Merge pull request #3768 from david-driscoll/fix/github-actions-tag-build

Re-fixed github actions tag handling

Author: asbjornu

src/GitVersion.BuildAgents.Tests/Agents/GitHubActionsTests.cs

@@ -18,6 +18,7 @@ public void SetUp()
         this.environment = sp.GetRequiredService<IEnvironment>();
         this.buildServer = sp.GetRequiredService<GitHubActions>();
         this.environment.SetEnvironmentVariable(GitHubActions.EnvironmentVariableName, "true");
+        this.environment.SetEnvironmentVariable("GITHUB_REF_TYPE", "branch");
 
         this.githubSetEnvironmentTempFilePath = Path.GetTempFileName();
         this.environment.SetEnvironmentVariable(GitHubActions.GitHubSetEnvTempFileEnvironmentVariableName, this.githubSetEnvironmentTempFilePath);
@@ -75,13 +76,14 @@ public void GetCurrentBranchShouldHandleBranches()
     public void GetCurrentBranchShouldHandleTags()
     {
         // Arrange
+        this.environment.SetEnvironmentVariable("GITHUB_REF_TYPE", "tag");
         this.environment.SetEnvironmentVariable("GITHUB_REF", "refs/tags/1.0.0");
 
         // Act
         var result = this.buildServer.GetCurrentBranch(false);
 
         // Assert
-        result.ShouldBe("refs/tags/1.0.0");
+        result.ShouldBeNull();
     }
 
     [Test]

src/GitVersion.BuildAgents/Agents/GitHubActions.cs

@@ -50,7 +50,16 @@ public override void WriteIntegration(Action<string?> writer, GitVersionVariable
         }
     }
 
-    public override string? GetCurrentBranch(bool usingDynamicRepos) => Environment.GetEnvironmentVariable("GITHUB_REF");
+
+    public override string? GetCurrentBranch(bool usingDynamicRepos)
+    {
+        // https://docs.github.com/en/actions/learn-github-actions/environment-variables#default-environment-variables
+        // GITHUB_REF must be used only for "real" branches, not for tags.
+        // Bug fix for https://github.com/GitTools/GitVersion/issues/2838
+
+        var refType = Environment.GetEnvironmentVariable("GITHUB_REF_TYPE") ?? "";
+        return refType.Equals("tag", StringComparison.OrdinalIgnoreCase) ? null : Environment.GetEnvironmentVariable("GITHUB_REF");
+    }
 
     public override bool PreventFetch() => true;
 }