When loading the compiler settings, raise an exception if no compiler can be found.

compressor/base.py

@@ -29,6 +29,7 @@ class Compressor(object):
         self.storage = default_storage
         self.split_content = []
         self.extra_context = {}
+        self.all_mimetypes = dict(settings.COMPRESS_PRECOMPILERS)
 
     def split_contents(self):
         """
@@ -105,10 +106,13 @@ class Compressor(object):
         attrs = self.parser.elem_attribs(elem)
         mimetype = attrs.get("type", None)
         if mimetype is not None:
-            for mimetypes, command in settings.COMPRESS_PRECOMPILERS:
-                if not isinstance(mimetypes, (list, tuple)):
-                    mimetypes = (mimetypes,)
-                if mimetype in mimetypes:
+            command = self.all_mimetypes.get(mimetype)
+            if command is None:
+                if mimetype not in ("text/css", "text/javascript"):
+                    raise CompressorError(
+                        "Couldn't find any configured precompiler "
+                        "for mimetype '%s'." % mimetype)
+            else:
                 content = CompilerFilter(content, filter_type=self.type,
                                          command=command).output(**kwargs)
         return content