Add a second goal for second resolving in case of unavailable packages

An unavailable package is not a critical error, therefore, it's reported
only as a warning and it may be skipped.

One option would be to check all the specs before adding them to goal,
but that seems more error-prone.

The other option, which was chosen in this commit, is to resolve
the selection (up to) two times, the second time with skip_unavailable
set to True. It is not possible to resolve the same goal twice with
different settings, therefore, another goal is created and the specs are
added to both.

The tests are updated to match the behavior (no warnings with
sip_unavailable, warnings and not errors without skip_unavailable).

pyanaconda/modules/payloads/payload/dnf/dnf_manager.py

@@ -35,6 +35,7 @@
     URL_TYPE_METALINK,
     URL_TYPE_MIRRORLIST,
 )
+from pyanaconda.core.i18n import _
 from pyanaconda.core.path import join_paths
 from pyanaconda.core.payload import ProxyString, ProxyStringError
 from pyanaconda.core.util import get_os_release_value
@@ -94,6 +95,7 @@ class DNFManager:
     def __init__(self):
         self.__base = None
         self.__goal = None
+        self.__goal_skip_unavailable = None
 
         # Protect access to _base.repos to ensure that the dictionary is not
         # modified while another thread is attempting to iterate over it. The
@@ -127,6 +129,14 @@ def _goal(self):
 
         return self.__goal
 
+    @property
+    def _goal_skip_unavailable(self):
+        """The DNF goal that will be used if there are unavailable packages."""
+        if self.__goal_skip_unavailable is None:
+            self.__goal_skip_unavailable = libdnf5.base.Goal(self._base)
+
+        return self.__goal_skip_unavailable
+
     @classmethod
     def _create_base(cls):
         """Create a new DNF base."""
@@ -189,6 +199,7 @@ def reset_base(self):
         """
         self.__base = None
         self.__goal = None
+        self.__goal_skip_unavailable = None
         self._transaction = None
         self._ignore_missing_packages = False
         self._ignore_broken_packages = False
@@ -589,6 +600,7 @@ def apply_specs(self, include_list, exclude_list):
         log.info("Including specs: %s", include_list)
         for spec in include_list:
             self._goal.add_install(spec)
+            self._goal_skip_unavailable.add_install(spec)
 
         log.info("Excluding specs: %s", exclude_list)
         # FIXME: Make the excludes work also for groups. Right now, only packages are excluded.
@@ -603,12 +615,27 @@ def resolve_selection(self):
         log.debug("Resolving the software selection.")
         self._transaction = self._goal.resolve()
 
+        if (self._transaction.get_problems() != libdnf5.base.GoalProblem_NO_PROBLEM and \
+            self._transaction.get_problems() == libdnf5.base.GoalProblem_NOT_FOUND):
+            # There is only a problem with specs that were not found, which is not critical
+            # -> put the logs into the warning_messages, so that user can decide to continue
+            # with the transaction anyway, and resolve it again with skip_unavailable.
+            for message in self._transaction.get_resolve_logs_as_strings():
+                report.warning_messages.append(message)
+            if not self._base.get_config().skip_unavailable:
+                # Temporarily set skip_unavailable to True, resolve, and set it back
+                self._base.get_config().skip_unavailable = True
+                self._transaction = self._goal_skip_unavailable.resolve()
+                self._base.get_config().skip_unavailable = False
+
         if self._transaction.get_problems() != libdnf5.base.GoalProblem_NO_PROBLEM:
+            # There are critical errors -> put the logs into the error_messages.
+            report.error_messages.append(_(
+                "The following software marked for installation has errors.\n"
+                "This is likely caused by an error with your installation source.\n\n"
+            ))
             for message in self._transaction.get_resolve_logs_as_strings():
                 report.error_messages.append(message)
-        else:
-            for message in self._transaction.get_resolve_logs_as_strings():
-                report.warning_messages.append(message)
 
         if report.is_valid():
             log.info("The software selection has been resolved (%d packages selected).",

tests/unit_tests/pyanaconda_tests/modules/payloads/payload/test_module_payload_dnf5_manager.py

@@ -322,11 +322,11 @@ def test_resolve_missing_selection(self):
         )
 
         report = self.dnf_manager.resolve_selection()
-        assert report.error_messages == [
+        assert report.error_messages == []
+        assert report.warning_messages == [
             'No match for argument: p1',
             'No match for argument: g1',
         ]
-        assert report.warning_messages == []
 
     def test_ignore_missing_packages(self):
         """Test the ignore_missing_packages attribute."""
@@ -343,10 +343,7 @@ def test_ignore_missing_packages(self):
         report = self.dnf_manager.resolve_selection()
 
         assert report.error_messages == []
-        assert report.warning_messages == [
-            'No match for argument: p1',
-            'No match for argument: g1',
-        ]
+        assert report.warning_messages == []
 
     @pytest.mark.skip("Not implemented")
     def test_ignore_broken_packages(self):