load external lockfiles also on checkout --update

When running the checkout plugin (or any derived plugin) with --update,
lockfiles were not considered. This logic ensures that the repos can be
updated and later-on be pinned to the new revisions (by updating the
lockfiles). However, any external lockfile (from an external repo)
should always be loaded, as these are not under our control and we
cannot update them. By that, it also makes no sense to move the
externally-pinned repos forward as the next kas invocation without
--update will bring them back to the pinned state.

To fix this, we now always load the lockfiles of external repos (by
that, also on --update).

Note: This introduces a slight behavior change, but only on executions
with --update.

Signed-off-by: Felix Moessbauer <[email protected]>

docs/userguide/project-configuration.rst

@@ -197,6 +197,11 @@ If this is found, kas loads this file right before processing the current one
 .. note::
   The locking logic applies to both files on the kas cmdline and include files.
 
+When performing any kas operation with ``--update``, kas will not load the
+lockfiles of the local repository. By that, the repos can be checked out to
+the latest version and later the lockfiles can be regenerated (e.g. by the
+``lock`` plugin).
+
 The following example shows this mechanism for a file ``kas/kas-isar.yml``
 and its corresponding lockfile ``kas/kas-isar.lock.yml``.
 

kas/includehandler.py

@@ -347,7 +347,10 @@ def _internal_dict_merge(dest, upd):
 
         config_files = self.config_files
         if not self.use_lock:
-            config_files = [x for x in config_files if not x.is_lockfile]
+            # remove all local lockfiles from the list.
+            # remote locks cannot be updated, hence keep them
+            config_files = [x for x in config_files
+                            if x.is_external or not x.is_lockfile]
 
         config = functools.reduce(_internal_dict_merge,
                                   map(lambda x: x.config, config_files))