(GH-2456) Correctly assert version number for tagged commit

src/GitVersion.App.Tests/TagCheckoutInBuildAgentTests.cs

@@ -0,0 +1,77 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using GitTools.Testing;
+using GitVersion.BuildAgents;
+using GitVersion.Core.Tests.Helpers;
+using LibGit2Sharp;
+using NUnit.Framework;
+using Shouldly;
+
+namespace GitVersion.App.Tests
+{
+    [TestFixture]
+    public class TagCheckoutInBuildAgentTests
+    {
+        [Test]
+        public async Task VerifyTagCheckoutOnAzurePipelines()
+        {
+            var env = new Dictionary<string, string>
+            {
+                { AzurePipelines.EnvironmentVariableName, "true" },
+                { "BUILD_SOURCEBRANCH", "refs/tags/0.2.0" },
+            };
+
+            await VerifyTagCheckoutVersionIsCalculatedProperly(env);
+        }
+
+        [Test]
+        public async Task VerifyTagCheckoutOnGitHubActions()
+        {
+            var env = new Dictionary<string, string>
+            {
+                { GitHubActions.EnvironmentVariableName, "true" },
+                { "GITHUB_REF", "ref/tags/0.2.0" },
+            };
+
+            await VerifyTagCheckoutVersionIsCalculatedProperly(env);
+        }
+
+        private static async Task VerifyTagCheckoutVersionIsCalculatedProperly(Dictionary<string, string> env)
+        {
+            using var fixture = new EmptyRepositoryFixture();
+            var remoteRepositoryPath = PathHelper.GetTempPath();
+            RepositoryFixtureBase.Init(remoteRepositoryPath);
+            using (var remoteRepository = new Repository(remoteRepositoryPath))
+            {
+                remoteRepository.Config.Set("user.name", "Test");
+                remoteRepository.Config.Set("user.email", "[email protected]");
+                fixture.Repository.Network.Remotes.Add("origin", remoteRepositoryPath);
+                Console.WriteLine("Created git repository at {0}", remoteRepositoryPath);
+                remoteRepository.MakeATaggedCommit("0.1.0");
+                Commands.Checkout(remoteRepository, remoteRepository.CreateBranch("develop"));
+                remoteRepository.MakeACommit();
+                Commands.Checkout(remoteRepository, remoteRepository.CreateBranch("release/0.2.0"));
+                remoteRepository.MakeACommit();
+                Commands.Checkout(remoteRepository, TestBase.MainBranch);
+                remoteRepository.MergeNoFF("release/0.2.0", Generate.SignatureNow());
+                remoteRepository.MakeATaggedCommit("0.2.0");
+
+                Commands.Fetch((Repository)fixture.Repository, "origin", new string[0], new FetchOptions(), null);
+                Commands.Checkout(fixture.Repository, "0.2.0");
+            }
+
+            var programFixture = new ProgramFixture(fixture.RepositoryPath);
+            programFixture.WithEnv(env.ToArray());
+
+            var result = await programFixture.Run();
+
+            result.ExitCode.ShouldBe(0);
+            result.OutputVariables.FullSemVer.ShouldBe("0.2.0");
+
+            // Cleanup repository files
+            DirectoryHelper.DeleteDirectory(remoteRepositoryPath);
+        }
+    }
+}

src/GitVersion.Core/VersionCalculation/NextVersionCalculator.cs

@@ -56,15 +56,23 @@ public SemanticVersion FindVersion()
             }
 
             var baseVersion = baseVersionCalculator.GetBaseVersion();
+            baseVersion.SemanticVersion.BuildMetaData = mainlineVersionCalculator.CreateVersionBuildMetaData(baseVersion.BaseVersionSource);
             SemanticVersion semver;
             if (context.Configuration.VersioningMode == VersioningMode.Mainline)
             {
                 semver = mainlineVersionCalculator.FindMainlineModeVersion(baseVersion);
             }
             else
             {
-                semver = PerformIncrement(baseVersion);
-                semver.BuildMetaData = mainlineVersionCalculator.CreateVersionBuildMetaData(baseVersion.BaseVersionSource);
+                if (taggedSemanticVersion?.BuildMetaData == null || (taggedSemanticVersion.BuildMetaData.Sha != baseVersion.SemanticVersion.BuildMetaData.Sha))
+                {
+                    semver = PerformIncrement(baseVersion);
+                    semver.BuildMetaData = mainlineVersionCalculator.CreateVersionBuildMetaData(baseVersion.BaseVersionSource);
+                }
+                else
+                {
+                    semver = baseVersion.SemanticVersion;
+                }
             }
 
             var hasPreReleaseTag = semver.PreReleaseTag.HasTag();