Fix GitVersion calculates the wrong version after main is merged back…

… to develop.

src/GitVersion.Configuration/BranchConfiguration.cs

@@ -107,11 +107,4 @@ public virtual IBranchConfiguration Inherit(IBranchConfiguration configuration)
             PreReleaseWeight = PreReleaseWeight ?? configuration.PreReleaseWeight
         };
     }
-
-    public IBranchConfiguration Empty() => new BranchConfiguration
-    {
-        RegularExpression = string.Empty,
-        Label = ConfigurationConstants.BranchNamePlaceholder,
-        Increment = IncrementStrategy.Inherit
-    };
 }

src/GitVersion.Configuration/GitVersionConfiguration.cs

@@ -157,4 +157,11 @@ public string ToJsonString()
         stream.Flush();
         return stringBuilder.ToString();
     }
+
+    public IBranchConfiguration GetEmptyBranchConfiguration() => new BranchConfiguration
+    {
+        RegularExpression = string.Empty,
+        Label = ConfigurationConstants.BranchNamePlaceholder,
+        Increment = IncrementStrategy.Inherit
+    };
 }

src/GitVersion.Core.Tests/IntegrationTests/OtherScenarios.cs

@@ -1218,4 +1218,57 @@ public void EnsurePreventIncrementWhenCurrentCommitTaggedOnReleaseBranchAndIncre
 
         fixture.AssertFullSemver(semVersion, configuration);
     }
+
+    [TestCase(false, "2.0.0-alpha.3")]
+    [TestCase(true, "2.0.0-alpha.2")]
+    public void EnsureVersionAfterMainIsMergedBackToDevelopIsCorrectForTrunkBased(bool applyTag, string semanticVersion)
+    {
+        var configuration = GitFlowConfigurationBuilder.New
+            .WithVersionStrategy(VersionStrategies.TrunkBased)
+            .Build();
+
+        using var fixture = new EmptyRepositoryFixture("main");
+
+        fixture.MakeACommit("A");
+        fixture.ApplyTag("1.0.0");
+        fixture.BranchTo("develop");
+        fixture.MakeACommit("B +semver: major");
+
+        // ✅ succeeds as expected
+        fixture.AssertFullSemver("2.0.0-alpha.1", configuration);
+
+        fixture.Checkout("main");
+        fixture.MakeACommit("C");
+        if (applyTag) fixture.ApplyTag("1.0.1");
+        fixture.Checkout("develop");
+        fixture.MergeNoFF("main");
+
+        // ✅ succeeds as expected
+        fixture.AssertFullSemver(semanticVersion, configuration);
+    }
+
+    [Test]
+    public void EnsureVersionAfterMainIsMergedBackToDevelopIsCorrectForGitFlow()
+    {
+        var configuration = GitFlowConfigurationBuilder.New.Build();
+
+        using var fixture = new EmptyRepositoryFixture("main");
+
+        fixture.MakeACommit("A");
+        fixture.ApplyTag("1.0.0");
+        fixture.BranchTo("develop");
+        fixture.MakeACommit("B +semver: major");
+
+        // ✅ succeeds as expected
+        fixture.AssertFullSemver("2.0.0-alpha.1", configuration);
+
+        fixture.Checkout("main");
+        fixture.MakeACommit("C");
+        fixture.ApplyTag("1.0.1");
+        fixture.Checkout("develop");
+        fixture.MergeNoFF("main");
+
+        // ✅ succeeds as expected
+        fixture.AssertFullSemver("2.0.0-alpha.3", configuration);
+    }
 }

src/GitVersion.Core/Configuration/IBranchConfiguration.cs

@@ -38,7 +38,5 @@ public bool IsMatch(string branchName)
 
     IReadOnlyCollection<string> IsSourceBranchFor { get; }
 
-    IBranchConfiguration Empty();
-
     IBranchConfiguration Inherit(IBranchConfiguration configuration);
 }

src/GitVersion.Core/Configuration/IGitVersionConfiguration.cs

@@ -51,4 +51,6 @@ public interface IGitVersionConfiguration : IBranchConfiguration
     IIgnoreConfiguration Ignore { get; }
 
     string ToJsonString();
+
+    IBranchConfiguration GetEmptyBranchConfiguration();
 }

src/GitVersion.Core/Extensions/ConfigurationExtensions.cs

@@ -24,7 +24,7 @@ public static IBranchConfiguration GetBranchConfiguration(this IGitVersionConfig
     public static IBranchConfiguration GetBranchConfiguration(this IGitVersionConfiguration configuration, ReferenceName branchName)
     {
         var branchConfiguration = GetBranchConfigurations(configuration, branchName.WithoutOrigin).FirstOrDefault();
-        branchConfiguration ??= configuration.Empty();
+        branchConfiguration ??= configuration.GetEmptyBranchConfiguration();
         return branchConfiguration;
     }
 

src/GitVersion.Core/PublicAPI.Unshipped.txt

@@ -147,7 +147,6 @@ GitVersion.Configuration.EffectiveConfiguration.VersionStrategy.get -> GitVersio
 GitVersion.Configuration.IBranchConfiguration
 GitVersion.Configuration.IBranchConfiguration.CommitMessageIncrementing.get -> GitVersion.VersionCalculation.CommitMessageIncrementMode?
 GitVersion.Configuration.IBranchConfiguration.DeploymentMode.get -> GitVersion.VersionCalculation.DeploymentMode?
-GitVersion.Configuration.IBranchConfiguration.Empty() -> GitVersion.Configuration.IBranchConfiguration!
 GitVersion.Configuration.IBranchConfiguration.Increment.get -> GitVersion.IncrementStrategy
 GitVersion.Configuration.IBranchConfiguration.Inherit(GitVersion.Configuration.IBranchConfiguration! configuration) -> GitVersion.Configuration.IBranchConfiguration!
 GitVersion.Configuration.IBranchConfiguration.IsMainBranch.get -> bool?
@@ -178,6 +177,7 @@ GitVersion.Configuration.IGitVersionConfiguration.AssemblyVersioningFormat.get -
 GitVersion.Configuration.IGitVersionConfiguration.AssemblyVersioningScheme.get -> GitVersion.Extensions.AssemblyVersioningScheme?
 GitVersion.Configuration.IGitVersionConfiguration.Branches.get -> System.Collections.Generic.IReadOnlyDictionary<string!, GitVersion.Configuration.IBranchConfiguration!>!
 GitVersion.Configuration.IGitVersionConfiguration.CommitDateFormat.get -> string?
+GitVersion.Configuration.IGitVersionConfiguration.GetEmptyBranchConfiguration() -> GitVersion.Configuration.IBranchConfiguration!
 GitVersion.Configuration.IGitVersionConfiguration.Ignore.get -> GitVersion.Configuration.IIgnoreConfiguration!
 GitVersion.Configuration.IGitVersionConfiguration.TagPreReleaseWeight.get -> int?
 GitVersion.Configuration.IGitVersionConfiguration.TagPrefix.get -> string?

src/GitVersion.Core/VersionCalculation/IncrementStrategyFinder.cs

@@ -40,7 +40,7 @@ public VersionField DetermineIncrementedField(
         configuration.NotNull();
 
         var commitMessageIncrement = FindCommitMessageIncrement(
-            configuration, baseVersion.BaseVersionSource, currentCommit, label);
+            configuration, baseVersion, currentCommit, label);
 
         var defaultIncrement = configuration.Increment.ToVersionField();
 
@@ -81,31 +81,38 @@ public VersionField DetermineIncrementedField(
     }
 
     private VersionField? FindCommitMessageIncrement(
-        EffectiveConfiguration configuration, ICommit? baseCommit, ICommit? currentCommit, string? label)
+        EffectiveConfiguration configuration, BaseVersion baseVersion, ICommit? currentCommit, string? label)
     {
         if (configuration.CommitMessageIncrementing == CommitMessageIncrementMode.Disabled)
         {
             return null;
         }
 
+        var baseCommit = baseVersion.BaseVersionSource;
+
         //get tags with valid version - depends on configuration (see #3757)
         var targetShas = new Lazy<IReadOnlySet<string>>(() =>
             this.taggedSemanticVersionRepository.GetTaggedSemanticVersions(configuration.TagPrefix, configuration.SemanticVersionFormat)
-            .SelectMany(_ => _).Where(_ => _.Value.IsMatchForBranchSpecificLabel(label)).Select(_ => _.Tag.TargetSha).ToHashSet()
+                .SelectMany(_ => _).Where(_ => _.Value.IsMatchForBranchSpecificLabel(label)).Select(_ => _.Tag.TargetSha).ToHashSet()
         );
 
-        var commits = GetIntermediateCommits(baseCommit, currentCommit);
+        var targetTags = this.taggedSemanticVersionRepository
+            .GetTaggedSemanticVersions(configuration.TagPrefix, configuration.SemanticVersionFormat)
+            .SelectMany(_ => _).Where(element => element.Value.IsMatchForBranchSpecificLabel(label)
+                && element.Value.CompareTo(baseVersion.GetSemanticVersion()) == 0).Select(_ => _.Tag.TargetSha).ToHashSet();
+
+        var intermediateCommits = GetIntermediateCommits(baseCommit, currentCommit);
         // consider commit messages since latest tag only (see #3071)
-        commits = commits
+        var commits = intermediateCommits
             .Reverse()
-            .TakeWhile(x => !targetShas.Value.Contains(x.Sha))
+            .TakeWhile(x => baseCommit != x)
+            .Where(element => !targetShas.Value.Contains(element.Sha))
             .Reverse();
 
         if (configuration.CommitMessageIncrementing == CommitMessageIncrementMode.MergeMessageOnly)
         {
             commits = commits.Where(c => c.Parents.Count() > 1);
         }
-
         return GetIncrementForCommits(
             majorVersionBumpMessage: configuration.MajorVersionBumpMessage,
             minorVersionBumpMessage: configuration.MinorVersionBumpMessage,