From f7853290b9c62ce07af648d78322a3c48914f336 Mon Sep 17 00:00:00 2001
From: Alexey Kudinkin <alexey.kudinkin@uber.com>
Date: Thu, 30 Jul 2020 12:27:50 -0700
Subject: [PATCH] Fixed backward-compatibility breaking change; Added test

---
 core/src/main/java/com/uber/m3/tally/ScopeImpl.java    | 10 +++++++++-
 .../src/test/java/com/uber/m3/tally/ScopeImplTest.java |  7 +++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/com/uber/m3/tally/ScopeImpl.java b/core/src/main/java/com/uber/m3/tally/ScopeImpl.java
index 3601581..7211040 100644
--- a/core/src/main/java/com/uber/m3/tally/ScopeImpl.java
+++ b/core/src/main/java/com/uber/m3/tally/ScopeImpl.java
@@ -25,6 +25,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentLinkedQueue;
@@ -89,7 +90,14 @@ public Timer timer(String name) {
     public Histogram histogram(String name, Buckets buckets) {
         return histograms.computeIfAbsent(name, ignored ->
                 // NOTE: This will called at most once
-                new HistogramImpl(this, fullyQualifiedName(name), tags, buckets));
+                new HistogramImpl(
+                        this,
+                        fullyQualifiedName(name),
+                        tags,
+                        Optional.ofNullable(buckets)
+                                .orElse(defaultBuckets)
+                )
+        );
     }
 
     @Override
diff --git a/core/src/test/java/com/uber/m3/tally/ScopeImplTest.java b/core/src/test/java/com/uber/m3/tally/ScopeImplTest.java
index 89de860..dd413a8 100644
--- a/core/src/test/java/com/uber/m3/tally/ScopeImplTest.java
+++ b/core/src/test/java/com/uber/m3/tally/ScopeImplTest.java
@@ -76,7 +76,14 @@ public void metricCreation() {
         );
         assertNotNull(histogram);
 
+        Histogram histogramDefaultBuckets = scope.histogram(
+                "new-histogram-default-buckets",
+                null
+        );
+        assertNotNull(histogramDefaultBuckets);
+
         Histogram sameHistogram = scope.histogram("new-histogram", null);
+
         // Should be the same Histogram object and not a new instance
         assertTrue(histogram == sameHistogram);
     }