Hack to fix source map URLs in production brunch.

config.coffee

@@ -31,6 +31,15 @@ exports.config =
   overrides:
     production:
       sourceMaps: 'absoluteUrl'
+      onCompile: (files) ->
+        # For some reason, production brunch produces two entries, the first of which is wrong:
+        # //# sourceMappingURL=public/javascripts/app.js.map
+        # //# sourceMappingURL=/javascripts/app.js.map
+        # So we remove the ones that have public in them.
+        exec = require('child_process').exec
+        for file in files
+          exec "perl -pi -e 's/\\/\\/# sourceMappingURL=public.*//g' #{file.path}"
+        exec c
 
   files:
     javascripts:
@@ -172,7 +181,6 @@ exports.config =
       defn = if path in needHeaders then commonjsHeader else ''
       return defn
 
-
 #- Find all .coffee and .jade files in /app
 
 dirStack = ['./app']