Support for GitHub Actions

src/GitVersion.sln.DotSettings

@@ -485,7 +485,7 @@ II.2.12 <HandlesEvent />
 </Patterns>
 </s:String>
 	<s:String x:Key="/Default/CodeStyle/CSharpMemberOrderPattern/LayoutType/@EntryValue">CustomLayout</s:String>
-	<s:Boolean x:Key="/Default/CodeStyle/CSharpUsing/AddImportsToDeepestScope/@EntryValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/CodeStyle/CSharpUsing/AddImportsToDeepestScope/@EntryValue">False</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeStyle/CSharpUsing/QualifiedUsingAtNestedScope/@EntryValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeStyle/Generate/=Constructor/@KeyIndexDefined">True</s:Boolean>
 	<s:String x:Key="/Default/CodeStyle/Generate/=Constructor/Options/=XmlDocumentation/@EntryIndexedValue">False</s:String>

src/GitVersionCore.Tests/BuildServers/GitHubActionsTests.cs

@@ -0,0 +1,167 @@
+using System;
+using GitVersion;
+using GitVersion.BuildServers;
+using GitVersion.Logging;
+using NUnit.Framework;
+using Shouldly;
+using System.Collections.Generic;
+using Environment = System.Environment;
+
+namespace GitVersionCore.Tests.BuildServers
+{
+
+    [TestFixture]
+    public class GitHubActionsTests : TestBase
+    {
+        private IEnvironment environment;
+        private ILog log;
+
+        [SetUp]
+        public void SetUp()
+        {
+            log = new NullLog();
+
+            environment = new TestEnvironment();
+            environment.SetEnvironmentVariable("GITHUB_ACTION", Guid.NewGuid().ToString());
+        }
+
+        [TearDown]
+        public void TearDown()
+        {
+            environment.SetEnvironmentVariable("GITHUB_ACTION", null);
+        }
+
+        [Test]
+        public void CanApplyToCurrentContextShouldBeTrueWhenEnvironmentVariableIsSet()
+        {
+            // Arrange
+            var buildServer = new GitHubActions(environment, log);
+
+            // Act
+            var result = buildServer.CanApplyToCurrentContext();
+
+            // Assert
+            result.ShouldBeTrue();
+        }
+
+        [Test]
+        public void CanApplyToCurrentContextShouldBeFalseWhenEnvironmentVariableIsNotSet()
+        {
+            // Arrange
+            environment.SetEnvironmentVariable("GITHUB_ACTION", "");
+            var buildServer = new GitHubActions(environment, log);
+
+            // Act
+            var result = buildServer.CanApplyToCurrentContext();
+
+            // Assert
+            result.ShouldBeFalse();
+        }
+
+        [Test]
+        public void GetCurrentBranchShouldGetBranchIfSet()
+        {
+            // Arrange
+            const string expected = "actionsBranch";
+
+            environment.SetEnvironmentVariable("GITHUB_REF", $"refs/heads/{expected}");
+
+            var buildServer = new GitHubActions(environment, log);
+
+            // Act
+            var result = buildServer.GetCurrentBranch(false);
+
+            // Assert
+            result.ShouldBe(expected);
+        }
+
+        [Test]
+        public void GetCurrentBranchShouldNotMatchTag()
+        {
+            // Arrange
+            environment.SetEnvironmentVariable("GITHUB_REF", $"refs/tags/v1.0.0");
+
+            var buildServer = new GitHubActions(environment, log);
+
+            // Act
+            var result = buildServer.GetCurrentBranch(false);
+
+            // Assert
+            result.ShouldBeNull();
+        }
+
+        [TestCase("Something", "1.0.0",
+            "::set-env name=GitVersion_Something::1.0.0")]
+        public void GetSetParameterMessage(string key, string value, string expectedResult)
+        {
+            // Arrange
+            var buildServer = new GitHubActions(environment, log);
+
+            // Assert
+            environment.GetEnvironmentVariable("GitVersion_Something").ShouldBeNullOrWhiteSpace();
+
+            // Act
+            var result = buildServer.GenerateSetParameterMessage(key, value);
+
+            // Assert
+            result.ShouldContain(s => true, 1);
+            result.ShouldBeEquivalentTo(new[] { expectedResult });
+        }
+
+        [Test]
+        public void SkipEmptySetParameterMessage()
+        {
+            // Arrange
+            var buildServer = new GitHubActions(environment, log);
+
+            // Act
+            var result = buildServer.GenerateSetParameterMessage("Hello", string.Empty);
+
+            // Assert
+            result.ShouldBeEquivalentTo(new string[0]);
+        }
+
+        [Test]
+        public void ShouldWriteIntegration()
+        {
+            // Arrange
+            var buildServer = new GitHubActions(environment, log);
+
+            var vars = new TestableVersionVariables("1.0.0");
+
+            var list = new List<string>();
+
+            // Assert
+            environment.GetEnvironmentVariable("GitVersion_Major").ShouldBeNullOrWhiteSpace();
+
+            // Act
+            buildServer.WriteIntegration(s => { list.Add(s); }, vars);
+
+            // Assert
+            var expected = new List<string>
+            {
+                "Executing GenerateSetVersionMessage for 'GitHubActions'.",
+                "",
+                "Executing GenerateBuildLogOutput for 'GitHubActions'.",
+                "::set-env name=GitVersion_Major::1.0.0"
+            };
+
+            string.Join(Environment.NewLine, list)
+                .ShouldBe(string.Join(Environment.NewLine, expected));
+        }
+
+        [Test]
+        public void GetEmptyGenerateSetVersionMessage()
+        {
+            // Arrange
+            var buildServer = new GitHubActions(environment, log);
+            var vars = new TestableVersionVariables("1.0.0");
+
+            // Act
+            var message = buildServer.GenerateSetVersionMessage(vars);
+
+            // Assert
+            message.ShouldBeEmpty();
+        }
+    }
+}

src/GitVersionCore/BuildServers/GitHubActions.cs

@@ -0,0 +1,65 @@
+using GitVersion.Logging;
+using GitVersion.OutputVariables;
+
+namespace GitVersion.BuildServers
+{
+    public class GitHubActions: BuildServerBase
+    {
+        // https://help.github.com/en/actions/automating-your-workflow-with-github-actions/using-environment-variables#default-environment-variables
+
+        public GitHubActions(IEnvironment environment, ILog log) : base(environment, log)
+        {
+        }
+
+        public const string EnvironmentVariableName = "GITHUB_ACTION";
+        protected override string EnvironmentVariable { get; } = EnvironmentVariableName;
+
+        public override string GenerateSetVersionMessage(VersionVariables variables)
+        {
+            // There is no equivalent function in GitHub Actions.
+
+            return string.Empty;
+        }
+
+        public override string[] GenerateSetParameterMessage(string name, string value)
+        {
+            // https://help.github.com/en/actions/automating-your-workflow-with-github-actions/development-tools-for-github-actions#set-an-environment-variable-set-env
+            // Example
+            // echo "::set-env name=action_state::yellow"
+
+            if (!string.IsNullOrWhiteSpace(value))
+            {
+                var key = $"GitVersion_{name}";
+
+                return new[]
+                {
+                    $"::set-env name={key}::{value}"
+                };
+            }
+
+            return new string[0];
+        }
+
+        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);
+        }
+    }
+}

src/GitVersionCore/GitVersionCoreModule.cs

@@ -57,6 +57,7 @@ private static void RegisterBuildServers(IServiceCollection services)
             services.AddSingleton<IBuildServer, EnvRun>();
             services.AddSingleton<IBuildServer, Drone>();
             services.AddSingleton<IBuildServer, CodeBuild>();
+            services.AddSingleton<IBuildServer, GitHubActions>();
         }
 
         private static void RegisterVersionStrategies(IServiceCollection services)