pes_events_scanner: ensure user's to_remove is reflected

Previously, pes_events_scanner used transaction configuration to
only modify the way it initializes event application. As a consequence,
if a user specified to_remove=['pkg'], then the information would
not make it to pes_events_scanner's output. This patch adds a
post-processing to explicitly add transaction configuration to the
result of applying PES events.

repos/system_upgrade/common/actors/peseventsscanner/libraries/pes_events_scanner.py

@@ -470,9 +470,8 @@ def replace_pesids_with_repoids_in_packages(packages, source_pkgs_repoids):
     return packages_with_repoid.union(packages_without_pesid)
 
 
-def apply_transaction_configuration(source_pkgs):
+def apply_transaction_configuration(source_pkgs, transaction_configuration):
     source_pkgs_with_conf_applied = set(source_pkgs)
-    transaction_configuration = get_transaction_configuration()
 
     source_pkgs_with_conf_applied = source_pkgs.union(transaction_configuration.to_install)
 
@@ -504,38 +503,64 @@ def remove_leapp_related_events(events):
     return res
 
 
+def include_to_remove_from_transaction_configuration(rpm_tasks, transaction_configuration, installed_pkgs):
+    """ Extend rpm_tasks.to_remove with packages from transaction_configuration.to_remove """
+    # We don't want to try removing packages that are not installed
+    installed_pkgs_requested_to_be_removed = transaction_configuration.to_remove.intersection(installed_pkgs)
+    pkgs_names_to_extend_to_remove_with = [pkg.name for pkg in installed_pkgs_requested_to_be_removed]
+
+    if not installed_pkgs_requested_to_be_removed:
+        return rpm_tasks
+
+    if not rpm_tasks:
+        return PESRpmTransactionTasks(to_install=[],
+                                      to_remove=sorted(pkgs_names_to_extend_to_remove_with),
+                                      modules_to_enable=[],
+                                      modules_to_reset=[])
+
+    new_to_remove_list = sorted(set(rpm_tasks.to_remove).union(pkgs_names_to_extend_to_remove_with))
+    return PESRpmTransactionTasks(to_install=rpm_tasks.to_install,
+                                  to_remove=new_to_remove_list,
+                                  modules_to_enable=rpm_tasks.modules_to_enable,
+                                  modules_to_reset=rpm_tasks.modules_to_reset)
+
+
 def process():
     # Retrieve data - installed_pkgs, transaction configuration, pes events
     events = get_pes_events('/etc/leapp/files', 'pes-events.json')
     if not events:
         return
 
     releases = get_relevant_releases(events)
-    source_pkgs = get_installed_pkgs()
-    source_pkgs = apply_transaction_configuration(source_pkgs)
+    installed_pkgs = get_installed_pkgs()
+    transaction_configuration = get_transaction_configuration()
+    pkgs_to_begin_computation_with = apply_transaction_configuration(installed_pkgs, transaction_configuration)
 
     # Keep track of what repoids have the source packages to be able to determine what are the PESIDs of the computed
     # packages of the target system, so we can distinguish what needs to be repomapped
-    repoids_of_source_pkgs = {pkg.repository for pkg in source_pkgs}
+    repoids_of_source_pkgs = {pkg.repository for pkg in pkgs_to_begin_computation_with}
 
     events = remove_leapp_related_events(events)
     events = remove_undesired_events(events, releases)
 
     # Apply events - compute what packages should the target system have
-    target_pkgs, pkgs_to_demodularize = compute_packages_on_target_system(source_pkgs, events, releases)
+    target_pkgs, pkgs_to_demodularize = compute_packages_on_target_system(pkgs_to_begin_computation_with,
+                                                                          events, releases)
 
     # Packages coming out of the events have PESID as their repository, however, we need real repoid
     target_pkgs = replace_pesids_with_repoids_in_packages(target_pkgs, repoids_of_source_pkgs)
 
     # Apply the desired repository blacklisting
-    blacklisted_repoids, target_pkgs = remove_new_packages_from_blacklisted_repos(source_pkgs, target_pkgs)
+    blacklisted_repoids, target_pkgs = remove_new_packages_from_blacklisted_repos(pkgs_to_begin_computation_with,
+                                                                                  target_pkgs)
 
     # Look at the target packages and determine what repositories to enable
     target_repoids = sorted(set(p.repository for p in target_pkgs) - blacklisted_repoids - repoids_of_source_pkgs)
     repos_to_enable = RepositoriesSetupTasks(to_enable=target_repoids)
     api.produce(repos_to_enable)
 
     # Compare the packages on source system and the computed packages on target system and determine what to install
-    rpm_tasks = compute_rpm_tasks_from_pkg_set_diff(source_pkgs, target_pkgs, pkgs_to_demodularize)
+    rpm_tasks = compute_rpm_tasks_from_pkg_set_diff(pkgs_to_begin_computation_with, target_pkgs, pkgs_to_demodularize)
+    rpm_tasks = include_to_remove_from_transaction_configuration(rpm_tasks, transaction_configuration, installed_pkgs)
     if rpm_tasks:
         api.produce(rpm_tasks)

repos/system_upgrade/common/actors/peseventsscanner/tests/test_pes_event_scanner.py

@@ -284,17 +284,14 @@ def test_actor_performs(monkeypatch):
 def test_transaction_configuration_has_effect(monkeypatch):
     _Pkg = partial(Package, repository=None, modulestream=None)
 
-    def mocked_transaction_conf():
-        return TransactionConfiguration(
-            to_install=[_Pkg('pkg-a'), _Pkg('pkg-b')],
-            to_remove=[_Pkg('pkg-c'), _Pkg('pkg-d')],
-            to_keep=[]
-        )
-
-    monkeypatch.setattr(pes_events_scanner, 'get_transaction_configuration', mocked_transaction_conf)
+    transaction_cfg = TransactionConfiguration(
+        to_install=[_Pkg('pkg-a'), _Pkg('pkg-b')],
+        to_remove=[_Pkg('pkg-c'), _Pkg('pkg-d')],
+        to_keep=[]
+    )
 
     packages = {_Pkg('pkg-a'), _Pkg('pkg-c')}
-    _result = pes_events_scanner.apply_transaction_configuration(packages)
+    _result = pes_events_scanner.apply_transaction_configuration(packages, transaction_cfg)
     result = {(p.name, p.repository, p.modulestream) for p in _result}
     expected = {('pkg-a', None, None), ('pkg-b', None, None)}
 
@@ -338,7 +335,7 @@ def test_blacklisted_repoid_is_not_produced(monkeypatch):
 
     monkeypatch.setattr(pes_events_scanner, 'get_installed_pkgs', lambda: installed_pkgs)
     monkeypatch.setattr(pes_events_scanner, 'get_pes_events', lambda folder, filename: events)
-    monkeypatch.setattr(pes_events_scanner, 'apply_transaction_configuration', lambda pkgs: pkgs)
+    monkeypatch.setattr(pes_events_scanner, 'apply_transaction_configuration', lambda pkgs, transaction_cfg: pkgs)
     monkeypatch.setattr(pes_events_scanner, 'get_blacklisted_repoids', lambda: {'blacklisted-rhel8'})
     monkeypatch.setattr(pes_events_scanner, 'replace_pesids_with_repoids_in_packages',
                         lambda pkgs, src_pkgs_repoids: pkgs)
@@ -479,6 +476,7 @@ def test_transaction_configuration_is_applied(monkeypatch):
     installed_pkgs = {
          Package(name='moved-in', repository='rhel7-base', modulestream=None),
          Package(name='split-in', repository='rhel7-base', modulestream=None),
+         Package(name='pkg-not-in-events', repository='rhel7-base', modulestream=None),
     }
     monkeypatch.setattr(pes_events_scanner, 'get_installed_pkgs', lambda *args, **kwags: installed_pkgs)
 
@@ -504,7 +502,9 @@ def test_transaction_configuration_is_applied(monkeypatch):
 
     msgs = [
         RpmTransactionTasks(to_remove=['split-in', 'split-in']),
-        RpmTransactionTasks(to_remove=['split-in'])
+        RpmTransactionTasks(to_remove=['split-in']),
+        RpmTransactionTasks(to_remove=['pkg-not-in-events']),
+        RpmTransactionTasks(to_remove=['pkg-not-in-events', 'pkg-not-in-events']),
     ]
     mocked_actor = CurrentActorMocked(arch='x86_64', src_ver='7.9', dst_ver='8.8', msgs=msgs)
     monkeypatch.setattr(api, 'current_actor', mocked_actor)
@@ -521,4 +521,5 @@ def test_transaction_configuration_is_applied(monkeypatch):
 
     assert len(produced_rpm_transaction_tasks) == 1
     rpm_transaction_tasks = produced_rpm_transaction_tasks[0]
-    assert sorted(rpm_transaction_tasks.to_remove) == ['moved-in', 'split-in']
+    # It is important to see 'pkg-not-in-events' in the list - if the user says remove pkg A, we really remove it
+    assert sorted(rpm_transaction_tasks.to_remove) == ['moved-in', 'pkg-not-in-events', 'split-in']