From 5b18e1cafef22fafe9d5fa8bc56406017c65bd3e Mon Sep 17 00:00:00 2001
From: Anton Makeev <Anton.Makeev@jetbrains.com>
Date: Mon, 17 Jun 2019 13:07:28 +0200
Subject: [PATCH] revert: ContainerUtil.unmodifiableOrEmpty* methods optimized
 for 1-element collections

Creating a new singleton collection might break comparison policy of the original collection.

(original commit e66890a6d2b19f54fa6fd2eec7ef6339e79a9e32)

GitOrigin-RevId: b4092dc49b60881385f31553ffd504e59e483e41
---
 .../intellij/util/containers/ContainerUtil.java | 17 +----------------
 1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/platform/util/src/com/intellij/util/containers/ContainerUtil.java b/platform/util/src/com/intellij/util/containers/ContainerUtil.java
index e7f452e29673..79dabd1a5652 100644
--- a/platform/util/src/com/intellij/util/containers/ContainerUtil.java
+++ b/platform/util/src/com/intellij/util/containers/ContainerUtil.java
@@ -260,9 +260,6 @@ public class ContainerUtil extends ContainerUtilRt {
     if (size == 0) {
       return emptyList();
     }
-    if (size == 1) {
-      return Collections.singletonList(original.iterator().next());
-    }
     return Collections.unmodifiableCollection(original);
   }
 
@@ -273,9 +270,6 @@ public class ContainerUtil extends ContainerUtilRt {
     if (size == 0) {
       return emptyList();
     }
-    if (size == 1) {
-      return Collections.singletonList(original.iterator().next());
-    }
     return Collections.unmodifiableList(original);
   }
 
@@ -286,9 +280,6 @@ public class ContainerUtil extends ContainerUtilRt {
     if (size == 0) {
       return Collections.emptySet();
     }
-    if (size == 1) {
-      return Collections.singleton(original.iterator().next());
-    }
     return Collections.unmodifiableSet(original);
   }
 
@@ -299,13 +290,7 @@ public class ContainerUtil extends ContainerUtilRt {
     if (size == 0) {
       return Collections.emptyMap();
     }
-    if (size == 1) {
-      Map.Entry<? extends K, ? extends V> entry = original.entrySet().iterator().next();
-      return Collections.singletonMap(entry.getKey(), entry.getValue());
-    }
-    else {
-      return Collections.unmodifiableMap(original);
-    }
+    return Collections.unmodifiableMap(original);
   }
 
   @NotNull