don't compile if not outdated in development, but force compilation when running collectstatic

pipeline/compilers/__init__.py

@@ -23,13 +23,15 @@ class Compiler(object):
         return [to_class(compiler) for compiler in settings.PIPELINE_COMPILERS]
     compilers = property(compilers)
 
-    def compile(self, paths):
+    def compile(self, paths, force=False):
         for index, path in enumerate(paths):
             for compiler in self.compilers:
                 compiler = compiler(self.verbose)
                 if compiler.match_file(path):
                     new_path = self.output_path(path, compiler.output_extension)
                     paths[index] = new_path
+                    if not force and not self.is_outdated(path, new_path):
+                        continue
                     try:
                         content = self.read_file(path)
                         compiled_content = compiler.compile_file(content, finders.find(path))
@@ -52,7 +54,7 @@ class Compiler(object):
     def is_outdated(self, path, new_path):
         try:
             return self.storage.modified_time(path) > self.storage.modified_time(new_path)
-        except OSError:
+        except (OSError, NotImplementedError):
             return True
 
     def save_file(self, path, content):

pipeline/packager.py

@@ -89,14 +89,14 @@ class Packager(object):
             output_filename=package.output_filename,
             variant=package.variant, **kwargs)
 
-    def compile(self, paths):
-        return self.compiler.compile(paths)
+    def compile(self, paths, force=False):
+        return self.compiler.compile(paths, force=force)
 
     def pack(self, package, compress, signal, **kwargs):
         output_filename = package.output_filename
         if self.verbose:
             print "Saving: %s" % output_filename
-        paths = self.compile(package.paths)
+        paths = self.compile(package.paths, force=True)
         content = compress(paths, **kwargs)
         self.save_file(output_filename, content)
         signal.send(sender=self, package=package, **kwargs)