From 069c4249dc10a71e0fef455bf4ebea17776dbcf2 Mon Sep 17 00:00:00 2001
From: Peng Yang <yorkttg@gmail.com>
Date: Tue, 25 May 2021 04:38:40 +0800
Subject: [PATCH] fix(postcss-merge-rules): check all intersections when
 merging rules (#1116)

* fix: 1112

* test: test-case
---
 .../src/__tests__/index.js                    |  8 ++++++++
 packages/postcss-merge-rules/src/index.js     | 20 ++++++++++---------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/packages/postcss-merge-rules/src/__tests__/index.js b/packages/postcss-merge-rules/src/__tests__/index.js
index 2213f89cf..94f8b63eb 100644
--- a/packages/postcss-merge-rules/src/__tests__/index.js
+++ b/packages/postcss-merge-rules/src/__tests__/index.js
@@ -815,3 +815,11 @@ test(
     'a,a:link,a:visited{color:#555}'
   )
 );
+
+test(
+  'should not merge colors',
+  processCSS(
+    'h1{color:#001;color:#002;color:#003}h2{color:#001;color:#002}',
+    'h1{color:#001;color:#002;color:#003}h2{color:#001;color:#002}'
+  )
+);
diff --git a/packages/postcss-merge-rules/src/index.js b/packages/postcss-merge-rules/src/index.js
index 04f6e9175..d735f83be 100644
--- a/packages/postcss-merge-rules/src/index.js
+++ b/packages/postcss-merge-rules/src/index.js
@@ -206,23 +206,25 @@ function partialMerge(first, second) {
 
   // Filter out intersections with later conflicts in First
   intersection = intersection.filter((decl, intersectIndex) => {
-    const index = indexOfDeclaration(firstDecls, decl);
+    const indexOfDecl = indexOfDeclaration(firstDecls, decl);
     const nextConflictInFirst = firstDecls
-      .slice(index + 1)
-      .find((d) => isConflictingProp(d.prop, decl.prop));
-    if (!nextConflictInFirst) {
+      .slice(indexOfDecl + 1)
+      .filter((d) => isConflictingProp(d.prop, decl.prop));
+    if (!nextConflictInFirst.length) {
       return true;
     }
     const nextConflictInIntersection = intersection
       .slice(intersectIndex + 1)
-      .find((d) => isConflictingProp(d.prop, decl.prop));
-    if (!nextConflictInIntersection) {
+      .filter((d) => isConflictingProp(d.prop, decl.prop));
+    if (!nextConflictInIntersection.length) {
       return false;
     }
-    if (declarationIsEqual(nextConflictInFirst, nextConflictInIntersection)) {
-      return true;
+    if (nextConflictInFirst.length !== nextConflictInIntersection.length) {
+      return false;
     }
-    return false;
+    return nextConflictInFirst.every((d, index) =>
+      declarationIsEqual(d, nextConflictInIntersection[index])
+    );
   });
 
   // Filter out intersections with previous conflicts in Second