From 1a65fb9123588081f71969b1066dd6be53ecf81e Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Fri, 15 Jun 2018 18:38:34 +0100
Subject: [PATCH] When starting an anonymous transaction then transaction
 starts on the same commit

---
 src/main/java/net/kemitix/gitdb/impl/GitDBRepo.java  |  2 +-
 .../net/kemitix/gitdb/impl/GitDBTransactionImpl.java |  2 +-
 src/test/java/net/kemitix/gitdb/test/GitDBTest.java  | 12 ++++++++++++
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/main/java/net/kemitix/gitdb/impl/GitDBRepo.java b/src/main/java/net/kemitix/gitdb/impl/GitDBRepo.java
index 88093a3..2095f5b 100644
--- a/src/main/java/net/kemitix/gitdb/impl/GitDBRepo.java
+++ b/src/main/java/net/kemitix/gitdb/impl/GitDBRepo.java
@@ -229,6 +229,6 @@ class GitDBRepo {
     }
 
     Ref createBranch(final Ref branchRef, final String name) throws IOException {
-        return repository.getRefDatabase().newUpdate(name, false).getRef();
+        return writeHead(branchRef.getName(), branchRef.getObjectId());
     }
 }
diff --git a/src/main/java/net/kemitix/gitdb/impl/GitDBTransactionImpl.java b/src/main/java/net/kemitix/gitdb/impl/GitDBTransactionImpl.java
index 0e1630c..d468567 100644
--- a/src/main/java/net/kemitix/gitdb/impl/GitDBTransactionImpl.java
+++ b/src/main/java/net/kemitix/gitdb/impl/GitDBTransactionImpl.java
@@ -79,6 +79,6 @@ class GitDBTransactionImpl implements GitDBTransaction {
 
     @Override
     public String getCommitId() {
-        return null;
+        return branch.getCommitId();
     }
 }
diff --git a/src/test/java/net/kemitix/gitdb/test/GitDBTest.java b/src/test/java/net/kemitix/gitdb/test/GitDBTest.java
index 6cfd077..79f7a76 100644
--- a/src/test/java/net/kemitix/gitdb/test/GitDBTest.java
+++ b/src/test/java/net/kemitix/gitdb/test/GitDBTest.java
@@ -353,6 +353,18 @@ class GitDBTest implements WithAssertions {
         assertThat(gitDB.branch("master").map(GitDBBranch::getCommitId)).contains(commitId);
     }
 
+    // When starting an anonymous transaction then transaction starts on the same commit
+    @Test
+    void startAnonymousTransaction_thenTransactionCommitMatchesOriginal() throws IOException {
+        //given
+        final GitDBBranch gitDBBranch = gitDBBranch();
+        final String commitId = gitDBBranch.getCommitId();
+        //when
+        final GitDBTransaction transaction = gitDBBranch.transaction();
+        //then
+        assertThat(transaction.getCommitId()).isEqualTo(commitId);
+    }
+
     // Given a GitDbTransaction handle (i.e. a new branch)
     // When putting a new key/value pair then the original GitDbBranch can't find it
     @Test