From 1489879b80c1b1af9832936a410d5264f038d168 Mon Sep 17 00:00:00 2001
From: Ethan Atkins <ethan.atkins@gmail.com>
Date: Thu, 7 Feb 2019 17:03:41 -0800
Subject: [PATCH] Fix equals for FileCacheEntry

The equals method didn't work exactly the way I thought. By delegating
to the equivStamp object in sbt we can be more confident that it is
actually comparing the stamp values and not object references or
some other equals implementation.
---
 .../src/main/scala/sbt/internal/FileCacheEntry.scala     | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/main-command/src/main/scala/sbt/internal/FileCacheEntry.scala b/main-command/src/main/scala/sbt/internal/FileCacheEntry.scala
index 417f49136..f7c0e71a4 100644
--- a/main-command/src/main/scala/sbt/internal/FileCacheEntry.scala
+++ b/main-command/src/main/scala/sbt/internal/FileCacheEntry.scala
@@ -36,6 +36,9 @@ object FileCacheEntry {
     }
   }
 
+  private implicit class Equiv(val xstamp: XStamp) extends AnyVal {
+    def equiv(that: XStamp): Boolean = Stamp.equivStamp.equiv(xstamp, that)
+  }
   private case class DelegateFileCacheEntry(private val stamp: XStamp)
       extends FileCacheEntry
       with XStamp {
@@ -52,9 +55,9 @@ object FileCacheEntry {
       case _                => None
     }
     override def equals(o: Any): Boolean = o match {
-      case that: DelegateFileCacheEntry => this.stamp == that.stamp
-      case that: XStamp                 => this.stamp == that
-      case _                            => false
+      case DelegateFileCacheEntry(thatStamp) => this.stamp equiv thatStamp
+      case xStamp: XStamp                    => this.stamp equiv xStamp
+      case _                                 => false
     }
     override def hashCode: Int = stamp.hashCode
     override def toString: String = s"FileCacheEntry(hash = $hash, lastModified = $lastModified)"