Teach Checkout() to cope with revparse syntax

Saaman · Saaman · commit 902ed7d3b5b9 · 2013-04-25T10:30:56.000+02:00
diff --git a/LibGit2Sharp.Tests/CheckoutFixture.cs b/LibGit2Sharp.Tests/CheckoutFixture.cs
@@ -80,6 +80,7 @@ public void CanCheckoutAnExistingBranchByName(string branchName)
         [Theory]
         [InlineData("6dcf9bf")]
         [InlineData("refs/tags/lw")]
+        [InlineData("HEAD~2")]
         public void CanCheckoutAnArbitraryCommit(string commitPointer)
         {
             string path = CloneStandardTestRepo();
@@ -93,10 +94,12 @@ public void CanCheckoutAnArbitraryCommit(string commitPointer)
 
                 Assert.False(repo.Index.RetrieveStatus().IsDirty);
 
+                var commitSha = repo.Lookup(commitPointer).Sha;
+
                 Branch detachedHead = repo.Checkout(commitPointer);
 
                 Assert.Equal(repo.Head, detachedHead);
-                Assert.Equal(repo.Lookup(commitPointer).Sha, detachedHead.Tip.Sha);
+                Assert.Equal(commitSha, detachedHead.Tip.Sha);
                 Assert.True(repo.Head.IsCurrentRepositoryHead);
                 Assert.True(repo.Info.IsHeadDetached);
                 Assert.False(repo.Index.RetrieveStatus().IsDirty);
diff --git a/LibGit2Sharp/Repository.cs b/LibGit2Sharp/Repository.cs
@@ -579,7 +579,7 @@ public Branch Checkout(string committishOrBranchSpec, CheckoutOptions checkoutOp
         {
             Ensure.ArgumentNotNullOrEmptyString(committishOrBranchSpec, "committishOrBranchSpec");
 
-            var branch = Branches[committishOrBranchSpec];
+            Branch branch = TryResolveBranch(committishOrBranchSpec);
 
             if (branch != null)
             {
@@ -595,6 +595,18 @@ public Branch Checkout(string committishOrBranchSpec, CheckoutOptions checkoutOp
             return Head;
         }
 
+        private Branch TryResolveBranch(string committishOrBranchSpec)
+        {
+            try
+            {
+                return Branches[committishOrBranchSpec];
+            }
+            catch (InvalidSpecificationException)
+            {
+                return null;
+            }
+        }
+
         /// <summary>
         ///   Checkout the tip commit of the specified <see cref = "Branch" /> object. If this commit is the
         ///   current tip of the branch, will checkout the named branch. Otherwise, will checkout the tip commit
