From 3fd5f796f0415b5cd83f02d33809a3a65e0837e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Wed, 28 Feb 2018 00:43:54 +0100
Subject: [PATCH] style: Handle properly potentially-disabled longhands in a
 shorthand.

---
 components/style/properties/data.py         |  5 +++++
 components/style/properties/helpers.mako.rs | 20 +++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/components/style/properties/data.py b/components/style/properties/data.py
index e2c68964cb0..5340e6afadf 100644
--- a/components/style/properties/data.py
+++ b/components/style/properties/data.py
@@ -229,6 +229,11 @@ class Longhand(object):
     def enabled_in_content(self):
         return self.enabled_in == "content"
 
+    def may_be_disabled_in(self, shorthand, product):
+        if product == "gecko":
+            return self.gecko_pref and self.gecko_pref != shorthand.gecko_pref
+        return self.servo_pref and self.servo_pref != shorthand.servo_pref
+
     def base_type(self):
         if self.predefined_type and not self.is_vector:
             return "::values::specified::{}".format(self.predefined_type)
diff --git a/components/style/properties/helpers.mako.rs b/components/style/properties/helpers.mako.rs
index b1bdbf95453..060d4010e21 100644
--- a/components/style/properties/helpers.mako.rs
+++ b/components/style/properties/helpers.mako.rs
@@ -688,7 +688,13 @@
         pub struct LonghandsToSerialize<'a> {
             % for sub_property in shorthand.sub_properties:
                 pub ${sub_property.ident}:
+                % if sub_property.may_be_disabled_in(shorthand, product):
+                    Option<
+                % endif
                     &'a longhands::${sub_property.ident}::SpecifiedValue,
+                % if sub_property.may_be_disabled_in(shorthand, product):
+                    >,
+                % endif
             % endfor
         }
 
@@ -725,12 +731,16 @@
 
                     (
                     % for sub_property in shorthand.sub_properties:
+                        % if sub_property.may_be_disabled_in(shorthand, product):
+                        ${sub_property.ident},
+                        % else:
                         Some(${sub_property.ident}),
+                        % endif
                     % endfor
                     ) =>
                     Ok(LonghandsToSerialize {
                         % for sub_property in shorthand.sub_properties:
-                            ${sub_property.ident}: ${sub_property.ident},
+                            ${sub_property.ident},
                         % endfor
                     }),
                     _ => Err(())
@@ -745,11 +755,19 @@
             context: &ParserContext,
             input: &mut Parser<'i, 't>,
         ) -> Result<(), ParseError<'i>> {
+            #[allow(unused_imports)]
+            use properties::{NonCustomPropertyId, LonghandId};
             input.parse_entirely(|input| parse_value(context, input)).map(|longhands| {
                 % for sub_property in shorthand.sub_properties:
+                % if sub_property.may_be_disabled_in(shorthand, product):
+                if NonCustomPropertyId::from(LonghandId::${sub_property.camel_case}).allowed_in(context) {
+                % endif
                     declarations.push(PropertyDeclaration::${sub_property.camel_case}(
                         longhands.${sub_property.ident}
                     ));
+                % if sub_property.may_be_disabled_in(shorthand, product):
+                }
+                % endif
                 % endfor
             })
         }