applied code review changes

Author: arturcic

src/GitVersionCore.Tests/SemanticVersionTests.cs

@@ -37,7 +37,7 @@ public void ValidateVersionParsing(
             string versionString, int major, int minor, int patch, string tag, int? tagNumber, int? numberOfBuilds,
             string branchName, string sha, string otherMetaData, string fullFormattedVersionString, string tagPrefixRegex)
         {
-            fullFormattedVersionString = fullFormattedVersionString ?? versionString;
+            fullFormattedVersionString ??= versionString;
 
             SemanticVersion.TryParse(versionString, tagPrefixRegex, out var version).ShouldBe(true, versionString);
             Assert.AreEqual(major, version.Major);

src/GitVersionCore/GitVersionContext.cs

@@ -182,7 +182,7 @@ private static Branch GetTargetBranch(IRepository repository, string targetBranc
                             b.NameWithoutRemote() == targetBranch);
 
                     // Failsafe in case the specified branch is invalid
-                    desiredBranch = desiredBranch ?? repository.Head;
+                    desiredBranch ??= repository.Head;
                 }
             }
 

src/GitVersionCore/Helpers/EnumerableExtensions.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+
+namespace GitVersion.Helpers
+{
+    public static class EnumerableExtensions
+    {
+        public static T OnlyOrDefault<T>(this IEnumerable<T> source)
+        {
+            switch (source)
+            {
+                case null:
+                    throw new ArgumentNullException(nameof(source));
+                case IList<T> list when list.Count == 1:
+                    return list[0];
+            }
+
+            using (var e = source.GetEnumerator())
+            {
+                if (!e.MoveNext())
+                    return default;
+                var current = e.Current;
+                if (!e.MoveNext())
+                    return current;
+            }
+
+            return default;
+        }
+    }
+}

src/GitVersionCore/Helpers/ExtensionMethods.cs

@@ -138,5 +138,22 @@ public static void DumpGraph(string workingDirectory, Action<string> writer = nu
                 Console.Write(output.ToString());
             }
         }
+
+        public static bool IsBranch(this string branchName, string branchNameToCompareAgainst)
+        {
+            // "develop" == "develop"
+            if (String.Equals(branchName, branchNameToCompareAgainst, StringComparison.OrdinalIgnoreCase))
+            {
+                return true;
+            }
+
+            // "refs/head/develop" == "develop"
+            if (branchName.EndsWith($"/{branchNameToCompareAgainst}", StringComparison.OrdinalIgnoreCase))
+            {
+                return true;
+            }
+
+            return false;
+        }
     }
 }

src/GitVersionCore/Helpers/LibGitExtensions.cs

@@ -1,17 +1,18 @@
 using System;
 using System.IO;
 using System.Linq;
+using System.Text;
 using System.Text.RegularExpressions;
 
-namespace GitVersion
+namespace GitVersion.Helpers
 {
-    public static class ExtensionMethods
+    public static class StringExtensions
     {
         private static readonly string[] trues;
         private static readonly string[] falses;
 
 
-        static ExtensionMethods()
+        static StringExtensions()
         {
             trues = new[]
             {
@@ -115,5 +116,16 @@ public static bool ArgumentRequiresValue(this string argument, int argumentIndex
 
             return argumentMightRequireValue;
         }
+
+        public static void AppendLineFormat(this StringBuilder stringBuilder, string format, params object[] args)
+        {
+            stringBuilder.AppendFormat(format, args);
+            stringBuilder.AppendLine();
+        }
+
+        public static string RegexReplace(this string input, string pattern, string replace, RegexOptions options = RegexOptions.None)
+        {
+            return Regex.Replace(input, pattern, replace, options);
+        }
     }
 }

src/GitVersionExe/ExtensionMethods.cs renamed to src/GitVersionCore/Helpers/StringExtensions.cs

@@ -5,6 +5,7 @@
 using System.Linq;
 using GitVersion.Configuration;
 using GitVersion.Exceptions;
+using GitVersion.Helpers;
 using GitVersion.Logging;
 using GitVersion.OutputVariables;
 using GitVersion.OutputFormatters;
@@ -416,7 +417,7 @@ private static NameValueCollection CollectSwitchesAndValuesFromArguments(IList<s
             string currentKey = null;
             var argumentRequiresValue = false;
 
-            for (var i = 0; i < namedArguments.Count; i = i + 1)
+            for (var i = 0; i < namedArguments.Count; i += 1)
             {
                 var arg = namedArguments[i];