# HG changeset patch
# User Marcin Kuzminski <marcin@rhodecode.com>
# Date 2018-01-15 18:13:31
# Node ID 0d428e35b2d95f0d0c924505ea4264fb2668d927
# Parent  4400cfcf1c119c67aa48dacc0001f046541828ea

git: merge test, fetch other branch if it's different from target. This
prevents potentially missing commits when doing a test merge.

diff --git a/rhodecode/lib/vcs/backends/base.py b/rhodecode/lib/vcs/backends/base.py
--- a/rhodecode/lib/vcs/backends/base.py
+++ b/rhodecode/lib/vcs/backends/base.py
@@ -461,7 +461,7 @@ class BaseRepository(object):
                 raise ValueError('message cannot be empty')
 
         shadow_repository_path = self._maybe_prepare_merge_workspace(
-            workspace_id, target_ref)
+            workspace_id, target_ref, source_ref)
 
         try:
             return self._merge_repo(
@@ -482,7 +482,7 @@ class BaseRepository(object):
         """Internal implementation of merge."""
         raise NotImplementedError
 
-    def _maybe_prepare_merge_workspace(self, workspace_id, target_ref):
+    def _maybe_prepare_merge_workspace(self, workspace_id, target_ref, source_ref):
         """
         Create the merge workspace.
 
diff --git a/rhodecode/lib/vcs/backends/git/repository.py b/rhodecode/lib/vcs/backends/git/repository.py
--- a/rhodecode/lib/vcs/backends/git/repository.py
+++ b/rhodecode/lib/vcs/backends/git/repository.py
@@ -402,6 +402,12 @@ class GitRepository(BaseRepository):
             node = tree
         return tree
 
+    def get_remote_ref(self, ref_name):
+        try:
+            return self._ref_tree['refs']['remotes']['origin'][ref_name]
+        except Exception:
+            return
+
     def get_commit(self, commit_id=None, commit_idx=None, pre_load=None):
         """
         Returns `GitCommit` object representing commit from git repository
@@ -722,16 +728,26 @@ class GitRepository(BaseRepository):
         stdout, _ = self.run_git_command(['rev-parse', 'HEAD'])
         return stdout.strip()
 
-    def _local_clone(self, clone_path, branch_name):
+    def _local_clone(self, clone_path, branch_name, source_branch=None):
         """
         Create a local clone of the current repo.
         """
         # N.B.(skreft): the --branch option is required as otherwise the shallow
         # clone will only fetch the active branch.
-        cmd = ['clone', '--branch', branch_name, '--single-branch',
+        cmd = ['clone', '--branch', branch_name,
                self.path, os.path.abspath(clone_path)]
+
         self.run_git_command(cmd, fail_on_stderr=False)
 
+        # if we get the different source branch, make sure we also fetch it for
+        # merge conditions
+        if source_branch and source_branch != branch_name:
+            # check if the ref exists.
+            shadow_repo = GitRepository(os.path.abspath(clone_path))
+            if shadow_repo.get_remote_ref(source_branch):
+                cmd = ['fetch', self.path, source_branch]
+                self.run_git_command(cmd, fail_on_stderr=False)
+
     def _local_fetch(self, repository_path, branch_name):
         """
         Fetch a branch from a local repository.
@@ -873,8 +889,16 @@ class GitRepository(BaseRepository):
                 False, False, None, MergeFailureReason.TARGET_IS_NOT_HEAD)
 
         shadow_repo = GitRepository(shadow_repository_path)
+        # checkout source, if it's different. Otherwise we could not
+        # fetch proper commits for merge testing
+        if source_ref.name != target_ref.name:
+            if shadow_repo.get_remote_ref(source_ref.name):
+                shadow_repo._checkout(source_ref.name)
+
+        # checkout target
         shadow_repo._checkout(target_ref.name)
         shadow_repo._local_pull(self.path, target_ref.name)
+
         # Need to reload repo to invalidate the cache, or otherwise we cannot
         # retrieve the last target commit.
         shadow_repo = GitRepository(shadow_repository_path)
@@ -939,10 +963,11 @@ class GitRepository(BaseRepository):
             os.path.dirname(self.path),
             '.__shadow_%s_%s' % (os.path.basename(self.path), workspace_id))
 
-    def _maybe_prepare_merge_workspace(self, workspace_id, target_ref):
+    def _maybe_prepare_merge_workspace(self, workspace_id, target_ref, source_ref):
         shadow_repository_path = self._get_shadow_repository_path(workspace_id)
         if not os.path.exists(shadow_repository_path):
-            self._local_clone(shadow_repository_path, target_ref.name)
+            self._local_clone(
+                shadow_repository_path, target_ref.name, source_ref.name)
 
         return shadow_repository_path
 
diff --git a/rhodecode/lib/vcs/backends/hg/repository.py b/rhodecode/lib/vcs/backends/hg/repository.py
--- a/rhodecode/lib/vcs/backends/hg/repository.py
+++ b/rhodecode/lib/vcs/backends/hg/repository.py
@@ -693,7 +693,7 @@ class MercurialRepository(BaseRepository
             os.path.dirname(self.path),
             '.__shadow_%s_%s' % (os.path.basename(self.path), workspace_id))
 
-    def _maybe_prepare_merge_workspace(self, workspace_id, unused_target_ref):
+    def _maybe_prepare_merge_workspace(self, workspace_id, unused_target_ref, unused_source_ref):
         shadow_repository_path = self._get_shadow_repository_path(workspace_id)
         if not os.path.exists(shadow_repository_path):
             self._local_clone(shadow_repository_path)