Unity Editor log is now forwarded to output if build error happens.

src/Cake.Unity/UnityAliases.cs

@@ -48,7 +48,7 @@ public static void UnityBuild(this ICakeContext context, DirectoryPath projectPa
         [CakeMethodAlias]
         [CakeAliasCategory("Build")]
         public static void UnityEditor(this ICakeContext context, FilePath unityEditorPath, UnityEditorArguments arguments) =>
-            new UnityEditor(context.FileSystem, context.Environment, context.ProcessRunner, context.Tools)
+            new UnityEditor(context.FileSystem, context.Environment, context.ProcessRunner, context.Tools, context.Log)
                 .Run(unityEditorPath, arguments);
 
         /// <summary>

src/Cake.Unity/UnityEditor.cs

@@ -1,28 +1,89 @@
 using System.Collections.Generic;
+using System.IO;
 using Cake.Core;
+using Cake.Core.Diagnostics;
 using Cake.Core.IO;
 using Cake.Core.Tooling;
 
 namespace Cake.Unity
 {
     internal class UnityEditor : Tool<UnityEditorSettings>
     {
+        private readonly IFileSystem fileSystem;
         private readonly ICakeEnvironment environment;
+        private readonly ICakeLog log;
 
-        public UnityEditor(IFileSystem fileSystem, ICakeEnvironment environment, IProcessRunner processRunner, IToolLocator tools)
-            : base(fileSystem, environment, processRunner, tools) =>
+        public UnityEditor(IFileSystem fileSystem, ICakeEnvironment environment, IProcessRunner processRunner, IToolLocator tools, ICakeLog log)
+            : base(fileSystem, environment, processRunner, tools)
+        {
+            this.fileSystem = fileSystem;
             this.environment = environment;
+            this.log = log;
+        }
 
         protected override string GetToolName() => "Unity Editor";
 
         protected override IEnumerable<string> GetToolExecutableNames() => new[] { "Unity.exe" };
 
-        public void Run(FilePath unityEditorPath, UnityEditorArguments arguments) =>
-            Run(
-                new UnityEditorSettings(arguments, environment)
+        public void Run(FilePath unityEditorPath, UnityEditorArguments arguments)
+        {
+            WarnIfLogLocationNotSet(arguments);
+
+            try
+            {
+                Run(new UnityEditorSettings(arguments, environment) { ToolPath = unityEditorPath });
+            }
+            catch
+            {
+                if (arguments.LogFile == null)
+                {
+                    log.Error("Execution of Unity Editor failed.");
+                    log.Warning("Cannot forward log file to output because LogFile argument is missing.");
+                }
+                else
                 {
-                    ToolPath = unityEditorPath,
-                },
-                new ProcessArgumentBuilder());
+                    log.Error("Execution of Unity Editor failed.");
+                    log.Error("Please analyze log below for the reasons of failure.");
+                    ForwardLogFileToOutput(arguments.LogFile);
+                }
+
+                throw;
+            }
+        }
+
+        private void Run(UnityEditorSettings settings) => Run(settings, new ProcessArgumentBuilder());
+
+        private void ForwardLogFileToOutput(FilePath logPath)
+        {
+            var logFile = fileSystem.GetFile(logPath);
+
+            if (!logFile.Exists)
+            {
+                log.Warning("Unity Editor log file not found: {0}", logPath);
+                return;
+            }
+
+            foreach (var line in ReadLogSafe(logFile))
+            {
+                log.Information(line);
+            }
+        }
+
+        private static IEnumerable<string> ReadLogSafe(IFile file)
+        {
+            using (var stream = file.Open(FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
+            using (var reader = new StreamReader(stream))
+                while (!reader.EndOfStream)
+                    yield return reader.ReadLine();
+        }
+
+        private void WarnIfLogLocationNotSet(UnityEditorArguments arguments)
+        {
+            if (arguments.LogFile == null)
+            {
+                log.Warning("LogFile is not specified by Unity Editor arguments.");
+                log.Warning("Please specify it for ability to forward Unity log to console.");
+            }
+        }
     }
 }