Optimize Launchpad collection handling

Various methods in `ubuntutools.lp.lpapicache` iterated over collections
in a pessimal way: they fetched the collection and then fetched each
individual entry in it, when the same information was already available
in the collection response.  Use more idiomatic launchpadlib code for
this instead, which is also much faster.

debian/changelog

@@ -1,7 +1,11 @@
 ubuntu-dev-tools (0.207) UNRELEASED; urgency=medium
 
+  [ Dan Streetman ]
   * Fix pull-lp-source --upload-queue (LP: #2110061)
 
+  [ Colin Watson ]
+  * Optimize Launchpad collection handling.
+
  -- Dan Streetman <ddstreet@ieee.org>  Tue, 06 May 2025 13:25:22 -0400
 
 ubuntu-dev-tools (0.206) unstable; urgency=medium

ubuntutools/lp/lpapicache.py

@@ -290,9 +290,8 @@ class Distribution(BaseWrapper):
         Returns a list of all DistroSeries objects.
         """
         if not self._have_all_series:
-            for series in Launchpad.load(self.series_collection_link).entries:
-                series_link = DistroSeries(series["self_link"])
-                self._cache_series(series_link)
+            for series in self.series:
+                self._cache_series(DistroSeries(series))
             self._have_all_series = True
 
         allseries = filter(lambda s: s.active, self._series.values())
@@ -1406,10 +1405,7 @@ class PersonTeam(BaseWrapper, metaclass=MetaPersonTeam):
 
     def getPPAs(self):
         if self._ppas is None:
-            ppas = [
-                Archive(ppa["self_link"])
-                for ppa in Launchpad.load(self._lpobject.ppas_collection_link).entries
-            ]
+            ppas = [Archive(ppa) for ppa in self._lpobject.ppas]
             self._ppas = {ppa.name: ppa for ppa in ppas}
         return self._ppas
 
@@ -1434,10 +1430,7 @@ class Project(BaseWrapper):
         The list will be sorted by date_created, in descending order.
         """
         if not self._series:
-            series = [
-                ProjectSeries(s["self_link"])
-                for s in Launchpad.load(self._lpobject.series_collection_link).entries
-            ]
+            series = [ProjectSeries(s) for s in self._lpobject.series]
             self._series = sorted(series, key=lambda s: s.date_created, reverse=True)
         return self._series.copy()