Create a MigrationItemFactory and migrate most code to use it

This is a step towards making migration unit-testable.  This step
reduces the need for global state (in the MigrationItem class as class
fields) and with another step we can remove the global state entirely
and enable unit tests to create migration items without having to
worry about other unit tests.

Signed-off-by: Niels Thykier <niels@thykier.net>

britney.py

@@ -200,13 +200,13 @@ from britney2.inputs.suiteloader import DebMirrorLikeSuiteContentLoader, Missing
 from britney2.installability.builder import build_installability_tester
 from britney2.installability.solver import InstallabilitySolver
 from britney2.migration import MigrationManager
-from britney2.migrationitem import MigrationItem
+from britney2.migrationitem import MigrationItem, MigrationItemFactory
 from britney2.policies import PolicyVerdict
 from britney2.policies.policy import AgePolicy, RCBugPolicy, PiupartsPolicy, BuildDependsPolicy
 from britney2.policies.autopkgtest import AutopkgtestPolicy
 from britney2.utils import (log_and_format_old_libraries, get_dependency_solvers,
                             read_nuninst, write_nuninst, write_heidi,
-                            format_and_log_uninst, newly_uninst, make_migrationitem,
+                            format_and_log_uninst, newly_uninst,
                             write_excuses, write_heidi_delta, write_controlfiles,
                             old_libraries, is_nuninst_asgood_generous,
                             clone_nuninst,
@@ -283,7 +283,6 @@ class Britney(object):
 
         # parse the command line arguments
         self.policies = []
-        self._hint_parser = HintParser()
         self.suite_info = None  # Initialized during __parse_arguments
         self.__parse_arguments()
         MigrationItem.set_architectures(self.options.architectures)
@@ -329,6 +328,8 @@ class Britney(object):
         target_suite = self.suite_info.target_suite
         target_suite.inst_tester = self._inst_tester
 
+        self._migration_item_factory = MigrationItemFactory(self.suite_info)
+        self._hint_parser = HintParser(self._migration_item_factory)
         self._migration_manager = MigrationManager(self.options, self.suite_info, self.all_binaries, self.pkg_universe,
                                                    self.constraints)
 
@@ -1442,7 +1443,8 @@ class Britney(object):
         invalidate_excuses(excuses, upgrade_me, unconsidered)
 
         # sort the list of candidates
-        self.upgrade_me = sorted(make_migrationitem(x, suite_info) for x in upgrade_me)
+        mi_factory = self._migration_item_factory
+        self.upgrade_me = sorted(mi_factory.parse_item(x, versioned=False, auto_correct=False) for x in upgrade_me)
 
         # write excuses to the output file
         if not self.options.dry_run:
@@ -1591,7 +1593,7 @@ class Britney(object):
 
         if try_removals and self.options.smooth_updates:
             self.logger.info("> Removing old packages left in the target suite from smooth updates")
-            removals = old_libraries(self.suite_info, self.options.outofsync_arches)
+            removals = old_libraries(self._migration_item_factory, self.suite_info, self.options.outofsync_arches)
             if removals:
                 output_logger.info("Removing packages left in the target suite for smooth updates (%d):", len(removals))
                 log_and_format_old_libraries(self.output_logger, removals)
@@ -1847,11 +1849,12 @@ class Britney(object):
             target_suite = self.suite_info.target_suite
             sources_t = target_suite.sources
             binaries_t = target_suite.binaries
+            mi_factory = self._migration_item_factory
             used = set(binaries_t[arch][binary].source
                        for arch in binaries_t
                        for binary in binaries_t[arch]
                        )
-            removals = [MigrationItem("-%s/%s" % (source, sources_t[source].version))
+            removals = [mi_factory.parse_item("-%s/%s" % (source, sources_t[source].version), auto_correct=False)
                         for source in sources_t if source not in used
                         ]
             if removals:
@@ -1859,14 +1862,14 @@ class Britney(object):
                 self.do_all(actions=removals)
 
         # smooth updates
-        removals = old_libraries(self.suite_info, self.options.outofsync_arches)
+        removals = old_libraries(self._migration_item_factory, self.suite_info, self.options.outofsync_arches)
         if self.options.smooth_updates:
             self.logger.info("> Removing old packages left in the target suite from smooth updates")
             if removals:
                 output_logger.info("Removing packages left in the target suite for smooth updates (%d):", len(removals))
                 log_and_format_old_libraries(self.output_logger, removals)
                 self.do_all(actions=removals)
-                removals = old_libraries(self.suite_info, self.options.outofsync_arches)
+                removals = old_libraries(self._migration_item_factory, self.suite_info, self.options.outofsync_arches)
         else:
             self.logger.info("> Not removing old packages left in the target suite from smooth updates"
                              " (smooth-updates disabled)")
@@ -1951,9 +1954,9 @@ class Britney(object):
                 break
                 # run a hint
             elif user_input and user_input[0] in ('easy', 'hint', 'force-hint'):
+                mi_factory = self._migration_item_factory
                 try:
-                    self.do_hint(user_input[0], 'hint-tester',
-                                 [k.rsplit("/", 1) for k in user_input[1:] if "/" in k])
+                    self.do_hint(user_input[0], 'hint-tester', mi_factory.parse_items(user_input[1:]))
                     self.printuninstchange()
                 except KeyboardInterrupt:
                     continue
@@ -1975,21 +1978,17 @@ class Britney(object):
         """
 
         output_logger = self.output_logger
-        if isinstance(pkgvers[0], tuple) or isinstance(pkgvers[0], list):
-            _pkgvers = [ MigrationItem('%s/%s' % (p, v)) for (p,v) in pkgvers ]
-        else:
-            _pkgvers = pkgvers
 
         suites = self.suite_info
         self.logger.info("> Processing '%s' hint from %s", hinttype, who)
         output_logger.info("Trying %s from %s: %s", hinttype, who,
-                           " ".join("%s/%s" % (x.uvname, x.version) for x in _pkgvers)
+                           " ".join("%s/%s" % (x.uvname, x.version) for x in pkgvers)
                            )
 
         issues = []
         # loop on the requested packages and versions
-        for idx in range(len(_pkgvers)):
-            pkg = _pkgvers[idx]
+        for idx in range(len(pkgvers)):
+            pkg = pkgvers[idx]
             # skip removal requests
             if pkg.is_removal:
                 continue
@@ -2003,7 +2002,7 @@ class Britney(object):
                                                                             pkg.version) == 0:
                         suite = s
                         pkg.suite = s
-                        _pkgvers[idx] = pkg
+                        pkgvers[idx] = pkg
                         break
 
             if suite.suite_class.is_additional_source:
@@ -2022,7 +2021,7 @@ class Britney(object):
             output_logger.warning("%s: Not using hint", ", ".join(issues))
             return False
 
-        self.do_all(hinttype, _pkgvers)
+        self.do_all(hinttype, pkgvers)
         return True
 
     def get_auto_hinter_hints(self, upgrade_me):
@@ -2111,9 +2110,11 @@ class Britney(object):
         return [ candidates, mincands ]
 
     def run_auto_hinter(self):
+        mi_factory = self._migration_item_factory
         for l in self.get_auto_hinter_hints(self.upgrade_me):
             for hint in l:
-                self.do_hint("easy", "autohinter", [ MigrationItem("%s/%s" % (x[0], x[1])) for x in sorted(hint) ])
+                self.do_hint("easy", "autohinter", [mi_factory.parse_item("%s/%s" % (x[0], x[1]), auto_correct=False)
+                                                    for x in sorted(hint)])
 
     def nuninst_arch_report(self, nuninst, arch):
         """Print a report of uninstallable packages for one architecture."""

britney2/hints.py

@@ -16,8 +16,6 @@ import logging
 
 from itertools import chain
 
-from britney2.migrationitem import MigrationItem
-
 
 class MalformedHintException(Exception):
     pass
@@ -57,11 +55,6 @@ class Hint(object):
         self._active = True
         self._type = hint_type
         self._packages = packages
-
-        if isinstance(self._packages, str):
-            self._packages = self._packages.split(' ')
-
-        self._packages = [MigrationItem(x) for x in self._packages]
         
         self.check()
         
@@ -122,21 +115,22 @@ class Hint(object):
             return None
 
 
-def split_into_one_hint_per_package(hints, who, hint_name, *args):
-    for package in args:
-        hints.add_hint(Hint(who, hint_name, package))
+def split_into_one_hint_per_package(mi_factory, hints, who, hint_name, *args):
+    for item in mi_factory.parse_items(*args):
+        hints.add_hint(Hint(who, hint_name, [item]))
 
 
-def single_hint_taking_list_of_packages(hints, who, hint_type, *args):
-    hints.add_hint(Hint(who, hint_type, args))
+def single_hint_taking_list_of_packages(mi_factory, hints, who, hint_type, *args):
+    hints.add_hint(Hint(who, hint_type, mi_factory.parse_items(*args)))
 
 
 class HintParser(object):
 
-    def __init__(self):
+    def __init__(self, mi_factory):
         logger_name = ".".join((self.__class__.__module__, self.__class__.__name__))
         self.logger = logging.getLogger(logger_name)
         self.hints = HintCollection()
+        self.mi_factory = mi_factory
         self._hint_table = {
             'remark': (0, lambda *x: None),
 
@@ -205,6 +199,7 @@ class HintParser(object):
         line_no = 0
         hints = self.hints
         aliases = self._aliases
+        mi_factory = self.mi_factory
         for line in lines:
             line = line.strip()
             line_no += 1
@@ -231,7 +226,7 @@ class HintParser(object):
                                     filename, line_no, min_args, len(l) - 1)
                 continue
             try:
-                hint_parser_impl(hints, who, *l)
+                hint_parser_impl(mi_factory, hints, who, *l)
             except MalformedHintException as e:
                 self.logger.warning("Malformed hint found in %s (line %d): \"%s\"", filename, line_no, e.args[0])
                 continue

britney2/migrationitem.py

@@ -12,6 +12,9 @@
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 
+import logging
+from britney2 import SuiteClass
+
 
 class MigrationItem(object):
     _architectures = []
@@ -33,7 +36,7 @@ class MigrationItem(object):
     def get_suites(cls):
         return cls._suites
 
-    def __init__(self, name=None, versionned=True):
+    def __init__(self, name=None, versionned=True, package=None, version=None, architecture=None, uvname=None, suite=None):
         self._name = None
         self._uvname = None
         self._package = None
@@ -44,6 +47,16 @@ class MigrationItem(object):
 
         if name:
             self.name = name
+        else:
+            self._uvname = uvname
+            self._package = package
+            self._version = version
+            self._architecture = architecture
+            self._suite = suite
+            if version is not None:
+                self._name = "%s/%s" % (uvname, version)
+            else:
+                self._name = uvname
 
     def __str__(self):
         if self._versionned and self.version is not None:
@@ -161,6 +174,101 @@ class MigrationItem(object):
         return self._uvname
 
 
-class UnversionnedMigrationItem(MigrationItem):
-    def __init__(self, name=None):
-        super().__init__(name=name, versionned=False)
+class MigrationItemFactory(object):
+
+    def __init__(self, suites):
+        self._suites = suites
+        self._all_architectures = frozenset(suites.target_suite.binaries)
+        logger_name = ".".join((self.__class__.__module__, self.__class__.__name__))
+        self.logger = logging.getLogger(logger_name)
+
+    def generate_removal_for_cruft_item(self, pkg_id):
+        uvname = "-%s/%s" % (pkg_id.package_name, pkg_id.architecture)
+        return MigrationItem(package=pkg_id.package_name,
+                             version=pkg_id.version,
+                             architecture=pkg_id.architecture,
+                             uvname=uvname,
+                             suite=self._suites.target_suite
+                             )
+
+    def parse_item(self, item_text, versioned=True, auto_correct=True):
+        """
+
+        :param item_text: The string describing the item (e.g. "glibc/2.5")
+        :param versioned: If true, a two-part item is assumed to be versioned.
+          otherwise, it is assumed to be versionless.  This determines how
+          items like "foo/bar" is parsed (if versioned, "bar" is assumed to
+          be a version and otherwise "bar" is assumed to be an architecture).
+          If in doubt, use versioned=True with auto_correct=True and the
+          code will figure it out on its own.
+        :param auto_correct: If True, minor issues are automatically fixed
+          where possible. This includes handling architecture and version
+          being in the wrong order and missing/omitting a suite reference
+          for items.  This feature is useful for migration items provided
+          by humans (e.g. via hints) to avoid rejecting the input over
+          trivial/minor issues with the input.
+          When False, there will be no attempt to correct the migration
+          input.
+        :return: A MigrationItem matching the spec
+        """
+        suites = self._suites
+        version = None
+        architecture = None
+        is_removal = False
+        if item_text.startswith('-'):
+            item_text = item_text[1:]
+            is_removal = True
+        parts = item_text.split('/', 3)
+        package_name = parts[0]
+        suite_name = suites.primary_source_suite.name
+        if '_' in package_name:
+            package_name, suite_name = package_name.split('_', 2)
+
+        if len(parts) == 3:
+            architecture = parts[1]
+            version = parts[2]
+        elif len(parts) == 2:
+            if versioned:
+                version = parts[1]
+            else:
+                architecture = parts[1]
+
+        if auto_correct and version in self._all_architectures:
+            (architecture, version) = (version, architecture)
+
+        if architecture is None:
+            architecture = 'source'
+
+        if '_' in architecture:
+            architecture, suite_name = architecture.split('_', 2)
+
+        if is_removal:
+            suite = suites.target_suite
+        else:
+            suite = suites.by_name_or_alias[suite_name]
+            assert suite.suite_class != SuiteClass.TARGET_SUITE
+
+        uvname = self._canonicalise_uvname(item_text, package_name, architecture, suite, is_removal)
+
+        return MigrationItem(package=package_name,
+                             version=version,
+                             architecture=architecture,
+                             uvname=uvname,
+                             suite=suite,
+                             )
+
+    def parse_items(self, *args, **kwargs):
+        return [self.parse_item(x, **kwargs) for x in args]
+
+    @staticmethod
+    def _canonicalise_uvname(item_text_sans_removal, package, architecture, suite, is_removal):
+        parts = item_text_sans_removal.split('/', 3)
+        if len(parts) == 1 or architecture == 'source':
+            uvname = package
+        else:
+            uvname = "%s/%s" % (package, architecture)
+        if suite.suite_class.is_additional_source:
+            uvname = '%s_%s' % (uvname, suite.suite_short_name)
+        if is_removal:
+            uvname = '-%s' % (uvname)
+        return uvname

britney2/policies/policy.py

@@ -135,9 +135,9 @@ class IgnoreRCBugHint(SimplePolicyHint):
 
 
 def simple_policy_hint_parser_function(class_name, converter):
-    def f(hints, who, hint_name, policy_parameter, *args):
-        for package in args:
-            hints.add_hint(class_name(who, hint_name, converter(policy_parameter), package))
+    def f(mi_factory, hints, who, hint_name, policy_parameter, *args):
+        for item in mi_factory.parse_items(*args):
+            hints.add_hint(class_name(who, hint_name, converter(policy_parameter), [item]))
     return f
 
 

britney2/utils.py

@@ -39,9 +39,9 @@ from britney2.consts import (VERSION, PROVIDES, DEPENDS, CONFLICTS,
                              ARCHITECTURE, SECTION,
                              SOURCE, MAINTAINER, MULTIARCH,
                              ESSENTIAL)
-from britney2.migrationitem import MigrationItem, UnversionnedMigrationItem
 from britney2.policies import PolicyVerdict
 
+
 class MigrationConstraintException(Exception):
     pass
 
@@ -283,17 +283,6 @@ def write_heidi_delta(filename, all_selected):
                                            item.version, item.architecture))
 
 
-def make_migrationitem(package, suite_info):
-    """Convert a textual package specification to a MigrationItem
-    
-    sources is a list of source packages in each suite, used to determine
-    the version which should be used for the MigrationItem.
-    """
-    
-    item = UnversionnedMigrationItem(package)
-    return MigrationItem("%s/%s" % (item.uvname, suite_info[item.suite.name].sources[item.package].version))
-
-
 def write_excuses(excuselist, dest_file, output_format="yaml"):
     """Write the excuses to dest_file
 
@@ -410,7 +399,7 @@ def write_controlfiles(target_suite):
     write_sources(sources_s, os.path.join(basedir, 'Sources'))
 
 
-def old_libraries(suite_info, outofsync_arches=frozenset()):
+def old_libraries(mi_factory, suite_info, outofsync_arches=frozenset()):
     """Detect old libraries left in the target suite for smooth transitions
 
     This method detects old libraries which are in the target suite but no
@@ -430,9 +419,8 @@ def old_libraries(suite_info, outofsync_arches=frozenset()):
         for pkg_name in binaries_t[arch]:
             pkg = binaries_t[arch][pkg_name]
             if sources_t[pkg.source].version != pkg.source_version and \
-                (arch not in outofsync_arches or pkg_name not in binaries_s[arch]):
-                migration = "-" + "/".join((pkg_name, arch, pkg.source_version))
-                removals.append(MigrationItem(migration))
+                    (arch not in outofsync_arches or pkg_name not in binaries_s[arch]):
+                removals.append(mi_factory.generate_removal_for_cruft_item(pkg.pkg_id))
     return removals
 
 

tests/test_hint_parser.py

@@ -2,7 +2,7 @@ import unittest
 
 from britney2 import Suite, Suites, SuiteClass
 from britney2.hints import HintParser, single_hint_taking_list_of_packages
-from britney2.migrationitem import MigrationItem
+from britney2.migrationitem import MigrationItemFactory
 
 from . import HINTS_ALL, TEST_HINTER
 
@@ -12,11 +12,9 @@ SUITES = Suites(
 )
 
 
-MigrationItem.set_suites(SUITES)
-
-
 def new_hint_parser():
-    return HintParser()
+    mi_factory = MigrationItemFactory(SUITES)
+    return HintParser(mi_factory)
 
 
 def parse_should_not_call_this_function(*args, **kwargs):

tests/test_policy.py

@@ -6,7 +6,7 @@ import unittest
 from britney2 import Suites, Suite, SuiteClass, SourcePackage, BinaryPackageId, BinaryPackage
 from britney2.excuse import Excuse
 from britney2.hints import HintParser
-from britney2.migrationitem import MigrationItem
+from britney2.migrationitem import MigrationItemFactory
 from britney2.policies.policy import AgePolicy, RCBugPolicy, PiupartsPolicy, PolicyVerdict
 from britney2.policies.autopkgtest import AutopkgtestPolicy
 
@@ -43,10 +43,10 @@ def initialize_policy(test_name, policy_class, *args, **kwargs):
         Suite(SuiteClass.TARGET_SUITE, target, os.path.join(test_dir, target), ''),
         [Suite(SuiteClass.PRIMARY_SOURCE_SUITE, 'unstable', os.path.join(test_dir, 'unstable'), '')],
     )
-    MigrationItem.set_suites(suite_info)
+    mi_factory = MigrationItemFactory(suite_info)
     policy = policy_class(options, suite_info, *args)
     fake_britney = MockObject(log=lambda x, y='I': None)
-    hint_parser = HintParser()
+    hint_parser = HintParser(mi_factory)
     policy.initialise(fake_britney)
     policy.register_hints(hint_parser)
     hint_parser.parse_hints(TEST_HINTER, HINTS_ALL, 'test-%s' % test_name, hints)