Improved Repository.ApplyTag() error handling.

libgit2sharp.Tests/ApplyingATag.cs

@@ -6,16 +6,29 @@ namespace libgit2sharp.Tests
     [TestFixture]
     public class ApplyingATag : ReadWriteRepositoryFixtureBase
     {
+        private static readonly Signature _signature = new Signature("me", "me@me.me", DateTimeOffset.Now);
+
+        [Test]
+        public void ShouldThrowIfPassedANonExistingTarget()
+        {
+            const string invalidTargetId = "deadbeef1b46c854b31185ea97743be6a8774479";
+
+            using (var repo = new Repository(PathToRepository))
+            {
+                Assert.Throws<ObjectNotFoundException>(() => repo.ApplyTag(invalidTargetId, "tagged", "messaged", _signature));
+            }
+
+        }
+
         [Test]
         public void ShouldWork() // TODO: Split into different tests (returnATag, PersistTheObject, MultipleApplies, ...)
         {
             const string targetId = "8496071c1b46c854b31185ea97743be6a8774479";
-            var signature = new Signature("me", "me@me.me", DateTimeOffset.Now);
 
             Tag appliedTag;
             using (var repo = new Repository(PathToRepository))
             {
-                appliedTag = repo.ApplyTag(targetId, "tagged", "messaged", signature);
+                appliedTag = repo.ApplyTag(targetId, "tagged", "messaged", _signature);
             }
 
             var target = appliedTag.Target as Commit;

libgit2sharp/ObjectNotFoundException.cs

+using System;
+
+namespace libgit2sharp
+{
+    public class ObjectNotFoundException : Exception
+    {
+    }
+}
\ No newline at end of file

libgit2sharp/Repository.cs

@@ -101,9 +101,19 @@ public Tag ApplyTag(string targetId, string tagName, string tagMessage, Signatur
         {
             // TODO: To be refactored.
             IntPtr tag;
-            OperationResult t = LibGit2Api.wrapped_git_apply_tag(out tag, _lifecycleManager.RepositoryPtr, targetId, tagName, tagMessage, signature.Name, signature.Email, (ulong)((GitDate)signature.When).UnixTimeStamp);
-            
-            return (Tag)_builder.BuildFrom(tag, ObjectType.Tag);
+            OperationResult result = LibGit2Api.wrapped_git_apply_tag(out tag, _lifecycleManager.RepositoryPtr, targetId, tagName, tagMessage, signature.Name, signature.Email, (ulong)((GitDate)signature.When).UnixTimeStamp);
+
+            switch (result)
+            {
+                case OperationResult.GIT_SUCCESS:
+                    return (Tag)_builder.BuildFrom(tag, ObjectType.Tag);
+
+                case OperationResult.GIT_ENOTFOUND:
+                    throw new ObjectNotFoundException();
+
+                default:
+                    throw new Exception(Enum.GetName(typeof(OperationResult), result));
+            }
         }
     }
 }
\ No newline at end of file

libgit2sharp/libgit2sharp.csproj

@@ -49,6 +49,7 @@
     <Compile Include="IResolver.cs" />
     <Compile Include="NotAValidRepositoryException.cs" />
     <Compile Include="ObjectId.cs" />
+    <Compile Include="ObjectNotFoundException.cs" />
     <Compile Include="ObjectResolver.cs" />
     <Compile Include="RepositoryLifecycleManager.cs" />
     <Compile Include="Signature.cs" />