linelog: add a Python implementation of the linelog datastructure
This datastructure was originally developed by Jun Wu at Facebook,
inspired by SCCS weaves. It's useful as a cache for blame information,
but also is the magic that makes `hg absorb` easy to implement. In
service of importing the code to Mercurial, I wanted to actually
/understand/ it, and once I did I decided to take a run at
implementing it.
The help/internals/linelog.txt document is the README from Jun Wu's
implementaiton. It all applies to our linelog implementation.
Differential Revision: https://phab.mercurial-scm.org/D3990
# show.py - Extension implementing `hg show`
#
# Copyright 2017 Gregory Szorc <gregory.szorc@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""unified command to show various repository information (EXPERIMENTAL)
This extension provides the :hg:`show` command, which provides a central
command for displaying commonly-accessed repository data and views of that
data.
The following config options can influence operation.
``commands``
------------
``show.aliasprefix``
List of strings that will register aliases for views. e.g. ``s`` will
effectively set config options ``alias.s<view> = show <view>`` for all
views. i.e. `hg swork` would execute `hg show work`.
Aliases that would conflict with existing registrations will not be
performed.
"""
from __future__ import absolute_import
from mercurial.i18n import _
from mercurial.node import (
nullrev,
)
from mercurial import (
cmdutil,
commands,
destutil,
error,
formatter,
graphmod,
logcmdutil,
phases,
pycompat,
registrar,
revset,
revsetlang,
scmutil,
)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'
cmdtable = {}
command = registrar.command(cmdtable)
revsetpredicate = registrar.revsetpredicate()
class showcmdfunc(registrar._funcregistrarbase):
"""Register a function to be invoked for an `hg show <thing>`."""
# Used by _formatdoc().
_docformat = '%s -- %s'
def _extrasetup(self, name, func, fmtopic=None, csettopic=None):
"""Called with decorator arguments to register a show view.
``name`` is the sub-command name.
``func`` is the function being decorated.
``fmtopic`` is the topic in the style that will be rendered for
this view.
``csettopic`` is the topic in the style to be used for a changeset
printer.
If ``fmtopic`` is specified, the view function will receive a
formatter instance. If ``csettopic`` is specified, the view
function will receive a changeset printer.
"""
func._fmtopic = fmtopic
func._csettopic = csettopic
showview = showcmdfunc()
@command('show', [
# TODO: Switch this template flag to use cmdutil.formatteropts if
# 'hg show' becomes stable before --template/-T is stable. For now,
# we are putting it here without the '(EXPERIMENTAL)' flag because it
# is an important part of the 'hg show' user experience and the entire
# 'hg show' experience is experimental.
('T', 'template', '', ('display with template'), _('TEMPLATE')),
], _('VIEW'))
def show(ui, repo, view=None, template=None):
"""show various repository information
A requested view of repository data is displayed.
If no view is requested, the list of available views is shown and the
command aborts.
.. note::
There are no backwards compatibility guarantees for the output of this
command. Output may change in any future Mercurial release.
Consumers wanting stable command output should specify a template via
``-T/--template``.
List of available views:
"""
if ui.plain() and not template:
hint = _('invoke with -T/--template to control output format')
raise error.Abort(_('must specify a template in plain mode'), hint=hint)
views = showview._table
if not view:
ui.pager('show')
# TODO consider using formatter here so available views can be
# rendered to custom format.
ui.write(_('available views:\n'))
ui.write('\n')
for name, func in sorted(views.items()):
ui.write(('%s\n') % pycompat.sysbytes(func.__doc__))
ui.write('\n')
raise error.Abort(_('no view requested'),
hint=_('use "hg show VIEW" to choose a view'))
# TODO use same logic as dispatch to perform prefix matching.
if view not in views:
raise error.Abort(_('unknown view: %s') % view,
hint=_('run "hg show" to see available views'))
template = template or 'show'
fn = views[view]
ui.pager('show')
if fn._fmtopic:
fmtopic = 'show%s' % fn._fmtopic
with ui.formatter(fmtopic, {'template': template}) as fm:
return fn(ui, repo, fm)
elif fn._csettopic:
ref = 'show%s' % fn._csettopic
spec = formatter.lookuptemplate(ui, ref, template)
displayer = logcmdutil.changesettemplater(ui, repo, spec, buffered=True)
return fn(ui, repo, displayer)
else:
return fn(ui, repo)
@showview('bookmarks', fmtopic='bookmarks')
def showbookmarks(ui, repo, fm):
"""bookmarks and their associated changeset"""
marks = repo._bookmarks
if not len(marks):
# This is a bit hacky. Ideally, templates would have a way to
# specify an empty output, but we shouldn't corrupt JSON while
# waiting for this functionality.
if not isinstance(fm, formatter.jsonformatter):
ui.write(_('(no bookmarks set)\n'))
return
revs = [repo[node].rev() for node in marks.values()]
active = repo._activebookmark
longestname = max(len(b) for b in marks)
nodelen = longestshortest(repo, revs)
for bm, node in sorted(marks.items()):
fm.startitem()
fm.context(ctx=repo[node])
fm.write('bookmark', '%s', bm)
fm.write('node', fm.hexfunc(node), fm.hexfunc(node))
fm.data(active=bm == active,
longestbookmarklen=longestname,
nodelen=nodelen)
@showview('stack', csettopic='stack')
def showstack(ui, repo, displayer):
"""current line of work"""
wdirctx = repo['.']
if wdirctx.rev() == nullrev:
raise error.Abort(_('stack view only available when there is a '
'working directory'))
if wdirctx.phase() == phases.public:
ui.write(_('(empty stack; working directory parent is a published '
'changeset)\n'))
return
# TODO extract "find stack" into a function to facilitate
# customization and reuse.
baserev = destutil.stackbase(ui, repo)
basectx = None
if baserev is None:
baserev = wdirctx.rev()
stackrevs = {wdirctx.rev()}
else:
stackrevs = set(repo.revs('%d::.', baserev))
ctx = repo[baserev]
if ctx.p1().rev() != nullrev:
basectx = ctx.p1()
# And relevant descendants.
branchpointattip = False
cl = repo.changelog
for rev in cl.descendants([wdirctx.rev()]):
ctx = repo[rev]
# Will only happen if . is public.
if ctx.phase() == phases.public:
break
stackrevs.add(ctx.rev())
# ctx.children() within a function iterating on descandants
# potentially has severe performance concerns because revlog.children()
# iterates over all revisions after ctx's node. However, the number of
# draft changesets should be a reasonably small number. So even if
# this is quadratic, the perf impact should be minimal.
if len(ctx.children()) > 1:
branchpointattip = True
break
stackrevs = list(sorted(stackrevs, reverse=True))
# Find likely target heads for the current stack. These are likely
# merge or rebase targets.
if basectx:
# TODO make this customizable?
newheads = set(repo.revs('heads(%d::) - %ld - not public()',
basectx.rev(), stackrevs))
else:
newheads = set()
allrevs = set(stackrevs) | newheads | set([baserev])
nodelen = longestshortest(repo, allrevs)
try:
cmdutil.findcmd('rebase', commands.table)
haverebase = True
except (error.AmbiguousCommand, error.UnknownCommand):
haverebase = False
# TODO use templating.
# TODO consider using graphmod. But it may not be necessary given
# our simplicity and the customizations required.
# TODO use proper graph symbols from graphmod
tres = formatter.templateresources(ui, repo)
shortesttmpl = formatter.maketemplater(ui, '{shortest(node, %d)}' % nodelen,
resources=tres)
def shortest(ctx):
return shortesttmpl.renderdefault({'ctx': ctx, 'node': ctx.hex()})
# We write out new heads to aid in DAG awareness and to help with decision
# making on how the stack should be reconciled with commits made since the
# branch point.
if newheads:
# Calculate distance from base so we can render the count and so we can
# sort display order by commit distance.
revdistance = {}
for head in newheads:
# There is some redundancy in DAG traversal here and therefore
# room to optimize.
ancestors = cl.ancestors([head], stoprev=basectx.rev())
revdistance[head] = len(list(ancestors))
sourcectx = repo[stackrevs[-1]]
sortedheads = sorted(newheads, key=lambda x: revdistance[x],
reverse=True)
for i, rev in enumerate(sortedheads):
ctx = repo[rev]
if i:
ui.write(': ')
else:
ui.write(' ')
ui.write(('o '))
displayer.show(ctx, nodelen=nodelen)
displayer.flush(ctx)
ui.write('\n')
if i:
ui.write(':/')
else:
ui.write(' /')
ui.write(' (')
ui.write(_('%d commits ahead') % revdistance[rev],
label='stack.commitdistance')
if haverebase:
# TODO may be able to omit --source in some scenarios
ui.write('; ')
ui.write(('hg rebase --source %s --dest %s' % (
shortest(sourcectx), shortest(ctx))),
label='stack.rebasehint')
ui.write(')\n')
ui.write(':\n: ')
ui.write(_('(stack head)\n'), label='stack.label')
if branchpointattip:
ui.write(' \\ / ')
ui.write(_('(multiple children)\n'), label='stack.label')
ui.write(' |\n')
for rev in stackrevs:
ctx = repo[rev]
symbol = '@' if rev == wdirctx.rev() else 'o'
if newheads:
ui.write(': ')
else:
ui.write(' ')
ui.write(symbol, ' ')
displayer.show(ctx, nodelen=nodelen)
displayer.flush(ctx)
ui.write('\n')
# TODO display histedit hint?
if basectx:
# Vertically and horizontally separate stack base from parent
# to reinforce stack boundary.
if newheads:
ui.write(':/ ')
else:
ui.write(' / ')
ui.write(_('(stack base)'), '\n', label='stack.label')
ui.write(('o '))
displayer.show(basectx, nodelen=nodelen)
displayer.flush(basectx)
ui.write('\n')
@revsetpredicate('_underway([commitage[, headage]])')
def underwayrevset(repo, subset, x):
args = revset.getargsdict(x, 'underway', 'commitage headage')
if 'commitage' not in args:
args['commitage'] = None
if 'headage' not in args:
args['headage'] = None
# We assume callers of this revset add a topographical sort on the
# result. This means there is no benefit to making the revset lazy
# since the topographical sort needs to consume all revs.
#
# With this in mind, we build up the set manually instead of constructing
# a complex revset. This enables faster execution.
# Mutable changesets (non-public) are the most important changesets
# to return. ``not public()`` will also pull in obsolete changesets if
# there is a non-obsolete changeset with obsolete ancestors. This is
# why we exclude obsolete changesets from this query.
rs = 'not public() and not obsolete()'
rsargs = []
if args['commitage']:
rs += ' and date(%s)'
rsargs.append(revsetlang.getstring(args['commitage'],
_('commitage requires a string')))
mutable = repo.revs(rs, *rsargs)
relevant = revset.baseset(mutable)
# Add parents of mutable changesets to provide context.
relevant += repo.revs('parents(%ld)', mutable)
# We also pull in (public) heads if they a) aren't closing a branch
# b) are recent.
rs = 'head() and not closed()'
rsargs = []
if args['headage']:
rs += ' and date(%s)'
rsargs.append(revsetlang.getstring(args['headage'],
_('headage requires a string')))
relevant += repo.revs(rs, *rsargs)
# Add working directory parent.
wdirrev = repo['.'].rev()
if wdirrev != nullrev:
relevant += revset.baseset({wdirrev})
return subset & relevant
@showview('work', csettopic='work')
def showwork(ui, repo, displayer):
"""changesets that aren't finished"""
# TODO support date-based limiting when calling revset.
revs = repo.revs('sort(_underway(), topo)')
nodelen = longestshortest(repo, revs)
revdag = graphmod.dagwalker(repo, revs)
ui.setconfig('experimental', 'graphshorten', True)
logcmdutil.displaygraph(ui, repo, revdag, displayer, graphmod.asciiedges,
props={'nodelen': nodelen})
def extsetup(ui):
# Alias `hg <prefix><view>` to `hg show <view>`.
for prefix in ui.configlist('commands', 'show.aliasprefix'):
for view in showview._table:
name = '%s%s' % (prefix, view)
choice, allcommands = cmdutil.findpossible(name, commands.table,
strict=True)
# This alias is already a command name. Don't set it.
if name in choice:
continue
# Same for aliases.
if ui.config('alias', name, None):
continue
ui.setconfig('alias', name, 'show %s' % view, source='show')
def longestshortest(repo, revs, minlen=4):
"""Return the length of the longest shortest node to identify revisions.
The result of this function can be used with the ``shortest()`` template
function to ensure that a value is unique and unambiguous for a given
set of nodes.
The number of revisions in the repo is taken into account to prevent
a numeric node prefix from conflicting with an integer revision number.
If we fail to do this, a value of e.g. ``10023`` could mean either
revision 10023 or node ``10023abc...``.
"""
if not revs:
return minlen
cl = repo.changelog
return max(len(scmutil.shortesthexnodeidprefix(repo, cl.node(r), minlen))
for r in revs)
# Adjust the docstring of the show command so it shows all registered views.
# This is a bit hacky because it runs at the end of module load. When moved
# into core or when another extension wants to provide a view, we'll need
# to do this more robustly.
# TODO make this more robust.
def _updatedocstring():
longest = max(map(len, showview._table.keys()))
entries = []
for key in sorted(showview._table.keys()):
entries.append(pycompat.sysstr(' %s %s' % (
key.ljust(longest), showview._table[key]._origdoc)))
cmdtable['show'][0].__doc__ = pycompat.sysstr('%s\n\n%s\n ') % (
cmdtable['show'][0].__doc__.rstrip(),
pycompat.sysstr('\n\n').join(entries))
_updatedocstring()