From fd184f6b4a991d2cc2feef3cb7d1e0477d827437 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Naz=C4=B1m=20Can=20Alt=C4=B1nova?= <canaltinova@gmail.com>
Date: Mon, 17 Jul 2017 23:18:56 -0700
Subject: [PATCH] Serialize 'minmax(auto, <flex>)' as '<flex>'

---
 components/style/values/generics/grid.rs | 32 +++++++++++++++++++++---
 tests/unit/style/parsing/position.rs     |  2 +-
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/components/style/values/generics/grid.rs b/components/style/values/generics/grid.rs
index 00049814482..fbbc6a4d532 100644
--- a/components/style/values/generics/grid.rs
+++ b/components/style/values/generics/grid.rs
@@ -203,7 +203,7 @@ impl<L: ToComputedValue> ToComputedValue for TrackBreadth<L> {
 ///
 /// https://drafts.csswg.org/css-grid/#typedef-track-size
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-#[derive(Clone, Debug, HasViewportPercentage, PartialEq, ToCss)]
+#[derive(Clone, Debug, HasViewportPercentage, PartialEq)]
 pub enum TrackSize<L> {
     /// A flexible `<track-breadth>`
     Breadth(TrackBreadth<L>),
@@ -211,12 +211,10 @@ pub enum TrackSize<L> {
     /// and a flexible `<track-breadth>`
     ///
     /// https://drafts.csswg.org/css-grid/#valdef-grid-template-columns-minmax
-    #[css(comma, function)]
     Minmax(TrackBreadth<L>, TrackBreadth<L>),
     /// A `fit-content` function.
     ///
     /// https://drafts.csswg.org/css-grid/#valdef-grid-template-columns-fit-content
-    #[css(function)]
     FitContent(L),
 }
 
@@ -259,6 +257,34 @@ impl<L: PartialEq> TrackSize<L> {
     }
 }
 
+impl<L: ToCss> ToCss for TrackSize<L> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            TrackSize::Breadth(ref breadth) => breadth.to_css(dest),
+            TrackSize::Minmax(ref min, ref max) => {
+                // According to gecko minmax(auto, <flex>) is equivalent to <flex>,
+                // and both are serialized as <flex>.
+                if let TrackBreadth::Keyword(TrackKeyword::Auto) = *min {
+                    if let TrackBreadth::Flex(_) = *max {
+                        return max.to_css(dest);
+                    }
+                }
+
+                dest.write_str("minmax(")?;
+                min.to_css(dest)?;
+                dest.write_str(", ")?;
+                max.to_css(dest)?;
+                dest.write_str(")")
+            },
+            TrackSize::FitContent(ref lop) => {
+                dest.write_str("fit-content(")?;
+                lop.to_css(dest)?;
+                dest.write_str(")")
+            },
+        }
+    }
+}
+
 impl<L: ToComputedValue> ToComputedValue for TrackSize<L> {
     type ComputedValue = TrackSize<L::ComputedValue>;
 
diff --git a/tests/unit/style/parsing/position.rs b/tests/unit/style/parsing/position.rs
index 9029e401355..87f11b90cfb 100644
--- a/tests/unit/style/parsing/position.rs
+++ b/tests/unit/style/parsing/position.rs
@@ -237,7 +237,7 @@ fn test_computed_grid_template_rows_colums() {
 
     assert_computed_serialization(grid_template_rows::parse,
         "10px repeat(2, 1fr auto minmax(200px, 1fr))",
-        "10px minmax(auto, 1fr) auto minmax(200px, 1fr) minmax(auto, 1fr) auto minmax(200px, 1fr)");
+        "10px 1fr auto minmax(200px, 1fr) 1fr auto minmax(200px, 1fr)");
 
     assert_computed_serialization(grid_template_rows::parse,
         "subgrid [a] [] repeat(auto-fill, [])", "subgrid [a] [] repeat(auto-fill, [])");