Don’t break pages when fixed-height elements don’t overflow page

Fix #2026.

Bookmark tests have to be fixed because height set to all elements was also
set to html an body tags.

tests/draw/test_overflow.py

@@ -92,6 +92,30 @@ def test_overflow_4(assert_pixels):
       ''')
 
 
+@assert_no_logs
+def test_overflow_5(assert_pixels):
+    # Regression test for https://github.com/Kozea/WeasyPrint/issues/2026
+    assert_pixels('''
+        BBBBBB__
+        BBBBBB__
+        BBBB____
+        BBBB____
+        BBBB____
+        ________
+        ________
+        ________
+    ''', '''
+      <style>
+        @font-face { src: url(weasyprint.otf); font-family: weasyprint }
+        @page { size: 8px }
+        body { font-family: weasyprint; line-height: 1; font-size: 2px }
+        p { color: blue }
+      </style>
+      <p>abc</p>
+      <p style="height: 3px; overflow: hidden">ab<br>ab<br>ab<br>ab</p>
+      ''')
+
+
 @assert_no_logs
 @pytest.mark.parametrize('number, css, pixels', (
     (1, '5px, 5px, 9px, auto', '''

tests/test_api.py

@@ -615,7 +615,7 @@ def test_low_level_api(assert_pixels_equal):
 
 @pytest.mark.parametrize('html, expected_by_page, expected_tree, round', (
     ('''
-        <style>* { height: 10px }</style>
+        <style>h1, h2, h3, h4 { height: 10px }</style>
         <h1>a</h1>
         <h4 style="page-break-after: always">b</h4>
         <h3 style="position: relative; top: 2px; left: 3px">c</h3>
@@ -634,7 +634,7 @@ def test_low_level_api(assert_pixels_equal):
     ], False),
     ('''
         <style>
-            * { height: 90px; margin: 0 0 10px 0 }
+            h1, h2, h3, span { height: 90px; margin: 0 0 10px 0 }
         </style>
         <h1>Title 1</h1>
         <h1>Title 2</h1>

tests/test_pdf.py

@@ -65,7 +65,7 @@ def test_bookmarks_3():
 def test_bookmarks_4():
     pdf = FakeHTML(string='''
       <style>
-        * { height: 90pt; margin: 0 0 10pt 0 }
+        h1, h2, h3, span { height: 90pt; margin: 0 0 10pt 0 }
       </style>
       <h1>1</h1>
       <h1>2</h1>

weasyprint/layout/block.py

@@ -741,6 +741,11 @@ def block_container_layout(context, box, bottom_space, skip_stack,
                 None, None, {'break': 'any', 'page': page}, [], False,
                 max_lines)
         elif stop:
+            if box.height != 'auto':
+                if position_y > box.position_y + box.height:
+                    # Box heigh is fixed and it doesn’t overflow page, forget
+                    # overflowing children.
+                    resume_at = None
             adjoining_margins = []
             break