Simplified getting branch configuration

Author: JakeGinnivan

src/GitVersionCore/BranchConfigurationCalculator.cs

@@ -13,50 +13,21 @@ public class BranchConfigurationCalculator
         /// </summary>
         public static BranchConfig GetBranchConfiguration(GitVersionContext context, Branch targetBranch, IList<Branch> excludedInheritBranches = null)
         {
-            var matchingBranches = LookupBranchConfiguration(context.FullConfiguration, targetBranch).ToArray();
-
-            BranchConfig branchConfiguration;
-            if (matchingBranches.Length > 0)
-            {
-                branchConfiguration = matchingBranches[0];
-
-                if (matchingBranches.Length > 1)
-                {
-                    Logger.WriteWarning(string.Format(
-                        "Multiple branch configurations match the current branch branchName of '{0}'. Using the first matching configuration, '{1}'. Matching configurations include: '{2}'",
-                        targetBranch.FriendlyName,
-                        branchConfiguration.Name,
-                        string.Join("', '", matchingBranches.Select(b => b.Name))));
-                }
-            }
-            else
+            var matchingBranches = context.FullConfiguration.GetConfigForBranch(targetBranch.FriendlyName);
+            
+            if (matchingBranches == null)
             {
                 Logger.WriteInfo(string.Format(
                     "No branch configuration found for branch {0}, falling back to default configuration",
                     targetBranch.FriendlyName));
 
-                branchConfiguration = new BranchConfig { Name = string.Empty };
-                ConfigurationProvider.ApplyBranchDefaults(context.FullConfiguration, branchConfiguration, "");
-            }
-
-            return branchConfiguration.Increment == IncrementStrategy.Inherit ?
-                InheritBranchConfiguration(context, targetBranch, branchConfiguration, excludedInheritBranches) :
-                branchConfiguration;
-        }
-
-        static IEnumerable<BranchConfig> LookupBranchConfiguration(Config config, Branch currentBranch)
-        {
-            if (config == null)
-            {
-                throw new ArgumentNullException(nameof(config));
-            }
-
-            if (currentBranch == null)
-            {
-                throw new ArgumentNullException(nameof(currentBranch));
+                matchingBranches = new BranchConfig { Name = string.Empty };
+                ConfigurationProvider.ApplyBranchDefaults(context.FullConfiguration, matchingBranches, "");
             }
 
-            return config.Branches.Where(b => Regex.IsMatch(currentBranch.FriendlyName, "^" + b.Value.Regex, RegexOptions.IgnoreCase)).Select(kvp => kvp.Value);
+            return matchingBranches.Increment == IncrementStrategy.Inherit ?
+                InheritBranchConfiguration(context, targetBranch, matchingBranches, excludedInheritBranches) :
+                matchingBranches;
         }
 
         static BranchConfig InheritBranchConfiguration(GitVersionContext context, Branch targetBranch, BranchConfig branchConfiguration, IList<Branch> excludedInheritBranches)
@@ -77,11 +48,9 @@ static BranchConfig InheritBranchConfiguration(GitVersionContext context, Branch
                 {
                     excludedInheritBranches = repository.Branches.Where(b =>
                     {
-                        var branchConfig = LookupBranchConfiguration(config, b).ToArray();
+                        var branchConfig = config.GetConfigForBranch(b.FriendlyName);
 
-                        // NOTE: if length is 0 we couldn't find the configuration for the branch e.g. "origin/master"
-                        // NOTE: if the length is greater than 1 we cannot decide which merge strategy to pick
-                        return (branchConfig.Length != 1) || (branchConfig.Length == 1 && branchConfig[0].Increment == IncrementStrategy.Inherit);
+                        return branchConfig != null && branchConfig.Increment == IncrementStrategy.Inherit;
                     }).ToList();
                 }
                 // Add new excluded branches.

src/GitVersionCore/Configuration/Config.cs

@@ -1,8 +1,10 @@
 namespace GitVersion
 {
+    using System;
     using System.Collections.Generic;
     using System.Globalization;
     using System.Linq;
+    using System.Text.RegularExpressions;
     using YamlDotNet.Serialization;
 
     public class Config
@@ -89,6 +91,33 @@ public Dictionary<string, BranchConfig> Branches
             }
         }
 
+        public BranchConfig GetConfigForBranch(string branchName)
+        {
+            if (branchName == null) throw new ArgumentNullException(nameof(branchName));
+            var matches = Branches
+                .Where(b => Regex.IsMatch(branchName, "^" + b.Value.Regex, RegexOptions.IgnoreCase));
+
+            try
+            {
+                return matches
+                    .Select(kvp => kvp.Value)
+                    .SingleOrDefault();
+            }
+            catch (InvalidOperationException)
+            {
+                var matchingConfigs = string.Join("\n - ", matches.Select(m => m.Key));
+                var picked = matches
+                    .Select(kvp => kvp.Value)
+                    .First();
+
+                Logger.WriteWarning(
+                    $"Multiple branch configurations match the current branch branchName of '{branchName}'. " +
+                    $"Using the first matching configuration, '{picked}'. Matching configurations include: '{matchingConfigs}'");
+
+                return picked;
+            }
+        }
+
         T MergeObjects<T>(T target, T source)
         {
             typeof(T).GetProperties()

src/GitVersionCore/MergeMessage.cs

@@ -31,7 +31,7 @@ public MergeMessage(string mergeMessage, Config config)
             }
 
             MergedBranch = ParseBranch();
-            
+
             // Remove remotes and branch prefixes like release/ feature/ hotfix/ etc
             var toMatch = Regex.Replace(MergedBranch, @"^(\w+[-/])*", "", RegexOptions.IgnoreCase);
             toMatch = Regex.Replace(toMatch, $"^{config.TagPrefix}", "");