Fixed #165. Switched the order of treeprocessors when attr_list and headerid extensions are used togeather. While this means headerid may alter IDs defined in attr_lists for uniqueness, automaticaly generated ids will not contain unparsed attr_lists. This is the lesser of two evils - and actually generates a more valid output (all IDs will be unique)

3 files changed, 20 insertions, 10 deletions

diff --git a/markdown/extensions/attr_list.py b/markdown/extensions/attr_list.py
index 36f3e3a..8734e9f 100644
--- a/markdown/extensions/attr_list.py
+++ b/markdown/extensions/attr_list.py
@@ -74,7 +74,6 @@ class AttrListTreeprocessor(markdown.treeprocessors.Treeprocessor):
 
     def run(self, doc):
         for elem in doc.getiterator():
-            #import pdb; pdb.set_trace()
             if isBlockLevel(elem.tag):
                 # Block level: check for attrs on last line of text
                 RE = self.BLOCK_RE
@@ -131,12 +130,7 @@ class AttrListTreeprocessor(markdown.treeprocessors.Treeprocessor):
 
 class AttrListExtension(markdown.extensions.Extension):
     def extendMarkdown(self, md, md_globals):
-        if 'headerid' in md.treeprocessors.keys():
-            # insert after 'headerid' treeprocessor
-            md.treeprocessors.add('attr_list', AttrListTreeprocessor(md), '>headerid')
-        else:
-            # insert after 'inline' treeprocessor
-            md.treeprocessors.add('attr_list', AttrListTreeprocessor(md), '>inline')
+        md.treeprocessors.add('attr_list', AttrListTreeprocessor(md), '>inline')
 
 
 def makeExtension(configs={}):
diff --git a/markdown/extensions/headerid.py b/markdown/extensions/headerid.py
index 2d18c15..1d158f9 100644
--- a/markdown/extensions/headerid.py
+++ b/markdown/extensions/headerid.py
@@ -133,7 +133,7 @@ class HeaderIdTreeprocessor(markdown.treeprocessors.Treeprocessor):
             if elem.tag in ['h1', 'h2', 'h3', 'h4', 'h5', 'h6']:
                 if force_id:
                     if "id" in elem.attrib:
-                        id = elem.id
+                        id = elem.get('id')
                     else:
                         id = slugify(u''.join(itertext(elem)), sep)
                     elem.set('id', unique(id, self.IDs))
@@ -183,8 +183,12 @@ class HeaderIdExtension (markdown.Extension):
         self.processor = HeaderIdTreeprocessor()
         self.processor.md = md
         self.processor.config = self.getConfigs()
-        # Replace existing hasheader in place.
-        md.treeprocessors.add('headerid', self.processor, '>inline')
+        if 'attr_list' in md.treeprocessors.keys():
+            # insert after attr_list treeprocessor
+            md.treeprocessors.add('headerid', self.processor, '>attr_list')
+        else:
+            # insert after 'inline' treeprocessor.
+            md.treeprocessors.add('headerid', self.processor, '>inline')
 
     def reset(self):
         self.processor.IDs = []
diff --git a/tests/test_extensions.py b/tests/test_extensions.py
index 315e7ef..b10414e 100644
--- a/tests/test_extensions.py
+++ b/tests/test_extensions.py
@@ -171,6 +171,18 @@ header_forceid: Off
         self.assertEqual(markdown.markdown(text, ['headerid', 'meta']),
             '<h2>A Header</h2>')
 
+    def testHeaderIdWithAttr_List(self):
+        """ Test HeaderIDs with Attr_List extension. """
+        
+        text = '# Header1 {: #foo }\n# Header2 {: .bar }'
+        self.assertEqual(markdown.markdown(text, ['headerid', 'attr_list']),
+            '<h1 id="foo">Header1</h1>\n'
+            '<h1 class="bar" id="header2">Header2</h1>')
+        # Switch order extensions are loaded - should be no change in behavior.
+        self.assertEqual(markdown.markdown(text, ['attr_list', 'headerid']),
+            '<h1 id="foo">Header1</h1>\n'
+            '<h1 class="bar" id="header2">Header2</h1>')
+
 class TestMetaData(unittest.TestCase):
     """ Test MetaData extension. """