Make the code less error-prone

Author: shana

src/GitHub.Api/Git/GitClient.cs

@@ -276,7 +276,7 @@ public ITask<string> Fetch(string remote,
         {
             //Logger.Trace("Fetch");
 
-            return new GitFetchTask(remote, cancellationToken, true, true, processor)
+            return new GitFetchTask(remote, cancellationToken, processor: processor)
                 .Configure(processManager);
         }
 

src/GitHub.Api/Git/Tasks/GitFetchTask.cs

@@ -1,5 +1,5 @@
 using System;
-using System.Text;
+using System.Collections.Generic;
 using System.Threading;
 
 namespace GitHub.Unity
@@ -10,30 +10,28 @@ class GitFetchTask : ProcessTask<string>
         private readonly string arguments;
 
         public GitFetchTask(string remote,
-            CancellationToken token, bool prune = false, bool tags = false, IOutputProcessor<string> processor = null)
+            CancellationToken token, bool prune = true, bool tags = true, IOutputProcessor<string> processor = null)
             : base(token, processor ?? new SimpleOutputProcessor())
         {
             Name = TaskName;
-            var stringBuilder = new StringBuilder();
-            stringBuilder.Append("fetch");
+            var args = new List<string> { "fetch" };
 
             if (prune)
             {
-                stringBuilder.Append(" -p");
+                args.Add("--prune");
             }
 
             if (tags)
             {
-                stringBuilder.Append(" --tags");
+                args.Add("--tags");
             }
 
             if (!String.IsNullOrEmpty(remote))
             {
-                stringBuilder.Append(" ");
-                stringBuilder.Append(remote);
+                args.Add(remote);
             }
 
-            arguments = stringBuilder.ToString();
+            arguments = args.Join(" ");
         }
 
         public override string ProcessArguments { get { return arguments; } }