For GitHub Actions, outgoing env vars need to be written to a temp file identified by $GITHUB_ENV

Author: DavidBoike

src/GitVersionCore.Tests/BuildAgents/GitHubActionsTests.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.IO;
 using GitVersion;
 using GitVersion.BuildAgents;
 using GitVersionCore.Tests.Helpers;
@@ -15,6 +16,7 @@ public class GitHubActionsTests : TestBase
     {
         private IEnvironment environment;
         private GitHubActions buildServer;
+        private string githubSetEnvironmentTempFilePath;
 
         [SetUp]
         public void SetUp()
@@ -26,12 +28,21 @@ public void SetUp()
             environment = sp.GetService<IEnvironment>();
             buildServer = sp.GetService<GitHubActions>();
             environment.SetEnvironmentVariable(GitHubActions.EnvironmentVariableName, "true");
+
+            githubSetEnvironmentTempFilePath = Path.GetTempFileName();
+            environment.SetEnvironmentVariable(GitHubActions.GitHubSetEnvTempFileEnvironmentVariableName, githubSetEnvironmentTempFilePath);
         }
 
         [TearDown]
         public void TearDown()
         {
             environment.SetEnvironmentVariable(GitHubActions.EnvironmentVariableName, null);
+            environment.SetEnvironmentVariable(GitHubActions.GitHubSetEnvTempFileEnvironmentVariableName, null);
+            if (githubSetEnvironmentTempFilePath != null && File.Exists(githubSetEnvironmentTempFilePath))
+            {
+                File.Delete(githubSetEnvironmentTempFilePath);
+                githubSetEnvironmentTempFilePath = null;
+            }
         }
 
         [Test]
@@ -97,8 +108,8 @@ public void GetCurrentBranchShouldHandlePullRequests()
         }
 
         [TestCase("Something", "1.0.0",
-            "\"GitVersion_Something=1.0.0\" >> $GITHUB_ENV")]
-        public void GetSetParameterMessage(string key, string value, string expectedResult)
+            "Writing \"GitVersion_Something=1.0.0\" to the file at $GITHUB_ENV", "GitVersion_Something=1.0.0")]
+        public void GetSetParameterMessage(string key, string value, string expectedResult, string expectedFileResult)
         {
             // Assert
             environment.GetEnvironmentVariable("GitVersion_Something").ShouldBeNullOrWhiteSpace();
@@ -109,6 +120,10 @@ public void GetSetParameterMessage(string key, string value, string expectedResu
             // Assert
             result.ShouldContain(s => true, 1);
             result.ShouldBeEquivalentTo(new[] { expectedResult });
+            var resultLines = File.ReadAllLines(githubSetEnvironmentTempFilePath);
+            resultLines.ShouldContain(s => true, 1);
+            resultLines.ShouldBeEquivalentTo(new[] { expectedFileResult });
+
         }
 
         [Test]
@@ -141,7 +156,7 @@ public void ShouldWriteIntegration()
                 "Executing GenerateSetVersionMessage for 'GitHubActions'.",
                 "",
                 "Executing GenerateBuildLogOutput for 'GitHubActions'.",
-                "\"GitVersion_Major=1.0.0\" >> $GITHUB_ENV"
+                "Writing \"GitVersion_Major=1.0.0\" to the file at $GITHUB_ENV"
             };
 
             string.Join(Environment.NewLine, list)

src/GitVersionCore/BuildAgents/GitHubActions.cs

@@ -1,5 +1,7 @@
 using GitVersion.Logging;
 using GitVersion.OutputVariables;
+using System.IO;
+using System.Text;
 
 namespace GitVersion.BuildAgents
 {
@@ -9,9 +11,13 @@ public class GitHubActions : BuildAgentBase
 
         public GitHubActions(IEnvironment environment, ILog log) : base(environment, log)
         {
+            this.environment = environment;
         }
 
         public const string EnvironmentVariableName = "GITHUB_ACTIONS";
+        public const string GitHubSetEnvTempFileEnvironmentVariableName = "GITHUB_ENV";
+        private readonly IEnvironment environment;
+
         protected override string EnvironmentVariable { get; } = EnvironmentVariableName;
 
         public override string GenerateSetVersionMessage(VersionVariables variables)
@@ -24,16 +30,31 @@ public override string GenerateSetVersionMessage(VersionVariables variables)
         public override string[] GenerateSetParameterMessage(string name, string value)
         {
             // https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-commands-for-github-actions#environment-files
-            // Example
-            // echo "name=action_state::yellow >> $GITHUB_ENV"
+            // However it's important that GitHub Actions does not parse the log output. The outgoing environment variables must be
+            // written to a temporary file (identified by the $GITHUB_ENV environment variable, which changes for every step in a workflow)
+            // which is then parsed. That file must also be UTF-8 or it will fail.
 
             if (!string.IsNullOrWhiteSpace(value))
             {
-                var key = $"GitVersion_{name}";
+                var gitHubSetEnvFilePath = environment.GetEnvironmentVariable(GitHubSetEnvTempFileEnvironmentVariableName);
+                var assignment = $"GitVersion_{name}={value}";
+
+                if (gitHubSetEnvFilePath != null)
+                {
+                    using (var streamWriter = File.AppendText(gitHubSetEnvFilePath)) // Already uses UTF-8 as required by GitHub
+                    {
+                        streamWriter.WriteLine(assignment);
+                    }
+
+                    return new[]
+                    {
+                        $"Writing \"{assignment}\" to the file at ${GitHubSetEnvTempFileEnvironmentVariableName}"
+                    };
+                }
 
                 return new[]
                 {
-                    $"\"{key}={value}\" >> $GITHUB_ENV"
+                    $"Unable to write \"{assignment}\" to ${GitHubSetEnvTempFileEnvironmentVariableName} because the environment variable is not set."
                 };
             }