[FIX] modules: avoid to have the docutils' warnings rendered inline.

The html rendering of the __openerp__.py description is done using docutils.
This patch removes the warnings that docutils inserts in the resulting document
and log them. Docutils still generates spurious output on stderr though.
(An alternative is to use the `report_level` option but in that case it seems
we can never witness the warnings being created.)

bzr revid: vmt@openerp.com-20121025130111-7l157hexh6ew9w34

openerp/addons/base/module/module.py

@@ -20,7 +20,10 @@
 ##############################################################################
 
 import base64
+from docutils import io, nodes
 from docutils.core import publish_string
+from docutils.transforms import Transform, writer_aux
+from docutils.writers.html4css1 import Writer
 import imp
 import logging
 import re
@@ -80,6 +83,32 @@ class module_category(osv.osv):
         'visible' : 1,
     }
 
+class MyFilterMessages(Transform):
+    """
+    Custom docutils transform to remove `system message` for a document and
+    generate warnings.
+
+    (The standard filter removes them based on some `report_level` passed in
+    the `settings_override` dictionary, but if we use it, we can't see them
+    and generate warnings.)
+    """
+
+    default_priority = 870
+
+    def apply(self):
+        for node in self.document.traverse(nodes.system_message):
+            _logger.warning("docutils' system message present: %s", str(node))
+            node.parent.remove(node)
+
+class MyWriter(Writer):
+    """
+    Custom docutils html4ccs1 writer that doesn't add the warnings to the
+    output document.
+    """
+
+    def get_transforms(self):
+        return [MyFilterMessages, writer_aux.Admonitions]
+
 class module(osv.osv):
     _name = "ir.module.module"
     _rec_name = "shortdesc"
@@ -100,7 +129,7 @@ class module(osv.osv):
         res = dict.fromkeys(ids, '')
         for module in self.browse(cr, uid, ids, context=context):
             overrides = dict(embed_stylesheet=False, doctitle_xform=False, output_encoding='unicode')
-            output = publish_string(source=module.description, writer_name='html', settings_overrides=overrides)
+            output = publish_string(source=module.description, settings_overrides=overrides, writer=MyWriter())
             res[module.id] = output
         return res