Fix crashes.

* Some fixed boxes did not have any layout
* Validator for the 'float' property masked the builtin,
  float('inf') returned None.

weasyprint/css/validation.py

@@ -516,9 +516,9 @@ def display(keyword):
         'table-row', 'table-column-group', 'table-column', 'table-cell')
 
 
-@validator()
+@validator('float')
 @single_keyword
-def float(keyword):
+def float_(keyword):  # XXX do not hide the "float" builtin
     """``float`` property validation."""
     return keyword in ('left', 'right', 'none')
 

weasyprint/layout/absolute.py

@@ -146,7 +146,11 @@ def absolute_height(box, document, containing_block):
     translate_box_height = False
     default_translate_y = cb_y - box.position_y
     if top == bottom == height == 'auto':
-        pass  # Keep the static position
+        # Keep the static position
+        if margin_t == 'auto':
+            box.margin_top = 0
+        if margin_b == 'auto':
+            box.margin_bottom = 0
     elif top != 'auto' and bottom != 'auto' and height != 'auto':
         height_for_margins = cb_height - (
             top + bottom + paddings_plus_borders_y)

weasyprint/layout/pages.py

@@ -494,24 +494,17 @@ def make_page(document, root_box, page_type, resume_at, content_empty):
     assert isinstance(root_box, boxes.BlockBox)
     page_is_empty = True
     adjoining_margins = []
-    absolute_boxes = []
-    fixed_boxes = []
+    positioned_boxes = []  # Mixed absolute and fixed
     root_box, resume_at, next_page, _, _ = block_level_layout(
         document, root_box, page_content_bottom, resume_at,
         initial_containing_block, device_size, page_is_empty,
-        absolute_boxes, fixed_boxes, adjoining_margins)
+        positioned_boxes, positioned_boxes, adjoining_margins)
     assert root_box
 
-    children = [root_box]
-
-    for absolute_box in absolute_boxes + fixed_boxes:
-        # Use an empty list as last argument because the fixed boxes in the
-        # fixed box has already been added to fixed_boxes, we don't want to get
-        # them again
-        absolute_layout(document, absolute_box, page, [])
-
-    page = page.copy_with_children(children)
+    for absolute_box in positioned_boxes:
+        absolute_layout(document, absolute_box, page, positioned_boxes)
 
+    page = page.copy_with_children([root_box])
     if content_empty:
         resume_at = previous_resume_at
     return page, resume_at, next_page