Fix inline box breaking function

Fix Kozea#580.

weasyprint/layout/inlines.py

@@ -792,23 +792,6 @@ def split_inline_box(context, box, position_x, max_x, skip_stack,
                             # let's break it!
                             break_found = True
 
-                            # We have to check whether the child we're breaking
-                            # is the one broken by the initial skip stack.
-                            broken_child = bool(
-                                initial_skip_stack and
-                                initial_skip_stack[0] == child_index and
-                                initial_skip_stack[1])
-                            if broken_child:
-                                # This child is already broken by the original
-                                # skip stack, let's skip the already rendered
-                                # part before rendering the waiting child
-                                # again.
-                                current_skip, child_skip = (
-                                    initial_skip_stack[1])
-                            else:
-                                # This child has to be rendered from its start.
-                                child_skip = None
-
                             # We break the waiting child at its last possible
                             # breaking point.
                             # TODO: The dirty solution chosen here is to
@@ -819,7 +802,7 @@ def split_inline_box(context, box, position_x, max_x, skip_stack,
                             child_new_child, child_resume_at, _, _, _ = (
                                 split_inline_level(
                                     context, child, child.position_x, max_x,
-                                    child_skip, box, device_size,
+                                    None, box, device_size,
                                     absolute_boxes, fixed_boxes,
                                     line_placeholders, waiting_floats,
                                     line_children))
@@ -830,14 +813,37 @@ def split_inline_box(context, box, position_x, max_x, skip_stack,
                             else:
                                 children += [(child_index, child_new_child)]
 
+                            # We have to check whether the child we're breaking
+                            # is the one broken by the initial skip stack.
+                            broken_child = bool(
+                                initial_skip_stack and
+                                initial_skip_stack[0] == child_index and
+                                initial_skip_stack[1])
                             if broken_child:
                                 # As this child has already been broken
                                 # following the original skip stack, we have to
                                 # add the original skip stack to the partial
                                 # skip stack we get after the new rendering.
+
+                                # We have to do:
+                                # child_resume_at += initial_skip_stack[1]
+                                # but adding skip stacks is a bit complicated
+                                current_skip, grandchild_skip = (
+                                    initial_skip_stack[1])
+                                current_resume_at, grandchild_resume_at = (
+                                    child_resume_at)
+                                if grandchild_skip is None:
+                                    grandchild_resume_at = child_resume_at[1]
+                                elif grandchild_resume_at is None:
+                                    grandchild_resume_at = grandchild_skip
+                                else:
+                                    grandchild_resume_at = (
+                                        grandchild_skip[0] +
+                                        grandchild_resume_at[0],
+                                        None)
                                 child_resume_at = (
-                                    child_resume_at[0] + current_skip,
-                                    child_resume_at[1])
+                                    current_resume_at + current_skip,
+                                    grandchild_resume_at)
 
                             resume_at = (child_index, child_resume_at)
                             break

weasyprint/tests/test_layout.py

@@ -715,8 +715,8 @@ def test_breaking_linebox():
         'aaaa aaaa a [<span>aaa</span>]')
     html, = page.children
     body, = html.children
-    pre, = body.children
-    line1, line2, line3, line4 = pre.children
+    div, = body.children
+    line1, line2, line3, line4 = div.children
     assert line1.children[0].text == line2.children[0].text == 'aaaa'
     assert line3.children[0].text == 'a'
     text1, span, text2 = line4.children
@@ -730,14 +730,28 @@ def test_breaking_linebox():
         'aaaa a <span>b c</span>d')
     html, = page.children
     body, = html.children
-    pre, = body.children
-    line1, line2, line3 = pre.children
+    div, = body.children
+    line1, line2, line3 = div.children
     assert line1.children[0].text == 'aaaa'
     assert line2.children[0].text == 'a '
     assert line2.children[1].children[0].text == 'b'
     assert line3.children[0].children[0].text == 'c'
     assert line3.children[1].text == 'd'
 
+    # Regression test #1 for https://github.com/Kozea/WeasyPrint/issues/580
+    page, = parse(
+        '<div style="width: 5.5em; font-family: ahem">'
+        '<span>aaaa aaaa a a a</span><span>bc</span>')
+    html, = page.children
+    body, = html.children
+    div, = body.children
+    line1, line2, line3, line4 = div.children
+    assert line1.children[0].children[0].text == 'aaaa'
+    assert line2.children[0].children[0].text == 'aaaa'
+    assert line3.children[0].children[0].text == 'a a'
+    assert line4.children[0].children[0].text == 'a'
+    assert line4.children[1].children[0].text == 'bc'
+
 
 @assert_no_logs
 def test_linebox_text():