Allow var functions in shorthand properties

Related to #1219.

tests/test_variables.py

@@ -3,7 +3,7 @@
 import pytest
 from weasyprint.css.properties import KNOWN_PROPERTIES
 
-from .testing_utils import assert_no_logs, render_pages
+from .testing_utils import assert_no_logs, capture_logs, render_pages
 
 SIDES = ('top', 'right', 'bottom', 'left')
 
@@ -106,7 +106,7 @@ def test_variable_chain_root_missing():
 
 
 @assert_no_logs
-def test_variable_partial_1():
+def test_variable_shorthand_margin():
     page, = render_pages('''
       <style>
         html { --var: 10px }
@@ -123,6 +123,155 @@ def test_variable_partial_1():
     assert div.margin_left == 10
 
 
+@assert_no_logs
+def test_variable_shorthand_margin_multiple():
+    page, = render_pages('''
+      <style>
+        html { --var1: 10px; --var2: 20px }
+        div { margin: var(--var2) 0 0 var(--var1) }
+      </style>
+      <div></div>
+    ''')
+    html, = page.children
+    body, = html.children
+    div, = body.children
+    assert div.margin_top == 20
+    assert div.margin_right == 0
+    assert div.margin_bottom == 0
+    assert div.margin_left == 10
+
+
+@assert_no_logs
+def test_variable_shorthand_margin_invalid():
+    with capture_logs() as logs:
+        page, = render_pages('''
+          <style>
+            html { --var: blue }
+            div { margin: 0 0 0 var(--var) }
+          </style>
+          <div></div>
+        ''')
+        log, = logs
+        assert 'invalid value' in log
+    html, = page.children
+    body, = html.children
+    div, = body.children
+    assert div.margin_top == 0
+    assert div.margin_right == 0
+    assert div.margin_bottom == 0
+    assert div.margin_left == 0
+
+
+@assert_no_logs
+def test_variable_shorthand_border():
+    page, = render_pages('''
+      <style>
+        html { --var: 1px solid blue }
+        div { border: var(--var) }
+      </style>
+      <div></div>
+    ''')
+    html, = page.children
+    body, = html.children
+    div, = body.children
+    assert div.border_top_width == 1
+    assert div.border_right_width == 1
+    assert div.border_bottom_width == 1
+    assert div.border_left_width == 1
+
+
+@assert_no_logs
+def test_variable_shorthand_border_side():
+    page, = render_pages('''
+      <style>
+        html { --var: 1px solid blue }
+        div { border-top: var(--var) }
+      </style>
+      <div></div>
+    ''')
+    html, = page.children
+    body, = html.children
+    div, = body.children
+    assert div.border_top_width == 1
+    assert div.border_right_width == 0
+    assert div.border_bottom_width == 0
+    assert div.border_left_width == 0
+
+
+@assert_no_logs
+def test_variable_shorthand_border_mixed():
+    page, = render_pages('''
+      <style>
+        html { --var: 1px solid }
+        div { border: blue var(--var) }
+      </style>
+      <div></div>
+    ''')
+    html, = page.children
+    body, = html.children
+    div, = body.children
+    assert div.border_top_width == 1
+    assert div.border_right_width == 1
+    assert div.border_bottom_width == 1
+    assert div.border_left_width == 1
+
+
+def test_variable_shorthand_border_mixed_invalid():
+    with capture_logs() as logs:
+        page, = render_pages('''
+          <style>
+            html { --var: 1px solid blue }
+            div { border: blue var(--var) }
+          </style>
+          <div></div>
+        ''')
+        # TODO: we should only get one warning here
+        assert 'multiple color values' in logs[0]
+    html, = page.children
+    body, = html.children
+    div, = body.children
+    assert div.border_top_width == 0
+    assert div.border_right_width == 0
+    assert div.border_bottom_width == 0
+    assert div.border_left_width == 0
+
+
+@assert_no_logs
+@pytest.mark.parametrize('var, background', (
+    ('blue', 'var(--v)'),
+    ('padding-box url(pattern.png)', 'var(--v)'),
+    ('padding-box url(pattern.png)', 'white var(--v) center'),
+    ('100%', 'url(pattern.png) var(--v) var(--v) / var(--v) var(--v)'),
+    ('left / 100%', 'url(pattern.png) top var(--v) 100%'),
+))
+def test_variable_shorthand_background(var, background):
+    page, = render_pages('''
+      <style>
+        html { --v: %s }
+        div { background: %s }
+      </style>
+      <div></div>
+    ''' % (var, background))
+
+
+@pytest.mark.parametrize('var, background', (
+    ('invalid', 'var(--v)'),
+    ('blue', 'var(--v) var(--v)'),
+    ('100%', 'url(pattern.png) var(--v) var(--v) var(--v)'),
+))
+def test_variable_shorthand_background_invalid(var, background):
+    with capture_logs() as logs:
+        page, = render_pages('''
+          <style>
+            html { --v: %s }
+            div { background: %s }
+          </style>
+          <div></div>
+        ''' % (var, background))
+        log, = logs
+        assert 'invalid value' in log
+
+
 @assert_no_logs
 def test_variable_initial():
     page, = render_pages('''

weasyprint/css/__init__.py

@@ -26,11 +26,11 @@
 from .computed_values import (
     COMPUTER_FUNCTIONS, ZERO_PIXELS, compute_var, resolve_var)
 from .properties import INHERITED, INITIAL_NOT_COMPUTED, INITIAL_VALUES
-from .utils import check_var_function, get_url, remove_whitespace
+from .utils import (
+    InvalidValues, check_var_function, get_url, remove_whitespace)
 from .validation import preprocess_declarations
 from .validation.descriptors import preprocess_descriptors
 from .validation.expanders import PendingExpander
-from .validation.properties import validate_non_shorthand
 
 # Reject anything not in here:
 PSEUDO_ELEMENTS = (
@@ -732,6 +732,8 @@ def __missing__(self, key):
             return self[key]
 
         if isinstance(value, PendingExpander):
+            # Expander with pending values, validate them.
+            computed = False
             solved_tokens = []
             for token in value.tokens:
                 variable = check_var_function(token)
@@ -743,8 +745,19 @@ def __missing__(self, key):
                 else:
                     solved_tokens.append(token)
             original_key = key.replace('_', '-')
-            solved = value.solve(solved_tokens, original_key)
-            value = validate_non_shorthand(None, original_key, solved)[0][1]
+            try:
+                value = value.solve(solved_tokens, original_key)
+            except InvalidValues:
+                if key in INHERITED:
+                    # Values in parent_style are already computed.
+                    self[key] = value = parent_style[key]
+                    return value
+                else:
+                    value = INITIAL_VALUES[key]
+                    if key not in INITIAL_NOT_COMPUTED:
+                        # The value is the same as when computed.
+                        self[key] = value
+                        return value
 
         if not computed and key in COMPUTER_FUNCTIONS:
             # Value not computed yet: compute.

weasyprint/css/validation/__init__.py

@@ -115,7 +115,7 @@ def validation_error(level, reason):
         tokens = remove_whitespace(declaration.value)
         try:
             # Use list() to consume generators now and catch any error.
-            result = list(expander(base_url, name, tokens))
+            result = list(expander(tokens, name, base_url))
         except InvalidValues as exc:
             validation_error(
                 'warning',

weasyprint/css/validation/descriptors.py

@@ -198,7 +198,7 @@ def font_variant(tokens):
     for name, sub_tokens in expand_font_variant(tokens):
         try:
             values.append(properties.validate_non_shorthand(
-                None, f'font-variant{name}', sub_tokens, required=True))
+                sub_tokens, f'font-variant{name}', None, required=True))
         except InvalidValues:
             return None
     return values