Index: dashboard/dashboard/pinpoint/models/change/change.py |
diff --git a/dashboard/dashboard/pinpoint/models/change/change.py b/dashboard/dashboard/pinpoint/models/change/change.py |
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+# Copyright 2016 The Chromium Authors. All rights reserved. |
+# Use of this source code is governed by a BSD-style license that can be |
+# found in the LICENSE file. |
+ |
+import collections |
+import itertools |
+ |
+from dashboard.pinpoint.models.change import commit as commit_module |
+from dashboard.pinpoint.models.change import patch as patch_module |
+ |
+ |
+class Change(collections.namedtuple('Change', ('commits', 'patch'))): |
+ """A particular set of Commits with or without an additional patch applied. |
+ |
+ For example, a Change might sync to src@9064a40 and catapult@8f26966, |
+ then apply patch 2423293002. |
+ """ |
+ |
+ def __new__(cls, commits, patch=None): |
+ """Creates a Change. |
+ |
+ Args: |
+ commits: An iterable of Commits representing this Change's dependencies. |
+ patch: An optional Patch to apply to the Change. |
+ """ |
+ if not commits: |
+ raise TypeError('At least one commit required.') |
+ return super(Change, cls).__new__(cls, tuple(commits), patch) |
+ |
+ def __str__(self): |
+ """Returns an informal short string representation of this Change.""" |
+ string = ' '.join(str(commit) for commit in self.commits) |
+ if self.patch: |
+ string += ' + ' + str(self.patch) |
+ return string |
+ |
+ @property |
+ def id_string(self): |
+ """Returns a string that is unique to this list of commits and patch.""" |
+ string = ' '.join(commit.id_string for commit in self.commits) |
+ if self.patch: |
+ string += ' + ' + self.patch.id_string |
+ return string |
+ |
+ @property |
+ def base_commit(self): |
+ return self.commits[0] |
+ |
+ @property |
+ def last_commit(self): |
+ return self.commits[-1] |
+ |
+ @property |
+ def deps(self): |
+ return tuple(self.commits[1:]) |
+ |
+ def AsDict(self): |
+ return { |
+ 'commits': [commit.AsDict() for commit in self.commits], |
+ 'patch': self.patch.AsDict() if self.patch else None, |
+ } |
+ |
+ @classmethod |
+ def FromDict(cls, data): |
+ commits = tuple(commit_module.Commit.FromDict(commit) |
+ for commit in data['commits']) |
+ if 'patch' in data: |
+ patch = patch_module.Patch.FromDict(data['patch']) |
+ else: |
+ patch = None |
+ |
+ return cls(commits, patch=patch) |
+ |
+ @classmethod |
+ def Midpoint(cls, change_a, change_b): |
+ """Returns a Change halfway between the two given Changes. |
+ |
+ This function does two passes over the Changes' Commits: |
+ * The first pass attempts to match the lengths of the Commit lists by |
+ expanding DEPS to fill in any repositories that are missing from one, |
+ but included in the other. |
+ * The second pass takes the midpoint of every matched pair of Commits, |
+ expanding DEPS rolls as it comes across them. |
+ |
+ A NonLinearError is raised if there is no valid midpoint. The Changes are |
+ not linear if any of the following is true: |
+ * They have different patches. |
+ * Their repositories don't match even after expanding DEPS rolls. |
+ * The left Change comes after the right Change. |
+ * They are the same or adjacent. |
+ See change_test.py for examples of linear and nonlinear Changes. |
+ |
+ Args: |
+ change_a: The first Change in the range. |
+ change_b: The last Change in the range. |
+ |
+ Returns: |
+ A new Change representing the midpoint. |
+ The Change before the midpoint if the range has an even number of commits. |
+ |
+ Raises: |
+ NonLinearError: The Changes are not linear. |
+ """ |
+ if change_a.patch != change_b.patch: |
+ raise commit_module.NonLinearError( |
+ 'Change A has patch "%s" and Change B has patch "%s".' % |
+ (change_a.patch, change_b.patch)) |
+ |
+ commits_a = list(change_a.commits) |
+ commits_b = list(change_b.commits) |
+ |
+ _ExpandDepsToMatchRepositories(commits_a, commits_b) |
+ commits_midpoint = _FindMidpoints(commits_a, commits_b) |
+ |
+ if commits_a == commits_midpoint: |
+ raise commit_module.NonLinearError('Changes are the same or adjacent.') |
+ |
+ return cls(commits_midpoint, change_a.patch) |
+ |
+ |
+def _ExpandDepsToMatchRepositories(commits_a, commits_b): |
+ """Expands DEPS in a Commit list to match the repositories in another. |
+ |
+ Given two lists of Commits, with one bigger than the other, this function |
+ looks through the DEPS files for smaller commit list to fill out any missing |
+ Commits that are already in the bigger commit list. |
+ |
+ Mutates the lists in-place, and doesn't return anything. The lists will not |
+ have the same size if one Commit list contains a repository that is not found |
+ in the DEPS of the other Commit list. |
perezju
2017/09/13 12:52:24
(Let's revisit again on a follow up CL)
Add a tes
dtu
2017/09/13 15:49:26
testDifferingCommitCount is the test for this case
|
+ |
+ Example: |
+ commits_a == [chromium@a, v8@c] |
+ commits_b == [chromium@b] |
+ This function looks through the DEPS file at chromium@b to find v8, then |
+ appends that v8 Commit to commits_b, making the lists match. |
+ |
+ Args: |
+ commits_a: A list of Commits. |
+ commits_b: A list of Commits. |
+ """ |
+ # The lists may be given in any order. Let's make commits_b the bigger list. |
+ if len(commits_a) > len(commits_b): |
+ commits_a, commits_b = commits_b, commits_a |
+ |
+ # Loop through every DEPS file in commits_a. |
+ for commit_a in commits_a: |
+ if len(commits_a) == len(commits_b): |
+ break |
+ deps_a = commit_a.Deps() |
+ |
+ # Look through commits_b for any extra slots to fill with the DEPS. |
+ for commit_b in commits_b[len(commits_a):]: |
+ dep_a = _FindCommitWithRepository(deps_a, commit_b.repository) |
+ if dep_a: |
+ commits_a.append(dep_a) |
+ else: |
+ break |
+ |
+ |
+def _FindMidpoints(commits_a, commits_b): |
+ """Returns the midpoint of two Commit lists. |
+ |
+ Loops through each pair of Commits and takes the midpoint. If the repositories |
+ don't match, a NonLinearError is raised. If the Commits are adjacent and |
+ represent a DEPS roll, the differing DEPs are added to the end of the lists. |
+ |
+ Args: |
+ commits_a: A list of Commits. |
+ commits_b: A list of Commits. |
+ |
+ Returns: |
+ A list of Commits, each of which is the midpoint of the respective Commit in |
+ commits_a and commits_b. |
+ |
+ Raises: |
+ NonLinearError: The lists have a different number of commits even after |
+ expanding DEPS rolls, a Commit pair contains differing repositories, or a |
+ Commit pair is in the wrong order. |
+ """ |
+ commits_midpoint = [] |
+ |
+ for commit_a, commit_b in itertools.izip_longest(commits_a, commits_b): |
+ if not (commit_a and commit_b): |
+ # If the commit lists are not the same length, bail out. That could happen |
+ # if commits_b has a repository that was not found in the DEPS of |
+ # commits_a (or vice versa); or a DEPS roll added or removed a DEP. |
+ raise commit_module.NonLinearError( |
+ 'Changes have a different number of commits.') |
+ |
+ commit_midpoint = commit_module.Commit.Midpoint(commit_a, commit_b) |
+ commits_midpoint.append(commit_midpoint) |
+ if commit_a == commit_midpoint != commit_b: |
+ # Commits are adjacent. |
+ # Add any DEPS changes to the commit lists. |
+ deps_a = commit_a.Deps() |
+ deps_b = commit_b.Deps() |
+ commits_a += sorted( |
perezju
2017/09/13 12:52:24
:( :( :(
dtu
2017/09/13 15:49:26
:( :( :(
|
+ dep for dep in deps_a.difference(deps_b) |
+ if not _FindCommitWithRepository(commits_a, dep.repository)) |
+ commits_b += sorted( |
+ dep for dep in deps_b.difference(deps_a) |
+ if not _FindCommitWithRepository(commits_b, dep.repository)) |
+ |
+ return commits_midpoint |
+ |
+ |
+def _FindCommitWithRepository(commits, repository): |
+ for commit in commits: |
+ if commit.repository == repository: |
+ return commit |
+ return None |