sparse: add comment for an if condition which I tried to refactor

I tried to refactor this if condition and make it part of the if-else above but
tests failed. I decided to add a comment about the check we are doing and why
it's a separate if.

Differential Revision: https://phab.mercurial-scm.org/D8833

mercurial/sparse.py

@@ -1,828 +1,834 b''
 # sparse.py - functionality for sparse checkouts
 #
 # Copyright 2014 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.
 
 from __future__ import absolute_import
 
 import os
 
 from .i18n import _
 from .node import (
     hex,
     nullid,
 )
 from . import (
     error,
     match as matchmod,
     merge as mergemod,
     mergestate as mergestatemod,
     pathutil,
     pycompat,
     scmutil,
     util,
 )
 from .utils import hashutil
 
 # Whether sparse features are enabled. This variable is intended to be
 # temporary to facilitate porting sparse to core. It should eventually be
 # a per-repo option, possibly a repo requirement.
 enabled = False
 
 
 def parseconfig(ui, raw, action):
     """Parse sparse config file content.
 
     action is the command which is trigerring this read, can be narrow, sparse
 
     Returns a tuple of includes, excludes, and profiles.
     """
     includes = set()
     excludes = set()
     profiles = set()
     current = None
     havesection = False
 
     for line in raw.split(b'\n'):
         line = line.strip()
         if not line or line.startswith(b'#'):
             # empty or comment line, skip
             continue
         elif line.startswith(b'%include '):
             line = line[9:].strip()
             if line:
                 profiles.add(line)
         elif line == b'[include]':
             if havesection and current != includes:
                 # TODO pass filename into this API so we can report it.
                 raise error.Abort(
                     _(
                         b'%(action)s config cannot have includes '
                         b'after excludes'
                     )
                     % {b'action': action}
                 )
             havesection = True
             current = includes
             continue
         elif line == b'[exclude]':
             havesection = True
             current = excludes
         elif line:
             if current is None:
                 raise error.Abort(
                     _(
                         b'%(action)s config entry outside of '
                         b'section: %(line)s'
                     )
                     % {b'action': action, b'line': line},
                     hint=_(
                         b'add an [include] or [exclude] line '
                         b'to declare the entry type'
                     ),
                 )
 
             if line.strip().startswith(b'/'):
                 ui.warn(
                     _(
                         b'warning: %(action)s profile cannot use'
                         b' paths starting with /, ignoring %(line)s\n'
                     )
                     % {b'action': action, b'line': line}
                 )
                 continue
             current.add(line)
 
     return includes, excludes, profiles
 
 
 # Exists as separate function to facilitate monkeypatching.
 def readprofile(repo, profile, changeid):
     """Resolve the raw content of a sparse profile file."""
     # TODO add some kind of cache here because this incurs a manifest
     # resolve and can be slow.
     return repo.filectx(profile, changeid=changeid).data()
 
 
 def patternsforrev(repo, rev):
     """Obtain sparse checkout patterns for the given rev.
 
     Returns a tuple of iterables representing includes, excludes, and
     patterns.
     """
     # Feature isn't enabled. No-op.
     if not enabled:
         return set(), set(), set()
 
     raw = repo.vfs.tryread(b'sparse')
     if not raw:
         return set(), set(), set()
 
     if rev is None:
         raise error.Abort(
             _(b'cannot parse sparse patterns from working directory')
         )
 
     includes, excludes, profiles = parseconfig(repo.ui, raw, b'sparse')
     ctx = repo[rev]
 
     if profiles:
         visited = set()
         while profiles:
             profile = profiles.pop()
             if profile in visited:
                 continue
 
             visited.add(profile)
 
             try:
                 raw = readprofile(repo, profile, rev)
             except error.ManifestLookupError:
                 msg = (
                     b"warning: sparse profile '%s' not found "
                     b"in rev %s - ignoring it\n" % (profile, ctx)
                 )
                 # experimental config: sparse.missingwarning
                 if repo.ui.configbool(b'sparse', b'missingwarning'):
                     repo.ui.warn(msg)
                 else:
                     repo.ui.debug(msg)
                 continue
 
             pincludes, pexcludes, subprofs = parseconfig(
                 repo.ui, raw, b'sparse'
             )
             includes.update(pincludes)
             excludes.update(pexcludes)
             profiles.update(subprofs)
 
         profiles = visited
 
     if includes:
         includes.add(b'.hg*')
 
     return includes, excludes, profiles
 
 
 def activeconfig(repo):
     """Determine the active sparse config rules.
 
     Rules are constructed by reading the current sparse config and bringing in
     referenced profiles from parents of the working directory.
     """
     revs = [
         repo.changelog.rev(node)
         for node in repo.dirstate.parents()
         if node != nullid
     ]
 
     allincludes = set()
     allexcludes = set()
     allprofiles = set()
 
     for rev in revs:
         includes, excludes, profiles = patternsforrev(repo, rev)
         allincludes |= includes
         allexcludes |= excludes
         allprofiles |= profiles
 
     return allincludes, allexcludes, allprofiles
 
 
 def configsignature(repo, includetemp=True):
     """Obtain the signature string for the current sparse configuration.
 
     This is used to construct a cache key for matchers.
     """
     cache = repo._sparsesignaturecache
 
     signature = cache.get(b'signature')
 
     if includetemp:
         tempsignature = cache.get(b'tempsignature')
     else:
         tempsignature = b'0'
 
     if signature is None or (includetemp and tempsignature is None):
         signature = hex(hashutil.sha1(repo.vfs.tryread(b'sparse')).digest())
         cache[b'signature'] = signature
 
         if includetemp:
             raw = repo.vfs.tryread(b'tempsparse')
             tempsignature = hex(hashutil.sha1(raw).digest())
             cache[b'tempsignature'] = tempsignature
 
     return b'%s %s' % (signature, tempsignature)
 
 
 def writeconfig(repo, includes, excludes, profiles):
     """Write the sparse config file given a sparse configuration."""
     with repo.vfs(b'sparse', b'wb') as fh:
         for p in sorted(profiles):
             fh.write(b'%%include %s\n' % p)
 
         if includes:
             fh.write(b'[include]\n')
             for i in sorted(includes):
                 fh.write(i)
                 fh.write(b'\n')
 
         if excludes:
             fh.write(b'[exclude]\n')
             for e in sorted(excludes):
                 fh.write(e)
                 fh.write(b'\n')
 
     repo._sparsesignaturecache.clear()
 
 
 def readtemporaryincludes(repo):
     raw = repo.vfs.tryread(b'tempsparse')
     if not raw:
         return set()
 
     return set(raw.split(b'\n'))
 
 
 def writetemporaryincludes(repo, includes):
     repo.vfs.write(b'tempsparse', b'\n'.join(sorted(includes)))
     repo._sparsesignaturecache.clear()
 
 
 def addtemporaryincludes(repo, additional):
     includes = readtemporaryincludes(repo)
     for i in additional:
         includes.add(i)
     writetemporaryincludes(repo, includes)
 
 
 def prunetemporaryincludes(repo):
     if not enabled or not repo.vfs.exists(b'tempsparse'):
         return
 
     s = repo.status()
     if s.modified or s.added or s.removed or s.deleted:
         # Still have pending changes. Don't bother trying to prune.
         return
 
     sparsematch = matcher(repo, includetemp=False)
     dirstate = repo.dirstate
     actions = []
     dropped = []
     tempincludes = readtemporaryincludes(repo)
     for file in tempincludes:
         if file in dirstate and not sparsematch(file):
             message = _(b'dropping temporarily included sparse files')
             actions.append((file, None, message))
             dropped.append(file)
 
     typeactions = mergemod.emptyactions()
     typeactions[b'r'] = actions
     mergemod.applyupdates(
         repo, typeactions, repo[None], repo[b'.'], False, wantfiledata=False
     )
 
     # Fix dirstate
     for file in dropped:
         dirstate.drop(file)
 
     repo.vfs.unlink(b'tempsparse')
     repo._sparsesignaturecache.clear()
     msg = _(
         b'cleaned up %d temporarily added file(s) from the '
         b'sparse checkout\n'
     )
     repo.ui.status(msg % len(tempincludes))
 
 
 def forceincludematcher(matcher, includes):
     """Returns a matcher that returns true for any of the forced includes
     before testing against the actual matcher."""
     kindpats = [(b'path', include, b'') for include in includes]
     includematcher = matchmod.includematcher(b'', kindpats)
     return matchmod.unionmatcher([includematcher, matcher])
 
 
 def matcher(repo, revs=None, includetemp=True):
     """Obtain a matcher for sparse working directories for the given revs.
 
     If multiple revisions are specified, the matcher is the union of all
     revs.
 
     ``includetemp`` indicates whether to use the temporary sparse profile.
     """
     # If sparse isn't enabled, sparse matcher matches everything.
     if not enabled:
         return matchmod.always()
 
     if not revs or revs == [None]:
         revs = [
             repo.changelog.rev(node)
             for node in repo.dirstate.parents()
             if node != nullid
         ]
 
     signature = configsignature(repo, includetemp=includetemp)
 
     key = b'%s %s' % (signature, b' '.join(map(pycompat.bytestr, revs)))
 
     result = repo._sparsematchercache.get(key)
     if result:
         return result
 
     matchers = []
     for rev in revs:
         try:
             includes, excludes, profiles = patternsforrev(repo, rev)
 
             if includes or excludes:
                 matcher = matchmod.match(
                     repo.root,
                     b'',
                     [],
                     include=includes,
                     exclude=excludes,
                     default=b'relpath',
                 )
                 matchers.append(matcher)
         except IOError:
             pass
 
     if not matchers:
         result = matchmod.always()
     elif len(matchers) == 1:
         result = matchers[0]
     else:
         result = matchmod.unionmatcher(matchers)
 
     if includetemp:
         tempincludes = readtemporaryincludes(repo)
         result = forceincludematcher(result, tempincludes)
 
     repo._sparsematchercache[key] = result
 
     return result
 
 
 def filterupdatesactions(repo, wctx, mctx, branchmerge, mresult):
     """Filter updates to only lay out files that match the sparse rules."""
     if not enabled:
         return
 
     oldrevs = [pctx.rev() for pctx in wctx.parents()]
     oldsparsematch = matcher(repo, oldrevs)
 
     if oldsparsematch.always():
         return
 
     files = set()
     prunedactions = {}
 
     if branchmerge:
         # If we're merging, use the wctx filter, since we're merging into
         # the wctx.
         sparsematch = matcher(repo, [wctx.p1().rev()])
     else:
         # If we're updating, use the target context's filter, since we're
         # moving to the target context.
         sparsematch = matcher(repo, [mctx.rev()])
 
     temporaryfiles = []
     for file, action in pycompat.iteritems(mresult.actions):
         type, args, msg = action
         files.add(file)
         if sparsematch(file):
             prunedactions[file] = action
         elif type == mergestatemod.ACTION_MERGE:
             temporaryfiles.append(file)
             prunedactions[file] = action
         elif branchmerge:
             if type != mergestatemod.ACTION_KEEP:
                 temporaryfiles.append(file)
                 prunedactions[file] = action
         elif type == mergestatemod.ACTION_FORGET:
             prunedactions[file] = action
         elif file in wctx:
             prunedactions[file] = (mergestatemod.ACTION_REMOVE, args, msg)
 
+        # in case or rename on one side, it is possible that f1 might not
+        # be present in sparse checkout we should include it
+        # TODO: should we do the same for f2?
+        # exists as a separate check because file can be in sparse and hence
+        # if we try to club this condition in above `elif type == ACTION_MERGE`
+        # it won't be triggered
         if branchmerge and type == mergestatemod.ACTION_MERGE:
             f1, f2, fa, move, anc = args
             if not sparsematch(f1):
                 temporaryfiles.append(f1)
 
     if len(temporaryfiles) > 0:
         repo.ui.status(
             _(
                 b'temporarily included %d file(s) in the sparse '
                 b'checkout for merging\n'
             )
             % len(temporaryfiles)
         )
         addtemporaryincludes(repo, temporaryfiles)
 
         # Add the new files to the working copy so they can be merged, etc
         actions = []
         message = b'temporarily adding to sparse checkout'
         wctxmanifest = repo[None].manifest()
         for file in temporaryfiles:
             if file in wctxmanifest:
                 fctx = repo[None][file]
                 actions.append((file, (fctx.flags(), False), message))
 
         typeactions = mergemod.emptyactions()
         typeactions[mergestatemod.ACTION_GET] = actions
         mergemod.applyupdates(
             repo, typeactions, repo[None], repo[b'.'], False, wantfiledata=False
         )
 
         dirstate = repo.dirstate
         for file, flags, msg in actions:
             dirstate.normal(file)
 
     profiles = activeconfig(repo)[2]
     changedprofiles = profiles & files
     # If an active profile changed during the update, refresh the checkout.
     # Don't do this during a branch merge, since all incoming changes should
     # have been handled by the temporary includes above.
     if changedprofiles and not branchmerge:
         mf = mctx.manifest()
         for file in mf:
             old = oldsparsematch(file)
             new = sparsematch(file)
             if not old and new:
                 flags = mf.flags(file)
                 prunedactions[file] = (
                     mergestatemod.ACTION_GET,
                     (flags, False),
                     b'',
                 )
             elif old and not new:
                 prunedactions[file] = (mergestatemod.ACTION_REMOVE, [], b'')
 
     mresult.setactions(prunedactions)
 
 
 def refreshwdir(repo, origstatus, origsparsematch, force=False):
     """Refreshes working directory by taking sparse config into account.
 
     The old status and sparse matcher is compared against the current sparse
     matcher.
 
     Will abort if a file with pending changes is being excluded or included
     unless ``force`` is True.
     """
     # Verify there are no pending changes
     pending = set()
     pending.update(origstatus.modified)
     pending.update(origstatus.added)
     pending.update(origstatus.removed)
     sparsematch = matcher(repo)
     abort = False
 
     for f in pending:
         if not sparsematch(f):
             repo.ui.warn(_(b"pending changes to '%s'\n") % f)
             abort = not force
 
     if abort:
         raise error.Abort(
             _(b'could not update sparseness due to pending changes')
         )
 
     # Calculate actions
     dirstate = repo.dirstate
     ctx = repo[b'.']
     added = []
     lookup = []
     dropped = []
     mf = ctx.manifest()
     files = set(mf)
 
     actions = {}
 
     for file in files:
         old = origsparsematch(file)
         new = sparsematch(file)
         # Add files that are newly included, or that don't exist in
         # the dirstate yet.
         if (new and not old) or (old and new and not file in dirstate):
             fl = mf.flags(file)
             if repo.wvfs.exists(file):
                 actions[file] = (b'e', (fl,), b'')
                 lookup.append(file)
             else:
                 actions[file] = (b'g', (fl, False), b'')
                 added.append(file)
         # Drop files that are newly excluded, or that still exist in
         # the dirstate.
         elif (old and not new) or (not old and not new and file in dirstate):
             dropped.append(file)
             if file not in pending:
                 actions[file] = (b'r', [], b'')
 
     # Verify there are no pending changes in newly included files
     abort = False
     for file in lookup:
         repo.ui.warn(_(b"pending changes to '%s'\n") % file)
         abort = not force
     if abort:
         raise error.Abort(
             _(
                 b'cannot change sparseness due to pending '
                 b'changes (delete the files or use '
                 b'--force to bring them back dirty)'
             )
         )
 
     # Check for files that were only in the dirstate.
     for file, state in pycompat.iteritems(dirstate):
         if not file in files:
             old = origsparsematch(file)
             new = sparsematch(file)
             if old and not new:
                 dropped.append(file)
 
     # Apply changes to disk
     typeactions = mergemod.emptyactions()
     for f, (m, args, msg) in pycompat.iteritems(actions):
         typeactions[m].append((f, args, msg))
 
     mergemod.applyupdates(
         repo, typeactions, repo[None], repo[b'.'], False, wantfiledata=False
     )
 
     # Fix dirstate
     for file in added:
         dirstate.normal(file)
 
     for file in dropped:
         dirstate.drop(file)
 
     for file in lookup:
         # File exists on disk, and we're bringing it back in an unknown state.
         dirstate.normallookup(file)
 
     return added, dropped, lookup
 
 
 def aftercommit(repo, node):
     """Perform actions after a working directory commit."""
     # This function is called unconditionally, even if sparse isn't
     # enabled.
     ctx = repo[node]
 
     profiles = patternsforrev(repo, ctx.rev())[2]
 
     # profiles will only have data if sparse is enabled.
     if profiles & set(ctx.files()):
         origstatus = repo.status()
         origsparsematch = matcher(repo)
         refreshwdir(repo, origstatus, origsparsematch, force=True)
 
     prunetemporaryincludes(repo)
 
 
 def _updateconfigandrefreshwdir(
     repo, includes, excludes, profiles, force=False, removing=False
 ):
     """Update the sparse config and working directory state."""
     raw = repo.vfs.tryread(b'sparse')
     oldincludes, oldexcludes, oldprofiles = parseconfig(repo.ui, raw, b'sparse')
 
     oldstatus = repo.status()
     oldmatch = matcher(repo)
     oldrequires = set(repo.requirements)
 
     # TODO remove this try..except once the matcher integrates better
     # with dirstate. We currently have to write the updated config
     # because that will invalidate the matcher cache and force a
     # re-read. We ideally want to update the cached matcher on the
     # repo instance then flush the new config to disk once wdir is
     # updated. But this requires massive rework to matcher() and its
     # consumers.
 
     if b'exp-sparse' in oldrequires and removing:
         repo.requirements.discard(b'exp-sparse')
         scmutil.writereporequirements(repo)
     elif b'exp-sparse' not in oldrequires:
         repo.requirements.add(b'exp-sparse')
         scmutil.writereporequirements(repo)
 
     try:
         writeconfig(repo, includes, excludes, profiles)
         return refreshwdir(repo, oldstatus, oldmatch, force=force)
     except Exception:
         if repo.requirements != oldrequires:
             repo.requirements.clear()
             repo.requirements |= oldrequires
             scmutil.writereporequirements(repo)
         writeconfig(repo, oldincludes, oldexcludes, oldprofiles)
         raise
 
 
 def clearrules(repo, force=False):
     """Clears include/exclude rules from the sparse config.
 
     The remaining sparse config only has profiles, if defined. The working
     directory is refreshed, as needed.
     """
     with repo.wlock():
         raw = repo.vfs.tryread(b'sparse')
         includes, excludes, profiles = parseconfig(repo.ui, raw, b'sparse')
 
         if not includes and not excludes:
             return
 
         _updateconfigandrefreshwdir(repo, set(), set(), profiles, force=force)
 
 
 def importfromfiles(repo, opts, paths, force=False):
     """Import sparse config rules from files.
 
     The updated sparse config is written out and the working directory
     is refreshed, as needed.
     """
     with repo.wlock():
         # read current configuration
         raw = repo.vfs.tryread(b'sparse')
         includes, excludes, profiles = parseconfig(repo.ui, raw, b'sparse')
         aincludes, aexcludes, aprofiles = activeconfig(repo)
 
         # Import rules on top; only take in rules that are not yet
         # part of the active rules.
         changed = False
         for p in paths:
             with util.posixfile(util.expandpath(p), mode=b'rb') as fh:
                 raw = fh.read()
 
             iincludes, iexcludes, iprofiles = parseconfig(
                 repo.ui, raw, b'sparse'
             )
             oldsize = len(includes) + len(excludes) + len(profiles)
             includes.update(iincludes - aincludes)
             excludes.update(iexcludes - aexcludes)
             profiles.update(iprofiles - aprofiles)
             if len(includes) + len(excludes) + len(profiles) > oldsize:
                 changed = True
 
         profilecount = includecount = excludecount = 0
         fcounts = (0, 0, 0)
 
         if changed:
             profilecount = len(profiles - aprofiles)
             includecount = len(includes - aincludes)
             excludecount = len(excludes - aexcludes)
 
             fcounts = map(
                 len,
                 _updateconfigandrefreshwdir(
                     repo, includes, excludes, profiles, force=force
                 ),
             )
 
         printchanges(
             repo.ui, opts, profilecount, includecount, excludecount, *fcounts
         )
 
 
 def updateconfig(
     repo,
     pats,
     opts,
     include=False,
     exclude=False,
     reset=False,
     delete=False,
     enableprofile=False,
     disableprofile=False,
     force=False,
     usereporootpaths=False,
 ):
     """Perform a sparse config update.
 
     Only one of the actions may be performed.
 
     The new config is written out and a working directory refresh is performed.
     """
     with repo.wlock():
         raw = repo.vfs.tryread(b'sparse')
         oldinclude, oldexclude, oldprofiles = parseconfig(
             repo.ui, raw, b'sparse'
         )
 
         if reset:
             newinclude = set()
             newexclude = set()
             newprofiles = set()
         else:
             newinclude = set(oldinclude)
             newexclude = set(oldexclude)
             newprofiles = set(oldprofiles)
 
         if any(os.path.isabs(pat) for pat in pats):
             raise error.Abort(_(b'paths cannot be absolute'))
 
         if not usereporootpaths:
             # let's treat paths as relative to cwd
             root, cwd = repo.root, repo.getcwd()
             abspats = []
             for kindpat in pats:
                 kind, pat = matchmod._patsplit(kindpat, None)
                 if kind in matchmod.cwdrelativepatternkinds or kind is None:
                     ap = (kind + b':' if kind else b'') + pathutil.canonpath(
                         root, cwd, pat
                     )
                     abspats.append(ap)
                 else:
                     abspats.append(kindpat)
             pats = abspats
 
         if include:
             newinclude.update(pats)
         elif exclude:
             newexclude.update(pats)
         elif enableprofile:
             newprofiles.update(pats)
         elif disableprofile:
             newprofiles.difference_update(pats)
         elif delete:
             newinclude.difference_update(pats)
             newexclude.difference_update(pats)
 
         profilecount = len(newprofiles - oldprofiles) - len(
             oldprofiles - newprofiles
         )
         includecount = len(newinclude - oldinclude) - len(
             oldinclude - newinclude
         )
         excludecount = len(newexclude - oldexclude) - len(
             oldexclude - newexclude
         )
 
         fcounts = map(
             len,
             _updateconfigandrefreshwdir(
                 repo,
                 newinclude,
                 newexclude,
                 newprofiles,
                 force=force,
                 removing=reset,
             ),
         )
 
         printchanges(
             repo.ui, opts, profilecount, includecount, excludecount, *fcounts
         )
 
 
 def printchanges(
     ui,
     opts,
     profilecount=0,
     includecount=0,
     excludecount=0,
     added=0,
     dropped=0,
     conflicting=0,
 ):
     """Print output summarizing sparse config changes."""
     with ui.formatter(b'sparse', opts) as fm:
         fm.startitem()
         fm.condwrite(
             ui.verbose,
             b'profiles_added',
             _(b'Profiles changed: %d\n'),
             profilecount,
         )
         fm.condwrite(
             ui.verbose,
             b'include_rules_added',
             _(b'Include rules changed: %d\n'),
             includecount,
         )
         fm.condwrite(
             ui.verbose,
             b'exclude_rules_added',
             _(b'Exclude rules changed: %d\n'),
             excludecount,
         )
 
         # In 'plain' verbose mode, mergemod.applyupdates already outputs what
         # files are added or removed outside of the templating formatter
         # framework. No point in repeating ourselves in that case.
         if not fm.isplain():
             fm.condwrite(
                 ui.verbose, b'files_added', _(b'Files added: %d\n'), added
             )
             fm.condwrite(
                 ui.verbose, b'files_dropped', _(b'Files dropped: %d\n'), dropped
             )
             fm.condwrite(
                 ui.verbose,
                 b'files_conflicting',
                 _(b'Files conflicting: %d\n'),
                 conflicting,
             )