From 26d5a40229a99c3896f43c90cfb0416a9bec5718 Mon Sep 17 00:00:00 2001
From: Googler <noreply@google.com>
Date: Thu, 17 Jan 2019 03:28:07 -0800
Subject: [PATCH] Don't iterate over a large map just to delete an empty list
 of SkyKeys.

RELNOTES: None.
PiperOrigin-RevId: 229715756
---
 .../build/lib/skyframe/SequencedSkyframeExecutor.java         | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SequencedSkyframeExecutor.java b/src/main/java/com/google/devtools/build/lib/skyframe/SequencedSkyframeExecutor.java
index a8264d5626a375..cda7742938e4b4 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SequencedSkyframeExecutor.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SequencedSkyframeExecutor.java
@@ -353,6 +353,10 @@ private void invalidateDeletedPackages(Iterable<PackageIdentifier> deletedPackag
     for (PackageIdentifier deletedPackage : deletedPackages) {
       packagesToInvalidate.add(PackageLookupValue.key(deletedPackage));
     }
+    // Exit early if there are no packages to be deleted to avoid iterating over a large map.
+    if (packagesToInvalidate.isEmpty()) {
+      return;
+    }
     memoizingEvaluator.delete(Predicates.in(packagesToInvalidate));
   }