rhodecode/tests/vcs/test_hg_vcsserver_cache_invalidation.py

# -*- coding: utf-8 -*-

# Copyright (C) 2016-2017 RhodeCode GmbH
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License, version 3
# (only), as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# This program is dual-licensed. If you wish to learn more about the
# RhodeCode Enterprise Edition, including its added features, Support services,
# and proprietary license terms, please see https://rhodecode.com/licenses/

import pytest

from mock import call, patch

from rhodecode.lib.vcs.backends.base import Reference


class TestMercurialRemoteRepoInvalidation(object):
    """
    If the VCSServer is running with multiple processes or/and instances.
    Operations on repositories are potentially handled by different processes
    in a random fashion. The mercurial repository objects used in the VCSServer
    are caching the commits of the repo. Therefore we have to invalidate the
    VCSServer caching of these objects after a writing operation.
    """

    # Default reference used as a dummy during tests.
    default_ref = Reference('branch', 'default', None)

    # Methods of vcsserver.hg.HgRemote that are "writing" operations.
    writing_methods = [
        'bookmark',
        'commit',
        'merge',
        'pull',
        'pull_cmd',
        'rebase',
        'strip',
        'tag',
    ]

    @pytest.mark.parametrize('method_name, method_args', [
        ('_local_merge', [default_ref, None, None, None, default_ref]),
        ('_local_pull', ['', default_ref]),
        ('bookmark', [None]),
        ('pull', ['', default_ref]),
        ('remove_tag', ['mytag', None]),
        ('strip', [None]),
        ('tag', ['newtag', None]),
    ])
    def test_method_invokes_invalidate_on_remote_repo(
            self, method_name, method_args, backend_hg):
        """
        Check that the listed methods are invalidating the VCSServer cache
        after invoking a writing method of their remote repository object.
        """
        tags = {'mytag': 'mytag-id'}

        def add_tag(name, raw_id, *args, **kwds):
            tags[name] = raw_id

        repo = backend_hg.repo.scm_instance()
        with patch.object(repo, '_remote') as remote:
            remote.lookup.return_value = ('commit-id', 'commit-idx')
            remote.tags.return_value = tags
            remote._get_tags.return_value = tags
            remote.tag.side_effect = add_tag

            # Invoke method.
            method = getattr(repo, method_name)
            method(*method_args)

            # Assert that every "writing" method is followed by an invocation
            # of the cache invalidation method.
            for counter, method_call in enumerate(remote.method_calls):
                call_name = method_call[0]
                if call_name in self.writing_methods:
                    next_call = remote.method_calls[counter + 1]
                    assert next_call == call.invalidate_vcs_cache()

    def _prepare_shadow_repo(self, pull_request):
        """
        Helper that creates a shadow repo that can be used to reproduce the
        CommitDoesNotExistError when pulling in from target and source
        references.
        """
        from rhodecode.model.pull_request import PullRequestModel

        target_vcs = pull_request.target_repo.scm_instance()
        target_ref = pull_request.target_ref_parts
        source_ref = pull_request.source_ref_parts

        # Create shadow repository.
        pr = PullRequestModel()
        workspace_id = pr._workspace_id(pull_request)
        shadow_repository_path = target_vcs._maybe_prepare_merge_workspace(
            workspace_id, target_ref)
        shadow_repo = target_vcs._get_shadow_instance(shadow_repository_path)

        # This will populate the cache of the mercurial repository object
        # inside of the VCSServer.
        shadow_repo.get_commit()

        return shadow_repo, source_ref, target_ref

    @pytest.mark.backends('hg')
    def test_commit_does_not_exist_error_happens(self, pr_util, app):
        """
        This test is somewhat special. It does not really test the system
        instead it is more or less a precondition for the
        "test_commit_does_not_exist_error_does_not_happen". It deactivates the
        cache invalidation and asserts that the error occurs.
        """
        from rhodecode.lib.vcs.exceptions import CommitDoesNotExistError

        pull_request = pr_util.create_pull_request()
        target_vcs = pull_request.target_repo.scm_instance()
        source_vcs = pull_request.source_repo.scm_instance()
        shadow_repo, source_ref, target_ref = self._prepare_shadow_repo(
            pull_request)

        # Pull from target and source references but without invalidation of
        # RemoteRepo objects and without VCSServer caching of mercurial
        # repository objects.
        with patch.object(shadow_repo._remote, 'invalidate_vcs_cache'):
            # NOTE: Do not use patch.dict() to disable the cache because it
            # restores the WHOLE dict and not only the patched keys.
            shadow_repo._remote._wire['cache'] = False
            shadow_repo._local_pull(target_vcs.path, target_ref)
            shadow_repo._local_pull(source_vcs.path, source_ref)
            shadow_repo._remote._wire.pop('cache')

        # Try to lookup the target_ref in shadow repo. This should work because
        # the shadow repo is a clone of the target and always contains all off
        # it's commits in the initial cache.
        shadow_repo.get_commit(target_ref.commit_id)

        # If we try to lookup the source_ref it should fail because the shadow
        # repo commit cache doesn't get invalidated. (Due to patched
        # invalidation and caching above).
        with pytest.raises(CommitDoesNotExistError):
            shadow_repo.get_commit(source_ref.commit_id)

    @pytest.mark.backends('hg')
    def test_commit_does_not_exist_error_does_not_happen(self, pr_util, app):
        """
        This test simulates a pull request merge in which the pull operations
        are handled by a different VCSServer process than all other operations.
        Without correct cache invalidation this leads to an error when
        retrieving the pulled commits afterwards.
        """

        pull_request = pr_util.create_pull_request()
        target_vcs = pull_request.target_repo.scm_instance()
        source_vcs = pull_request.source_repo.scm_instance()
        shadow_repo, source_ref, target_ref = self._prepare_shadow_repo(
            pull_request)

        # Pull from target and source references without without VCSServer
        # caching of mercurial repository objects but with active invalidation
        # of RemoteRepo objects.
        # NOTE: Do not use patch.dict() to disable the cache because it
        # restores the WHOLE dict and not only the patched keys.
        shadow_repo._remote._wire['cache'] = False
        shadow_repo._local_pull(target_vcs.path, target_ref)
        shadow_repo._local_pull(source_vcs.path, source_ref)
        shadow_repo._remote._wire.pop('cache')

        # Try to lookup the target and source references in shadow repo. This
        # should work because the RemoteRepo object gets invalidated during the
        # above pull operations.
        shadow_repo.get_commit(target_ref.commit_id)
        shadow_repo.get_commit(source_ref.commit_id)