Merge ~cjwatson/launchpad:dominator-channel-map into launchpad:master

[Colin Watson]

Support dominating publications by channel

This means that, once we start publishing binaries to snap-store-style semantic channels (e.g. "stable", "1.0/candidate", etc.), the dominator will be able to correctly supersede publications that have been replaced with a different version of the same package in the same channel.

I had to prepare for this by adding channel support to various publishing primitives. There's no UI or API support for any of this yet, but I at least needed enough to support the dominator and its tests.

[William Grant (wgrant)]

review: Approve (code)

diff --git a/lib/lp/archivepublisher/domination.py b/lib/lp/archivepublisher/domination.py
index 5cc9422..526c8ea 100644
--- a/lib/lp/archivepublisher/domination.py
+++ b/lib/lp/archivepublisher/domination.py
@@ -64,6 +64,7 @@ from storm.expr import (
     And,
     Count,
     Desc,
+    Not,
     Select,
     )
 from zope.component import getUtility
@@ -74,7 +75,9 @@ from lp.services.database.constants import UTC_NOW
 from lp.services.database.decoratedresultset import DecoratedResultSet
 from lp.services.database.interfaces import IStore
 from lp.services.database.sqlbase import flush_database_updates
+from lp.services.database.stormexpr import IsDistinctFrom
 from lp.services.orderingcheck import OrderingCheck
+from lp.soyuz.adapters.packagelocation import PackageLocation
 from lp.soyuz.enums import (
     BinaryPackageFormat,
     PackagePublishingStatus,
@@ -204,6 +207,17 @@ class GeneralizedPublication:
         return sorted(publications, key=cmp_to_key(self.compare), reverse=True)
 
 
+def make_package_location(pub):
+    """Make a `PackageLocation` representing a publication."""
+    return PackageLocation(
+        archive=pub.archive,
+        distribution=pub.distroseries.distribution,
+        distroseries=pub.distroseries,
+        pocket=pub.pocket,
+        channel=pub.channel,
+        )
+
+
 def find_live_source_versions(sorted_pubs):
     """Find versions out of Published publications that should stay live.
 
@@ -336,10 +350,19 @@ def find_live_binary_versions_pass_2(sorted_pubs, cache):
         [pub.binarypackagerelease for pub in arch_indep_pubs], ['buildID'])
     load_related(SourcePackageRelease, bpbs, ['source_package_release_id'])
 
+    # XXX cjwatson 2022-05-01: Skip the architecture-specific check for
+    # publications from CI builds for now, until we figure out how to
+    # approximate source package releases for groups of CI builds.  We don't
+    # currently expect problematic situations to come up on production; CI
+    # builds are currently only expected to be used in situations where
+    # either we don't build both architecture-specific and
+    # architecture-independent packages, or where tight dependencies between
+    # the two aren't customary.
     reprieved_pubs = [
         pub
         for pub in arch_indep_pubs
-            if cache.hasArchSpecificPublications(pub)]
+            if pub.binarypackagerelease.ci_build_id is None and
+               cache.hasArchSpecificPublications(pub)]
 
     return get_binary_versions([latest] + arch_specific_pubs + reprieved_pubs)
 
@@ -382,9 +405,9 @@ class Dominator:
         list we import.
 
         :param sorted_pubs: A list of publications for the same package,
-            in the same archive, series, and pocket, all with status
-            `PackagePublishingStatus.PUBLISHED`.  They must be sorted from
-            most current to least current, as would be the result of
+            in the same archive, series, pocket, and channel, all with
+            status `PackagePublishingStatus.PUBLISHED`.  They must be sorted
+            from most current to least current, as would be the result of
             `generalization.sortPublications`.
         :param live_versions: Iterable of versions that are still considered
             "live" for this package.  For any of these, the latest publication
@@ -458,31 +481,47 @@ class Dominator:
         return supersede, keep, delete
 
     def _sortPackages(self, publications, generalization):
-        """Partition publications by package name, and sort them.
+        """Partition publications by package name and location, and sort them.
 
         The publications are sorted from most current to least current,
-        as required by `planPackageDomination` etc.
+        as required by `planPackageDomination` etc.  Locations are currently
+        (package name, channel).
 
         :param publications: An iterable of `SourcePackagePublishingHistory`
             or of `BinaryPackagePublishingHistory`.
         :param generalization: A `GeneralizedPublication` helper representing
             the kind of publications these are: source or binary.
-        :return: A dict mapping each package name to a sorted list of
-            publications from `publications`.
+        :return: A dict mapping each package location (package name,
+            channel) to a sorted list of publications from `publications`.
         """
-        pubs_by_package = defaultdict(list)
+        # XXX cjwatson 2022-05-19: Traditional suites (distroseries/pocket)
+        # are divided up in the loop in Publisher.B_dominate.  However, this
+        # doesn't scale to channel-map-style suites (distroseries/channel),
+        # since there may be a very large number of channels and we don't
+        # want to have to loop over all the possible ones, so we divide
+        # those up here instead.
+        #
+        # This is definitely confusing.  In the longer term, we should
+        # probably push the loop down from the publisher to here, and sort
+        # and dominate all candidates in a given archive at once: there's no
+        # particularly obvious reason not to, and it might perform better as
+        # well.
+
+        pubs_by_name_and_location = defaultdict(list)
         for pub in publications:
-            pubs_by_package[generalization.getPackageName(pub)].append(pub)
+            name = generalization.getPackageName(pub)
+            location = make_package_location(pub)
+            pubs_by_name_and_location[(name, location)].append(pub)
 
         # Sort the publication lists.  This is not an in-place sort, so
         # it involves altering the dict while we iterate it.  Listify
-        # the keys so that we can be sure that we're not altering the
+        # the items so that we can be sure that we're not altering the
         # iteration order while iteration is underway.
-        for package in list(pubs_by_package.keys()):
-            pubs_by_package[package] = generalization.sortPublications(
-                pubs_by_package[package])
+        for (name, location), pubs in list(pubs_by_name_and_location.items()):
+            pubs_by_name_and_location[(name, location)] = (
+                generalization.sortPublications(pubs))
 
-        return pubs_by_package
+        return pubs_by_name_and_location
 
     def _setScheduledDeletionDate(self, pub_record):
         """Set the scheduleddeletiondate on a publishing record.
@@ -541,7 +580,10 @@ class Dominator:
                 BinaryPackagePublishingHistory.binarypackagerelease ==
                     BinaryPackageRelease.id,
                 BinaryPackageRelease.build == BinaryPackageBuild.id,
-                BinaryPackagePublishingHistory.pocket == pub_record.pocket)
+                BinaryPackagePublishingHistory.pocket == pub_record.pocket,
+                Not(IsDistinctFrom(
+                    BinaryPackagePublishingHistory._channel,
+                    pub_record._channel)))
 
             # There is at least one non-removed binary to consider
             if not considered_binaries.is_empty():
@@ -552,6 +594,7 @@ class Dominator:
                     SourcePackagePublishingHistory,
                     distroseries=pub_record.distroseries,
                     pocket=pub_record.pocket,
+                    channel=pub_record.channel,
                     status=PackagePublishingStatus.PUBLISHED,
                     archive=self.archive,
                     sourcepackagerelease=srcpkg_release)
@@ -588,7 +631,8 @@ class Dominator:
             ]
         candidate_binary_names = Select(
             BPPH.binarypackagenameID, And(*bpph_location_clauses),
-            group_by=BPPH.binarypackagenameID, having=(Count() > 1))
+            group_by=(BPPH.binarypackagenameID, BPPH._channel),
+            having=(Count() > 1))
         main_clauses = bpph_location_clauses + [
             BPR.id == BPPH.binarypackagereleaseID,
             BPR.binarypackagenameID.is_in(candidate_binary_names),
@@ -664,13 +708,14 @@ class Dominator:
             bins = self.findBinariesForDomination(distroarchseries, pocket)
             sorted_packages = self._sortPackages(bins, generalization)
             self.logger.info("Planning domination of binaries...")
-            for name, pubs in sorted_packages.items():
-                self.logger.debug("Planning domination of %s" % name)
+            for (name, location), pubs in sorted_packages.items():
+                self.logger.debug(
+                    "Planning domination of %s in %s" % (name, location))
                 assert len(pubs) > 0, "Dominating zero binaries!"
                 live_versions = find_live_binary_versions_pass_1(pubs)
                 plan(pubs, live_versions)
                 if contains_arch_indep(pubs):
-                    packages_w_arch_indep.add(name)
+                    packages_w_arch_indep.add((name, location))
 
         execute_plan()
 
@@ -692,9 +737,11 @@ class Dominator:
             bins = self.findBinariesForDomination(distroarchseries, pocket)
             sorted_packages = self._sortPackages(bins, generalization)
             self.logger.info("Planning domination of binaries...(2nd pass)")
-            for name in packages_w_arch_indep.intersection(sorted_packages):
-                pubs = sorted_packages[name]
-                self.logger.debug("Planning domination of %s" % name)
+            for name, location in packages_w_arch_indep.intersection(
+                    sorted_packages):
+                pubs = sorted_packages[(name, location)]
+                self.logger.debug(
+                    "Planning domination of %s in %s" % (name, location))
                 assert len(pubs) > 0, "Dominating zero binaries in 2nd pass!"
                 live_versions = find_live_binary_versions_pass_2(
                     pubs, reprieve_cache)
@@ -732,7 +779,7 @@ class Dominator:
         candidate_source_names = Select(
             SPPH.sourcepackagenameID,
             And(join_spph_spr(), spph_location_clauses),
-            group_by=SPPH.sourcepackagenameID,
+            group_by=(SPPH.sourcepackagenameID, SPPH._channel),
             having=(Count() > 1))
 
         # We'll also access the SourcePackageReleases associated with
@@ -769,8 +816,8 @@ class Dominator:
         delete = []
 
         self.logger.debug("Dominating sources...")
-        for name, pubs in sorted_packages.items():
-            self.logger.debug("Dominating %s" % name)
+        for (name, location), pubs in sorted_packages.items():
+            self.logger.debug("Dominating %s in %s" % (name, location))
             assert len(pubs) > 0, "Dominating zero sources!"
             live_versions = find_live_source_versions(pubs)
             cur_supersede, _, cur_delete = self.planPackageDomination(
diff --git a/lib/lp/archivepublisher/publishing.py b/lib/lp/archivepublisher/publishing.py
index 0639716..69fb7e3 100644
--- a/lib/lp/archivepublisher/publishing.py
+++ b/lib/lp/archivepublisher/publishing.py
@@ -680,6 +680,9 @@ class Publisher:
         judgejudy = Dominator(self.log, self.archive)
         for distroseries in self.distro.series:
             for pocket in self.archive.getPockets():
+                # XXX cjwatson 2022-05-19: Channels are handled in the
+                # dominator instead; see the comment in
+                # Dominator._sortPackages.
                 if not self.isAllowed(distroseries, pocket):
                     continue
                 if not force_domination:
diff --git a/lib/lp/archivepublisher/tests/test_dominator.py b/lib/lp/archivepublisher/tests/test_dominator.py
old mode 100755
new mode 100644
index 01c56e4..23d5468
--- a/lib/lp/archivepublisher/tests/test_dominator.py
+++ b/lib/lp/archivepublisher/tests/test_dominator.py
@@ -30,7 +30,11 @@ from lp.archivepublisher.publishing import Publisher
 from lp.registry.interfaces.pocket import PackagePublishingPocket
 from lp.registry.interfaces.series import SeriesStatus
 from lp.services.log.logger import DevNullLogger
-from lp.soyuz.enums import PackagePublishingStatus
+from lp.soyuz.adapters.packagelocation import PackageLocation
+from lp.soyuz.enums import (
+    BinaryPackageFormat,
+    PackagePublishingStatus,
+    )
 from lp.soyuz.interfaces.publishing import (
     IPublishingSet,
     ISourcePackagePublishingHistory,
@@ -168,29 +172,39 @@ class TestDominator(TestNativePublishingBase):
         """Domination asserts for non-empty input list."""
         with lp_dbuser():
             distroseries = self.factory.makeDistroArchSeries().distroseries
+        pocket = self.factory.getAnyPocket()
         package = self.factory.makeBinaryPackageName()
+        location = PackageLocation(
+            archive=self.ubuntutest.main_archive,
+            distribution=distroseries.distribution, distroseries=distroseries,
+            pocket=pocket)
         dominator = Dominator(self.logger, self.ubuntutest.main_archive)
-        dominator._sortPackages = FakeMethod({package.name: []})
+        dominator._sortPackages = FakeMethod({(package.name, location): []})
         # This isn't a really good exception. It should probably be
         # something more indicative of bad input.
         self.assertRaises(
             AssertionError,
             dominator.dominateBinaries,
-            distroseries, self.factory.getAnyPocket())
+            distroseries, pocket)
 
     def test_dominateSources_rejects_empty_publication_list(self):
         """Domination asserts for non-empty input list."""
         with lp_dbuser():
             distroseries = self.factory.makeDistroSeries()
+        pocket = self.factory.getAnyPocket()
         package = self.factory.makeSourcePackageName()
+        location = PackageLocation(
+            archive=self.ubuntutest.main_archive,
+            distribution=distroseries.distribution, distroseries=distroseries,
+            pocket=pocket)
         dominator = Dominator(self.logger, self.ubuntutest.main_archive)
-        dominator._sortPackages = FakeMethod({package.name: []})
+        dominator._sortPackages = FakeMethod({(package.name, location): []})
         # This isn't a really good exception. It should probably be
         # something more indicative of bad input.
         self.assertRaises(
             AssertionError,
             dominator.dominateSources,
-            distroseries, self.factory.getAnyPocket())
+            distroseries, pocket)
 
     def test_archall_domination(self):
         # Arch-all binaries should not be dominated when a new source
@@ -398,6 +412,51 @@ class TestDominator(TestNativePublishingBase):
         for pub in overrides_2:
             self.assertEqual(PackagePublishingStatus.PUBLISHED, pub.status)
 
+    def test_dominate_by_channel(self):
+        # Publications only dominate other publications in the same channel.
+        # (Currently only tested for binary publications.)
+        with lp_dbuser():
+            archive = self.factory.makeArchive()
+            distroseries = self.factory.makeDistroSeries(
+                distribution=archive.distribution)
+            das = self.factory.makeDistroArchSeries(distroseries=distroseries)
+            repository = self.factory.makeGitRepository(
+                target=self.factory.makeDistributionSourcePackage(
+                    distribution=archive.distribution))
+            ci_builds = [
+                self.factory.makeCIBuild(
+                    git_repository=repository, distro_arch_series=das)
+                for _ in range(3)]
+        bpn = self.factory.makeBinaryPackageName()
+        bprs = [
+            self.factory.makeBinaryPackageRelease(
+                binarypackagename=bpn, version=version, ci_build=ci_build,
+                binpackageformat=BinaryPackageFormat.WHL)
+            for version, ci_build in zip(("1.0", "1.1", "1.2"), ci_builds)]
+        stable_bpphs = [
+            self.factory.makeBinaryPackagePublishingHistory(
+                binarypackagerelease=bpr, archive=archive,
+                distroarchseries=das, status=PackagePublishingStatus.PUBLISHED,
+                pocket=PackagePublishingPocket.RELEASE, channel="stable")
+            for bpr in bprs[:2]]
+        candidate_bpph = self.factory.makeBinaryPackagePublishingHistory(
+            binarypackagerelease=bprs[2], archive=archive,
+            distroarchseries=das, status=PackagePublishingStatus.PUBLISHED,
+            pocket=PackagePublishingPocket.RELEASE, channel="candidate")
+
+        dominator = Dominator(self.logger, archive)
+        dominator.judgeAndDominate(
+            distroseries, PackagePublishingPocket.RELEASE)
+
+        # The older of the two stable publications is superseded, while the
+        # current stable publication and the candidate publication are left
+        # alone.
+        self.checkPublication(
+            stable_bpphs[0], PackagePublishingStatus.SUPERSEDED)
+        self.checkPublications(
+            (stable_bpphs[1], candidate_bpph),
+            PackagePublishingStatus.PUBLISHED)
+
 
 class TestDomination(TestNativePublishingBase):
     """Test overall domination procedure."""
@@ -1315,7 +1374,7 @@ class TestArchSpecificPublicationsCache(TestCaseWithFactory):
         return removeSecurityProxy(self.factory.makeSourcePackageRelease())
 
     def makeBPPH(self, spr=None, arch_specific=True, archive=None,
-                 distroseries=None):
+                 distroseries=None, binpackageformat=None, channel=None):
         """Create a `BinaryPackagePublishingHistory`."""
         if spr is None:
             spr = self.makeSPR()
@@ -1323,12 +1382,13 @@ class TestArchSpecificPublicationsCache(TestCaseWithFactory):
         bpb = self.factory.makeBinaryPackageBuild(
             source_package_release=spr, distroarchseries=das)
         bpr = self.factory.makeBinaryPackageRelease(
-            build=bpb, architecturespecific=arch_specific)
+            build=bpb, binpackageformat=binpackageformat,
+            architecturespecific=arch_specific)
         return removeSecurityProxy(
             self.factory.makeBinaryPackagePublishingHistory(
                 binarypackagerelease=bpr, archive=archive,
                 distroarchseries=das, pocket=PackagePublishingPocket.UPDATES,
-                status=PackagePublishingStatus.PUBLISHED))
+                status=PackagePublishingStatus.PUBLISHED, channel=channel))
 
     def test_getKey_is_consistent_and_distinguishing(self):
         # getKey consistently returns the same key for the same BPPH,
@@ -1351,14 +1411,19 @@ class TestArchSpecificPublicationsCache(TestCaseWithFactory):
             spr, arch_specific=False, archive=dependent.archive,
             distroseries=dependent.distroseries)
         bpph2 = self.makeBPPH(arch_specific=False)
+        bpph3 = self.makeBPPH(
+            arch_specific=False, binpackageformat=BinaryPackageFormat.WHL,
+            channel="edge")
         cache = self.makeCache()
         self.assertEqual(
-            [True, True, False, False],
+            [True, True, False, False, False, False],
             [
                 cache.hasArchSpecificPublications(bpph1),
                 cache.hasArchSpecificPublications(bpph1),
                 cache.hasArchSpecificPublications(bpph2),
                 cache.hasArchSpecificPublications(bpph2),
+                cache.hasArchSpecificPublications(bpph3),
+                cache.hasArchSpecificPublications(bpph3),
             ])
 
     def test_hasArchSpecificPublications_caches_results(self):
diff --git a/lib/lp/code/interfaces/cibuild.py b/lib/lp/code/interfaces/cibuild.py
index 6146dfe..fc7a197 100644
--- a/lib/lp/code/interfaces/cibuild.py
+++ b/lib/lp/code/interfaces/cibuild.py
@@ -177,6 +177,14 @@ class ICIBuildView(IPackageBuildView, IPrivacy):
         :return: A collection of URLs for this build.
         """
 
+    def createBinaryPackageRelease(
+            binarypackagename, version, summary, description, binpackageformat,
+            architecturespecific, installedsize=None, homepage=None):
+        """Create and return a `BinaryPackageRelease` for this CI build.
+
+        The new binary package release will be linked to this build.
+        """
+
 
 class ICIBuildEdit(IBuildFarmJobEdit):
     """`ICIBuild` methods that require launchpad.Edit."""
diff --git a/lib/lp/code/model/cibuild.py b/lib/lp/code/model/cibuild.py
index d789a95..4e1ddbd 100644
--- a/lib/lp/code/model/cibuild.py
+++ b/lib/lp/code/model/cibuild.py
@@ -85,6 +85,7 @@ from lp.services.macaroons.interfaces import (
     )
 from lp.services.macaroons.model import MacaroonIssuerBase
 from lp.services.propertycache import cachedproperty
+from lp.soyuz.model.binarypackagerelease import BinaryPackageRelease
 from lp.soyuz.model.distroarchseries import DistroArchSeries
 
 
@@ -465,6 +466,18 @@ class CIBuild(PackageBuildMixin, StormBase):
         """See `IPackageBuild`."""
         # We don't currently send any notifications.
 
+    def createBinaryPackageRelease(
+            self, binarypackagename, version, summary, description,
+            binpackageformat, architecturespecific, installedsize=None,
+            homepage=None):
+        """See `ICIBuild`."""
+        return BinaryPackageRelease(
+            ci_build=self, binarypackagename=binarypackagename,
+            version=version, summary=summary, description=description,
+            binpackageformat=binpackageformat,
+            architecturespecific=architecturespecific,
+            installedsize=installedsize, homepage=homepage)
+
 
 @implementer(ICIBuildSet)
 class CIBuildSet(SpecificBuildFarmJobSourceMixin):
diff --git a/lib/lp/code/model/tests/test_cibuild.py b/lib/lp/code/model/tests/test_cibuild.py
index 899b09b..b7e0ca5 100644
--- a/lib/lp/code/model/tests/test_cibuild.py
+++ b/lib/lp/code/model/tests/test_cibuild.py
@@ -70,6 +70,7 @@ from lp.services.macaroons.interfaces import IMacaroonIssuer
 from lp.services.macaroons.testing import MacaroonTestMixin
 from lp.services.propertycache import clear_property_cache
 from lp.services.webapp.interfaces import OAuthPermission
+from lp.soyuz.enums import BinaryPackageFormat
 from lp.testing import (
     ANONYMOUS,
     api_url,
@@ -399,6 +400,24 @@ class TestCIBuild(TestCaseWithFactory):
                 commit_sha1=build.commit_sha1,
                 ci_build=build))
 
+    def test_createBinaryPackageRelease(self):
+        build = self.factory.makeCIBuild()
+        bpn = self.factory.makeBinaryPackageName()
+        bpr = build.createBinaryPackageRelease(
+            bpn, "1.0", "test summary", "test description",
+            BinaryPackageFormat.WHL, False, installedsize=1024,
+            homepage="https://example.com/")
+        self.assertThat(bpr, MatchesStructure(
+            binarypackagename=Equals(bpn),
+            version=Equals("1.0"),
+            summary=Equals("test summary"),
+            description=Equals("test description"),
+            binpackageformat=Equals(BinaryPackageFormat.WHL),
+            architecturespecific=Is(False),
+            installedsize=Equals(1024),
+            homepage=Equals("https://example.com/"),
+            ))
+
 
 class TestCIBuildSet(TestCaseWithFactory):
 
diff --git a/lib/lp/soyuz/adapters/packagelocation.py b/lib/lp/soyuz/adapters/packagelocation.py
index 6644f1e..2cf1cb4 100644
--- a/lib/lp/soyuz/adapters/packagelocation.py
+++ b/lib/lp/soyuz/adapters/packagelocation.py
@@ -29,9 +29,10 @@ class PackageLocation:
     pocket = None
     component = None
     packagesets = None
+    channel = None
 
     def __init__(self, archive, distribution, distroseries, pocket,
-                 component=None, packagesets=None):
+                 component=None, packagesets=None, channel=None):
         """Initialize the PackageLocation from the given parameters."""
         self.archive = archive
         self.distribution = distribution
@@ -39,6 +40,7 @@ class PackageLocation:
         self.pocket = pocket
         self.component = component
         self.packagesets = packagesets or []
+        self.channel = channel
 
     def __eq__(self, other):
         if (self.distribution == other.distribution and
@@ -46,10 +48,22 @@ class PackageLocation:
             self.distroseries == other.distroseries and
             self.component == other.component and
             self.pocket == other.pocket and
-            self.packagesets == other.packagesets):
+            self.packagesets == other.packagesets and
+            self.channel == other.channel):
             return True
         return False
 
+    def __hash__(self):
+        return hash((
+            self.archive,
+            self.distribution,
+            self.distroseries,
+            self.pocket,
+            self.component,
+            None if self.packagesets is None else tuple(self.packagesets),
+            self.channel,
+            ))
+
     def __str__(self):
         result = '%s: %s-%s' % (
             self.archive.reference, self.distroseries.name, self.pocket.name)
@@ -61,6 +75,9 @@ class PackageLocation:
             result += ' [%s]' % (
                 ", ".join([str(p.name) for p in self.packagesets]),)
 
+        if self.channel is not None:
+            result += ' {%s}' % self.channel
+
         return result
 
 
@@ -70,7 +87,7 @@ class PackageLocationError(Exception):
 
 def build_package_location(distribution_name, suite=None, purpose=None,
                            person_name=None, archive_name=None,
-                           packageset_names=None):
+                           packageset_names=None, channel=None):
     """Convenience function to build PackageLocation objects."""
 
     # XXX kiko 2007-10-24:
@@ -143,6 +160,10 @@ def build_package_location(distribution_name, suite=None, purpose=None,
         distroseries = distribution.currentseries
         pocket = PackagePublishingPocket.RELEASE
 
+    if pocket != PackagePublishingPocket.RELEASE and channel is not None:
+        raise PackageLocationError(
+            "Channels may only be used with the RELEASE pocket.")
+
     packagesets = []
     if packageset_names:
         packageset_set = getUtility(IPackagesetSet)
@@ -155,5 +176,6 @@ def build_package_location(distribution_name, suite=None, purpose=None,
                     "Could not find packageset %s" % err)
             packagesets.append(packageset)
 
-    return PackageLocation(archive, distribution, distroseries, pocket,
-            packagesets=packagesets)
+    return PackageLocation(
+        archive, distribution, distroseries, pocket,
+        packagesets=packagesets, channel=channel)
diff --git a/lib/lp/soyuz/adapters/tests/test_packagelocation.py b/lib/lp/soyuz/adapters/tests/test_packagelocation.py
index 3d45f14..9bbef24 100644
--- a/lib/lp/soyuz/adapters/tests/test_packagelocation.py
+++ b/lib/lp/soyuz/adapters/tests/test_packagelocation.py
@@ -22,11 +22,12 @@ class TestPackageLocation(TestCaseWithFactory):
 
     def getPackageLocation(self, distribution_name='ubuntu', suite=None,
                            purpose=None, person_name=None,
-                           archive_name=None, packageset_names=None):
+                           archive_name=None, packageset_names=None,
+                           channel=None):
         """Use a helper method to setup a `PackageLocation` object."""
         return build_package_location(
             distribution_name, suite, purpose, person_name, archive_name,
-            packageset_names=packageset_names)
+            packageset_names=packageset_names, channel=channel)
 
     def testSetupLocationForCOPY(self):
         """`PackageLocation` for COPY archives."""
@@ -150,6 +151,15 @@ class TestPackageLocation(TestCaseWithFactory):
             distribution_name='debian',
             packageset_names=[packageset_name, "unknown"])
 
+    def test_build_package_location_with_channel_outside_release_pocket(self):
+        """It doesn't make sense to use non-RELEASE pockets with channels."""
+        self.assertRaisesWithContent(
+            PackageLocationError,
+            "Channels may only be used with the RELEASE pocket.",
+            self.getPackageLocation,
+            suite="warty-security",
+            channel="stable")
+
     def testSetupLocationPPANotMatchingDistribution(self):
         """`PackageLocationError` is raised when PPA does not match the
         distribution."""
@@ -214,6 +224,14 @@ class TestPackageLocation(TestCaseWithFactory):
         self.assertEqual(
             location_ubuntu_hoary, location_ubuntu_hoary_again)
 
+    def testCompareChannels(self):
+        location_ubuntu_hoary = self.getPackageLocation(channel="stable")
+        location_ubuntu_hoary_again = self.getPackageLocation(channel="edge")
+        self.assertNotEqual(location_ubuntu_hoary, location_ubuntu_hoary_again)
+
+        location_ubuntu_hoary_again.channel = "stable"
+        self.assertEqual(location_ubuntu_hoary, location_ubuntu_hoary_again)
+
     def testRepresentation(self):
         """Check if PackageLocation is represented correctly."""
         location_ubuntu_hoary = self.getPackageLocation()
diff --git a/lib/lp/soyuz/enums.py b/lib/lp/soyuz/enums.py
index d60ea48..9953f43 100644
--- a/lib/lp/soyuz/enums.py
+++ b/lib/lp/soyuz/enums.py
@@ -208,6 +208,13 @@ class BinaryPackageFileType(DBEnumeratedType):
         build environment.
         """)
 
+    WHL = DBItem(6, """
+        Python Wheel
+
+        The "wheel" binary package format for Python, originally defined in
+        U{https://peps.python.org/pep-0427/}.
+        """)
+
 
 class BinaryPackageFormat(DBEnumeratedType):
     """Binary Package Format
@@ -251,6 +258,13 @@ class BinaryPackageFormat(DBEnumeratedType):
         This is the binary package format used for shipping debug symbols
         in Ubuntu and similar distributions.""")
 
+    WHL = DBItem(6, """
+        Python Wheel
+
+        The "wheel" binary package format for Python, originally defined in
+        U{https://peps.python.org/pep-0427/}.
+        """)
+
 
 class PackageCopyPolicy(DBEnumeratedType):
     """Package copying policy.
diff --git a/lib/lp/soyuz/interfaces/publishing.py b/lib/lp/soyuz/interfaces/publishing.py
index a1cfeab..21a3cac 100644
--- a/lib/lp/soyuz/interfaces/publishing.py
+++ b/lib/lp/soyuz/interfaces/publishing.py
@@ -50,7 +50,6 @@ from zope.schema import (
     Date,
     Datetime,
     Int,
-    List,
     Text,
     TextLine,
     )
@@ -269,9 +268,8 @@ class ISourcePackagePublishingHistoryPublic(IPublishingView):
             vocabulary=PackagePublishingPocket,
             required=True, readonly=True,
             ))
-    channel = List(
-        value_type=TextLine(), title=_("Channel"),
-        required=False, readonly=False,
+    channel = TextLine(
+        title=_("Channel"), required=False, readonly=False,
         description=_(
             "The channel into which this entry is published "
             "(only for archives published using Artifactory)"))
@@ -700,9 +698,8 @@ class IBinaryPackagePublishingHistoryPublic(IPublishingView):
             vocabulary=PackagePublishingPocket,
             required=True, readonly=True,
             ))
-    channel = List(
-        value_type=TextLine(), title=_("Channel"),
-        required=False, readonly=False,
+    channel = TextLine(
+        title=_("Channel"), required=False, readonly=False,
         description=_(
             "The channel into which this entry is published "
             "(only for archives published using Artifactory)"))
@@ -970,7 +967,8 @@ class IPublishingSet(Interface):
     def newSourcePublication(archive, sourcepackagerelease, distroseries,
                              component, section, pocket, ancestor,
                              create_dsd_job=True, copied_from_archive=None,
-                             creator=None, sponsor=None, packageupload=None):
+                             creator=None, sponsor=None, packageupload=None,
+                             channel=None):
         """Create a new `SourcePackagePublishingHistory`.
 
         :param archive: An `IArchive`
diff --git a/lib/lp/soyuz/model/binarypackagerelease.py b/lib/lp/soyuz/model/binarypackagerelease.py
index 25cae48..7134895 100644
--- a/lib/lp/soyuz/model/binarypackagerelease.py
+++ b/lib/lp/soyuz/model/binarypackagerelease.py
@@ -157,6 +157,8 @@ class BinaryPackageRelease(SQLBase):
             determined_filetype = BinaryPackageFileType.UDEB
         elif file.filename.endswith(".ddeb"):
             determined_filetype = BinaryPackageFileType.DDEB
+        elif file.filename.endswith(".whl"):
+            determined_filetype = BinaryPackageFileType.WHL
         else:
             raise AssertionError(
                 'Unsupported file type: %s' % file.filename)
diff --git a/lib/lp/soyuz/model/publishing.py b/lib/lp/soyuz/model/publishing.py
index cdab414..8a397b6 100644
--- a/lib/lp/soyuz/model/publishing.py
+++ b/lib/lp/soyuz/model/publishing.py
@@ -12,6 +12,7 @@ __all__ = [
 
 from collections import defaultdict
 from datetime import datetime
+import json
 from operator import (
     attrgetter,
     itemgetter,
@@ -20,6 +21,7 @@ from pathlib import Path
 import sys
 
 import pytz
+from storm.databases.postgres import JSON
 from storm.expr import (
     And,
     Cast,
@@ -31,10 +33,6 @@ from storm.expr import (
     Sum,
     )
 from storm.info import ClassAlias
-from storm.properties import (
-    List,
-    Unicode,
-    )
 from storm.store import Store
 from storm.zope import IResultSet
 from storm.zope.interfaces import ISQLObjectResultSet
@@ -51,6 +49,10 @@ from lp.registry.interfaces.person import validate_public_person
 from lp.registry.interfaces.pocket import PackagePublishingPocket
 from lp.registry.interfaces.sourcepackage import SourcePackageType
 from lp.registry.model.sourcepackagename import SourcePackageName
+from lp.services.channels import (
+    channel_list_to_string,
+    channel_string_to_list,
+    )
 from lp.services.database import bulk
 from lp.services.database.constants import UTC_NOW
 from lp.services.database.datetimecol import UtcDateTimeCol
@@ -267,7 +269,7 @@ class SourcePackagePublishingHistory(SQLBase, ArchivePublisherBase):
     pocket = DBEnum(name='pocket', enum=PackagePublishingPocket,
                     default=PackagePublishingPocket.RELEASE,
                     allow_none=False)
-    channel = List(name="channel", type=Unicode(), allow_none=True)
+    _channel = JSON(name="channel", allow_none=True)
     archive = ForeignKey(dbName="archive", foreignKey="Archive", notNull=True)
     copied_from_archive = ForeignKey(
         dbName="copied_from_archive", foreignKey="Archive", notNull=False)
@@ -315,6 +317,13 @@ class SourcePackagePublishingHistory(SQLBase, ArchivePublisherBase):
         self.distroseries.setNewerDistroSeriesVersions([self])
         return get_property_cache(self).newer_distroseries_version
 
+    @property
+    def channel(self):
+        """See `ISourcePackagePublishingHistory`."""
+        if self._channel is None:
+            return None
+        return channel_list_to_string(*self._channel)
+
     def getPublishedBinaries(self):
         """See `ISourcePackagePublishingHistory`."""
         publishing_set = getUtility(IPublishingSet)
@@ -538,7 +547,8 @@ class SourcePackagePublishingHistory(SQLBase, ArchivePublisherBase):
             component=new_component,
             section=new_section,
             creator=creator,
-            archive=self.archive)
+            archive=self.archive,
+            channel=self.channel)
 
     def copyTo(self, distroseries, pocket, archive, override=None,
                create_dsd_job=True, creator=None, sponsor=None,
@@ -564,7 +574,8 @@ class SourcePackagePublishingHistory(SQLBase, ArchivePublisherBase):
             creator=creator,
             sponsor=sponsor,
             copied_from_archive=self.archive,
-            packageupload=packageupload)
+            packageupload=packageupload,
+            channel=self.channel)
 
     def getStatusSummaryForBuilds(self):
         """See `ISourcePackagePublishingHistory`."""
@@ -685,7 +696,7 @@ class BinaryPackagePublishingHistory(SQLBase, ArchivePublisherBase):
     datemadepending = UtcDateTimeCol(default=None)
     dateremoved = UtcDateTimeCol(default=None)
     pocket = DBEnum(name='pocket', enum=PackagePublishingPocket)
-    channel = List(name="channel", type=Unicode(), allow_none=True)
+    _channel = JSON(name="channel", allow_none=True)
     archive = ForeignKey(dbName="archive", foreignKey="Archive", notNull=True)
     copied_from_archive = ForeignKey(
         dbName="copied_from_archive", foreignKey="Archive", notNull=False)
@@ -779,6 +790,13 @@ class BinaryPackagePublishingHistory(SQLBase, ArchivePublisherBase):
                                    distroseries.name,
                                    self.distroarchseries.architecturetag)
 
+    @property
+    def channel(self):
+        """See `ISourcePackagePublishingHistory`."""
+        if self._channel is None:
+            return None
+        return channel_list_to_string(*self._channel)
+
     def getDownloadCount(self):
         """See `IBinaryPackagePublishingHistory`."""
         return self.archive.getPackageDownloadTotal(self.binarypackagerelease)
@@ -836,21 +854,26 @@ class BinaryPackagePublishingHistory(SQLBase, ArchivePublisherBase):
                     dominant.distroarchseries.architecturetag))
 
             dominant_build = dominant.binarypackagerelease.build
-            distroarchseries = dominant_build.distro_arch_series
-            if logger is not None:
-                logger.debug(
-                    "The %s build of %s has been judged as superseded by the "
-                    "build of %s.  Arch-specific == %s" % (
-                    distroarchseries.architecturetag,
-                    self.binarypackagerelease.title,
-                    dominant_build.source_package_release.title,
-                    self.binarypackagerelease.architecturespecific))
-            # Binary package releases are superseded by the new build,
-            # not the new binary package release. This is because
-            # there may not *be* a new matching binary package -
-            # source packages can change the binaries they build
-            # between releases.
-            self.supersededby = dominant_build
+            # XXX cjwatson 2022-05-01: We can't currently dominate with CI
+            # builds, since supersededby is a reference to a BPB.  Just
+            # leave supersededby unset in that case for now, which isn't
+            # ideal but will work well enough.
+            if dominant_build is not None:
+                distroarchseries = dominant_build.distro_arch_series
+                if logger is not None:
+                    logger.debug(
+                        "The %s build of %s has been judged as superseded by "
+                        "the build of %s.  Arch-specific == %s" % (
+                        distroarchseries.architecturetag,
+                        self.binarypackagerelease.title,
+                        dominant_build.source_package_release.title,
+                        self.binarypackagerelease.architecturespecific))
+                # Binary package releases are superseded by the new build,
+                # not the new binary package release. This is because
+                # there may not *be* a new matching binary package -
+                # source packages can change the binaries they build
+                # between releases.
+                self.supersededby = dominant_build
 
         debug = getUtility(IPublishingSet).findCorrespondingDDEBPublications(
             [self])
@@ -941,7 +964,8 @@ class BinaryPackagePublishingHistory(SQLBase, ArchivePublisherBase):
                 priority=new_priority,
                 creator=creator,
                 archive=debug.archive,
-                phased_update_percentage=new_phased_update_percentage)
+                phased_update_percentage=new_phased_update_percentage,
+                _channel=removeSecurityProxy(debug)._channel)
 
         # Append the modified package publishing entry
         return BinaryPackagePublishingHistory(
@@ -957,7 +981,8 @@ class BinaryPackagePublishingHistory(SQLBase, ArchivePublisherBase):
             priority=new_priority,
             archive=self.archive,
             creator=creator,
-            phased_update_percentage=new_phased_update_percentage)
+            phased_update_percentage=new_phased_update_percentage,
+            _channel=self._channel)
 
     def copyTo(self, distroseries, pocket, archive):
         """See `BinaryPackagePublishingHistory`."""
@@ -1086,10 +1111,15 @@ class PublishingSet:
     """Utilities for manipulating publications in batches."""
 
     def publishBinaries(self, archive, distroseries, pocket, binaries,
-                        copied_from_archives=None):
+                        copied_from_archives=None, channel=None):
         """See `IPublishingSet`."""
         if copied_from_archives is None:
             copied_from_archives = {}
+        if channel is not None:
+            if pocket != PackagePublishingPocket.RELEASE:
+                raise AssertionError(
+                    "Channel publications must be in the RELEASE pocket")
+            channel = channel_string_to_list(channel)
         # Expand the dict of binaries into a list of tuples including the
         # architecture.
         if distroseries.distribution != archive.distribution:
@@ -1124,6 +1154,9 @@ class PublishingSet:
              BinaryPackageRelease.binarypackagenameID,
              BinaryPackageRelease.version),
             BinaryPackagePublishingHistory.pocket == pocket,
+            Not(IsDistinctFrom(
+                BinaryPackagePublishingHistory._channel,
+                json.dumps(channel) if channel is not None else None)),
             BinaryPackagePublishingHistory.status.is_in(
                 active_publishing_status),
             BinaryPackageRelease.id ==
@@ -1141,12 +1174,13 @@ class PublishingSet:
         BPPH = BinaryPackagePublishingHistory
         return bulk.create(
             (BPPH.archive, BPPH.copied_from_archive,
-             BPPH.distroarchseries, BPPH.pocket,
+             BPPH.distroarchseries, BPPH.pocket, BPPH._channel,
              BPPH.binarypackagerelease, BPPH.binarypackagename,
+             BPPH._binarypackageformat,
              BPPH.component, BPPH.section, BPPH.priority,
              BPPH.phased_update_percentage, BPPH.status, BPPH.datecreated),
-            [(archive, copied_from_archives.get(bpr), das, pocket, bpr,
-              bpr.binarypackagename,
+            [(archive, copied_from_archives.get(bpr), das, pocket, channel,
+              bpr, bpr.binarypackagename, bpr.binpackageformat,
               get_component(archive, das.distroseries, component),
               section, priority, phased_update_percentage,
               PackagePublishingStatus.PENDING, UTC_NOW)
@@ -1156,7 +1190,7 @@ class PublishingSet:
             get_objects=True)
 
     def copyBinaries(self, archive, distroseries, pocket, bpphs, policy=None,
-                     source_override=None):
+                     source_override=None, channel=None):
         """See `IPublishingSet`."""
         from lp.soyuz.adapters.overrides import BinaryOverride
         if distroseries.distribution != archive.distribution:
@@ -1228,13 +1262,14 @@ class PublishingSet:
             bpph.binarypackagerelease: bpph.archive for bpph in bpphs}
         return self.publishBinaries(
             archive, distroseries, pocket, with_overrides,
-            copied_from_archives)
+            copied_from_archives, channel=channel)
 
     def newSourcePublication(self, archive, sourcepackagerelease,
                              distroseries, component, section, pocket,
                              ancestor=None, create_dsd_job=True,
                              copied_from_archive=None,
-                             creator=None, sponsor=None, packageupload=None):
+                             creator=None, sponsor=None, packageupload=None,
+                             channel=None):
         """See `IPublishingSet`."""
         # Circular import.
         from lp.registry.model.distributionsourcepackage import (
@@ -1246,6 +1281,15 @@ class PublishingSet:
                 "Series distribution %s doesn't match archive distribution %s."
                 % (distroseries.distribution.name, archive.distribution.name))
 
+        if channel is not None:
+            if sourcepackagerelease.format == SourcePackageType.DPKG:
+                raise AssertionError(
+                    "Can't publish dpkg source packages to a channel")
+            if pocket != PackagePublishingPocket.RELEASE:
+                raise AssertionError(
+                    "Channel publications must be in the RELEASE pocket")
+            channel = channel_string_to_list(channel)
+
         pub = SourcePackagePublishingHistory(
             distroseries=distroseries,
             pocket=pocket,
@@ -1261,7 +1305,8 @@ class PublishingSet:
             ancestor=ancestor,
             creator=creator,
             sponsor=sponsor,
-            packageupload=packageupload)
+            packageupload=packageupload,
+            _channel=channel)
         DistributionSourcePackage.ensure(pub)
 
         if create_dsd_job and archive == distroseries.main_archive:
diff --git a/lib/lp/soyuz/tests/test_publishing.py b/lib/lp/soyuz/tests/test_publishing.py
index 41cdf25..7d91f43 100644
--- a/lib/lp/soyuz/tests/test_publishing.py
+++ b/lib/lp/soyuz/tests/test_publishing.py
@@ -36,6 +36,7 @@ from lp.registry.interfaces.sourcepackage import (
     SourcePackageUrgency,
     )
 from lp.registry.interfaces.sourcepackagename import ISourcePackageNameSet
+from lp.services.channels import channel_string_to_list
 from lp.services.config import config
 from lp.services.database.constants import UTC_NOW
 from lp.services.librarian.interfaces import ILibraryFileAliasSet
@@ -212,7 +213,8 @@ class SoyuzTestPublisher:
                      build_conflicts_indep=None,
                      dsc_maintainer_rfc822='Foo Bar <[e-mail]>',
                      maintainer=None, creator=None, date_uploaded=UTC_NOW,
-                     spr_only=False, user_defined_fields=None):
+                     spr_only=False, user_defined_fields=None,
+                     format=SourcePackageType.DPKG, channel=None):
         """Return a mock source publishing record.
 
         if spr_only is specified, the source is not published and the
@@ -238,7 +240,7 @@ class SoyuzTestPublisher:
 
         spr = distroseries.createUploadedSourcePackageRelease(
             sourcepackagename=spn,
-            format=SourcePackageType.DPKG,
+            format=format,
             maintainer=maintainer,
             creator=creator,
             component=component,
@@ -289,6 +291,8 @@ class SoyuzTestPublisher:
             datepublished = UTC_NOW
         else:
             datepublished = None
+        if channel is not None:
+            channel = channel_string_to_list(channel)
 
         spph = SourcePackagePublishingHistory(
             distroseries=distroseries,
@@ -304,7 +308,8 @@ class SoyuzTestPublisher:
             scheduleddeletiondate=scheduleddeletiondate,
             pocket=pocket,
             archive=archive,
-            creator=creator)
+            creator=creator,
+            _channel=channel)
 
         return spph
 
@@ -328,7 +333,8 @@ class SoyuzTestPublisher:
                        builder=None,
                        component='main',
                        phased_update_percentage=None,
-                       with_debug=False, user_defined_fields=None):
+                       with_debug=False, user_defined_fields=None,
+                       channel=None):
         """Return a list of binary publishing records."""
         if distroseries is None:
             distroseries = self.distroseries
@@ -366,7 +372,7 @@ class SoyuzTestPublisher:
                 pub_binaries += self.publishBinaryInArchive(
                     binarypackagerelease_ddeb, archive, status,
                     pocket, scheduleddeletiondate, dateremoved,
-                    phased_update_percentage)
+                    phased_update_percentage, channel=channel)
             else:
                 binarypackagerelease_ddeb = None
 
@@ -378,7 +384,8 @@ class SoyuzTestPublisher:
                 user_defined_fields=user_defined_fields)
             pub_binaries += self.publishBinaryInArchive(
                 binarypackagerelease, archive, status, pocket,
-                scheduleddeletiondate, dateremoved, phased_update_percentage)
+                scheduleddeletiondate, dateremoved, phased_update_percentage,
+                channel=channel)
             published_binaries.extend(pub_binaries)
             package_upload = self.addPackageUpload(
                 archive, distroseries, pocket,
@@ -476,7 +483,7 @@ class SoyuzTestPublisher:
         status=PackagePublishingStatus.PENDING,
         pocket=PackagePublishingPocket.RELEASE,
         scheduleddeletiondate=None, dateremoved=None,
-        phased_update_percentage=None):
+        phased_update_percentage=None, channel=None):
         """Return the corresponding BinaryPackagePublishingHistory."""
         distroarchseries = binarypackagerelease.build.distro_arch_series
 
@@ -485,6 +492,8 @@ class SoyuzTestPublisher:
             archs = [distroarchseries]
         else:
             archs = distroarchseries.distroseries.architectures
+        if channel is not None:
+            channel = channel_string_to_list(channel)
 
         pub_binaries = []
         for arch in archs:
@@ -502,7 +511,8 @@ class SoyuzTestPublisher:
                 datecreated=UTC_NOW,
                 pocket=pocket,
                 archive=archive,
-                phased_update_percentage=phased_update_percentage)
+                phased_update_percentage=phased_update_percentage,
+                _channel=channel)
             if status == PackagePublishingStatus.PUBLISHED:
                 pub.datepublished = UTC_NOW
             pub_binaries.append(pub)
@@ -1583,19 +1593,24 @@ class TestPublishBinaries(TestCaseWithFactory):
 
     layer = LaunchpadZopelessLayer
 
-    def makeArgs(self, bprs, distroseries, archive=None):
+    def makeArgs(self, bprs, distroseries, archive=None, channel=None):
         """Create a dict of arguments for publishBinaries."""
         if archive is None:
             archive = distroseries.main_archive
-        return {
+        args = {
             'archive': archive,
             'distroseries': distroseries,
-            'pocket': PackagePublishingPocket.BACKPORTS,
+            'pocket': (
+                PackagePublishingPocket.BACKPORTS if channel is None
+                else PackagePublishingPocket.RELEASE),
             'binaries': {
                 bpr: (self.factory.makeComponent(),
                  self.factory.makeSection(),
                  PackagePublishingPriority.REQUIRED, 50) for bpr in bprs},
             }
+        if channel is not None:
+            args['channel'] = channel
+        return args
 
     def test_architecture_dependent(self):
         # Architecture-dependent binaries get created as PENDING in the
@@ -1614,8 +1629,8 @@ class TestPublishBinaries(TestCaseWithFactory):
         overrides = args['binaries'][bpr]
         self.assertEqual(bpr, bpph.binarypackagerelease)
         self.assertEqual(
-            (args['archive'], target_das, args['pocket']),
-            (bpph.archive, bpph.distroarchseries, bpph.pocket))
+            (args['archive'], target_das, args['pocket'], None),
+            (bpph.archive, bpph.distroarchseries, bpph.pocket, bpph.channel))
         self.assertEqual(
             overrides,
             (bpph.component, bpph.section, bpph.priority,
@@ -1670,30 +1685,59 @@ class TestPublishBinaries(TestCaseWithFactory):
         args['pocket'] = PackagePublishingPocket.RELEASE
         [another_bpph] = getUtility(IPublishingSet).publishBinaries(**args)
 
+    def test_channel(self):
+        bpr = self.factory.makeBinaryPackageRelease(
+            binpackageformat=BinaryPackageFormat.WHL)
+        target_das = self.factory.makeDistroArchSeries()
+        args = self.makeArgs([bpr], target_das.distroseries, channel="stable")
+        [bpph] = getUtility(IPublishingSet).publishBinaries(**args)
+        self.assertEqual(bpr, bpph.binarypackagerelease)
+        self.assertEqual(
+            (args["archive"], target_das, args["pocket"], args["channel"]),
+            (bpph.archive, bpph.distroarchseries, bpph.pocket, bpph.channel))
+        self.assertEqual(PackagePublishingStatus.PENDING, bpph.status)
+
+    def test_does_not_duplicate_by_channel(self):
+        bpr = self.factory.makeBinaryPackageRelease(
+            binpackageformat=BinaryPackageFormat.WHL)
+        target_das = self.factory.makeDistroArchSeries()
+        args = self.makeArgs([bpr], target_das.distroseries, channel="stable")
+        [bpph] = getUtility(IPublishingSet).publishBinaries(**args)
+        self.assertContentEqual(
+            [], getUtility(IPublishingSet).publishBinaries(**args))
+        args["channel"] = "edge"
+        [another_bpph] = getUtility(IPublishingSet).publishBinaries(**args)
+
 
 class TestChangeOverride(TestNativePublishingBase):
     """Test that changing overrides works."""
 
     def setUpOverride(self, status=SeriesStatus.DEVELOPMENT,
-                      pocket=PackagePublishingPocket.RELEASE, binary=False,
-                      ddeb=False, **kwargs):
+                      pocket=PackagePublishingPocket.RELEASE, channel=None,
+                      binary=False, format=None, ddeb=False, **kwargs):
         self.distroseries.status = status
+        get_pub_kwargs = {"pocket": pocket, "channel": channel}
+        if format is not None:
+            get_pub_kwargs["format"] = format
         if ddeb:
-            pub = self.getPubBinaries(pocket=pocket, with_debug=True)[2]
+            pub = self.getPubBinaries(with_debug=True, **get_pub_kwargs)[2]
             self.assertEqual(
                 BinaryPackageFormat.DDEB,
                 pub.binarypackagerelease.binpackageformat)
         elif binary:
-            pub = self.getPubBinaries(pocket=pocket)[0]
+            pub = self.getPubBinaries(**get_pub_kwargs)[0]
         else:
-            pub = self.getPubSource(pocket=pocket)
+            pub = self.getPubSource(**get_pub_kwargs)
         return pub.changeOverride(**kwargs)
 
     def assertCanOverride(self, status=SeriesStatus.DEVELOPMENT,
-                          pocket=PackagePublishingPocket.RELEASE, **kwargs):
-        new_pub = self.setUpOverride(status=status, pocket=pocket, **kwargs)
+                          pocket=PackagePublishingPocket.RELEASE, channel=None,
+                          **kwargs):
+        new_pub = self.setUpOverride(
+            status=status, pocket=pocket, channel=channel, **kwargs)
         self.assertEqual(new_pub.status, PackagePublishingStatus.PENDING)
         self.assertEqual(new_pub.pocket, pocket)
+        self.assertEqual(new_pub.channel, channel)
         if "new_component" in kwargs:
             self.assertEqual(kwargs["new_component"], new_pub.component.name)
         if "new_section" in kwargs:
@@ -1784,6 +1828,12 @@ class TestChangeOverride(TestNativePublishingBase):
         self.assertCannotOverride(new_component="partner")
         self.assertCannotOverride(binary=True, new_component="partner")
 
+    def test_preserves_channel(self):
+        self.assertCanOverride(
+            binary=True, format=BinaryPackageFormat.WHL, channel="stable",
+            new_component="universe", new_section="misc", new_priority="extra",
+            new_phased_update_percentage=90)
+
 
 class TestPublishingHistoryView(TestCaseWithFactory):
     layer = LaunchpadFunctionalLayer
diff --git a/lib/lp/testing/factory.py b/lib/lp/testing/factory.py
index 89925b6..29c6059 100644
--- a/lib/lp/testing/factory.py
+++ b/lib/lp/testing/factory.py
@@ -4029,6 +4029,7 @@ class BareLaunchpadObjectFactory(ObjectFactory):
                                            creator=None,
                                            packageupload=None,
                                            spr_creator=None,
+                                           channel=None,
                                            **kwargs):
         """Make a `SourcePackagePublishingHistory`.
 
@@ -4050,6 +4051,7 @@ class BareLaunchpadObjectFactory(ObjectFactory):
             is scheduled to be removed.
         :param ancestor: The publication ancestor parameter.
         :param creator: The publication creator.
+        :param channel: An optional channel to publish into, as a string.
         :param **kwargs: All other parameters are passed through to the
             makeSourcePackageRelease call if needed.
         """
@@ -4087,7 +4089,7 @@ class BareLaunchpadObjectFactory(ObjectFactory):
                 archive, sourcepackagerelease, distroseries,
                 sourcepackagerelease.component, sourcepackagerelease.section,
                 pocket, ancestor=ancestor, creator=creator,
-                packageupload=packageupload)
+                packageupload=packageupload, channel=channel)
 
         naked_spph = removeSecurityProxy(spph)
         naked_spph.status = status
@@ -4113,7 +4115,7 @@ class BareLaunchpadObjectFactory(ObjectFactory):
                                            version=None,
                                            architecturespecific=False,
                                            with_debug=False, with_file=False,
-                                           creator=None):
+                                           creator=None, channel=None):
         """Make a `BinaryPackagePublishingHistory`."""
         if distroarchseries is None:
             if archive is None:
@@ -4144,7 +4146,10 @@ class BareLaunchpadObjectFactory(ObjectFactory):
         if priority is None:
             priority = PackagePublishingPriority.OPTIONAL
         if binpackageformat is None:
-            binpackageformat = BinaryPackageFormat.DEB
+            if binarypackagerelease is not None:
+                binpackageformat = binarypackagerelease.binpackageformat
+            else:
+                binpackageformat = BinaryPackageFormat.DEB
 
         if binarypackagerelease is None:
             # Create a new BinaryPackageBuild and BinaryPackageRelease
@@ -4182,7 +4187,8 @@ class BareLaunchpadObjectFactory(ObjectFactory):
             archive, distroarchseries.distroseries, pocket,
             {binarypackagerelease: (
                 binarypackagerelease.component, binarypackagerelease.section,
-                priority, None)})
+                priority, None)},
+            channel=channel)
         for bpph in bpphs:
             naked_bpph = removeSecurityProxy(bpph)
             naked_bpph.status = status
@@ -4256,7 +4262,7 @@ class BareLaunchpadObjectFactory(ObjectFactory):
             libraryfile=library_file, filetype=filetype))
 
     def makeBinaryPackageRelease(self, binarypackagename=None,
-                                 version=None, build=None,
+                                 version=None, build=None, ci_build=None,
                                  binpackageformat=None, component=None,
                                  section_name=None, priority=None,
                                  architecturespecific=False,
@@ -4270,22 +4276,27 @@ class BareLaunchpadObjectFactory(ObjectFactory):
                                  date_created=None, debug_package=None,
                                  homepage=None):
         """Make a `BinaryPackageRelease`."""
-        if build is None:
+        if build is None and ci_build is None:
             build = self.makeBinaryPackageBuild()
         if binarypackagename is None or isinstance(binarypackagename, str):
             binarypackagename = self.getOrMakeBinaryPackageName(
                 binarypackagename)
-        if version is None:
+        if version is None and build is not None:
             version = build.source_package_release.version
         if binpackageformat is None:
             binpackageformat = BinaryPackageFormat.DEB
-        if component is None:
+        if component is None and build is not None:
             component = build.source_package_release.component
         elif isinstance(component, str):
             component = getUtility(IComponentSet)[component]
         if isinstance(section_name, str):
             section_name = self.makeSection(section_name)
-        section = section_name or build.source_package_release.section
+        if section_name is not None:
+            section = section_name
+        elif build is not None:
+            section = build.source_package_release.section
+        else:
+            section = None
         if priority is None:
             priority = PackagePublishingPriority.OPTIONAL
         if summary is None:
@@ -4294,18 +4305,35 @@ class BareLaunchpadObjectFactory(ObjectFactory):
             description = self.getUniqueString("description")
         if installed_size is None:
             installed_size = self.getUniqueInteger()
-        bpr = build.createBinaryPackageRelease(
-                binarypackagename=binarypackagename, version=version,
-                binpackageformat=binpackageformat,
-                component=component, section=section, priority=priority,
-                summary=summary, description=description,
-                architecturespecific=architecturespecific,
-                shlibdeps=shlibdeps, depends=depends, recommends=recommends,
-                suggests=suggests, conflicts=conflicts, replaces=replaces,
-                provides=provides, pre_depends=pre_depends,
-                enhances=enhances, breaks=breaks, essential=essential,
-                installedsize=installed_size, debug_package=debug_package,
-                homepage=homepage)
+        kwargs = {
+            "binarypackagename": binarypackagename,
+            "version": version,
+            "binpackageformat": binpackageformat,
+            "summary": summary,
+            "description": description,
+            "architecturespecific": architecturespecific,
+            "installedsize": installed_size,
+            "homepage": homepage,
+            }
+        if build is not None:
+            kwargs.update({
+                "component": component,
+                "section": section,
+                "priority": priority,
+                "shlibdeps": shlibdeps,
+                "depends": depends,
+                "recommends": recommends,
+                "suggests": suggests,
+                "conflicts": conflicts,
+                "replaces": replaces,
+                "provides": provides,
+                "pre_depends": pre_depends,
+                "enhances": enhances,
+                "breaks": breaks,
+                "essential": essential,
+                "debug_package": debug_package,
+                })
+        bpr = (build or ci_build).createBinaryPackageRelease(**kwargs)
         if date_created is not None:
             removeSecurityProxy(bpr).datecreated = date_created
         return bpr