[CS2] Fix #2870: Allow specifying output filename (#4661)

* Fix #2870: If --output ends with a filename, and the input is a file and not a path, save as the desired filename

* If an output path ends in a slash, force saving into an output folder even if that folder name would contain a period (e.g. /scripts.js/); if output filename is only periods, treat it as a path

* Restrict exceptions

Author: GeoffreyBooth

lib/coffeescript/command.js

@@ -32,25 +32,25 @@ BANNER = '''
 
 # The list of all the valid option flags that `coffee` knows how to handle.
 SWITCHES = [
-  ['-b', '--bare',            'compile without a top-level function wrapper']
-  ['-c', '--compile',         'compile to JavaScript and save as .js files']
-  ['-e', '--eval',            'pass a string from the command line as input']
-  ['-h', '--help',            'display this help message']
-  ['-i', '--interactive',     'run an interactive CoffeeScript REPL']
-  ['-j', '--join [FILE]',     'concatenate the source CoffeeScript before compiling']
-  ['-m', '--map',             'generate source map and save as .js.map files']
-  ['-M', '--inline-map',      'generate source map and include it directly in output']
-  ['-n', '--nodes',           'print out the parse tree that the parser produces']
-  [      '--nodejs [ARGS]',   'pass options directly to the "node" binary']
-  [      '--no-header',       'suppress the "Generated by" header']
-  ['-o', '--output [DIR]',    'set the output directory for compiled JavaScript']
-  ['-p', '--print',           'print out the compiled JavaScript']
+  ['-b', '--bare',              'compile without a top-level function wrapper']
+  ['-c', '--compile',           'compile to JavaScript and save as .js files']
+  ['-e', '--eval',              'pass a string from the command line as input']
+  ['-h', '--help',              'display this help message']
+  ['-i', '--interactive',       'run an interactive CoffeeScript REPL']
+  ['-j', '--join [FILE]',       'concatenate the source CoffeeScript before compiling']
+  ['-m', '--map',               'generate source map and save as .js.map files']
+  ['-M', '--inline-map',        'generate source map and include it directly in output']
+  ['-n', '--nodes',             'print out the parse tree that the parser produces']
+  [      '--nodejs [ARGS]',     'pass options directly to the "node" binary']
+  [      '--no-header',         'suppress the "Generated by" header']
+  ['-o', '--output [PATH]',     'set the output path or path/filename for compiled JavaScript']
+  ['-p', '--print',             'print out the compiled JavaScript']
   ['-r', '--require [MODULE*]', 'require the given module before eval or REPL']
-  ['-s', '--stdio',           'listen for and compile scripts over stdio']
-  ['-l', '--literate',        'treat stdio as literate style coffeescript']
-  ['-t', '--tokens',          'print out the tokens that the lexer/rewriter produce']
-  ['-v', '--version',         'display the version number']
-  ['-w', '--watch',           'watch scripts for changes and rerun commands']
+  ['-s', '--stdio',             'listen for and compile scripts over stdio']
+  ['-l', '--literate',          'treat stdio as literate style coffeescript']
+  ['-t', '--tokens',            'print out the tokens that the lexer/rewriter produce']
+  ['-v', '--version',           'display the version number']
+  ['-w', '--watch',             'watch scripts for changes and rerun commands']
 ]
 
 # Top-level objects shared by all the functions.
@@ -102,7 +102,19 @@ exports.run = ->
   process.argv = process.argv[0..1].concat literals
   process.argv[0] = 'coffee'
 
-  opts.output = path.resolve opts.output  if opts.output
+  if opts.output
+    outputBasename = path.basename opts.output
+    if '.' in outputBasename and
+       outputBasename not in ['.', '..'] and
+       not helpers.ends(opts.output, path.sep)
+      # An output filename was specified, e.g. `/dist/scripts.js`.
+      opts.outputFilename = outputBasename
+      opts.outputPath = path.resolve path.dirname opts.output
+    else
+      # An output path was specified, e.g. `/dist`.
+      opts.outputFilename = null
+      opts.outputPath = path.resolve opts.output
+
   if opts.join
     opts.join = path.resolve opts.join
     console.error '''
@@ -167,7 +179,7 @@ compilePath = (source, topLevel, base) ->
       code = fs.readFileSync source
     catch err
       if err.code is 'ENOENT' then return else throw err
-    compileScript(source, code.toString(), base)
+    compileScript source, code.toString(), base
   else
     notSources[source] = yes
 
@@ -182,43 +194,46 @@ findDirectoryIndex = (source) ->
   process.exit 1
 
 # Compile a single source script, containing the given code, according to the
-# requested options. If evaluating the script directly sets `__filename`,
+# requested options. If evaluating the script directly, set `__filename`,
 # `__dirname` and `module.filename` to be correct relative to the script's path.
 compileScript = (file, input, base = null) ->
-  o = opts
   options = compileOptions file, base
   try
-    t = task = {file, input, options}
+    task = {file, input, options}
     CoffeeScript.emit 'compile', task
-    if o.tokens
-      printTokens CoffeeScript.tokens t.input, t.options
-    else if o.nodes
-      printLine CoffeeScript.nodes(t.input, t.options).toString().trim()
-    else if o.run
+    if opts.tokens
+      printTokens CoffeeScript.tokens task.input, task.options
+    else if opts.nodes
+      printLine CoffeeScript.nodes(task.input, task.options).toString().trim()
+    else if opts.run
       CoffeeScript.register()
-      CoffeeScript.eval opts.prelude, t.options if opts.prelude
-      CoffeeScript.run t.input, t.options
-    else if o.join and t.file isnt o.join
-      t.input = helpers.invertLiterate t.input if helpers.isLiterate file
-      sourceCode[sources.indexOf(t.file)] = t.input
+      CoffeeScript.eval opts.prelude, task.options if opts.prelude
+      CoffeeScript.run task.input, task.options
+    else if opts.join and task.file isnt opts.join
+      task.input = helpers.invertLiterate task.input if helpers.isLiterate file
+      sourceCode[sources.indexOf(task.file)] = task.input
       compileJoin()
     else
-      compiled = CoffeeScript.compile t.input, t.options
-      t.output = compiled
-      if o.map
-        t.output = compiled.js
-        t.sourceMap = compiled.v3SourceMap
+      compiled = CoffeeScript.compile task.input, task.options
+      task.output = compiled
+      if opts.map
+        task.output = compiled.js
+        task.sourceMap = compiled.v3SourceMap
 
       CoffeeScript.emit 'success', task
-      if o.print
-        printLine t.output.trim()
-      else if o.compile or o.map
-        writeJs base, t.file, t.output, options.jsPath, t.sourceMap
+      if opts.print
+        printLine task.output.trim()
+      else if opts.compile or opts.map
+        saveTo = if opts.outputFilename and sources.length is 1
+          path.join opts.outputPath, opts.outputFilename
+        else
+          options.jsPath
+        writeJs base, task.file, task.output, saveTo, task.sourceMap
   catch err
     CoffeeScript.emit 'failure', err, task
     return if CoffeeScript.listeners('failure').length
     message = err?.stack or "#{err}"
-    if o.watch
+    if opts.watch
       printLine message + '\x07'
     else
       printWarn message
@@ -352,12 +367,12 @@ silentUnlink = (path) ->
 outputPath = (source, base, extension=".js") ->
   basename  = helpers.baseFileName source, yes, useWinPathSep
   srcDir    = path.dirname source
-  if not opts.output
-    dir = srcDir
+  dir = unless opts.outputPath
+    srcDir
   else if source is base
-    dir = opts.output
+    opts.outputPath
   else
-    dir = path.join opts.output, path.relative base, srcDir
+    path.join opts.outputPath, path.relative base, srcDir
   path.join dir, basename + extension
 
 # Recursively mkdir, like `mkdir -p`.

src/command.coffee

@@ -130,7 +130,7 @@ If called without options, `coffee` will run your script.
   -n, --nodes        print out the parse tree that the parser produces
       --nodejs       pass options directly to the "node" binary
       --no-header    suppress the "Generated by" header
-  -o, --output       set the output directory for compiled JavaScript
+  -o, --output       set the output path or path/filename for compiled JavaScript
   -p, --print        print out the compiled JavaScript
   -r, --require      require the given module before eval or REPL
   -s, --stdio        listen for and compile scripts over stdio