# smartfixup.py
#
# Copyright 2016 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""apply working directory changes to changesets
The smartfixup extension provides a command to use annotate information to
amend modified chunks into the corresponding non-public changesets.
::
[smartfixup]
# only check 50 recent non-public changesets at most
maxstacksize = 50
# whether to add noise to new commits to avoid obsolescence cycle
addnoise = 1
[color]
smartfixup.node = blue bold
smartfixup.path = bold
"""
from __future__ import absolute_import
from collections import defaultdict
import linelog
from mercurial import (
cmdutil,
commands,
context,
crecord,
error,
mdiff,
node,
obsolete,
patch,
phases,
repair,
scmutil,
util,
)
from mercurial.i18n import _
testedwith = 'internal'
cmdtable = {}
command = cmdutil.command(cmdtable)
colortable = {
'smartfixup.node': 'blue bold',
'smartfixup.path': 'bold',
}
class nullui(object):
"""blank ui object doing nothing"""
debugflag = False
verbose = False
quiet = True
def __getitem__(name):
def nullfunc(*args, **kwds):
return
return nullfunc
class emptyfilecontext(object):
"""minimal filecontext representing an empty file"""
def data(self):
return ''
def node(self):
return node.nullid
def uniq(lst):
"""list -> list. remove duplicated items without changing the order"""
seen = set()
result = []
for x in lst:
if x not in seen:
seen.add(x)
result.append(x)
return result
def getdraftstack(headctx, limit=None):
"""(ctx, int?) -> [ctx]. get a linear stack of non-public changesets.
changesets are sorted in topo order, oldest first.
return at most limit items, if limit is a positive number.
merges are considered as non-draft as well. i.e. every commit
returned has and only has 1 parent.
"""
ctx = headctx
result = []
while ctx.phase() != phases.public:
if limit and len(result) >= limit:
break
parents = ctx.parents()
if len(parents) != 1:
break
result.append(ctx)
ctx = parents[0]
result.reverse()
return result
class overlaystore(object):
"""read-only, hybrid store based on a dict and ctx.
memworkingcopy: {path: content}, overrides file contents.
"""
def __init__(self, basectx, memworkingcopy):
self.basectx = basectx
self.memworkingcopy = memworkingcopy
def getfile(self, path):
"""comply with mercurial.patch.filestore.getfile"""
fctx = self.basectx[path]
if path in self.memworkingcopy:
content = self.memworkingcopy[path]
else:
content = fctx.data()
mode = (fctx.islink(), fctx.isbinary())
renamed = fctx.renamed() # False or (path, node)
return content, mode, (renamed and renamed[0])
def overlaycontext(memworkingcopy, ctx, parents=None, extra=None):
"""({path: content}, ctx, (p1node, p2node)?, {}?) -> memctx
memworkingcopy overrides file contents.
"""
# parents must contain 2 items: (node1, node2)
if parents is None:
parents = ctx.repo().changelog.parents(ctx.node())
if extra is None:
extra = ctx.extra()
date = ctx.date()
desc = ctx.description()
user = ctx.user()
files = set(ctx.files()).union(memworkingcopy.iterkeys())
store = overlaystore(ctx, memworkingcopy)
return context.makememctx(ctx.repo(), parents, desc, user, date, None,
files, store, extra=extra)
class filefixupstate(object):
"""state needed to apply fixups to a single file
internally, it keeps file contents of several revisions and a linelog.
the linelog uses odd revision numbers for original contents (fctxs passed
to __init__), and even revision numbers for fixups, like:
linelog rev 1: self.fctxs[0] (from an immutable "public" changeset)
linelog rev 2: fixups made to self.fctxs[0]
linelog rev 3: self.fctxs[1] (a child of fctxs[0])
linelog rev 4: fixups made to self.fctxs[1]
...
a typical use is like:
1. call diffwith, to calculate self.fixups
2. (optionally), present self.fixups to the user, or change it
3. call apply, to apply changes
4. read results from "finalcontents", or call getfinalcontent
"""
def __init__(self, fctxs, ui=None):
"""([fctx], ui or None) -> None
fctxs should be linear, and sorted by topo order - oldest first.
fctxs[0] will be considered as "immutable" and will not be changed.
"""
self.fctxs = fctxs
self.ui = ui or nullui()
# following fields are built from fctxs. they exist for perf reason
self.contents = [f.data() for f in fctxs]
self.contentlines = map(mdiff.splitnewlines, self.contents)
self.linelog = self._buildlinelog()
if self.ui.debugflag:
assert self._checkoutlinelog() == self.contents
# following fields will be filled later
self.chunkstats = [0, 0] # [adopted, total : int]
self.targetlines = [] # [str]
self.fixups = [] # [(linelog rev, a1, a2, b1, b2)]
self.finalcontents = [] # [str]
def diffwith(self, targetfctx, showchanges=False):
"""calculate fixups needed by examining the differences between
self.fctxs[-1] and targetfctx, chunk by chunk.
targetfctx is the target state we move towards. we may or may not be
able to get there because not all modified chunks can be amended into
a non-public fctx unambiguously.
call this only once, before apply().
update self.fixups, self.chunkstats, and self.targetlines.
"""
a = self.contents[-1]
alines = self.contentlines[-1]
b = targetfctx.data()
blines = mdiff.splitnewlines(b)
self.targetlines = blines
self.linelog.annotate(self.linelog.maxrev)
annotated = self.linelog.annotateresult # [(linelog rev, linenum)]
assert len(annotated) == len(alines)
# add a dummy end line to make insertion at the end easier
if annotated:
dummyendline = (annotated[-1][0], annotated[-1][1] + 1)
annotated.append(dummyendline)
# analyse diff blocks
for chunk in self._alldiffchunks(a, b, alines, blines):
newfixups = self._analysediffchunk(chunk, annotated)
self.chunkstats[0] += bool(newfixups) # 1 or 0
self.chunkstats[1] += 1
self.fixups += newfixups
if showchanges:
self._showchanges(alines, blines, chunk, newfixups)
def apply(self):
"""apply self.fixups. update self.linelog, self.finalcontents.
call this only once, before getfinalcontent(), after diffwith().
"""
# the following is unnecessary, as it's done by "diffwith":
# self.linelog.annotate(self.linelog.maxrev)
for rev, a1, a2, b1, b2 in reversed(self.fixups):
blines = self.targetlines[b1:b2]
if self.ui.debugflag:
idx = (max(rev - 1, 0)) // 2
self.ui.write(_('%s: chunk %d:%d -> %d lines\n')
% (node.short(self.fctxs[idx].node()),
a1, a2, len(blines)))
self.linelog.replacelines(rev, a1, a2, b1, b2)
self.finalcontents = self._checkoutlinelog()
def getfinalcontent(self, fctx):
"""(fctx) -> str. get modified file content for a given filecontext"""
idx = self.fctxs.index(fctx)
return self.finalcontents[idx]
def _analysediffchunk(self, chunk, annotated):
"""analyse a different chunk and return new fixups found
return [] if no lines from the chunk can be safely applied.
the chunk (or lines) cannot be safely applied, if, for example:
- the modified (deleted) lines belong to a public changeset
(self.fctxs[0])
- the chunk is a pure insertion and the adjacent lines (at most 2
lines) belong to different non-public changesets, or do not belong
to any non-public changesets.
- the chunk is modifying lines from different changesets.
in this case, if the number of lines deleted equals to the number
of lines added, assume it's a simple 1:1 map (could be wrong).
otherwise, give up.
- the chunk is modifying lines from a single non-public changeset,
but other revisions touch the area as well. i.e. the lines are
not continuous as seen from the linelog.
"""
a1, a2, b1, b2 = chunk
# find involved indexes from annotate result
involved = annotated[a1:a2]
if not involved: # a1 == a2
# pure insertion, check nearby lines. ignore lines belong
# to the public (first) changeset (i.e. annotated[i][0] == 1)
nearbylinenums = set([a2, max(0, a1 - 1)])
involved = [annotated[i]
for i in nearbylinenums if annotated[i][0] != 1]
involvedrevs = list(set(r for r, l in involved))
newfixups = []
if len(involvedrevs) == 1 and self._iscontinuous(a1, a2 - 1, True):
# chunk belongs to a single revision
rev = involvedrevs[0]
if rev > 1:
fixuprev = rev + 1
newfixups.append((fixuprev, a1, a2, b1, b2))
elif a2 - a1 == b2 - b1 or b1 == b2:
# 1:1 line mapping, or chunk was deleted
for i in xrange(a1, a2):
rev, linenum = annotated[i]
if rev > 1:
if b1 == b2: # deletion, simply remove that single line
nb1 = nb2 = 0
else: # 1:1 line mapping, change the corresponding rev
nb1 = b1 + i - a1
nb2 = nb1 + 1
fixuprev = rev + 1
newfixups.append((fixuprev, i, i + 1, nb1, nb2))
return self._optimizefixups(newfixups)
@staticmethod
def _alldiffchunks(a, b, alines, blines):
"""like mdiff.allblocks, but only care about differences"""
blocks = mdiff.allblocks(a, b, lines1=alines, lines2=blines)
for chunk, btype in blocks:
if btype != '!':
continue
yield chunk
def _buildlinelog(self):
"""calculate the initial linelog based on self.content{,line}s.
this is similar to running a partial "annotate".
"""
llog = linelog.linelog()
a, alines = '', []
for i in xrange(len(self.contents)):
b, blines = self.contents[i], self.contentlines[i]
llrev = i * 2 + 1
chunks = self._alldiffchunks(a, b, alines, blines)
for a1, a2, b1, b2 in reversed(list(chunks)):
llog.replacelines(llrev, a1, a2, b1, b2)
a, alines = b, blines
return llog
def _checkoutlinelog(self):
"""() -> [str]. check out file contents from linelog"""
contents = []
for i in xrange(len(self.contents)):
rev = (i + 1) * 2
self.linelog.annotate(rev)
content = ''.join(map(self._getline, self.linelog.annotateresult))
contents.append(content)
return contents
def _getline(self, lineinfo):
"""((rev, linenum)) -> str. convert rev+line number to line content"""
rev, linenum = lineinfo
if rev & 1: # odd: original line taken from fctxs
return self.contentlines[rev // 2][linenum]
else: # even: fixup line from targetfctx
return self.targetlines[linenum]
def _iscontinuous(self, a1, a2, closedinterval=False):
"""(a1, a2 : int) -> bool
check if these lines are continuous. i.e. no other insertions or
deletions (from other revisions) among these lines.
closedinterval decides whether a2 should be included or not. i.e. is
it [a1, a2), or [a1, a2] ?
"""
if a1 >= a2:
return True
llog = self.linelog
offset1 = llog.getoffset(a1)
offset2 = llog.getoffset(a2) + int(closedinterval)
linesinbetween = llog.getalllines(offset1, offset2)
return len(linesinbetween) == a2 - a1 + int(closedinterval)
def _optimizefixups(self, fixups):
"""[(rev, a1, a2, b1, b2)] -> [(rev, a1, a2, b1, b2)].
merge adjacent fixups to make them less fragmented.
"""
result = []
pcurrentchunk = [[-1, -1, -1, -1, -1]]
def pushchunk():
if pcurrentchunk[0][0] != -1:
result.append(tuple(pcurrentchunk[0]))
for i, chunk in enumerate(fixups):
rev, a1, a2, b1, b2 = chunk
lastrev = pcurrentchunk[0][0]
lasta2 = pcurrentchunk[0][2]
lastb2 = pcurrentchunk[0][4]
if (a1 == lasta2 and b1 == lastb2 and rev == lastrev and
self._iscontinuous(max(a1 - 1, 0), a1)):
# merge into currentchunk
pcurrentchunk[0][2] = a2
pcurrentchunk[0][4] = b2
else:
pushchunk()
pcurrentchunk[0] = list(chunk)
pushchunk()
return result
def _showchanges(self, alines, blines, chunk, fixups):
ui = self.ui
if ui.quiet:
return
def label(line, label):
if line.endswith('\n'):
line = line[:-1]
return ui.label(line, label)
# this is not optimized for perf but _showchanges only gets executed
# with an extra command-line flag.
a1, a2, b1, b2 = chunk
aidxs, bidxs = [0] * (a2 - a1), [0] * (b2 - b1)
for idx, fa1, fa2, fb1, fb2 in fixups:
for i in xrange(fa1, fa2):
aidxs[i - a1] = (max(idx, 1) - 1) // 2
for i in xrange(fb1, fb2):
bidxs[i - b1] = (max(idx, 1) - 1) // 2
buf = [] # [(idx, content)]
buf.append((0, label('@@ -%d,%d +%d,%d @@'
% (a1, a2 - a1, b1, b2 - b1), 'diff.hunk')))
buf += [(aidxs[i - a1], label('-' + alines[i], 'diff.deleted'))
for i in xrange(a1, a2)]
buf += [(bidxs[i - b1], label('+' + blines[i], 'diff.inserted'))
for i in xrange(b1, b2)]
for idx, line in buf:
shortnode = idx and node.short(self.fctxs[idx].node()) or ''
ui.write(ui.label(shortnode[0:7].ljust(8), 'smartfixup.node') +
line + '\n')
class fixupstate(object):
"""state needed to run smartfixup
internally, it keeps paths and filefixupstates.
a typical use is like filefixupstates:
1. call diffwith, to calculate fixups
2. (optionally), present fixups to the user, or edit fixups
3. call apply, to apply changes to memory
4. call commit, to commit changes to hg database
"""
def __init__(self, stack, ui=None):
"""([ctx], ui or None) -> None
stack: should be linear, and sorted by topo order - oldest first.
all commits in stack are considered mutable.
"""
assert stack
self.ui = ui or nullui()
self.stack = stack
self.repo = stack[-1].repo().unfiltered()
# following fields will be filled later
self.paths = [] # [str]
self.fixupmap = {} # {path: filefixupstate}
self.replacemap = {} # {oldnode: newnode or None}
self.finalnode = None # head after all fixups
def diffwith(self, targetctx, match=None, showchanges=False):
"""diff and prepare fixups. update self.fixupmap, self.paths"""
# only care about modified files
self.paths = self.stack[-1].status(targetctx, match).modified
# prepare the filefixupstate
pctx = self.stack[0].p1()
for path in self.paths:
if self.ui.debugflag:
self.ui.write(_('calculating fixups for %s\n') % path)
targetfctx = targetctx[path]
fctxs = uniq(ctx[path] for ctx in self.stack if path in ctx)
# ignore symbolic links or binary files
if any(f.islink() or util.binary(f.data())
for f in [targetfctx] + fctxs):
continue
if targetfctx.data() == fctxs[-1].data():
continue
# insert an immutable (public) fctx at the beginning
if path in pctx:
fctxs.insert(0, pctx[path])
else:
fctxs.insert(0, emptyfilecontext())
fstate = filefixupstate(fctxs, ui=self.ui)
if showchanges:
colorpath = self.ui.label(path, 'smartfixup.path')
header = 'showing changes for ' + colorpath
self.ui.write(header + '\n')
fstate.diffwith(targetfctx, showchanges=showchanges)
self.fixupmap[path] = fstate
def apply(self):
"""apply fixups to individual filefixupstates"""
for path, state in self.fixupmap.iteritems():
if self.ui.debugflag:
self.ui.write(_('applying fixups to %s\n') % path)
state.apply()
@property
def chunkstats(self):
"""-> {path: chunkstats}. collect chunkstats from filefixupstates"""
return dict((path, state.chunkstats)
for path, state in self.fixupmap.iteritems())
def commit(self):
"""commit changes. update self.finalnode, self.replacemap"""
with self.repo.wlock(): # update bookmarks
with self.repo.lock(): # commit
with self.repo.transaction('smartfixup') as tr:
self._commitstack()
self._movebookmarks(tr)
if self.repo['.'].node() in self.replacemap:
self._moveworkingdirectoryparent()
if self._useobsolete:
self._obsoleteoldcommits()
if not self._useobsolete: # strip must be outside transactions
self._stripoldcommits()
return self.finalnode
def printchunkstats(self):
"""print things like '1 of 2 chunks(s) applied'"""
ui = self.ui
chunkstats = self.chunkstats
if ui.verbose:
# chunkstats for each file
for path, stat in chunkstats.iteritems():
if stat[0]:
ui.write(_('%s: %d of %d chunk(s) applied\n')
% (path, stat[0], stat[1]))
elif not ui.quiet:
# a summary for all files
stats = chunkstats.values()
applied, total = (sum(s[i] for s in stats) for i in (0, 1))
ui.write(_('%d of %d chunks(s) applied\n') % (applied, total))
def _commitstack(self):
"""make new commits. update self.finalnode, self.replacemap.
it is splitted from "commit" to avoid too much indentation.
"""
# last node (20-char) committed by us
lastcommitted = None
# p1 which overrides the parent of the next commit, "None" means use
# the original parent unchanged
nextp1 = None
for ctx in self.stack:
memworkingcopy = self._getnewfilecontents(ctx)
if not memworkingcopy and not lastcommitted:
# nothing changed, nothing commited
nextp1 = ctx
continue
msg = ''
if self._willbecomenoop(memworkingcopy, ctx, nextp1):
# changeset is no longer necessary
self.replacemap[ctx.node()] = None
msg = _('became empty and was dropped')
else:
# changset needs re-commit
nodestr = self._commitsingle(memworkingcopy, ctx, p1=nextp1)
lastcommitted = self.repo[nodestr]
nextp1 = lastcommitted
self.replacemap[ctx.node()] = lastcommitted.node()
if memworkingcopy:
msg = _('%d file(s) changed, became %s') % (
len(memworkingcopy), self._ctx2str(lastcommitted))
else:
msg = _('became %s') % self._ctx2str(lastcommitted)
if self.ui.verbose and msg:
self.ui.write(_('%s: %s\n') % (self._ctx2str(ctx), msg))
self.finalnode = lastcommitted and lastcommitted.node()
def _ctx2str(self, ctx):
if self.ui.debugflag:
return ctx.hex()
else:
return node.short(ctx.node())
def _getnewfilecontents(self, ctx):
"""(ctx) -> {path: str}
fetch file contents from filefixupstates.
return the working copy overrides - files different from ctx.
"""
result = {}
for path in self.paths:
if path not in ctx:
continue
fctx = ctx[path]
content = fctx.data()
newcontent = self.fixupmap[path].getfinalcontent(fctx)
if content != newcontent:
result[path] = newcontent
return result
def _movebookmarks(self, tr):
repo = self.repo
needupdate = [(name, self.replacemap[hsh])
for name, hsh in repo._bookmarks.iteritems()
if hsh in self.replacemap]
for name, hsh in needupdate:
if hsh:
repo._bookmarks[name] = hsh
if self.ui.verbose:
self.ui.write(_('moving bookmark %s to %s\n')
% (name, node.hex(hsh)))
else:
del repo._bookmarks[name]
if self.ui.verbose:
self.ui.write(_('deleting bookmark %s\n') % name)
repo._bookmarks.recordchange(tr)
def _moveworkingdirectoryparent(self):
ctx = self.repo[self.finalnode]
self.repo.dirstate.beginparentchange()
try:
self.repo.dirstate.rebuild(ctx.node(), ctx.manifest(), self.paths)
finally:
self.repo.dirstate.endparentchange()
@staticmethod
def _willbecomenoop(memworkingcopy, ctx, pctx=None):
"""({path: content}, ctx, ctx) -> bool. test if a commit will be noop
if it will become an empty commit (does not change anything, after the
memworkingcopy overrides), return True. otherwise return False.
"""
if not pctx:
parents = ctx.parents()
if len(parents) != 1:
return False
pctx = parents[0]
if set(ctx.files()) != set(memworkingcopy.iterkeys()):
return False
for path, content in memworkingcopy.iteritems():
if path not in pctx or path not in ctx:
return False
fctx = ctx[path]
pfctx = pctx[path]
if pfctx.flags() != fctx.flags():
return False
if pfctx.data() != content:
return False
return True
def _commitsingle(self, memworkingcopy, ctx, p1=None):
"""(ctx, {path: content}, node) -> node. make a single commit
the commit is a clone from ctx, with a (optionally) different p1, and
different file contents replaced by memworkingcopy.
"""
parents = p1 and (p1, node.nullid)
extra = ctx.extra()
if self._useobsolete and self.ui.configbool('smartfixup', 'addnoise',
True):
extra['smartfixup_source'] = ctx.hex()
mctx = overlaycontext(memworkingcopy, ctx, parents, extra=extra)
return mctx.commit()
@util.propertycache
def _useobsolete(self):
"""() -> bool"""
return obsolete.isenabled(self.repo, obsolete.createmarkersopt)
def _obsoleteoldcommits(self):
relations = [(self.repo[k], v and (self.repo[v],) or ())
for k, v in self.replacemap.iteritems()]
if relations:
obsolete.createmarkers(self.repo, relations)
def _stripoldcommits(self):
nodelist = self.replacemap.keys()
if nodelist:
repair.strip(self.repo.ui, self.repo, nodelist)
def _parsechunk(hunk):
"""(crecord.uihunk or patch.recordhunk) -> (path, (a1, a2, [bline]))"""
if type(hunk) not in (crecord.uihunk, patch.recordhunk):
return None, None
path = hunk.header.filename()
a1 = hunk.fromline + len(hunk.before) - 1
# remove before and after context
hunk.before = hunk.after = []
buf = util.stringio()
hunk.write(buf)
patchlines = mdiff.splitnewlines(buf.getvalue())
# hunk.prettystr() will update hunk.removed
a2 = a1 + hunk.removed
blines = [l[1:] for l in patchlines[1:] if l[0] != '-']
return path, (a1, a2, blines)
def overlaydiffcontext(ctx, chunks):
"""(ctx, [crecord.uihunk]) -> memctx
return a memctx with some [1] patches (chunks) applied to ctx.
[1]: modifications are handled. renames, mode changes, etc. are ignored.
"""
# sadly the applying-patch logic is hardly reusable, and messy:
# 1. the core logic "_applydiff" is too heavy - it writes .rej files, it
# needs a file stream of a patch and will re-parse it, while we have
# structured hunk objects at hand.
# 2. a lot of different implementations about "chunk" (patch.hunk,
# patch.recordhunk, crecord.uihunk)
# as we only care about applying changes to modified files, no mode
# change, no binary diff, and no renames, it's probably okay to
# re-invent the logic using much simpler code here.
memworkingcopy = {} # {path: content}
patchmap = defaultdict(lambda: []) # {path: [(a1, a2, [bline])]}
for path, info in map(_parsechunk, chunks):
if not path or not info:
continue
patchmap[path].append(info)
for path, patches in patchmap.iteritems():
if path not in ctx or not patches:
continue
patches.sort(reverse=True)
lines = mdiff.splitnewlines(ctx[path].data())
for a1, a2, blines in patches:
lines[a1:a2] = blines
memworkingcopy[path] = ''.join(lines)
return overlaycontext(memworkingcopy, ctx)
def smartfixup(ui, repo, stack=None, targetctx=None, pats=None, opts=None):
"""pick fixup chunks from targetctx, apply them to stack.
if targetctx is None, the working copy context will be used.
if stack is None, the current draft stack will be used.
return fixupstate.
"""
if stack is None:
limit = ui.configint('smartfixup', 'maxstacksize', 50)
stack = getdraftstack(repo['.'], limit)
if limit and len(stack) >= limit:
ui.warn(_('smartfixup: only the recent %d changesets will '
'be analysed\n')
% limit)
if not stack:
raise error.Abort(_('no changset to change'))
if targetctx is None: # default to working copy
targetctx = repo[None]
if pats is None:
pats = ()
if opts is None:
opts = {}
state = fixupstate(stack, ui=ui)
matcher = scmutil.match(targetctx, pats, opts)
if opts.get('interactive'):
diff = patch.diff(repo, stack[-1].node(), targetctx.node(), matcher)
origchunks = patch.parsepatch(diff)
chunks = cmdutil.recordfilter(ui, origchunks)[0]
targetctx = overlaydiffcontext(stack[-1], chunks)
state.diffwith(targetctx, matcher, showchanges=opts.get('print_changes'))
if not opts.get('dry_run'):
state.apply()
if state.commit():
state.printchunkstats()
elif not ui.quiet:
ui.write(_('nothing applied\n'))
return state
@command('^smartfixup|sf',
[('p', 'print-changes', None,
_('print which changesets are modified by which changes')),
('i', 'interactive', None,
_('interactively select which chunks to apply (EXPERIMENTAL)')),
] + commands.dryrunopts + commands.walkopts,
_('hg smartfixup [OPTION] [FILE]...'))
def smartfixupcmd(ui, repo, *pats, **opts):
"""incorporate corrections into the stack of draft changesets
Smartfixup analyzes each change in your working directory and attempts to
amend the changed lines into the changesets in your stack that first
introduced those lines.
If smartfixup cannot find an unambiguous changeset to amend for a change,
that change will be left in the working directory, untouched. They can be
observed by :hg:`status` or :hg:`diff` afterwards. In other words,
smartfixup does not write to the working directory.
Changesets outside the revset `::. and not public() and not merge()` will
not be changed.
Changesets that become empty after applying the changes will be deleted.
If in doubt, run :hg:`smartfixup -pn` to preview what changesets will
be amended by what changed lines, without actually changing anything.
Returns 0 on success, 1 if all chunks were ignored and nothing amended.
"""
state = smartfixup(ui, repo, pats=pats, opts=opts)
if sum(s[0] for s in state.chunkstats.values()) == 0:
return 1