# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1515860704 -3600
# Node ID 1550293500d7b6608c2dd8aea12728db2e4e6837
# Parent  ffcb65f7b8e5a579716bb7f7c2e1a8582c73c1e4
Adjusted the logic around counter-proposals, replacing the "retained modified"
group of periods with a "newly-replaced" group, because all retained periods
should be unmodified, whereas previously-retained periods become classified as
replaced when modified.

diff -r ffcb65f7b8e5 -r 1550293500d7 imiptools/editing.py
--- a/imiptools/editing.py	Fri Jan 12 21:56:34 2018 +0100
+++ b/imiptools/editing.py	Sat Jan 13 17:25:04 2018 +0100
@@ -1434,17 +1434,18 @@
     active_periods = new + replaced + retained
     active_non_rule = filter(lambda p: p.origin != "RRULE", active_periods)
 
-    # Modified replaced and retained recurrences are used for incremental
-    # updates.
+    # Modified replaced recurrences are used for incremental updates.
 
     replaced_modified = select_recurrences(replaced, modified).values()
-    retained_modified = select_recurrences(retained, modified).values()
 
-    # Unmodified replaced and retained recurrences are used in the complete
-    # event summary.
+    # Unmodified replaced recurrences are used in the complete event summary.
 
     replaced_unmodified = subtract_recurrences(replaced, modified).values()
-    retained_unmodified = subtract_recurrences(retained, modified).values()
+
+    # Determine any new replacement periods. These are edited periods that were
+    # not previously replacements.
+
+    replaced_new = filter(lambda p: p.new_replacement, replaced)
 
     # Obtain the removed periods in terms of existing periods. These are used in
     # incremental updates.
@@ -1466,18 +1467,12 @@
     # Cancelled periods originating from rules must be excluded since there are
     # no explicit instances to be deleted.
 
-    cancelled_rule = []
-    for p in cancelled_removed:
-        if p.origin == "RRULE":
-            cancelled_rule.append(p)
+    cancelled_rule = filter(lambda p: p.origin == "RRULE", cancelled_removed)
 
     # Obsolete periods (replaced by other periods) originating from rules must
     # be excluded if no explicit instance will be used to replace them.
 
-    obsolete_rule = []
-    for p in obsolete:
-        if p.origin == "RRULE":
-            obsolete_rule.append(p)
+    obsolete_rule = filter(lambda p: p.origin == "RRULE", obsolete)
 
     # As organiser...
 
@@ -1509,7 +1504,7 @@
             to_set = []
             to_exclude = []
             to_unschedule = cancelled_removed
-            to_reschedule = list(chain(replaced_modified, retained_modified, reinstated))
+            to_reschedule = list(chain(replaced_modified, reinstated))
             to_add = new
             all_unscheduled = cancelled_unmodified
             all_rescheduled = list(chain(replaced_unmodified, to_reschedule))
@@ -1520,27 +1515,27 @@
         to_unschedule = []
         to_add = []
 
-        # Changed periods without new or removed periods are proposed as
-        # separate changes. Parent event changes cause redefinition of the
-        # entire event.
+        # Parent event changes cause redefinition of the entire event.
+        # The event is defined in terms of new periods and exceptions for
+        # removed periods or obsolete rule periods.
 
-        if not new and not removed and not is_changed:
-            to_set = []
-            to_exclude = []
-            to_reschedule = list(chain(replaced_modified, retained_modified, reinstated))
-            all_unscheduled = list(cancelled_unmodified)
-            all_rescheduled = list(chain(replaced_unmodified, to_reschedule))
-
-        # Otherwise, the event is defined in terms of new periods and
-        # exceptions for removed periods or obsolete rule periods.
-
-        else:
+        if new or removed or is_changed or reinstated or replaced_new:
             to_set = active_non_rule
             to_exclude = list(chain(cancelled, obsolete_rule, cancelled_main))
             to_reschedule = []
             all_unscheduled = []
             all_rescheduled = []
 
+        # Changed periods without new or removed periods are proposed as
+        # separate changes.
+
+        else:
+            to_set = []
+            to_exclude = []
+            to_reschedule = replaced_modified
+            all_unscheduled = cancelled_unmodified
+            all_rescheduled = list(chain(replaced_unmodified, to_reschedule))
+
     return to_unschedule, to_reschedule, to_add, to_exclude, to_set, all_unscheduled, all_rescheduled
 
 def get_period_mapping(periods):