x/git-upstream
Code Issues Proposed changes

Find additional missing commit scenarios

Browse Source 
Add explicit searching for the previous merge that discarded the history
of earlier imports. Include searching for a posible merge of additional
branches such as packing branches that may have been included in a
previous run.

Change-Id: I3e0adeb792dae03262dd4f8322572427fa2ec35d
This commit is contained in:
Darragh Bailey
2014-12-11 12:38:15 +00:00
parent 964d5c784e
commit 66004d051c
3 changed files with 43 additions and 88 deletions
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119
git_upstream/lib/searchers.py
View File

@@ -71,22 +71,51 @@ class Searcher(GitMixin):
if not self.commit:
self.find()
revision_spec = "{0}..{1}".format(self.commit.hexsha, self.branch)
# search for previous import commit first, if found, wish to include
# the discarded parents as part of the set of changes to ignore in the
# final list.
self.log.debug(
"""\
Searching for previous merges that exclude one side of the history
since the last import.
git rev-list --ancestry-path --merges %s
""", revision_spec)
merge_list = list(Commit.iter_items(self.repo, revision_spec,
topo_order=True,
ancestry_path=True, merges=True))
ignore_args = []
for c in merge_list:
for p in c.parents:
# previous merge using 'ours' strategy to ignore commits
if (self.git.rev_parse("%s^{tree}" % p.hexsha) ==
self.git.rev_parse("%s^{tree}" % c.hexsha)):
ignore_args.extend(["^%s" % ip
for ip in c.parents if ip != p])
break
if merge_list:
for p in merge_list[-1].parents:
if p.hexsha == self.commit.hexsha:
ignore_args.extend(["^%s" % ip
for ip in c.parents if ip != p])
# walk the tree and find all commits that lie in the path between the
# commit found by find() and head of the branch to provide a list of
# commits to the caller
self.log.info(
"""\
Walking the changes between found commit and target
git rev-list --parents --simplify-merges %s..%s
""", self.commit.hexsha, self.branch)
Walking the changes between found commit and target, excluding
those behind the previous import or merged as an additional branch
during the previous import
git rev-list --topo-order %s %s
""", revision_spec, " ".join(ignore_args))
# depending on how many commits are returned, may need to examine use
# of a generator rather than storing the entire list. Such a generator
# would require a custom git object or direct use of popen
commit_list = Commit.iter_items(self.repo,
"{0}..{1}".format(self.commit.hexsha,
self.branch),
topo_order=True, simplify_merges=True)
commit_list = Commit._iter_from_process_or_stream(
self.repo, self.git.rev_list(revision_spec, *ignore_args,
as_process=True, topo_order=True))
# chain the filters as generators so that we don't need to allocate new
# lists for each step in the filter chain.
@@ -279,54 +308,6 @@ class UpstreamMergeBaseSearcher(LogDedentMixin, Searcher):
return self.commit.hexsha
def list(self, include_all=False):
"""
If a particular commit has been merged in mulitple times, walking the
history and returning all results will return all commits from
each merge point, not just the last set which are usually what is
desired.
X --- Y --- Z - other branch
\ \
B --- C --- D --- C' - HEAD
/ /
A --------------- E - upstream
When importing "E" from the upstream branch, the previous import commit
is detected as "A". The commits that we are actually interested in are:
D --- C' - HEAD
/
A ----------- - upstream
However due to the DAG nature of git, when walking the direct ancestry
path, it cannot for certain determine which parent of merge commits
was the original mainline. Thus it will return the following graph.
B --- C --- D --- C' - HEAD
/ /
A ----------- - upstream
With the following topological order ABCADC'
The BeforeFirstParentCommitFilter can be given the "A" commit to use
when walking the list of commits from the most recent "C'" to the
earliest and will stop at the first occurance of "A", ignoring all
other earlier commits.
Setting the parameter 'include_all' to True, will return the entire
list.
if include_all == False -> return ADC'
if include_all == True -> return ABCADC'
"""
if not include_all:
self.filters.insert(0, BeforeFirstParentCommitFilter(self.find()))
return super(UpstreamMergeBaseSearcher, self).list()
class CommitMessageSearcher(LogDedentMixin, Searcher):
"""
@@ -563,28 +544,6 @@ class NoMergeCommitFilter(CommitFilter):
yield commit
class BeforeFirstParentCommitFilter(LogDedentMixin, CommitFilter):
"""
Generator that iterates over commit objects until it encounters a one that
has a parent commit SHA1 that matches the 'stopcommit' SHA1.
"""
def __init__(self, stopcommit, *args, **kwargs):
self.stop = stopcommit
super(BeforeFirstParentCommitFilter, self).__init__(*args, **kwargs)
def filter(self, commit_iter):
for commit in commit_iter:
# return the commit object first before checking if the parent
# matches the stop commit otherwise we'll also trim the commit
# before the one we wanted to match as well.
yield commit
if any(parent.hexsha == self.stop for parent in commit.parents):
self.log.debug("Discarding all commits before '%s'",
commit.hexsha)
break
class DiscardDuplicateGerritChangeId(LogDedentMixin, GitMixin, CommitFilter):
"""
Filter out commit objects where the message footer contains a ChangeId

6
git_upstream/tests/test_searchers.py
View File

@@ -405,7 +405,5 @@ class TestUpstreamMergeBaseSearcher(BaseTestCase):
'upstream': ('upstream/master', 'M'),
}
expected_changes = ["B1", "C1", "D1", "G", "O", "H", "I", "J", "K"]
self.expectFailure(
"Should fail to find change 'O'",
self._verify_expected, tree, branches, expected_changes)
expected_changes = ["O", "H", "B1", "C1", "D1", "G", "I", "J", "K"]
self._verify_expected(tree, branches, expected_changes)

6
git_upstream/tests/test_strategies.py
View File

@@ -232,7 +232,5 @@ class TestStrategies(BaseTestCase):
'upstream': ('upstream/master', 'M'),
}
expected_changes = ["B1", "C1", "D1", "O", "J", "K"]
self.expectFailure(
"Should fail to find change 'O'",
self._verify_expected, tree, branches, expected_changes)
expected_changes = ["O", "B1", "C1", "D1", "J", "K"]
self._verify_expected(tree, branches, expected_changes)