Fix grid gap inheritance from row-gap and column-gap longhands

lib/hacks/grid-utils.js

@@ -5,6 +5,8 @@ let uniq = require('../utils').uniq
 let escapeRegexp = require('../utils').escapeRegexp
 let splitSelector = require('../utils').splitSelector
 
+const GAP_PROPS = /^(grid-)?((row|column)-)?gap$/
+
 function convert(value) {
   if (
     value &&
@@ -878,8 +880,7 @@ function getGridGap(decl) {
   let gap = {}
 
   // try to find gap
-  let testGap = /^(grid-)?((row|column)-)?gap$/
-  decl.parent.walkDecls(testGap, ({ prop, value }) => {
+  decl.parent.walkDecls(GAP_PROPS, ({ prop, value }) => {
     if (/^(grid-)?gap$/.test(prop)) {
       let [row, , column] = parser(value).nodes
 
@@ -1014,8 +1015,8 @@ function inheritGridGap(decl, gap) {
       return false
     }
 
-    // find grid-gap values
-    r.walkDecls('grid-gap', d => (gridGap = getGridGap(d)))
+    // find gap values, set either by the shorthand or by the longhands
+    r.walkDecls(GAP_PROPS, d => (gridGap = getGridGap(d)))
 
     // skip rule without gaps
     if (!gridGap || Object.keys(gridGap).length === 0) {

test/cases/grid-gap.css

@@ -301,3 +301,23 @@
     grid-template-rows: repeat(2, 100px);
   }
 }
+
+.longhand-gap {
+  display: grid;
+  grid-column-gap: 50px;
+  grid-row-gap: 40px;
+  grid-template-areas:
+    "p   p"
+    "q   q";
+  grid-template-columns: repeat(2, 1fr);
+  grid-template-rows: repeat(2, 100px);
+}
+
+/* must inherit gap from .longhand-gap */
+.longhand-gap.modifier {
+  grid-template-areas:
+    "p   p"
+    "q   q";
+  grid-template-columns: repeat(2, 1fr);
+  grid-template-rows: repeat(2, 100px);
+}

test/cases/grid-gap.out.css

@@ -435,3 +435,28 @@
     grid-template-rows: repeat(2, 100px);
   }
 }
+
+.longhand-gap {
+  display: -ms-grid;
+  display: grid;
+  grid-column-gap: 50px;
+  grid-row-gap: 40px;
+  grid-template-areas:
+    "p   p"
+    "q   q";
+  -ms-grid-columns: 1fr 50px 1fr;
+  grid-template-columns: repeat(2, 1fr);
+  -ms-grid-rows: 100px 40px 100px;
+  grid-template-rows: repeat(2, 100px);
+}
+
+/* must inherit gap from .longhand-gap */
+.longhand-gap.modifier {
+  grid-template-areas:
+    "p   p"
+    "q   q";
+  -ms-grid-columns: 1fr 50px 1fr;
+  grid-template-columns: repeat(2, 1fr);
+  -ms-grid-rows: 100px 40px 100px;
+  grid-template-rows: repeat(2, 100px);
+}