Introduce internal ICommittish

LibGit2Sharp.Tests/MetaFixture.cs

@@ -114,7 +114,7 @@ public void LibGit2SharpInterfacesCoverAllPublicMembers()
             var methodsMissingFromInterfaces =
                 from t in Assembly.GetAssembly(typeof(IRepository)).GetExportedTypes()
                 where !t.IsInterface
-                where t.GetInterfaces().Any(i => i.Namespace == typeof(IRepository).Namespace)
+                where t.GetInterfaces().Any(i => i.IsPublic && i.Namespace == typeof(IRepository).Namespace)
                 let interfaceTargetMethods = from i in t.GetInterfaces()
                                              from im in t.GetInterfaceMap(i).TargetMethods
                                              select im

LibGit2Sharp/ObjectId.cs

@@ -8,7 +8,7 @@ namespace LibGit2Sharp
     /// <summary>
     /// Uniquely identifies a <see cref="GitObject"/>.
     /// </summary>
-    public sealed class ObjectId : IEquatable<ObjectId>
+    public sealed class ObjectId : IEquatable<ObjectId>, ICommittish
     {
         private readonly GitOid oid;
         private const int rawSize = 20;
@@ -320,5 +320,7 @@ public bool StartsWith(string shortSha)
 
             return Sha.StartsWith(shortSha, StringComparison.OrdinalIgnoreCase);
         }
+
+        string ICommittish.Identifier { get { return Sha; } }
     }
 }

LibGit2Sharp/Reference.cs

@@ -10,7 +10,7 @@ namespace LibGit2Sharp
     /// A Reference to another git object
     /// </summary>
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
-    public abstract class Reference : IEquatable<Reference>
+    public abstract class Reference : IEquatable<Reference>, ICommittish
     {
         private static readonly LambdaEqualityHelper<Reference> equalityHelper =
             new LambdaEqualityHelper<Reference>(x => x.CanonicalName, x => x.TargetIdentifier);
@@ -179,5 +179,7 @@ private string DebuggerDisplay
                     "{0} => \"{1}\"", CanonicalName, TargetIdentifier);
             }
         }
+
+        string ICommittish.Identifier { get { return CanonicalName; } }
     }
 }

LibGit2Sharp/RepositoryExtensions.cs

@@ -5,7 +5,6 @@
 using System.IO;
 using System.Linq;
 using LibGit2Sharp.Core;
-using LibGit2Sharp.Handlers;
 
 namespace LibGit2Sharp
 {
@@ -377,24 +376,14 @@ private static ObjectId SingleCommittish(this Repository repo, object identifier
                 return DereferenceToCommit(repo, (string)identifier);
             }
 
-            if (identifier is ObjectId)
-            {
-                return DereferenceToCommit(repo, ((ObjectId)identifier).Sha);
-            }
-
             if (identifier is Commit)
             {
                 return ((Commit)identifier).Id;
             }
 
-            if (identifier is TagAnnotation)
-            {
-                return DereferenceToCommit(repo, ((TagAnnotation)identifier).Target.Id.Sha);
-            }
-
-            if (identifier is Tag)
+            if (identifier is ICommittish)
             {
-                return DereferenceToCommit(repo, ((Tag)identifier).Target.Id.Sha);
+                return DereferenceToCommit(repo, ((ICommittish)identifier).Identifier);
             }
 
             var branch = identifier as Branch;
@@ -407,11 +396,6 @@ private static ObjectId SingleCommittish(this Repository repo, object identifier
                 }
             }
 
-            if (identifier is Reference)
-            {
-                return DereferenceToCommit(repo, ((Reference)identifier).CanonicalName);
-            }
-
             return null;
         }
 
@@ -463,4 +447,9 @@ internal static ObjectId Committish(this Repository repo, object identifier)
             return repo.Committishes(identifier, true).First();
         }
     }
+
+    internal interface ICommittish
+    {
+        string Identifier { get; }
+    }
 }

LibGit2Sharp/Tag.cs

@@ -3,7 +3,7 @@
     /// <summary>
     /// A Tag
     /// </summary>
-    public class Tag : ReferenceWrapper<GitObject>
+    public class Tag : ReferenceWrapper<GitObject>, ICommittish
     {
         /// <summary>
         /// Needed for mocking purposes.
@@ -57,5 +57,7 @@ protected override string Shorten()
         {
             return CanonicalName.Substring(Reference.TagPrefix.Length);
         }
+
+        string ICommittish.Identifier { get { return Target.Id.Sha; } }
     }
 }

LibGit2Sharp/TagAnnotation.cs

@@ -5,7 +5,7 @@ namespace LibGit2Sharp
     /// <summary>
     /// A TagAnnotation
     /// </summary>
-    public class TagAnnotation : GitObject
+    public class TagAnnotation : GitObject, ICommittish
     {
         private readonly GitObjectLazyGroup group;
         private readonly ILazy<GitObject> lazyTarget;
@@ -50,5 +50,7 @@ internal TagAnnotation(Repository repo, ObjectId id)
         /// Gets the tagger.
         /// </summary>
         public virtual Signature Tagger { get { return lazyTagger.Value; } }
+
+        string ICommittish.Identifier { get { return Target.Id.Sha; } }
     }
 }