fix appveyor build

Author: arturcic

src/GitVersionCore/BuildServers/AppVeyor.cs

@@ -66,6 +66,17 @@ public override string[] GenerateSetParameterMessage(string name, string value)
                 $"Adding Environment Variable. name='GitVersion_{name}' value='{value}']"
             };
         }
+
+        public override string GetCurrentBranch(bool usingDynamicRepos)
+        {
+            var pullRequestBranchName = Environment.GetEnvironmentVariable("APPVEYOR_PULL_REQUEST_HEAD_REPO_BRANCH");
+            if (!string.IsNullOrWhiteSpace(pullRequestBranchName))
+            {
+                return pullRequestBranchName;
+            }
+            return Environment.GetEnvironmentVariable("APPVEYOR_REPO_BRANCH");
+        }
+
         public override bool PreventFetch() => false;
     }
 }

src/GitVersionCore/Log/FileAppender.cs

@@ -31,7 +31,7 @@ public void WriteTo(LogLevel level, string message)
                     WriteLogEntry(filePath, message);
                 }
             }
-            catch (Exception ex)
+            catch (Exception)
             {
                 // 
             }

src/GitVersionCore/Log/LogExtensions.cs

@@ -90,7 +90,7 @@ public static void Write(this ILog log, LogLevel level, string format, params ob
             if (log == null)
                 return;
 
-            var verbosity = verbosityMaps[level];
+            var verbosity = GetVerbosityForLevel(level);
             if (verbosity > log.Verbosity)
             {
                 return;
@@ -118,7 +118,7 @@ public static void Write(this ILog log, LogLevel level, LogAction logAction)
             if (log == null || logAction == null)
                 return;
 
-            var verbosity = verbosityMaps[level];
+            var verbosity = GetVerbosityForLevel(level);
             if (verbosity > log.Verbosity)
             {
                 return;
@@ -164,7 +164,9 @@ public static IDisposable WithVerbosity(this ILog log, Verbosity verbosity)
             return Disposable.Create(() => log.Verbosity = lastVerbosity);
         }
 
-        private static IDictionary<LogLevel, Verbosity> verbosityMaps = new Dictionary<LogLevel, Verbosity>
+        public static Verbosity GetVerbosityForLevel(LogLevel level) => verbosityMaps[level];
+
+        private static readonly IDictionary<LogLevel, Verbosity> verbosityMaps = new Dictionary<LogLevel, Verbosity>
         {
             { LogLevel.Debug, Verbosity.Diagnostic },
             { LogLevel.Info, Verbosity.Normal },

src/GitVersionExe/ArgumentParser.cs

@@ -379,7 +379,12 @@ public Arguments ParseArguments(List<string> commandLineArguments)
 
                 if (name.IsSwitch("verbosity"))
                 {
-                    if (!Enum.TryParse(value, true, out arguments.Verbosity))
+                    // first try the old version
+                    if (Enum.TryParse(value, true, out LogLevel logLevel))
+                    {
+                        arguments.Verbosity = LogExtensions.GetVerbosityForLevel(logLevel);
+                    }
+                    else if (!Enum.TryParse(value, true, out arguments.Verbosity))
                     {
                         throw new WarningException($"Could not parse Verbosity value '{value}'");
                     }

src/GitVersionExe/Program.cs

@@ -10,7 +10,7 @@ class Program
     {
         static void Main()
         {
-            var log = new Logging.Log();
+            var log = new Log();
             var fileSystem = new FileSystem();
             var environment = new Environment();
             var argumentParser = new ArgumentParser(fileSystem, log);