Merge in support for --dont-squash-empty-commits.

2 files changed, 27 insertions, 1 deletions

diff --git a/NEWS b/NEWS
index 3926888..32c469a 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,9 @@ Features
 
 * New option --rewrite-tag-names for 'bzr fast-export'. (Alex Usov, #872601)
 
+* New option --dont-squash-empty-commits for 'bzr fast-import-filter'.
+  (Alex Usov, #877303)
+
 0.11 2011-08-22
 
 Bug fixes
diff --git a/cmds.py b/cmds.py
index d5aedd6..06dc1f7 100644
--- a/cmds.py
+++ b/cmds.py
@@ -387,6 +387,15 @@ class cmd_fast_import_filter(Command):
         User mapping is supported by both the fast-import and
         fast-import-filter commands.
 
+    :History rewriting:
+
+     By default fast-import-filter does quite aggressive history rewriting.
+     Empty commits (or commits which had all their content filtered out) will
+     be removed, and so are the references to commits not included in the stream.
+
+     Flag --dont-squash-empty-commits reverses this behavior and makes it possible to
+     use fast-import-filter on incremental streams.
+
     :Examples:
 
      Create a new project from a library (note the trailing / on the
@@ -415,16 +424,30 @@ class cmd_fast_import_filter(Command):
                     Option('user-map', type=str,
                         help="Path to file containing a map of user-ids.",
                         ),
+                    Option('dont-squash-empty-commits',
+                        help="Preserve all commits and links between them"
+                        ),
                      ]
     encoding_type = 'exact'
     def run(self, source=None, verbose=False, include_paths=None,
-        exclude_paths=None, user_map=None):
+        exclude_paths=None, user_map=None, dont_squash_empty_commits=False):
+        from bzrlib.errors import BzrCommandError
         load_fastimport()
         from fastimport.processors import filter_processor
         params = {
             'include_paths': include_paths,
             'exclude_paths': exclude_paths,
             }
+        if ('squash_empty_commits' in
+                filter_processor.FilterProcessor.known_params):
+            params['squash_empty_commits'] = (not dont_squash_empty_commits)
+        else:
+            if dont_squash_empty_commits:
+                raise BzrCommandError("installed python-fastimport does not "
+                    "support not squashing empty commits. Please install "
+                    " a newer python-fastimport to use "
+                    "--dont-squash-empty-commits")
+
         from fastimport import parser
         stream = _get_source_stream(source)
         user_mapper = _get_user_mapper(user_map)