fix(processing): preserve order of pending items

This fix means that the order of pending items is preserved and ensures
that the ranges given in the daily processing don't lead to duplicate
days.

ch_pipeline/processing/base.py

@@ -339,9 +339,10 @@ def pending(self):
         """Jobs available to run."""
 
         waiting, running = self.queued()
-        pending = set(self.available()).difference(self.ls(), waiting, running)
+        not_pending = set(self.ls()) | set(waiting) | set(running)
+        pending = [job for job in self.available() if job not in not_pending]
 
-        return sorted(list(pending))
+        return pending
 
 
 def find_venv():

ch_pipeline/processing/daily.py

@@ -223,8 +223,12 @@ def _available_tags(self):
         # - Figure out which sidereal days are covered by this range
 
         csds = []
+
+        # For each interval find and add all CSDs that have not already been added
         for interval in self._intervals:
-            csds += csds_in_range(*interval)
+            csd_i = csds_in_range(*interval)
+            csd_set = set(csds)
+            csds += [csd for csd in csd_i if csd not in csd_set]
 
         tags = ["%i" % csd for csd in csds]