git-upstream/git_upstream/commands/import.py

646 lines
25 KiB
Python

#
# Copyright (c) 2012, 2013, 2014 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
from git_upstream.errors import GitUpstreamError
from git_upstream.log import LogDedentMixin
from git_upstream.lib.utils import GitMixin
from git_upstream.lib.rebaseeditor import RebaseEditor
from git_upstream import subcommand, log
from git_upstream.lib.searchers import UpstreamMergeBaseSearcher
from abc import ABCMeta, abstractmethod
from collections import Sequence
from git import GitCommandError
import inspect
class ImportUpstreamError(GitUpstreamError):
"""Exception thrown by L{ImportUpstream}"""
pass
class ImportUpstream(LogDedentMixin, GitMixin):
"""
Import code from an upstream project and merge in additional branches
to create a new branch unto which changes that are not upstream but are
on the local branch are applied.
"""
def __init__(self, branch=None, upstream=None, import_branch=None,
extra_branches=None, *args, **kwargs):
if not extra_branches: extra_branches = []
self._branch = branch
self._upstream = upstream
self._import_branch = import_branch
self._extra_branches = extra_branches
# make sure to correctly initialise inherited objects before performing
# any computation
super(ImportUpstream, self).__init__(*args, **kwargs)
# test that we can use this git repo
if not self.is_detached():
raise ImportUpstreamError("In 'detached HEAD' state")
if self.repo.bare:
raise ImportUpstreamError("Cannot perform imports in bare repos")
if self.branch == 'HEAD':
self._branch = str(self.repo.active_branch)
# validate branches exist and log all failures
branches = [
self.branch,
self.upstream
]
branches.extend(self.extra_branches)
invalid_ref = False
for branch in branches:
if not any(head for head in self.repo.heads if head.name == branch):
msg = "Specified ref does not exist: '%s'"
self.log.error(msg, branch)
invalid_ref = True
if invalid_ref:
raise ImportUpstreamError("Invalid ref")
@property
def branch(self):
"""Branch to search for branch changes to apply when importing."""
return self._branch
@property
def upstream(self):
"""Branch containing the upstream project code base to track."""
return self._upstream
@property
def import_branch(self):
"""
Pattern to use to generate the name, or user specified branch name
to use for import.
"""
return self._import_branch
@property
def extra_branches(self):
"""
Branch containing the additional branches to be merged with the
upstream when importing.
"""
return self._extra_branches
def _set_branch(self, branch, commit, checkout=False, force=False):
if str(self.repo.active_branch) == branch:
self.log.info(
"""\
Resetting branch '%s' to specified commit '%s'
git reset --hard %s
""", branch, commit, commit)
self.git.reset(commit, hard=True)
elif checkout:
if force:
checkout_opt = '-B'
else:
checkout_opt = '-b'
self.log.info(
"""\
Checking out branch '%s' using specified commit '%s'
git checkout %s %s %s
""", branch, commit, checkout_opt, branch, commit)
self.git.checkout(checkout_opt, branch, commit)
else:
self.log.info(
"""\
Creating branch '%s' from specified commit '%s'
git branch --force %s %s
""", branch, commit, branch, commit)
self.git.branch(branch, commit, force=force)
def create_import(self, commit=None, import_branch=None, checkout=False,
force=False):
"""
Create the import branch from the specified commit.
If the branch already exists abort if force is false
If current branch, reset the head to the specified commit
If checkout is true, switch and reset the branch to the commit
Otherwise just reset the branch to the specified commit
If the branch doesn't exist, create it and switch to it
automatically if checkout is true.
"""
if not commit:
commit = self.upstream
try:
self.git.show_ref(commit, quiet=True, heads=True)
except GitCommandError as e:
msg = "Invalid commit '%s' specified to import from"
self.log.error(msg, commit)
raise ImportUpstreamError((msg + ": %s"), commit, e)
if not import_branch:
import_branch = self.import_branch
# use describe in order to be certain about unique identifying 'commit'
# Create a describe string with the following format:
# <describe upstream>[-<extra branch abbref hash>]*
#
# Simply appends the 7 character ref abbreviation for each extra branch
# prefixed with '-', for each extra branch in the order they are given.
describe_commit = self.git.describe(commit, tags=True,
with_exceptions=False)
if not describe_commit:
self.log.warning("No tag describes the upstream branch")
describe_commit = self.git.describe(commit, always=True, tags=True)
self.log.info("""\
Using '%s' to describe:
%s
""", describe_commit, commit)
describe_branches = [describe_commit]
describe_branches.extend([self.git.rev_parse(b, short=True)
for b in self.extra_branches])
import_describe = "-".join(describe_branches)
self._import_branch = self.import_branch.format(
describe=import_describe)
self._import_branch = import_branch.format(describe=import_describe)
base = self._import_branch + "-base"
self.log.debug("Creating and switching to import branch base '%s' "
"created from '%s' (%s)", base, self.upstream, commit)
self.log.info(
"""\
Checking if import branch '%s' already exists:
git branch --list %s
""", base, base)
if self.git.show_ref("refs/heads/" + base, verify=True,
with_exceptions=False) and not force:
msg = "Import branch '%s' already exists, set 'force' to replace"
self.log.error(msg, self.import_branch)
raise ImportUpstreamError(msg % self.import_branch)
self._set_branch(base, commit, checkout, force)
if self.extra_branches:
self.log.info(
"""\
Merging additional branch(es) '%s' into import branch '%s'
git checkout %s
git merge %s
""", ", ".join(self.extra_branches), base, base,
" ".join(self.extra_branches))
self.git.checkout(base)
self.git.merge(*self.extra_branches)
def _linearise(self, branch, sequence, previous_import):
counter = len(sequence) - 1
ancestors = set()
self._set_branch(branch, previous_import, checkout=True, force=True)
root = previous_import.hexsha
while counter > 0:
# add commit to list of ancestors to check
ancestors.add(root)
# look for merge commits that are not part of ancestry path
for idx in xrange(counter - 1, -1, -1):
commit = sequence[idx]
# if there is only one parent, no need to check the others
if len(commit.parents) < 2:
ancestors.add(commit.hexsha)
elif any(p.hexsha not in ancestors for p in commit.parents):
self.log.debug("Rebase upto commit SHA1: %s", commit.hexsha)
idx = idx + 1
break
else:
ancestors.add(commit.hexsha)
tip = sequence[idx].hexsha
self.log.info("Rebasing from %s to %s", root, tip)
previous = self.git.rev_parse(branch)
self.log.info("Rebasing onto '%s'", previous)
if root == previous and idx == 0:
# special case, we are already linear
self.log.info("Already in a linear layout")
return
self._set_branch(branch, tip, force=True)
try:
self.log.debug(
"""\
git rebase -p --onto=%s \\
%s %s
""", previous, root, branch)
self.git.rebase(root, branch, onto=previous, p=True)
except:
self.git.rebase(abort=True, with_exceptions=False)
raise
counter = idx - 1
# set root commit for next loop
root = sequence[counter].hexsha
def apply(self, strategy, interactive=False):
"""Apply list of commits given onto latest import of upstream"""
commit_list = list(strategy.filtered_iter())
if len(commit_list) == 0:
self.log.notice("There are no local changes to be applied!")
return False
self.log.debug(
"""\
Should apply the following list of commits
%s
""", "\n ".join([c.hexsha for c in commit_list]))
base = self.import_branch + "-base"
self._set_branch(self.import_branch, self.branch, force=True)
self.log.info(
"""\
Creating import branch '%s' from specified commit '%s' in prep to
linearize the local changes before transposing to the new upstream:
git branch --force %s %s
""", self.import_branch, self.branch, self.import_branch,
self.branch)
self.log.notice("Attempting to linearise previous changes")
# attempt to silently linearize the current carried changes as a branch
# based on the previous located import commit. This provides a sane
# abort result for if the user needs to abort the rebase of this branch
# onto the new point upstream that was requested to import from.
try:
self._linearise(self.import_branch, strategy,
strategy.searcher.commit)
except:
# Could ask user if they want to try and use the non clean route
# provided they don't mind that 'git rebase --abort' will result
# in a virtually useless local import branch
self.log.warning(
"""\
Exception occurred during linearisation of local changes on to
previous import to simplify behaviour should user need to abort
the rebase that applies these changes to the latest import
point. Attempting to tidy up state.
Do not Ctrl+C unless you wish to need to clean up your git
repository by hand.
""")
# reset head back to the tip of the changes to be rebased
self._set_branch(self.import_branch, self.branch, force=True)
rebase = RebaseEditor(interactive, repo=self.repo)
if len(commit_list):
first = commit_list[0]
self.log.info(
"""\
Rebase changes, dropping merges through editor:
git rebase --onto %s \\
%s %s
""", base, first.parents[0].hexsha, self.import_branch)
status, out, err = rebase.run(commit_list,
first.parents[0].hexsha,
self.import_branch,
onto=base)
if status:
if err and err.startswith("Nothing to do"):
# cancelled by user
self.log.notice("Cancelled by user")
return False
self.log.error("Rebase failed, will need user intervention to "
"resolve.")
if out:
self.log.notice(out)
if err:
self.log.notice(err)
# once we support resuming/finishing add a message here to tell
# the user to rerun this tool with the appropriate options to
# complete
return False
self.log.notice("Successfully applied all locally carried changes")
else:
self.log.warning("Warning, nothing to do: locally carried " +
"changes already rebased onto " + self.upstream)
return True
def resume(self, args):
"""Resume previous partial import"""
raise NotImplementedError
def finish(self):
"""
Finish merge according to the selected strategy while performing
suitable verification checks.
"""
self.log.info("No verification checks enabled")
self.git.checkout(self.branch)
current_sha = self.git.rev_parse("HEAD")
try:
self.log.info(
"""\
Merging by inverting the 'ours' strategy discard all changes
and replace existing branch contents with the new import.
""")
self.log.info(
"""\
Merging import branch to HEAD and ignoring changes:
git merge -s ours --no-commit %s
""", self.import_branch)
self.git.merge('-s', 'ours', self.import_branch, no_commit=True)
self.log.info(
"""\
Replacing tree contents with those from the import branch:
git read-tree %s
""", self.import_branch)
self.git.read_tree(self.import_branch)
self.log.info(
"""\
Committing merge commit:
git commit --no-edit
""")
self.git.commit(no_edit=True)
self.log.info(
"""\
Checking out updated index:
git checkout -- .
""")
self.git.checkout("--", ".")
# finally test that everything worked correctly by comparing if
# the tree object id's match
if self.git.rev_parse("HEAD^{tree}") != \
self.git.rev_parse("%s^{tree}" % self.import_branch):
raise ImportUpstreamError("Resulting tree does not match import")
except (GitCommandError, ImportUpstreamError):
self.log.error(
"""\
Failed to finish import by merging branch:
'%s'
into and replacing the contents of:
'%s'
""", self.import_branch, self.branch)
self._set_branch(self.branch, current_sha, force=True)
return False
except:
self.log.exception("Unknown exception during finish")
self._set_branch(self.branch, current_sha, force=True)
raise
return True
class ImportStrategiesFactory(object):
__strategies = None
@classmethod
def create_strategy(cls, type, *args, **kwargs):
if type in cls.list_strategies():
return cls.__strategies[type](*args, **kwargs)
else:
raise RuntimeError("No class implements the requested strategy: "
"{0}".format(type))
@classmethod
def list_strategies(cls):
cls.__strategies = {
subclass._strategy: subclass
for subclass in LocateChangesStrategy.__subclasses__()
if subclass._strategy}
return cls.__strategies.keys()
from git_upstream.lib.searchers import (NoMergeCommitFilter,
ReverseCommitFilter,
DiscardDuplicateGerritChangeId,
SupersededCommitFilter,
DroppedCommitFilter)
class LocateChangesStrategy(GitMixin, Sequence):
"""
Base class that needs to be extended with the specific strategy on how to
handle changes locally that are not yet upstream.
"""
__metaclass__ = ABCMeta
@abstractmethod
def __init__(self, git=None, *args, **kwargs):
"""
Initialize an empty filters list
"""
self.data = None
self.filters = []
super(LocateChangesStrategy, self).__init__(*args, **kwargs)
def __getitem__(self, key):
if not self.data:
self.data = self._popdata()
return self.data[key]
def __len__(self):
if not self.data:
self.data = self._popdata()
return len(self.data)
@classmethod
def get_strategy_name(cls):
return cls._strategy
def filtered_iter(self):
# chain the filters as generators so that we don't need to allocate new
# lists for each step in the filter chain.
commit_list = self
for f in self.filters:
commit_list = f.filter(commit_list)
return commit_list
def filtered_list(self):
return list(self.filtered_iter())
def _popdata(self):
"""
Should return the list of commits from the searcher object
"""
return self.searcher.list()
class LocateChangesWalk(LocateChangesStrategy):
"""
"""
_strategy = "drop"
def __init__(self, branch="HEAD", search_ref=None, *args, **kwargs):
self.searcher = UpstreamMergeBaseSearcher(branch=branch,
pattern=search_ref)
self.search_ref = search_ref
super(LocateChangesWalk, self).__init__(*args, **kwargs)
def filtered_iter(self):
# may wish to make class used to remove duplicate objects configurable
# through git-upstream specific 'git config' settings
if self.search_ref:
self.filters.append(
DiscardDuplicateGerritChangeId(self.search_ref,
limit=self.searcher.commit))
self.filters.append(NoMergeCommitFilter())
self.filters.append(ReverseCommitFilter())
self.filters.append(DroppedCommitFilter())
self.filters.append(
SupersededCommitFilter(self.search_ref, limit=self.searcher.commit))
return super(LocateChangesWalk, self).filtered_iter()
@subcommand.arg('-d', '--dry-run', dest='dry_run', action='store_true',
default=False,
help='Only print out the list of commits that would be '
'applied.')
@subcommand.arg('-i', '--interactive', action='store_true', default=False,
help='Let the user edit the list of commits before applying.')
@subcommand.arg('-f', '--force', dest='force', required=False,
action='store_true', default=False,
help='Force overwrite of existing import branch if it exists.')
@subcommand.arg('--merge', dest='merge', required=False, action='store_true',
default=True,
help='Merge the resulting import branch into the target branch '
'once complete')
@subcommand.arg('--no-merge', dest='merge', required=False,
action='store_false',
help="Disable merge of the resulting import branch")
@subcommand.arg('-s', '--strategy', metavar='<strategy>',
choices=ImportStrategiesFactory.list_strategies(),
default=LocateChangesWalk.get_strategy_name(),
help='Use the given strategy to re-apply locally carried '
'changes to the import branch. (default: %(default)s)')
@subcommand.arg('--into', dest='branch', metavar='<branch>', default='HEAD',
help='Branch to take changes from, and replace with imported '
'branch.')
@subcommand.arg('--import-branch', metavar='<import-branch>',
help='Name of import branch to use',
default='import/{describe}')
@subcommand.arg('upstream_branch', metavar='<upstream-branch>', nargs='?',
default='upstream/master',
help='Upstream branch to import. Must be specified if '
'you wish to provide additional branches.')
@subcommand.arg('branches', metavar='<branches>', nargs='*',
help='Branches to additionally merge into the import branch '
'using default git merging behaviour')
def do_import(args):
"""
Import code from specified upstream branch.
Creates an import branch from the specified upstream branch, and optionally
merges additional branches given as arguments. Current branch, unless
overridden by the --into option, is used as the target branch from which a
list of changes to apply onto the new import is constructed based on the
the specified strategy.
Once complete it will merge and replace the contents of the target branch
with those from the import branch, unless --no-merge is specified.
"""
logger = log.get_logger('%s.%s' % (__name__,
inspect.stack()[0][0].f_code.co_name))
import_upstream = ImportUpstream(branch=args.branch,
upstream=args.upstream_branch,
import_branch=args.import_branch,
extra_branches=args.branches)
logger.notice("Searching for previous import")
strategy = ImportStrategiesFactory.create_strategy(
args.strategy, branch=args.branch, search_ref=args.upstream_branch)
if len(strategy) == 0:
raise ImportUpstreamError("Cannot find previous import")
# if last commit in the strategy was a merge, then the additional branches
# that were merged in previously can be extracted based on the commits
# merged.
prev_import_merge = strategy[-1]
if len(prev_import_merge.parents) > 1:
idx = next((idx for idx, commit in enumerate(prev_import_merge.parents)
if commit.hexsha == strategy.searcher.commit.hexsha), None)
if idx:
additional_commits = prev_import_merge.parents[idx + 1:]
if additional_commits and not args.branches:
logger.warning("""\
**************** WARNING ****************
Previous import merged additional branches but non have
been specified on the command line for this import.\n""")
if args.dry_run:
commit_list = [c.hexsha[:6] + " - " + c.summary[:60] +
(c.summary[60:] and "...")
for c in list(strategy.filtered_iter())]
logger.notice("""\
Requested a dry-run: printing the list of commit that should be
rebased
%s
""", "\n ".join(commit_list))
return True
logger.notice("Starting import of upstream")
import_upstream.create_import(force=args.force)
logger.notice("Successfully created import branch")
if not import_upstream.apply(strategy, args.interactive):
logger.notice("Import cancelled")
return False
if not args.merge:
logger.notice(
"""\
Import complete, not merging to target branch '%s' as requested.
""", args.branch)
return True
logger.notice("Merging import to requested branch '%s'", args.branch)
if import_upstream.finish():
logger.notice(
"""\
Successfully finished import:
target branch: '%s'
upstream branch: '%s'
import branch: '%s'""", args.branch, args.upstream_branch,
import_upstream.import_branch)
if args.branches:
for branch in args.branches:
logger.notice(" extra branch: '%s'", branch, dedent=False)
# vim:sw=4:sts=4:ts=4:et: