Mercurial > hg
view mercurial/hbisect.py @ 39559:07b58266bce3
wireprotov2: implement commands as a generator of objects
Previously, wire protocol version 2 inherited version 1's model of
having separate types to represent the results of different wire
protocol commands.
As I implemented more powerful commands in future commits, I found
I was using a common pattern of returning a special type to hold a
generator. This meant the command function required a closure to
do most of the work. That made logic flow more difficult to follow.
I also noticed that many commands were effectively a sequence of
objects to be CBOR encoded.
I think it makes sense to define version 2 commands as generators.
This way, commands can simply emit the data structures they wish to
send to the client. This eliminates the need for a closure in
command functions and removes encoding from the bodies of commands.
As part of this commit, the handling of response objects has been
moved into the serverreactor class. This puts the reactor in the
driver's seat with regards to CBOR encoding and error handling.
Having error handling in the function that emits frames is
particularly important because exceptions in that function can lead
to things getting in a bad state: I'm fairly certain that uncaught
exceptions in the frame generator were causing deadlocks.
I also introduced a dedicated error type for explicit error reporting
in command handlers. This will be used in subsequent commits.
There's still a bit of work to be done here, especially around
formalizing the error handling "protocol." I've added yet another
TODO to track this so we don't forget.
Test output changed because we're using generators and no longer know
we are at the end of the data until we hit the end of the generator.
This means we can't emit the end-of-stream flag until we've exhausted
the generator. Hence the introduction of 0-sized end-of-stream frames.
Differential Revision: https://phab.mercurial-scm.org/D4472
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 05 Sep 2018 09:06:40 -0700 |
parents | 71f189941791 |
children | 566daffc607d |
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# changelog bisection for mercurial # # Copyright 2007 Matt Mackall # Copyright 2005, 2006 Benoit Boissinot <benoit.boissinot@ens-lyon.org> # # Inspired by git bisect, extension skeleton taken from mq.py. # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import collections from .i18n import _ from .node import ( hex, short, ) from . import ( error, ) def bisect(repo, state): """find the next node (if any) for testing during a bisect search. returns a (nodes, number, good) tuple. 'nodes' is the final result of the bisect if 'number' is 0. Otherwise 'number' indicates the remaining possible candidates for the search and 'nodes' contains the next bisect target. 'good' is True if bisect is searching for a first good changeset, False if searching for a first bad one. """ changelog = repo.changelog clparents = changelog.parentrevs skip = set([changelog.rev(n) for n in state['skip']]) def buildancestors(bad, good): badrev = min([changelog.rev(n) for n in bad]) ancestors = collections.defaultdict(lambda: None) for rev in repo.revs("descendants(%ln) - ancestors(%ln)", good, good): ancestors[rev] = [] if ancestors[badrev] is None: return badrev, None return badrev, ancestors good = False badrev, ancestors = buildancestors(state['bad'], state['good']) if not ancestors: # looking for bad to good transition? good = True badrev, ancestors = buildancestors(state['good'], state['bad']) bad = changelog.node(badrev) if not ancestors: # now we're confused if (len(state['bad']) == 1 and len(state['good']) == 1 and state['bad'] != state['good']): raise error.Abort(_("starting revisions are not directly related")) raise error.Abort(_("inconsistent state, %d:%s is good and bad") % (badrev, short(bad))) # build children dict children = {} visit = collections.deque([badrev]) candidates = [] while visit: rev = visit.popleft() if ancestors[rev] == []: candidates.append(rev) for prev in clparents(rev): if prev != -1: if prev in children: children[prev].append(rev) else: children[prev] = [rev] visit.append(prev) candidates.sort() # have we narrowed it down to one entry? # or have all other possible candidates besides 'bad' have been skipped? tot = len(candidates) unskipped = [c for c in candidates if (c not in skip) and (c != badrev)] if tot == 1 or not unskipped: return ([changelog.node(c) for c in candidates], 0, good) perfect = tot // 2 # find the best node to test best_rev = None best_len = -1 poison = set() for rev in candidates: if rev in poison: # poison children poison.update(children.get(rev, [])) continue a = ancestors[rev] or [rev] ancestors[rev] = None x = len(a) # number of ancestors y = tot - x # number of non-ancestors value = min(x, y) # how good is this test? if value > best_len and rev not in skip: best_len = value best_rev = rev if value == perfect: # found a perfect candidate? quit early break if y < perfect and rev not in skip: # all downhill from here? # poison children poison.update(children.get(rev, [])) continue for c in children.get(rev, []): if ancestors[c]: ancestors[c] = list(set(ancestors[c] + a)) else: ancestors[c] = a + [c] assert best_rev is not None best_node = changelog.node(best_rev) return ([best_node], tot, good) def extendrange(repo, state, nodes, good): # bisect is incomplete when it ends on a merge node and # one of the parent was not checked. parents = repo[nodes[0]].parents() if len(parents) > 1: if good: side = state['bad'] else: side = state['good'] num = len(set(i.node() for i in parents) & set(side)) if num == 1: return parents[0].ancestor(parents[1]) return None def load_state(repo): state = {'current': [], 'good': [], 'bad': [], 'skip': []} for l in repo.vfs.tryreadlines("bisect.state"): kind, node = l[:-1].split() node = repo.lookup(node) if kind not in state: raise error.Abort(_("unknown bisect kind %s") % kind) state[kind].append(node) return state def save_state(repo, state): f = repo.vfs("bisect.state", "w", atomictemp=True) with repo.wlock(): for kind in sorted(state): for node in state[kind]: f.write("%s %s\n" % (kind, hex(node))) f.close() def resetstate(repo): """remove any bisect state from the repository""" if repo.vfs.exists("bisect.state"): repo.vfs.unlink("bisect.state") def checkstate(state): """check we have both 'good' and 'bad' to define a range Raise Abort exception otherwise.""" if state['good'] and state['bad']: return True if not state['good']: raise error.Abort(_('cannot bisect (no known good revisions)')) else: raise error.Abort(_('cannot bisect (no known bad revisions)')) def get(repo, status): """ Return a list of revision(s) that match the given status: - ``good``, ``bad``, ``skip``: csets explicitly marked as good/bad/skip - ``goods``, ``bads`` : csets topologically good/bad - ``range`` : csets taking part in the bisection - ``pruned`` : csets that are goods, bads or skipped - ``untested`` : csets whose fate is yet unknown - ``ignored`` : csets ignored due to DAG topology - ``current`` : the cset currently being bisected """ state = load_state(repo) if status in ('good', 'bad', 'skip', 'current'): return map(repo.changelog.rev, state[status]) else: # In the following sets, we do *not* call 'bisect()' with more # than one level of recursion, because that can be very, very # time consuming. Instead, we always develop the expression as # much as possible. # 'range' is all csets that make the bisection: # - have a good ancestor and a bad descendant, or conversely # that's because the bisection can go either way range = '( bisect(bad)::bisect(good) | bisect(good)::bisect(bad) )' _t = repo.revs('bisect(good)::bisect(bad)') # The sets of topologically good or bad csets if len(_t) == 0: # Goods are topologically after bads goods = 'bisect(good)::' # Pruned good csets bads = '::bisect(bad)' # Pruned bad csets else: # Goods are topologically before bads goods = '::bisect(good)' # Pruned good csets bads = 'bisect(bad)::' # Pruned bad csets # 'pruned' is all csets whose fate is already known: good, bad, skip skips = 'bisect(skip)' # Pruned skipped csets pruned = '( (%s) | (%s) | (%s) )' % (goods, bads, skips) # 'untested' is all cset that are- in 'range', but not in 'pruned' untested = '( (%s) - (%s) )' % (range, pruned) # 'ignored' is all csets that were not used during the bisection # due to DAG topology, but may however have had an impact. # E.g., a branch merged between bads and goods, but whose branch- # point is out-side of the range. iba = '::bisect(bad) - ::bisect(good)' # Ignored bads' ancestors iga = '::bisect(good) - ::bisect(bad)' # Ignored goods' ancestors ignored = '( ( (%s) | (%s) ) - (%s) )' % (iba, iga, range) if status == 'range': return repo.revs(range) elif status == 'pruned': return repo.revs(pruned) elif status == 'untested': return repo.revs(untested) elif status == 'ignored': return repo.revs(ignored) elif status == "goods": return repo.revs(goods) elif status == "bads": return repo.revs(bads) else: raise error.ParseError(_('invalid bisect state')) def label(repo, node): rev = repo.changelog.rev(node) # Try explicit sets if rev in get(repo, 'good'): # i18n: bisect changeset status return _('good') if rev in get(repo, 'bad'): # i18n: bisect changeset status return _('bad') if rev in get(repo, 'skip'): # i18n: bisect changeset status return _('skipped') if rev in get(repo, 'untested') or rev in get(repo, 'current'): # i18n: bisect changeset status return _('untested') if rev in get(repo, 'ignored'): # i18n: bisect changeset status return _('ignored') # Try implicit sets if rev in get(repo, 'goods'): # i18n: bisect changeset status return _('good (implicit)') if rev in get(repo, 'bads'): # i18n: bisect changeset status return _('bad (implicit)') return None def printresult(ui, repo, state, displayer, nodes, good): if len(nodes) == 1: # narrowed it down to a single revision if good: ui.write(_("The first good revision is:\n")) else: ui.write(_("The first bad revision is:\n")) displayer.show(repo[nodes[0]]) extendnode = extendrange(repo, state, nodes, good) if extendnode is not None: ui.write(_('Not all ancestors of this changeset have been' ' checked.\nUse bisect --extend to continue the ' 'bisection from\nthe common ancestor, %s.\n') % extendnode) else: # multiple possible revisions if good: ui.write(_("Due to skipped revisions, the first " "good revision could be any of:\n")) else: ui.write(_("Due to skipped revisions, the first " "bad revision could be any of:\n")) for n in nodes: displayer.show(repo[n]) displayer.close()