Enable custom merge message formats via configuration

docs/configuration.md

@@ -48,6 +48,7 @@ commit-date-format: 'yyyy-MM-dd'
 ignore:
   sha: []
   commits-before: yyyy-MM-ddTHH:mm:ss
+merge-message-formats: {}
 ```
 
 And the description of the available options are:
@@ -179,6 +180,24 @@ Date and time in the format `yyyy-MM-ddTHH:mm:ss` (eg `commits-before:
 2015-10-23T12:23:15`) to setup an exclusion range. Effectively any commit before
 `commits-before` will be ignored.
 
+### merge-message-formats
+Custom merge message formats to enable identification of merge messages that do not
+follow the built-in conventions.  Entries should be added as key-value pairs where
+the value is a regular expression.
+e.g.
+
+```
+merge-message-formats:
+    tfs: ^Merged (?:PR (?<PullRequestNumber>\d+)): Merge (?<SourceBranch>.+) to (?<TargetBranch>.+)
+```
+
+The regular expression should contain the following capture groups:
++ SourceBranch - Identifies the source branch of the merge
++ TargetBranch - Identifies the target of the merge
++ PullRequestNumber - Captures the pull-request number
+
+Custom merge message formats are evalauted _before_ any built in formats.
+
 ## Branch configuration
 Then we have branch specific configuration, which looks something like this:
 

src/GitVersionCore.Tests/ConfigProviderTests.CanWriteOutEffectiveConfiguration.approved.txt

@@ -122,3 +122,4 @@ branches:
 ignore:
   sha: []
 commit-date-format: yyyy-MM-dd
+merge-message-formats: {}

src/GitVersionCore.Tests/Init/InitScenarios.CanSetNextVersion.approved.txt

@@ -2,3 +2,4 @@ next-version: 2.0.0
 branches: {}
 ignore:
   sha: []
+merge-message-formats: {}

src/GitVersionCore.Tests/VersionCalculation/Strategies/MergeMessageBaseVersionStrategyTests.cs

@@ -47,8 +47,6 @@ public void ShouldNotAllowIncrementOfVersion()
         [TestCase("Merge branch 'Release-v2.2'", true, "2.2.0")]
         [TestCase("Merge remote-tracking branch 'origin/release/0.8.0' into develop/master", true, "0.8.0")]
         [TestCase("Merge remote-tracking branch 'refs/remotes/origin/release/2.0.0'", true, "2.0.0")]
-        [TestCase("Merge release/5.1.0 to master", true, "5.1.0")] // Team Foundation Server 2017 default merge message (en-US)
-        [TestCase("Zusammengeführter PR \"9\": release/5.1.0 mit master mergen", true, "5.1.0")] // Team Foundation Server 2017 default merge message (de-DE)
         public void TakesVersionFromMergeOfReleaseBranch(string message, bool isMergeCommit, string expectedVersion)
         {
             var parents = GetParents(isMergeCommit);

src/GitVersionCore/Configuration/Config.cs

@@ -145,5 +145,8 @@ T MergeObjects<T>(T target, T source)
 
         [YamlMember(Alias = "commit-date-format")]
         public string CommitDateFormat { get; set; }
+
+        [YamlMember(Alias = "merge-message-formats")]
+        public Dictionary<string, string> MergeMessageFormats { get; set; } = new Dictionary<string, string>();
     }
 }

src/GitVersionCore/MergeMessage.cs

@@ -1,33 +1,38 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.RegularExpressions;
 
 namespace GitVersion
 {
-    class MergeMessage
+    public class MergeMessage
     {
-        private static readonly IList<MergeMessagePattern> Patterns = new List<MergeMessagePattern>
+        private static readonly IList<MergeMessageFormat> DefaultFormats = new List<MergeMessageFormat>
         {
-            new MergeMessagePattern("Default", @"^Merge (branch|tag) '(?<SourceBranch>[^']*)'(?: into (?<TargetBranch>[^\s]*))*"),
-            new MergeMessagePattern("SmartGit",  @"^Finish (?<SourceBranch>[^\s]*)(?: into (?<TargetBranch>[^\s]*))*"),
-            new MergeMessagePattern("BitBucketPull", @"^Merge pull request #(?<PullRequestNumber>\d+) (from|in) (?<Source>.*) from (?<SourceBranch>[^\s]*) to (?<TargetBranch>[^\s]*)"),
-            new MergeMessagePattern("GitHubPull", @"^Merge pull request #(?<PullRequestNumber>\d+) (from|in) (?:(?<SourceBranch>[^\s]*))(?: into (?<TargetBranch>[^\s]*))*"),
-            new MergeMessagePattern("RemoteTracking", @"^Merge remote-tracking branch '(?<SourceBranch>[^\s]*)'(?: into (?<TargetBranch>[^\s]*))*"),
-            new MergeMessagePattern("TfsMergeMessageEnglishUS", @"^Merge (?<SourceBranch>[^\s]*) to (?<TargetBranch>[^\s]*)"),
-            new MergeMessagePattern("TfsMergeMessageGermanDE",@"^Zusammengeführter PR ""(?<PullRequestNumber>\d+)""\: (?<SourceBranch>.*) mit (?<TargetBranch>.*) mergen")
+            new MergeMessageFormat("Default", @"^Merge (branch|tag) '(?<SourceBranch>[^']*)'(?: into (?<TargetBranch>[^\s]*))*"),
+            new MergeMessageFormat("SmartGit",  @"^Finish (?<SourceBranch>[^\s]*)(?: into (?<TargetBranch>[^\s]*))*"),
+            new MergeMessageFormat("BitBucketPull", @"^Merge pull request #(?<PullRequestNumber>\d+) (from|in) (?<Source>.*) from (?<SourceBranch>[^\s]*) to (?<TargetBranch>[^\s]*)"),
+            new MergeMessageFormat("GitHubPull", @"^Merge pull request #(?<PullRequestNumber>\d+) (from|in) (?:(?<SourceBranch>[^\s]*))(?: into (?<TargetBranch>[^\s]*))*"),
+            new MergeMessageFormat("RemoteTracking", @"^Merge remote-tracking branch '(?<SourceBranch>[^\s]*)'(?: into (?<TargetBranch>[^\s]*))*")
         };
 
         public MergeMessage(string mergeMessage, Config config)
         {
             if (mergeMessage == null)
                 throw new NullReferenceException();
 
-            foreach (var pattern in Patterns)
+            // Concat config formats with the defaults.
+            // Ensure configs are processed first.
+            var allFormats = config.MergeMessageFormats
+                .Select(x => new MergeMessageFormat(x.Key, x.Value))
+                .Concat(DefaultFormats);
+
+            foreach (var format in allFormats)
             {
-                var match = pattern.Format.Match(mergeMessage);
+                var match = format.Pattern.Match(mergeMessage);
                 if (match.Success)
                 {
-                    MatchDefinition = pattern.Name;
+                    FormatName = format.Name;
                     MergedBranch = match.Groups["SourceBranch"].Value;
 
                     if (match.Groups["TargetBranch"].Success)
@@ -40,22 +45,21 @@ public MergeMessage(string mergeMessage, Config config)
                         PullRequestNumber = pullNumber;
                     }
 
-                    Version = ParseVersion(MergedBranch, config.TagPrefix);
+                    Version = ParseVersion(config.TagPrefix);
 
                     break;
                 }
             }
         }
 
-        public string MatchDefinition { get; }
+        public string FormatName { get; }
         public string TargetBranch { get; }
         public string MergedBranch { get; } = "";
         public bool IsMergedPullRequest => PullRequestNumber != null;
         public int? PullRequestNumber { get; }
         public SemanticVersion Version { get; }
 
-
-        private SemanticVersion ParseVersion(string branchName, string tagPrefix)
+        private SemanticVersion ParseVersion(string tagPrefix)
         {
             // Remove remotes and branch prefixes like release/ feature/ hotfix/ etc
             var toMatch = Regex.Replace(MergedBranch, @"^(\w+[-/])*", "", RegexOptions.IgnoreCase);
@@ -72,17 +76,17 @@ private SemanticVersion ParseVersion(string branchName, string tagPrefix)
             return null;
         }
 
-        private class MergeMessagePattern
+        private class MergeMessageFormat
         {
-            public MergeMessagePattern(string name, string format)
+            public MergeMessageFormat(string name, string pattern)
             {
                 Name = name;
-                Format = new Regex(format, RegexOptions.IgnoreCase | RegexOptions.Compiled);
+                Pattern = new Regex(pattern, RegexOptions.IgnoreCase | RegexOptions.Compiled);
             }
 
             public string Name { get; }
 
-            public Regex Format { get; }
+            public Regex Pattern { get; }
         }
     }
 }

src/GitVersionCore/VersionCalculation/BaseVersionCalculators/MergeMessageBaseVersionStrategy.cs

@@ -23,6 +23,7 @@ public override IEnumerable<BaseVersion> GetVersions(GitVersionContext context)
                         mergeMessage.Version != null &&
                         context.FullConfiguration.IsReleaseBranch(TrimRemote(mergeMessage.MergedBranch)))
                     {
+                        Logger.WriteInfo($"Found commit [{context.CurrentCommit.Sha}] matching merge message format: {mergeMessage.FormatName}");
                         var shouldIncrement = !context.Configuration.PreventIncrementForMergedBranchVersion;
                         return new[]
                         {