Save correct context boxes for broken out-of-flow boxes

Fix #2571.

Author: liZe

tests/draw/test_float.py

@@ -957,3 +957,49 @@ def test_float_split_large_parent(assert_pixels):
         <section>
         <div>bb bb bb bb bb</div>
         <article>aa</article>''')
+
+
+@assert_no_logs
+def test_float_split_in_stacking_context(assert_pixels):
+    assert_pixels('''
+        RRRR
+        RRRR
+        BBBB
+        BBBB
+        ____
+
+        BBBB
+        BBBB
+        RRRR
+        RRRR
+        ____
+
+        RRRR
+        RRRR
+        ____
+        ____
+        ____
+    ''', '''
+        <style>
+            @page {
+                size: 4px 5px;
+            }
+            body {
+                color: red;
+                font: 2px / 1 weasyprint;
+            }
+            section {
+                display: flow-root;
+            }
+            div {
+                color: blue;
+                float: left;
+            }
+            article {
+                clear: left;
+            }
+        </style>
+        <section>
+        aa
+        <div>bb bb</div>
+        cc cc''')

weasyprint/layout/__init__.py

@@ -229,13 +229,13 @@ def __init__(self, style_for, get_image_from_uri, font_config,
         self.font_config = font_config
         self.counter_style = counter_style
         self.target_collector = target_collector
-        self._excluded_shapes_lists = []
+        self._excluded_shapes_root_boxes = []
+        self._excluded_shapes = {}
         self.footnotes = []
         self.page_footnotes = {}
         self.current_page_footnotes = []
         self.reported_footnotes = []
         self.current_footnote_area = None  # Not initialized yet
-        self.excluded_shapes = None  # Not initialized yet
         self.page_bottom = None
         self.string_set = defaultdict(lambda: defaultdict(list))
         self.running_elements = defaultdict(lambda: defaultdict(list))
@@ -257,34 +257,39 @@ def overflows(bottom, position_y):
         # The 1e-9 value comes from PEP 485.
         return position_y > bottom * (1 + 1e-9)
 
-    def create_block_formatting_context(self):
-        self.excluded_shapes = []
-        self._excluded_shapes_lists.append(self.excluded_shapes)
+    @property
+    def excluded_shapes(self):
+        return self._excluded_shapes[self._excluded_shapes_root_boxes[-1]]
 
-    def finish_block_formatting_context(self, root_box):
+    @excluded_shapes.setter
+    def excluded_shapes(self, excluded_shapes):
+        self._excluded_shapes[self._excluded_shapes_root_boxes[-1]] = excluded_shapes
+
+    def create_block_formatting_context(self, root_box, new_list=None):
+        assert root_box not in self._excluded_shapes_root_boxes
+        self._excluded_shapes_root_boxes.append(root_box)
+        if root_box not in self._excluded_shapes:
+            self._excluded_shapes[root_box] = [] if new_list is None else new_list
+
+    def finish_block_formatting_context(self, root_box=None):
         # See https://www.w3.org/TR/CSS2/visudet.html#root-height
-        if root_box.style['height'] == 'auto' and self.excluded_shapes:
+        if root_box and root_box.style['height'] == 'auto' and self.excluded_shapes:
             box_bottom = root_box.content_box_y() + root_box.height
             max_shape_bottom = max([
                 shape.position_y + shape.margin_height()
                 for shape in self.excluded_shapes] + [box_bottom])
             root_box.height += max_shape_bottom - box_bottom
-        self._excluded_shapes_lists.pop()
-        if self._excluded_shapes_lists:
-            self.excluded_shapes = self._excluded_shapes_lists[-1]
-        else:
-            self.excluded_shapes = None
+        self._excluded_shapes.pop(self._excluded_shapes_root_boxes.pop())
 
-    def create_flex_formatting_context(self):
-        self.excluded_shapes = FakeList()
-        self._excluded_shapes_lists.append(self.excluded_shapes)
+    def create_flex_formatting_context(self, root_box):
+        self.create_block_formatting_context(root_box, FakeList())
 
     def finish_flex_formatting_context(self, root_box):
-        self._excluded_shapes_lists.pop()
-        if self._excluded_shapes_lists:
-            self.excluded_shapes = self._excluded_shapes_lists[-1]
-        else:
-            self.excluded_shapes = None
+        self.finish_block_formatting_context(root_box)
+
+    def add_broken_out_of_flow(self, new_box, box, containing_block, resume_at):
+        self.broken_out_of_flow[new_box] = (
+            box, containing_block, self._excluded_shapes_root_boxes[-1], resume_at)
 
     def get_string_set_for(self, page, name, keyword='first'):
         """Resolve value of string function."""

weasyprint/layout/absolute.py

@@ -237,8 +237,7 @@ def absolute_layout(context, placeholder, containing_block, fixed_boxes,
         context, box, containing_block, fixed_boxes, bottom_space, skip_stack)
     placeholder.set_laid_out_box(new_box)
     if resume_at:
-        context.broken_out_of_flow[placeholder] = (
-            box, containing_block, resume_at)
+        context.add_broken_out_of_flow(placeholder, box, containing_block, resume_at)
 
 
 def absolute_box_layout(context, box, containing_block, fixed_boxes,
@@ -259,7 +258,6 @@ def absolute_box_layout(context, box, containing_block, fixed_boxes,
     resolve_percentages(box, (cb_width, cb_height))
     resolve_position_percentages(box, (cb_width, cb_height))
 
-    context.create_block_formatting_context()
     if isinstance(box, boxes.BlockReplacedBox):
         new_box = absolute_replaced(
             context, box, cb_x, cb_y, cb_width, cb_height)
@@ -269,7 +267,6 @@ def absolute_box_layout(context, box, containing_block, fixed_boxes,
         new_box, resume_at = absolute_block(
             context, box, containing_block, fixed_boxes, bottom_space,
             skip_stack, cb_x, cb_y, cb_width, cb_height)
-    context.finish_block_formatting_context(new_box)
 
     return new_box, resume_at
 

weasyprint/layout/block.py

@@ -662,7 +662,7 @@ def block_container_layout(context, box, bottom_space, skip_stack,
     assert isinstance(box, boxes.BlockContainerBox)
 
     if box.establishes_formatting_context():
-        context.create_block_formatting_context()
+        context.create_block_formatting_context(box)
 
     # TODO: merge this with _in_flow_layout, flex_layout…
     is_start = skip_stack is None
@@ -728,8 +728,8 @@ def block_container_layout(context, box, bottom_space, skip_stack,
                     absolute_boxes, fixed_boxes, adjoining_margins,
                     bottom_space))
             if out_of_flow_resume_at:
-                context.broken_out_of_flow[new_child] = (
-                    child, box, out_of_flow_resume_at)
+                context.add_broken_out_of_flow(
+                    new_child, child, box, out_of_flow_resume_at)
             if child.is_outside_marker:
                 new_child.position_x = box.border_box_x()
                 if child.style['direction'] == 'rtl':
@@ -778,6 +778,8 @@ def block_container_layout(context, box, bottom_space, skip_stack,
                 context, box.children[skip:], absolute_boxes, fixed_boxes)
             for footnote in new_footnotes:
                 context.unlayout_footnote(footnote)
+            if box.establishes_formatting_context():
+                context.finish_block_formatting_context()
             return (
                 None, None, {'break': 'any', 'page': page}, [], False,
                 max_lines)
@@ -802,6 +804,8 @@ def block_container_layout(context, box, bottom_space, skip_stack,
             not page_is_empty):
         remove_placeholders(
             context, [*new_children, *box.children[skip:]], absolute_boxes, fixed_boxes)
+        if box.establishes_formatting_context():
+            context.finish_block_formatting_context()
         return None, None, {'break': 'any', 'page': None}, [], False, max_lines
 
     if collapsing_with_children:
@@ -870,7 +874,7 @@ def block_container_layout(context, box, bottom_space, skip_stack,
     for child in new_box.children:
         relative_positioning(child, (new_box.width, new_box.height))
 
-    if new_box.establishes_formatting_context():
+    if box.establishes_formatting_context():
         context.finish_block_formatting_context(new_box)
 
     if discard or not box_is_fragmented:

weasyprint/layout/flex.py

@@ -20,7 +20,7 @@ def flex_layout(context, box, bottom_space, skip_stack, containing_block, page_i
     from . import block
 
     # TODO: merge this with block_container_layout.
-    context.create_flex_formatting_context()
+    context.create_flex_formatting_context(box)
     resume_at = None
 
     is_start = skip_stack is None

weasyprint/layout/float.py

@@ -58,13 +58,11 @@ def float_layout(context, box, containing_block, absolute_boxes, fixed_boxes,
         table_wrapper_width(context, box, (cb_width, cb_height))
 
     if isinstance(box, boxes.BlockContainerBox):
-        context.create_block_formatting_context()
         box, resume_at, _, _, _, _ = block_container_layout(
             context, box, bottom_space=bottom_space,
             skip_stack=skip_stack, page_is_empty=True,
             absolute_boxes=absolute_boxes, fixed_boxes=fixed_boxes,
             adjoining_margins=None, discard=False, max_lines=None)
-        context.finish_block_formatting_context(box)
     elif isinstance(box, boxes.FlexContainerBox):
         box, resume_at, _, _, _ = flex_layout(
             context, box, bottom_space=bottom_space,

weasyprint/layout/grid.py

@@ -577,7 +577,7 @@ def _resolve_tracks_sizes(sizing_functions, box_size, children_positions,
 
 def grid_layout(context, box, bottom_space, skip_stack, containing_block,
                 page_is_empty, absolute_boxes, fixed_boxes):
-    context.create_block_formatting_context()
+    context.create_block_formatting_context(box)
 
     # Define explicit grid
     grid_areas = box.style['grid_template_areas']

weasyprint/layout/inline.py

@@ -178,8 +178,9 @@ def get_next_linebox(context, linebox, position_y, bottom_space, skip_stack,
             fixed_boxes, bottom_space, skip_stack=None)
         float_children.append(new_waiting_float)
         if waiting_float_resume_at:
-            context.broken_out_of_flow[new_waiting_float] = (
-                waiting_float, containing_block, waiting_float_resume_at)
+            context.add_broken_out_of_flow(
+                new_waiting_float, waiting_float, containing_block,
+                waiting_float_resume_at)
     if float_children:
         line.children += tuple(float_children)
 
@@ -574,8 +575,8 @@ def _out_of_flow_layout(context, box, containing_block, index, child,
                 context, child, containing_block, absolute_boxes, fixed_boxes,
                 bottom_space, skip_stack=None)
             if float_resume_at:
-                context.broken_out_of_flow[child] = (
-                    child, containing_block, float_resume_at)
+                context.add_broken_out_of_flow(
+                    child, child, containing_block, float_resume_at)
             waiting_children.append((index, new_child, child))
             child = new_child
 

weasyprint/layout/page.py

@@ -1,7 +1,7 @@
 """Layout for pages and CSS3 margin boxes."""
 
 import copy
-from collections import namedtuple
+from collections import defaultdict, namedtuple
 from math import inf
 
 from ..css import AnonymousStyle
@@ -606,7 +606,7 @@ def make_page(context, root_box, page_type, resume_at, page_number,
 
     # https://www.w3.org/TR/css-display-4/#root
     assert isinstance(root_box, boxes.BlockLevelBox)
-    context.create_block_formatting_context()
+    context.create_block_formatting_context(root_box)
     context.current_page = page_number
     context.current_page_footnotes = []
     context.current_footnote_area = footnote_area
@@ -627,15 +627,19 @@ def make_page(context, root_box, page_type, resume_at, page_number,
     adjoining_margins = []
     positioned_boxes = []  # Mixed absolute and fixed
     out_of_flow_boxes = []
+    excluded_shapes = defaultdict(list)
     broken_out_of_flow = {}
     context_out_of_flow = context.broken_out_of_flow.values()
     context.broken_out_of_flow = broken_out_of_flow
-    for box, containing_block, skip_stack in context_out_of_flow:
+    for box, containing_block, context_box, skip_stack in context_out_of_flow:
+        if context_box != root_box:
+            context.create_block_formatting_context(context_box)
         box.position_y = root_box.content_box_y()
         if box.is_floated():
             out_of_flow_box, out_of_flow_resume_at = float_layout(
                 context, box, containing_block, positioned_boxes,
                 positioned_boxes, 0, skip_stack)
+            excluded_shapes[context_box].append(out_of_flow_box)
         else:
             assert box.is_absolutely_positioned()
             out_of_flow_box, out_of_flow_resume_at = absolute_box_layout(
@@ -644,8 +648,14 @@ def make_page(context, root_box, page_type, resume_at, page_number,
         out_of_flow_boxes.append(out_of_flow_box)
         page_is_empty = False
         if out_of_flow_resume_at:
-            broken_out_of_flow[out_of_flow_box] = (
-                box, containing_block, out_of_flow_resume_at)
+            context.add_broken_out_of_flow(
+                out_of_flow_box, box, containing_block, out_of_flow_resume_at)
+        if context_box != root_box:
+            context.finish_block_formatting_context()
+
+    # Set excluded shapes from broken out of flow for in-flow content.
+    for context_box, shapes in excluded_shapes.items():
+        context._excluded_shapes[context_box] = shapes
 
     # Display in-flow content.
     initial_root_box = root_box