[StGit PATCH 00/13] Eliminate 'top' and 'bottom' files

@@ -85,6 +85,12 @@ test_expect_success 'Status after refresh' '
     diff -u expected.txt output.txt
 '
 
+test_expect_success 'Add another file' '
+    echo lajbans > fie &&
+    stg add fie &&
+    stg refresh
+'
+
 test_expect_success 'Make a conflicting patch' '
     stg pop &&
     stg new -m "third patch" &&

@@ -105,6 +111,28 @@ test_expect_success 'Status after conflicting push' '
 '
 
 cat > expected.txt <<EOF
+C foo/bar
+EOF
+test_expect_success 'Status of file' '
+    stg status foo/bar > output.txt &&
+    diff -u expected.txt output.txt
+'
+
+cat > expected.txt <<EOF
+EOF
+test_expect_success 'Status of dir' '
+    stg status foo > output.txt &&
+    diff -u expected.txt output.txt
+'
+
+cat > expected.txt <<EOF
+EOF
+test_expect_success 'Status of other file' '
+    stg status fie > output.txt &&
+    diff -u expected.txt output.txt
+'
+
+cat > expected.txt <<EOF
 M foo/bar
 EOF
 test_expect_success 'Status after resolving the push' '

@@ -65,6 +65,39 @@ options = [make_option('-m', '--modified',
                        action = 'store_true')]
 
 
+def status(files = None, modified = False, new = False, deleted = False,
+           conflict = False, unknown = False, noexclude = False,
+           diff_flags = []):
+    """Show the tree status
+    """
+    cache_files = git.tree_status(files,
+                                  unknown = (files == None),
+                                  noexclude = noexclude,
+                                  diff_flags = diff_flags)
+    filtered = (modified or new or deleted or conflict or unknown)
+
+    if filtered:
+        filestat = []
+        if modified:
+            filestat.append('M')
+        if new:
+            filestat.append('A')
+            filestat.append('N')
+        if deleted:
+            filestat.append('D')
+        if conflict:
+            filestat.append('C')
+        if unknown:
+            filestat.append('?')
+        cache_files = [x for x in cache_files if x[0] in filestat]
+
+    for fs in cache_files:
+        assert files == None or fs[1] in files
+        if not filtered:
+            out.stdout('%s %s' % (fs[0], fs[1]))
+        else:
+            out.stdout('%s' % fs[1])
+
 def func(parser, options, args):
     """Show the tree status
     """

@@ -85,6 +118,6 @@ def func(parser, options, args):
         # No args means all files
         if not args:
             args = None
-        git.status(args, options.modified, options.new, options.deleted,
-                   options.conflict, options.unknown, options.noexclude,
-                   diff_flags = diff_flags)
+        status(args, options.modified, options.new, options.deleted,
+               options.conflict, options.unknown, options.noexclude,
+               diff_flags = diff_flags)

@@ -711,39 +711,6 @@ def merge(base, head1, head2, recursive = False):
     if errors:
         raise GitException, 'GIT index merging failed (possible conflicts)'
 
-def status(files = None, modified = False, new = False, deleted = False,
-           conflict = False, unknown = False, noexclude = False,
-           diff_flags = []):
-    """Show the tree status
-    """
-    cache_files = tree_status(files,
-                              unknown = (files == None),
-                              noexclude = noexclude,
-                              diff_flags = diff_flags)
-    filtered = (modified or new or deleted or conflict or unknown)
-
-    if filtered:
-        filestat = []
-        if modified:
-            filestat.append('M')
-        if new:
-            filestat.append('A')
-            filestat.append('N')
-        if deleted:
-            filestat.append('D')
-        if conflict:
-            filestat.append('C')
-        if unknown:
-            filestat.append('?')
-        cache_files = [x for x in cache_files if x[0] in filestat]
-
-    for fs in cache_files:
-        assert files == None or fs[1] in files
-        if not filtered:
-            out.stdout('%s %s' % (fs[0], fs[1]))
-        else:
-            out.stdout('%s' % fs[1])
-
 def diff(files = None, rev1 = 'HEAD', rev2 = None, diff_flags = []):
     """Show the diff between rev1 and rev2
     """

@@ -60,6 +60,14 @@ test_expect_success 'Status with an added file' '
 '
 
 cat > expected.txt <<EOF
+foo/bar
+EOF
+test_expect_success 'Status with an added file and -n option' '
+    stg status -n > output.txt &&
+    diff -u expected.txt output.txt
+'
+
+cat > expected.txt <<EOF
 EOF
 test_expect_success 'Status after refresh' '
     stg new -m "first patch" &&

@@ -1029,46 +1029,19 @@ class Series(PatchSet):
         assert(name in unapplied)
 
         patch = self.get_patch(name)
-
         head = git.get_head()
-        bottom = patch.get_bottom()
-        top = patch.get_top()
-
-        ex = None
-        modified = False
 
-        # top != bottom always since we have a commit for each patch
-        # just make an empty patch (top = bottom = HEAD). This
-        # option is useful to allow undoing already merged
-        # patches. The top is updated by refresh_patch since we
-        # need an empty commit
+        # The top is updated by refresh_patch since we need an empty
+        # commit
         patch.set_bottom(head, backup = True)
         patch.set_top(head, backup = True)
-        modified = True
 
         append_string(self.__applied_file, name)
 
         unapplied.remove(name)
         write_strings(self.__unapplied_file, unapplied)
 
-        # head == bottom case doesn't need to refresh the patch
-        if not ex:
-            # if the merge was OK and no conflicts, just refresh the patch
-            # The GIT cache was already updated by the merge operation
-            if modified:
-                log = 'push(m)'
-            else:
-                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)')
-            raise StackException, str(ex)
-
-        return modified
+        self.refresh_patch(cache_update = False, log = 'push(m)')
 
     def push_patch(self, name):
         """Pushes a patch on the stack

@@ -82,6 +82,9 @@ def func(parser, options, args):
         else:
             diff_flags = []
 
+        # No args means all files
+        if not args:
+            args = None
         git.status(args, options.modified, options.new, options.deleted,
                    options.conflict, options.unknown, options.noexclude,
                    diff_flags = diff_flags)

@@ -167,15 +167,20 @@ def exclude_files():
 
 def tree_status(files = None, tree_id = 'HEAD', unknown = False,
                   noexclude = True, verbose = False, diff_flags = []):
-    """Returns a list of pairs - (status, filename)
+    """Get the status of all changed files, or of a selected set of
+    files. Returns a list of pairs - (status, filename).
+
+    If 'files' is None, it will check all files, and optionally all
+    unknown files.  If 'files' is a list, it will only check the files
+    in the list.
     """
+    assert files == None or not unknown
+
     if verbose:
         out.start('Checking for changes in the working directory')
 
     refresh_index()
 
-    if not files:
-        files = []
     cache_files = []
 
     # unknown files

@@ -197,11 +202,14 @@ def tree_status(files = None, tree_id = 'HEAD', unknown = False,
     conflicts = get_conflicts()
     if not conflicts:
         conflicts = []
-    cache_files += [('C', filename) for filename in conflicts]
+    cache_files += [('C', filename) for filename in conflicts
+                    if files == None or filename in files]
 
     # the rest
-    for line in GRun('git-diff-index', *(diff_flags + [tree_id, '--'] + files)
-                     ).output_lines():
+    args = diff_flags + [tree_id]
+    if files != None:
+        args += ['--'] + files
+    for line in GRun('git-diff-index', *args).output_lines():
         fs = tuple(line.rstrip().split(' ',4)[-1].split('\t',1))
         if fs[1] not in conflicts:
             cache_files.append(fs)

@@ -209,6 +217,7 @@ def tree_status(files = None, tree_id = 'HEAD', unknown = False,
     if verbose:
         out.done()
 
+    assert files == None or set(f for s,f in cache_files) <= set(files)
     return cache_files
 
 def local_changes(verbose = True):

@@ -538,9 +547,6 @@ def committer():
 def update_cache(files = None, force = False):
     """Update the cache information for the given files
     """
-    if not files:
-        files = []
-
     cache_files = tree_status(files, verbose = False)
 
     # everything is up-to-date

@@ -569,8 +575,6 @@ def commit(message, files = None, parents = None, allowempty = False,
            committer_name = None, committer_email = None):
     """Commit the current tree to repository
     """
-    if not files:
-        files = []
     if not parents:
         parents = []
 

@@ -712,14 +716,13 @@ def status(files = None, modified = False, new = False, deleted = False,
            diff_flags = []):
     """Show the tree status
     """
-    if not files:
-        files = []
-
-    cache_files = tree_status(files, unknown = True, noexclude = noexclude,
-                                diff_flags = diff_flags)
-    all = not (modified or new or deleted or conflict or unknown)
+    cache_files = tree_status(files,
+                              unknown = (files == None),
+                              noexclude = noexclude,
+                              diff_flags = diff_flags)
+    filtered = (modified or new or deleted or conflict or unknown)
 
-    if not all:
+    if filtered:
         filestat = []
         if modified:
             filestat.append('M')

@@ -735,9 +738,8 @@ def status(files = None, modified = False, new = False, deleted = False,
         cache_files = [x for x in cache_files if x[0] in filestat]
 
     for fs in cache_files:
-        if files and not fs[1] in files:
-            continue
-        if all:
+        assert files == None or fs[1] in files
+        if not filtered:
             out.stdout('%s %s' % (fs[0], fs[1]))
         else:
             out.stdout('%s' % fs[1])

@@ -184,7 +184,7 @@ def push_patches(patches, check_merged = False):
         out.start('Pushing patch "%s"' % p)
 
         if p in merged:
-            crt_series.push_patch(p, empty = True)
+            crt_series.push_empty_patch(p)
             out.done('merged upstream')
         else:
             modified = crt_series.push_patch(p)

@@ -1022,7 +1022,55 @@ class Series(PatchSet):
 
         return merged
 
-    def push_patch(self, name, empty = False):
+    def push_empty_patch(self, name):
+        """Pushes an empty patch on the stack
+        """
+        unapplied = self.get_unapplied()
+        assert(name in unapplied)
+
+        patch = self.get_patch(name)
+
+        head = git.get_head()
+        bottom = patch.get_bottom()
+        top = patch.get_top()
+
+        ex = None
+        modified = False
+
+        # top != bottom always since we have a commit for each patch
+        # just make an empty patch (top = bottom = HEAD). This
+        # option is useful to allow undoing already merged
+        # patches. The top is updated by refresh_patch since we
+        # need an empty commit
+        patch.set_bottom(head, backup = True)
+        patch.set_top(head, backup = True)
+        modified = True
+
+        append_string(self.__applied_file, name)
+
+        unapplied.remove(name)
+        write_strings(self.__unapplied_file, unapplied)
+
+        # head == bottom case doesn't need to refresh the patch
+        if not ex:
+            # if the merge was OK and no conflicts, just refresh the patch
+            # The GIT cache was already updated by the merge operation
+            if modified:
+                log = 'push(m)'
+            else:
+                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)')
+            raise StackException, str(ex)
+
+        return modified
+
+    def push_patch(self, name):
         """Pushes a patch on the stack
         """
         unapplied = self.get_unapplied()

@@ -1038,15 +1086,7 @@ class Series(PatchSet):
         modified = False
 
         # top != bottom always since we have a commit for each patch
-        if empty:
-            # just make an empty patch (top = bottom = HEAD). This
-            # option is useful to allow undoing already merged
-            # patches. The top is updated by refresh_patch since we
-            # need an empty commit
-            patch.set_bottom(head, backup = True)
-            patch.set_top(head, backup = True)
-            modified = True
-        elif head == bottom:
+        if head == bottom:
             # reset the backup information. No need for logging
             patch.set_bottom(bottom, backup = True)
             patch.set_top(top, backup = True)

@@ -1079,7 +1119,7 @@ class Series(PatchSet):
         write_strings(self.__unapplied_file, unapplied)
 
         # head == bottom case doesn't need to refresh the patch
-        if empty or head != bottom:
+        if head != bottom:
             if not ex:
                 # if the merge was OK and no conflicts, just refresh the patch
                 # The GIT cache was already updated by the merge operation

@@ -1054,60 +1054,65 @@ class Series(PatchSet):
         head = git.get_head()
         bottom = patch.get_bottom()
         top = patch.get_top()
-
-        ex = None
-        modified = False
-
         # top != bottom always since we have a commit for each patch
+
         if head == bottom:
-            # reset the backup information. No need for logging
+            # A fast-forward push. Just reset the backup
+            # information. No need for logging
             patch.set_bottom(bottom, backup = True)
             patch.set_top(top, backup = True)
 
             git.switch(top)
-        else:
-            # new patch needs to be refreshed.
-            # The current patch is empty after merge.
-            patch.set_bottom(head, backup = True)
-            patch.set_top(head, backup = True)
-
-            # Try the fast applying first. If this fails, fall back to the
-            # three-way merge
-            if not git.apply_diff(bottom, top):
-                # if git.apply_diff() fails, the patch requires a diff3
-                # merge and can be reported as modified
-                modified = True
-
-                # merge can fail but the patch needs to be pushed
-                try:
-                    git.merge(bottom, head, top, recursive = True)
-                except git.GitException, ex:
-                    out.error('The merge failed during "push".',
-                              'Use "refresh" after fixing the conflicts or'
-                              ' revert the operation with "push --undo".')
+            append_string(self.__applied_file, name)
+
+            unapplied.remove(name)
+            write_strings(self.__unapplied_file, unapplied)
+            return False
+
+        # Need to create a new commit an merge in the old patch
+        ex = None
+        modified = False
+
+        # new patch needs to be refreshed.
+        # The current patch is empty after merge.
+        patch.set_bottom(head, backup = True)
+        patch.set_top(head, backup = True)
+
+        # Try the fast applying first. If this fails, fall back to the
+        # three-way merge
+        if not git.apply_diff(bottom, top):
+            # if git.apply_diff() fails, the patch requires a diff3
+            # merge and can be reported as modified
+            modified = True
+
+            # merge can fail but the patch needs to be pushed
+            try:
+                git.merge(bottom, head, top, recursive = True)
+            except git.GitException, ex:
+                out.error('The merge failed during "push".',
+                          'Use "refresh" after fixing the conflicts or'
+                          ' revert the operation with "push --undo".')
 
         append_string(self.__applied_file, name)
 
         unapplied.remove(name)
         write_strings(self.__unapplied_file, unapplied)
 
-        # head == bottom case doesn't need to refresh the patch
-        if head != bottom:
-            if not ex:
-                # if the merge was OK and no conflicts, just refresh the patch
-                # The GIT cache was already updated by the merge operation
-                if modified:
-                    log = 'push(m)'
-                else:
-                    log = 'push'
-                self.refresh_patch(cache_update = False, log = log)
+        if not ex:
+            # if the merge was OK and no conflicts, just refresh the patch
+            # The GIT cache was already updated by the merge operation
+            if modified:
+                log = 'push(m)'
             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)')
-                raise StackException, str(ex)
+                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)')
+            raise StackException, str(ex)
 
         return modified
 

@@ -749,14 +749,12 @@ class Series(PatchSet):
                       committer_name = None, committer_email = None,
                       backup = False, sign_str = None, log = 'refresh',
                       notes = None):
-        """Generates a new commit for the given patch
+        """Generates a new commit for the topmost patch
         """
-        name = self.get_current()
-        if not name:
+        patch = self.get_current_patch()
+        if not patch:
             raise StackException, 'No patches applied'
 
-        patch = self.get_patch(name)
-
         descr = patch.get_description()
         if not (message or descr):
             edit = True

@@ -767,7 +765,7 @@ class Series(PatchSet):
         if not message and edit:
             descr = edit_file(self, descr.rstrip(), \
                               'Please edit the description for patch "%s" ' \
-                              'above.' % name, show_patch)
+                              'above.' % patch.get_name(), show_patch)
 
         if not author_name:
             author_name = patch.get_authname()

@@ -748,7 +748,7 @@ class Series(PatchSet):
                       author_date = None,
                       committer_name = None, committer_email = None,
                       backup = False, sign_str = None, log = 'refresh',
-                      notes = None):
+                      notes = None, bottom = None):
         """Generates a new commit for the topmost patch
         """
         patch = self.get_current_patch()

@@ -780,7 +780,8 @@ class Series(PatchSet):
 
         descr = add_sign_line(descr, sign_str, committer_name, committer_email)
 
-        bottom = patch.get_bottom()
+        if not bottom:
+            bottom = patch.get_bottom()
 
         commit_id = git.commit(files = files,
                                message = descr, parents = [bottom],

@@ -1026,20 +1027,15 @@ class Series(PatchSet):
         unapplied = self.get_unapplied()
         assert(name in unapplied)
 
-        patch = self.get_patch(name)
+        # patch = self.get_patch(name)
         head = git.get_head()
 
-        # The top is updated by refresh_patch since we need an empty
-        # commit
-        patch.set_bottom(head, backup = True)
-        patch.set_top(head, backup = True)
-
         append_string(self.__applied_file, name)
 
         unapplied.remove(name)
         write_strings(self.__unapplied_file, unapplied)
 
-        self.refresh_patch(cache_update = False, log = 'push(m)')
+        self.refresh_patch(bottom = head, cache_update = False, log = 'push(m)')
 
     def push_patch(self, name):
         """Pushes a patch on the stack

@@ -1071,11 +1067,6 @@ class Series(PatchSet):
         ex = None
         modified = False
 
-        # new patch needs to be refreshed.
-        # The current patch is empty after merge.
-        patch.set_bottom(head, backup = True)
-        patch.set_top(head, backup = True)
-
         # Try the fast applying first. If this fails, fall back to the
         # three-way merge
         if not git.apply_diff(bottom, top):

@@ -1103,13 +1094,14 @@ class Series(PatchSet):
                 log = 'push(m)'
             else:
                 log = 'push'
-            self.refresh_patch(cache_update = False, log = log)
+            self.refresh_patch(bottom = head, 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)')
+            self.refresh_patch(bottom = head, cache_update = False,
+                               log = 'push(c)')
             raise StackException, str(ex)
 
         return modified

@@ -148,7 +148,6 @@ def func(parser, options, args):
 
         # reset the patch backup information. That's needed in case we
         # undo the sync but there were no changes made
-        patch.set_bottom(bottom, backup = True)
         patch.set_top(top, backup = True)
 
         # the actual merging (either from a branch or an external file)

@@ -158,7 +158,6 @@ class Patch(StgitObject):
 
     def create(self):
         os.mkdir(self._dir())
-        self.create_empty_field('bottom')
         self.create_empty_field('top')
 
     def delete(self):

@@ -197,22 +196,10 @@ class Patch(StgitObject):
             self.__update_top_ref(top)
 
     def get_old_bottom(self):
-        old_bottom = self._get_field('bottom.old')
-        old_top = self.get_old_top()
-        assert old_bottom == git.get_commit(old_top).get_parent()
-        return old_bottom
+        return git.get_commit(self.get_old_top()).get_parent()
 
     def get_bottom(self):
-        bottom = self._get_field('bottom')
-        top = self.get_top()
-        assert bottom == git.get_commit(top).get_parent()
-        return self._get_field('bottom')
-
-    def set_bottom(self, value, backup = False):
-        if backup:
-            curr = self._get_field('bottom')
-            self._set_field('bottom.old', curr)
-        self._set_field('bottom', value)
+        return git.get_commit(self.get_top()).get_parent()
 
     def get_old_top(self):
         return self._get_field('top.old')

@@ -232,14 +219,11 @@ class Patch(StgitObject):
             self._set_field('top.old', curr)
         self._set_field('top', value)
         self.__update_top_ref(value)
-        self.get_bottom() # check the assert
 
     def restore_old_boundaries(self):
-        bottom = self._get_field('bottom.old')
         top = self._get_field('top.old')
 
-        if top and bottom:
-            self._set_field('bottom', bottom)
+        if top:
             self._set_field('top', top)
             self.__update_top_ref(top)
             return True

@@ -806,7 +790,6 @@ class Series(PatchSet):
                                committer_name = committer_name,
                                committer_email = committer_email)
 
-        patch.set_bottom(bottom, backup = backup)
         patch.set_top(commit_id, backup = backup)
         patch.set_description(descr)
         patch.set_authname(author_name)

@@ -914,11 +897,8 @@ class Series(PatchSet):
                                    committer_name = committer_name,
                                    committer_email = committer_email)
             # set the patch top to the new commit
-            patch.set_bottom(bottom)
             patch.set_top(commit_id)
         else:
-            assert top != bottom
-            patch.set_bottom(bottom)
             patch.set_top(top)
 
         self.log_patch(patch, 'new')

@@ -972,7 +952,6 @@ class Series(PatchSet):
             if head == bottom:
                 # reset the backup information. No logging since the
                 # patch hasn't changed
-                patch.set_bottom(head, backup = True)
                 patch.set_top(top, backup = True)
 
             else:

@@ -1000,7 +979,6 @@ class Series(PatchSet):
                                      committer_name = committer_name,
                                      committer_email = committer_email)
 
-                    patch.set_bottom(head, backup = True)
                     patch.set_top(top, backup = True)
 
                     self.log_patch(patch, 'push(f)')

@@ -1073,7 +1051,6 @@ class Series(PatchSet):
         if head == bottom:
             # A fast-forward push. Just reset the backup
             # information. No need for logging
-            patch.set_bottom(bottom, backup = True)
             patch.set_top(top, backup = True)
 
             git.switch(top)

@@ -864,13 +864,6 @@ class Series(PatchSet):
         patch = self.get_patch(name)
         patch.create()
 
-        if not bottom:
-            bottom = head
-        if not top:
-            top = head
-
-        patch.set_bottom(bottom)
-        patch.set_top(top)
         patch.set_description(descr)
         patch.set_authname(author_name)
         patch.set_authemail(author_email)

@@ -889,10 +882,15 @@ class Series(PatchSet):
             set_head = True
 
         if commit:
+            if top:
+                top_commit = git.get_commit(top)
+            else:
+                bottom = head
+                top_commit = git.get_commit(head)
+
             # create a commit for the patch (may be empty if top == bottom);
             # only commit on top of the current branch
             assert(unapplied or bottom == head)
-            top_commit = git.get_commit(top)
             commit_id = git.commit(message = descr, parents = [bottom],
                                    cache_update = False,
                                    tree_id = top_commit.get_tree(),

@@ -903,9 +901,12 @@ class Series(PatchSet):
                                    committer_name = committer_name,
                                    committer_email = committer_email)
             # set the patch top to the new commit
+            patch.set_bottom(bottom)
             patch.set_top(commit_id)
         else:
             assert top != bottom
+            patch.set_bottom(bottom)
+            patch.set_top(top)
 
         self.log_patch(patch, 'new')
 

@@ -197,9 +197,15 @@ class Patch(StgitObject):
             self.__update_top_ref(top)
 
     def get_old_bottom(self):
-        return self._get_field('bottom.old')
+        old_bottom = self._get_field('bottom.old')
+        old_top = self.get_old_top()
+        assert old_bottom == git.get_commit(old_top).get_parent()
+        return old_bottom
 
     def get_bottom(self):
+        bottom = self._get_field('bottom')
+        top = self.get_top()
+        assert bottom == git.get_commit(top).get_parent()
         return self._get_field('bottom')
 
     def set_bottom(self, value, backup = False):

@@ -212,7 +218,13 @@ class Patch(StgitObject):
         return self._get_field('top.old')
 
     def get_top(self):
-        return self._get_field('top')
+        top = self._get_field('top')
+        try:
+            ref = git.rev_parse(self.__top_ref)
+        except:
+            ref = None
+        assert not ref or top == ref
+        return top
 
     def set_top(self, value, backup = False):
         if backup:

@@ -220,6 +232,7 @@ class Patch(StgitObject):
             self._set_field('top.old', curr)
         self._set_field('top', value)
         self.__update_top_ref(value)
+        self.get_bottom() # check the assert
 
     def restore_old_boundaries(self):
         bottom = self._get_field('bottom.old')

@@ -129,6 +129,7 @@ def func(parser, options, args):
                      name_email_date(commit.get_author())
         crt_series.new_patch(patchname,
                              can_edit = False, before_existing = True,
+                             commit = False,
                              top = commit_id, bottom = parent,
                              message = commit.get_log(),
                              author_name = author_name,

@@ -833,9 +833,16 @@ class Series(PatchSet):
                   author_name = None, author_email = None, author_date = None,
                   committer_name = None, committer_email = None,
                   before_existing = False):
-        """Creates a new patch
+        """Creates a new patch, either pointing to an existing commit object,
+        or by creating a new commit object.
         """
 
+        assert commit or (top and bottom)
+        assert not before_existing or (top and bottom)
+        assert not (commit and before_existing)
+        assert (top and bottom) or (not top and not bottom)
+        assert not top or (bottom == git.get_commit(top).get_parent())
+
         if name != None:
             self.__patch_name_valid(name)
             if self.patch_exists(name):

@@ -873,9 +880,6 @@ class Series(PatchSet):
 
         if before_existing:
             insert_string(self.__applied_file, patch.get_name())
-            # no need to commit anything as the object is already
-            # present (mainly used by 'uncommit')
-            commit = False
         elif unapplied:
             patches = [patch.get_name()] + self.get_unapplied()
             write_strings(self.__unapplied_file, patches)

@@ -900,6 +904,8 @@ class Series(PatchSet):
                                    committer_email = committer_email)
             # set the patch top to the new commit
             patch.set_top(commit_id)
+        else:
+            assert top != bottom
 
         self.log_patch(patch, 'new')
 

@@ -158,7 +158,6 @@ class Patch(StgitObject):
 
     def create(self):
         os.mkdir(self._dir())
-        self.create_empty_field('top')
 
     def delete(self):
         for f in os.listdir(self._dir()):

@@ -190,11 +189,6 @@ class Patch(StgitObject):
     def __update_log_ref(self, ref):
         git.set_ref(self.__log_ref, ref)
 
-    def update_top_ref(self):
-        top = self.get_top()
-        if top:
-            self.__update_top_ref(top)
-
     def get_old_bottom(self):
         return git.get_commit(self.get_old_top()).get_parent()
 

@@ -205,26 +199,18 @@ class Patch(StgitObject):
         return self._get_field('top.old')
 
     def get_top(self):
-        top = self._get_field('top')
-        try:
-            ref = git.rev_parse(self.__top_ref)
-        except:
-            ref = None
-        assert not ref or top == ref
-        return top
+        return git.rev_parse(self.__top_ref)
 
     def set_top(self, value, backup = False):
         if backup:
-            curr = self._get_field('top')
+            curr = self.get_top()
             self._set_field('top.old', curr)
-        self._set_field('top', value)
         self.__update_top_ref(value)
 
     def restore_old_boundaries(self):
         top = self._get_field('top.old')
 
         if top:
-            self._set_field('top', top)
             self.__update_top_ref(top)
             return True
         else:

@@ -436,7 +422,13 @@ class Series(PatchSet):
                 patch = patch.strip()
                 os.rename(os.path.join(branch_dir, patch),
                           os.path.join(patch_dir, patch))
-                Patch(patch, patch_dir, refs_base).update_top_ref()
+                topfield = os.path.join(patch_dir, patch, 'top')
+                if os.path.isfile(topfield):
+                    top = read_string(topfield, False)
+                else:
+                    top = None
+                if top:
+                    git.set_ref(refs_base + '/' + patch, top)
             set_format_version(1)
 
         # Update 1 -> 2.