Fix GitHub Actions current branch and prevent fetch

Author: gitfool

src/GitVersionCore.Tests/BuildServers/GitHubActionsTests.cs

@@ -58,31 +58,42 @@ public void CanApplyToCurrentContextShouldBeFalseWhenEnvironmentVariableIsNotSet
         }
 
         [Test]
-        public void GetCurrentBranchShouldGetBranchIfSet()
+        public void GetCurrentBranchShouldHandleBranches()
         {
             // Arrange
-            const string expected = "actionsBranch";
+            environment.SetEnvironmentVariable("GITHUB_REF", "refs/heads/master");
 
-            environment.SetEnvironmentVariable("GITHUB_REF", $"refs/heads/{expected}");
+            // Act
+            var result = buildServer.GetCurrentBranch(false);
+
+            // Assert
+            result.ShouldBe("refs/heads/master");
+        }
+
+        [Test]
+        public void GetCurrentBranchShouldHandleTags()
+        {
+            // Arrange
+            environment.SetEnvironmentVariable("GITHUB_REF", "refs/tags/1.0.0");
 
             // Act
             var result = buildServer.GetCurrentBranch(false);
 
             // Assert
-            result.ShouldBe(expected);
+            result.ShouldBe("refs/tags/1.0.0");
         }
 
         [Test]
-        public void GetCurrentBranchShouldNotMatchTag()
+        public void GetCurrentBranchShouldHandlePullRequests()
         {
             // Arrange
-            environment.SetEnvironmentVariable("GITHUB_REF", $"refs/tags/v1.0.0");
+            environment.SetEnvironmentVariable("GITHUB_REF", "refs/pull/1/merge");
 
             // Act
             var result = buildServer.GetCurrentBranch(false);
 
             // Assert
-            result.ShouldBeNull();
+            result.ShouldBe("refs/pull/1/merge");
         }
 
         [TestCase("Something", "1.0.0",

src/GitVersionCore/BuildServers/GitHubActions.cs

@@ -42,26 +42,9 @@ public override string[] GenerateSetParameterMessage(string name, string value)
 
         public override string GetCurrentBranch(bool usingDynamicRepos)
         {
-            // GITHUB_REF
-            // The branch or tag ref that triggered the workflow.
-            // For example, refs/heads/feature-branch-1. If neither a branch or
-            // tag is available for the event type, the variable will not exist.
-
-            var value = Environment.GetEnvironmentVariable("GITHUB_REF");
-            if (!string.IsNullOrWhiteSpace(value))
-            {
-                const string refsHeads = "refs/heads/";
-
-                if (value.StartsWith(refsHeads))
-                {
-                    value = value.Substring(refsHeads.Length);
-                    return value;
-                }
-            }
-
-            return base.GetCurrentBranch(usingDynamicRepos);
+            return Environment.GetEnvironmentVariable("GITHUB_REF");
         }
 
-        public override bool PreventFetch() => false;
+        public override bool PreventFetch() => true;
     }
 }