[StGIT PATCH] Leave working dir and index alone after failed (conflicting) push

["Karl Hasselström" <kha@treskal.com>]

From: David Kågedal <davidk@lysator.liu.se>

This leaves the index and working tree in the state that merge-recursive
left it, with unmerged files in different stages, and the non-conflicting
changes in the index.

Signed-off-by: David Kågedal <davidk@lysator.liu.se>
Signed-off-by: Karl Hasselström <kha@treskal.com>

---

This is David's patch 2 and 3 clumped together, so that there is no
intermediate stage where the test suite fails.

 stgit/git.py   |   20 +-------------------
 stgit/stack.py |   18 +++++++++++++-----
 2 files changed, 14 insertions(+), 24 deletions(-)

diff --git a/stgit/git.py b/stgit/git.py
index 170c5d1..676314a 100644
--- a/stgit/git.py
+++ b/stgit/git.py
@@ -723,25 +723,7 @@ def merge_recursive(base, head1, head2):
         # error and we have to abort the merge
         raise GitException, err_output
 
-    # merge the unmerged files
-    errors = False
-    for path in files:
-        # remove additional files that might be generated for some
-        # newer versions of GIT
-        for suffix in [base, head1, head2]:
-            if not suffix:
-                continue
-            fname = path + '~' + suffix
-            if os.path.exists(fname):
-                os.remove(fname)
-
-        stages = files[path]
-        if gitmergeonefile.merge(stages['1'][1], stages['2'][1],
-                                 stages['3'][1], path, stages['1'][0],
-                                 stages['2'][0], stages['3'][0]) != 0:
-            errors = True
-
-    if errors:
+    if files:
         raise GitException, 'GIT index merging failed (possible conflicts)'
 
 def merge(base, head1, head2):
diff --git a/stgit/stack.py b/stgit/stack.py
index 95f20f1..123efac 100644
--- a/stgit/stack.py
+++ b/stgit/stack.py
@@ -732,6 +732,7 @@ class Series(PatchSet):
         config.unset(self.format_version_key())
 
     def refresh_patch(self, files = None, message = None, edit = False,
+                      empty = False,
                       show_patch = False,
                       cache_update = True,
                       author_name = None, author_email = None,
@@ -781,9 +782,16 @@ class Series(PatchSet):
 
         bottom = patch.get_bottom()
 
+        if empty:
+            tree_id = git.get_commit(bottom).get_tree()
+        else:
+            tree_id = None
+
         commit_id = git.commit(files = files,
                                message = descr, parents = [bottom],
                                cache_update = cache_update,
+                               tree_id = tree_id,
+                               set_head = True,
                                allowempty = True,
                                author_name = author_name,
                                author_email = author_email,
@@ -1086,11 +1094,11 @@ class Series(PatchSet):
                     log = 'push'
                 self.refresh_patch(cache_update = False, log = log)
             else:
-                # we store the correctly merged files only for
-                # tracking the conflict history. Note that the
-                # git.merge() operations should always leave the index
-                # in a valid state (i.e. only stage 0 files)
-                self.refresh_patch(cache_update = False, log = 'push(c)')
+                # We make the patch empty, with the merged state in
+                # the working tree and index just like after a failed
+                # git merge.
+                self.refresh_patch(cache_update = False, empty = True,
+                                   log = 'push(c)')
                 raise StackException, str(ex)
 
         return modified