Bug fix: properly build anonymous blocks when a block element is in an inline

weasy/formatting_structure/boxes.py

@@ -99,7 +99,8 @@ class Box(object):
         self.style = self.document.style_for(self.element).copy()
 
     def __repr__(self):
-        return '<%s %s>' % (type(self).__name__, self.element.tag)
+        return '<%s %s %i>' % (type(self).__name__, self.element.tag,
+                               self.element.sourceline)
 
     def ancestors(self):
         """Yield parent and recursively yield parent's parents."""
@@ -473,4 +474,3 @@ class InlineLevelReplacedBox(ReplacedBox, AtomicInlineLevelBox):
     A replaced element with a 'display' value of 'inline', 'inline-table', or
     'inline-block' generates an inline-level replaced box.
     """
-

weasy/formatting_structure/build.py

@@ -37,6 +37,7 @@ def build_formatting_structure(document):
     box = inline_in_block(box)
     box = block_in_inline(box)
     box = process_whitespace(box)
+    sanity_checks(box)
     return box
 
 
@@ -299,7 +300,7 @@ def block_in_inline(box):
                 if block_level_box is None:
                     break
                 _add_anonymous_block(new_box, new_line)
-                new_box.add_child(block_level_box)
+                new_box.add_child(block_in_inline(block_level_box))
                 # Loop with the same child
             if new_box.children:
                 # Some children were already added, this became a block
@@ -351,3 +352,30 @@ def _inner_block_in_inline(box):
             box.children.appendleft(child)
             break
     return new_box, block_level_box
+
+
+def sanity_checks(box):
+    """
+    Check that the rules regarding boxes are met:
+
+    * A block container can contain either only block-level boxes or
+      only line boxes
+    * Line boxes and inline boxes can only contain inline-level boxes.
+    """
+    if not isinstance(box, boxes.ParentBox):
+        return
+
+    for child in box.children:
+        sanity_checks(child)
+
+    if isinstance(box, boxes.BlockContainerBox):
+        types = [boxes.BlockLevelBox, boxes.LineBox]
+    elif isinstance(box, (boxes.LineBox, boxes.InlineBox)):
+        types = [boxes.InlineLevelBox]
+    else:
+        return
+
+    assert any(
+        all(isinstance(child, type_) for child in box.children)
+        for type_ in types
+    )

weasy/tests/test_boxes.py

@@ -188,12 +188,13 @@ def test_inline_in_block():
 @suite.test
 def test_block_in_inline():
     box = parse('''
-        <style>
+<style>
     p { display: inline-block; }
     span { display: block; }
-        </style>
-        <p>Lorem <em>ipsum <strong>dolor <span>sit</span>
-            <span>amet,</span></strong><span>consectetur</span></em></p>''')
+</style>
+<p>Lorem <em>ipsum <strong>dolor <span>sit</span>
+    <span>amet,</span></strong><span><em>consectetur<div/></em></span></em></p>
+    ''')
     box = build.inline_in_block(box)
     assert_tree(box, [
         ('body', 'line', [
@@ -214,7 +215,10 @@ def test_block_in_inline():
                                     ('span', 'text', 'amet,')])])]),
                         ('span', 'block', [ # This block is "pulled up"
                             ('span', 'line', [
-                                ('span', 'text', 'consectetur')])])])])])])])
+                                ('em', 'inline', [
+                                    ('em', 'text', 'consectetur'),
+                                    ('div', 'block', []),
+                                    ])])])])])])])])
 
     box = build.block_in_inline(box)
     assert_tree(box, [
@@ -245,8 +249,14 @@ def test_block_in_inline():
                         ('em', 'inline', [
                             ('strong', 'inline', [])])])]),
                 ('span', 'block', [
+                    ('span', 'anon_block', [
                         ('span', 'line', [
-                        ('span', 'text', 'consectetur')])]),
+                            ('em', 'inline', [
+                                ('em', 'text', 'consectetur')])])]),
+                    ('div', 'block', []),
+                    ('span', 'anon_block', [
+                        ('span', 'line', [
+                            ('em', 'inline', [])])])]),
                 ('p', 'anon_block', [
                     ('p', 'line', [
                         ('em', 'inline', [])])])])])])