From a9c3f4e173bd9f08ba5200e1986ea6e87c7a2655 Mon Sep 17 00:00:00 2001
From: Anton Tolmachev <ato@templafy.com>
Date: Fri, 9 Jun 2023 16:01:16 +0200
Subject: [PATCH 1/2] Add performance test using linear commit history and 500
 commits

---
 .../IntegrationTests/PerformanceScenarios.cs  | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 src/GitVersion.Core.Tests/IntegrationTests/PerformanceScenarios.cs

diff --git a/src/GitVersion.Core.Tests/IntegrationTests/PerformanceScenarios.cs b/src/GitVersion.Core.Tests/IntegrationTests/PerformanceScenarios.cs
new file mode 100644
index 0000000000..8506843fb7
--- /dev/null
+++ b/src/GitVersion.Core.Tests/IntegrationTests/PerformanceScenarios.cs
@@ -0,0 +1,29 @@
+using GitVersion.Configuration;
+using GitVersion.Core.Tests.Helpers;
+
+namespace GitVersion.Core.Tests.IntegrationTests;
+
+public class PerformanceScenarios : TestBase
+{
+    [Test]
+    public void RepositoryWithALotOfTags()
+    {
+        var configuration = GitFlowConfigurationBuilder.New.Build();
+
+        using var fixture = new EmptyRepositoryFixture();
+
+        const int maxCommits = 500;
+        for (int i = 0; i < maxCommits; i++)
+        {
+            fixture.MakeATaggedCommit($"1.0.{i}");
+        }
+
+        fixture.BranchTo("feature");
+        fixture.MakeACommit();
+
+        var sw = Stopwatch.StartNew();
+
+        fixture.AssertFullSemver($"1.0.{maxCommits}-feature.1+1", configuration);
+        sw.ElapsedMilliseconds.ShouldBeLessThan(5000);
+    }
+}

From 448de3eb81e0229f6b42a7011cf95cb723f79c6d Mon Sep 17 00:00:00 2001
From: Anton Tolmachev <ato@templafy.com>
Date: Fri, 9 Jun 2023 16:02:51 +0200
Subject: [PATCH 2/2] Cache tags in IncrementStrategyFinder to prevent multiple
 reads from repository

---
 .../VersionCalculation/IncrementStrategyFinder.cs   | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/GitVersion.Core/VersionCalculation/IncrementStrategyFinder.cs b/src/GitVersion.Core/VersionCalculation/IncrementStrategyFinder.cs
index 7519614147..dd8e02fc2b 100644
--- a/src/GitVersion.Core/VersionCalculation/IncrementStrategyFinder.cs
+++ b/src/GitVersion.Core/VersionCalculation/IncrementStrategyFinder.cs
@@ -16,6 +16,7 @@ internal class IncrementStrategyFinder : IIncrementStrategyFinder
     private readonly Dictionary<string, VersionField?> commitIncrementCache = new();
     private readonly Dictionary<string, Dictionary<string, int>> headCommitsMapCache = new();
     private readonly Dictionary<string, ICommit[]> headCommitsCache = new();
+    private readonly Lazy<IReadOnlySet<string?>> tagsShaCache;
 
     private static readonly Regex DefaultMajorPatternRegex = new(DefaultMajorPattern, RegexOptions.Compiled | RegexOptions.IgnoreCase);
     private static readonly Regex DefaultMinorPatternRegex = new(DefaultMinorPattern, RegexOptions.Compiled | RegexOptions.IgnoreCase);
@@ -24,7 +25,11 @@ internal class IncrementStrategyFinder : IIncrementStrategyFinder
 
     private readonly IGitRepository repository;
 
-    public IncrementStrategyFinder(IGitRepository repository) => this.repository = repository.NotNull();
+    public IncrementStrategyFinder(IGitRepository repository)
+    {
+        this.repository = repository.NotNull();
+        this.tagsShaCache = new Lazy<IReadOnlySet<string?>>(ReadRepositoryTagsSha);
+    }
 
     public VersionField DetermineIncrementedField(ICommit? currentCommit, BaseVersion baseVersion, EffectiveConfiguration configuration)
     {
@@ -79,12 +84,10 @@ public VersionField DetermineIncrementedField(ICommit? currentCommit, BaseVersio
         }
 
         var commits = GetIntermediateCommits(baseCommit, currentCommit);
-
         // consider commit messages since latest tag only (see #3071)
-        var tags = new HashSet<string?>(repository.Tags.Select(t => t.TargetSha));
         commits = commits
             .Reverse()
-            .TakeWhile(x => !tags.Contains(x.Sha))
+            .TakeWhile(x => !this.tagsShaCache.Value.Contains(x.Sha))
             .Reverse();
 
         if (configuration.CommitMessageIncrementing == CommitMessageIncrementMode.MergeMessageOnly)
@@ -101,6 +104,8 @@ public VersionField DetermineIncrementedField(ICommit? currentCommit, BaseVersio
         );
     }
 
+    private IReadOnlySet<string?> ReadRepositoryTagsSha() => repository.Tags.Select(t => t.TargetSha).ToHashSet();
+
     private static Regex TryGetRegexOrDefault(string? messageRegex, Regex defaultRegex) =>
         messageRegex == null
             ? defaultRegex