'rebuild the Jison parser (run build first)', ->
   helpers.extend global, require 'util'
   require 'jison'
-  parser = require('./lib/coffee-script/grammar').parser
-  fs.writeFileSync 'lib/coffee-script/parser.js', parser.generate()
+  parser = require('./lib/coffee-script/grammar').parser.generate()
+  # Patch Jison’s output, until https://github.com/zaach/jison/pull/339 is accepted,
+  # to ensure that require('fs') is only called where it exists.
+  parser = parser.replace "var source = require('fs')", """
+      var source = '';
+          var fs = require('fs');
+          if (typeof fs !== 'undefined' && fs !== null)
+              source = fs"""
+  fs.writeFileSync 'lib/coffee-script/parser.js', parser
 
 
 task 'build:browser', 'rebuild the merged script for inclusion in the browser', ->

docs/v1/browser-compiler/coffee-script.js

@@ -2882,6 +2882,16 @@ <h1>CoffeeScript Test Suite</h1>
   obj.method()
   eq obj.item, 3
 
+test "#4411: Allow @values as loop indices", ->
+  obj =
+    index: null
+    get: -> @index
+    method: ->
+      @get() for _, @index in [1, 2, 3]
+  eq obj.index, null
+  arrayEq obj.method(), [0, 1, 2]
+  eq obj.index, 3
+
 test "#2525, #1187, #1208, #1758, looping over an array forwards", ->
   list = [0, 1, 2, 3, 4]
 
@@ -3470,9 +3480,21 @@ <h1>CoffeeScript Test Suite</h1>
 
 
 if require?
+  os   = require 'os'
   fs   = require 'fs'
   path = require 'path'
 
+  test "patchStackTrace line patching", ->
+    err = new Error 'error'
+    ok err.stack.match /test[\/\\]error_messages\.coffee:\d+:\d+\b/
+
+  test "patchStackTrace stack prelude consistent with V8", ->
+    err = new Error
+    ok err.stack.match /^Error\n/ # Notice no colon when no message.
+
+    err = new Error 'error'
+    ok err.stack.match /^Error: error\n/
+
   test "#2849: compilation error in a require()d file", ->
     # Create a temporary file to require().
     ok not fs.existsSync 'test/syntax-error.coffee'
@@ -3490,6 +3512,57 @@ <h1>CoffeeScript Test Suite</h1>
     finally
       fs.unlinkSync 'test/syntax-error.coffee'
 
+  test "#3890 Error.prepareStackTrace doesn't throw an error if a compiled file is deleted", ->
+    # Adapted from https://github.com/atom/coffee-cash/blob/master/spec/coffee-cash-spec.coffee
+    filePath = path.join os.tmpdir(), 'PrepareStackTraceTestFile.coffee'
+    fs.writeFileSync filePath, "module.exports = -> throw new Error('hello world')"
+    throwsAnError = require filePath
+    fs.unlinkSync filePath
+
+    try
+      throwsAnError()
+    catch error
+
+    eq error.message, 'hello world'
+    doesNotThrow(-> error.stack)
+    notEqual error.stack.toString().indexOf(filePath), -1
+
+  test "#4418 stack traces for compiled files reference the correct line number", ->
+    filePath = path.join os.tmpdir(), 'StackTraceLineNumberTestFile.coffee'
+    fileContents = """
+      testCompiledFileStackTraceLineNumber = ->
+        # `a` on the next line is undefined and should throw a ReferenceError
+        console.log a if true
+
+      do testCompiledFileStackTraceLineNumber
+      """
+    fs.writeFileSync filePath, fileContents
+
+    try
+      require filePath
+    catch error
+    fs.unlinkSync filePath
+
+    # Make sure the line number reported is line 3 (the original Coffee source)
+    # and not line 6 (the generated JavaScript).
+    eq /StackTraceLineNumberTestFile.coffee:(\d)/.exec(error.stack.toString())[1], '3'
+
+
+test "#4418 stack traces for compiled strings reference the correct line number", ->
+  try
+    CoffeeScript.run """
+      testCompiledStringStackTraceLineNumber = ->
+        # `a` on the next line is undefined and should throw a ReferenceError
+        console.log a if true
+
+      do testCompiledStringStackTraceLineNumber
+      """
+  catch error
+
+  # Make sure the line number reported is line 3 (the original Coffee source)
+  # and not line 6 (the generated JavaScript).
+  eq /at testCompiledStringStackTraceLineNumber.*:(\d):/.exec(error.stack.toString())[1], '3'
+
 
 test "#1096: unexpected generated tokens", ->
   # Implicit ends
@@ -3844,7 +3917,7 @@ <h1>CoffeeScript Test Suite</h1>
   assertErrorFormat '''
     ///a \\u002 0 space///
   ''', '''
-    [stdin]:1:6: error: invalid escape sequence \\u002 
+    [stdin]:1:6: error: invalid escape sequence \\u002 \n\
     ///a \\u002 0 space///
          ^\^^^^^
   '''
@@ -4596,6 +4669,13 @@ <h1>CoffeeScript Test Suite</h1>
     ^
   '''
 
+test "can't use pattern matches for loop indices", ->
+  assertErrorFormat 'a for b, {c} in d', '''
+    [stdin]:1:10: error: index cannot be a pattern matching expression
+    a for b, {c} in d
+             ^^^
+  '''
+
 </script>
 <script type="text/x-coffeescript" class="test" id="eval">
 if vm = require? 'vm'
@@ -9227,7 +9307,7 @@ <h1>CoffeeScript Test Suite</h1>
 
 test "floor division operator compound assignment", ->
   a = 7
-  a //= 2
+  a //= 1 + 1
   eq 3, a
 
 test "modulo operator", ->
@@ -9823,7 +9903,9 @@ <h1>CoffeeScript Test Suite</h1>
 <script type="text/x-coffeescript" class="test" id="repl">
 return if global.testingBrowser
 
+os = require 'os'
 fs = require 'fs'
+path = require 'path'
 
 # REPL
 # ----
@@ -9851,7 +9933,7 @@ <h1>CoffeeScript Test Suite</h1>
     @written[@written.length - 1 + fromEnd].replace /\r?\n$/, ''
 
 # Create a dummy history file
-historyFile = '.coffee_history_test'
+historyFile = path.join os.tmpdir(), '.coffee_history_test'
 fs.writeFileSync historyFile, '1 + 2\n'
 
 testRepl = (desc, fn) ->