* 5.0.1

sandersaares · sandersaares · commit 59e06102d389 · 2021-08-19T16:07:46.000+03:00
- Bugfix: PowersOfTenDividedBuckets did not work with &gt;= 10 buckets due to overlap. Now skips overlapping region of generated series.
diff --git a/History b/History
@@ -1,3 +1,5 @@
+* 5.0.1
+- Bugfix: PowersOfTenDividedBuckets did not work with >= 10 buckets due to overlap. Now skips overlapping region of generated series.
 * 5.0.0
 - Added HTTP client metric that measures the response duration (time until response content reading is finished).
 - Added "client" label containing the name of HTTP client to HTTP client metrics.
diff --git a/Prometheus.NetStandard/Histogram.cs b/Prometheus.NetStandard/Histogram.cs
@@ -236,8 +236,17 @@ public static double[] PowersOfTenDividedBuckets(int startPower, int endPower, i
                     // The math we do can make it incur some tiny avoidable error due to floating point gremlins.
                     // We use decimal for the path to preserve as much accuracy as we can, before finally converting to double.
                     // It will not fix 100% of the cases where we end up with 0.0000000000000000000000000000001 offset but it helps a lot.
+                    var candidate = (double)bucket;
 
-                    buckets.Add((double)bucket);
+                    // Depending on the number of divisions, it may be that divisions from different powers overlap.
+                    // For example, a division into 20 would include:
+                    // 19th value in the 0th power: 9.5 (10/20*19=9.5)
+                    // 1st value in the 1st power: 5 (100/20*1 = 5)
+                    // To avoid this being a problem, we simply constrain all values to be increasing.
+                    if (buckets.Any() && buckets.Last() >= candidate)
+                        continue; // Skip this one, it is not greater.
+
+                    buckets.Add(candidate);
                 }
             }
 
diff --git a/Resources/SolutionAssemblyInfo.cs b/Resources/SolutionAssemblyInfo.cs
@@ -2,7 +2,7 @@
 using System.Runtime.CompilerServices;
 
 // This is the real version number, used in NuGet packages and for display purposes.
-[assembly: AssemblyFileVersion("5.0.0")]
+[assembly: AssemblyFileVersion("5.0.1")]
 
 // Only use major version here, with others kept at zero, for correct assembly binding logic.
 [assembly: AssemblyVersion("5.0.0")]
diff --git a/Tests.NetFramework/HistogramTests.cs b/Tests.NetFramework/HistogramTests.cs
@@ -57,6 +57,25 @@ public void PowersOfTenDividedBuckets_CreatesExpectedBuckets()
                 Assert.AreEqual(expected[i], actual[i]);
         }
 
+        [TestMethod]
+        public void PowersOfTenDividedBuckets_WithOverlappingEdges_CreatesExpectedBuckets()
+        {
+            var expected = new[]
+            {
+                // 10 should be in both power=1 and power=2 series
+                // But we expect it only to be emitted once.
+                1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
+                20, 30, 40, 50, 60, 70, 80, 90, 100
+            };
+
+            var actual = Histogram.PowersOfTenDividedBuckets(0, 2, 10);
+
+            Assert.AreEqual(expected.Length, actual.Length);
+
+            for (var i = 0; i < expected.Length; i++)
+                Assert.AreEqual(expected[i], actual[i]);
+        }
+
         [TestMethod]
         public void LinearBuckets_CreatesExpectedBuckets()
         {

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,5 @@`
	`1`	`+* 5.0.1`
	`2`	`+- Bugfix: PowersOfTenDividedBuckets did not work with >= 10 buckets due to overlap. Now skips overlapping region of generated series.`
`1`	`3`	`* 5.0.0`
`2`	`4`	`- Added HTTP client metric that measures the response duration (time until response content reading is finished).`
`3`	`5`	`- Added "client" label containing the name of HTTP client to HTTP client metrics.`