tersestatus: re-implement the functionality to terse the status

The previous terse status implementation was hacking around os.listdir() and was
flaky. There have been a lot of instances of mercurial buildbots failing
and google's internal builds failing because of the
hacky implementation of terse status. Even though I wrote the last
implementation but it was hard for me to find the reason for the flake.

The new implementation can be slower than the old one but is clean and easy to
understand.

In this we create a node object for each directory and create a tree
like structure starting from the root of the working copy. While building the
tree like structure we store some information on the nodes which will be helpful
for deciding later whether we can terse the dir or not.
Once the whole tree is build we traverse and built the list of files for each
status with required tersing.

There is no behaviour change as the old test, test-status-terse.t passes with
the new implementation.

Differential Revision: https://phab.mercurial-scm.org/D985

mercurial/cmdutil.py

@@ -402,177 +402,169 b' def dorecord(ui, repo, commitfunc, cmdsu'
 
     return commit(ui, repo, recordinwlock, pats, opts)
 
-def tersestatus(root, statlist, status, ignorefn, ignore):
-    """
-    Returns a list of statuses with directory collapsed if all the files in the
-    directory has the same status.
+
+# extracted at module level as it's required each time a file will be added
+# to dirnode class object below
+pathsep = pycompat.ossep
+
+class dirnode(object):
     """
-
-    def numfiles(dirname):
-        """
-        Calculates the number of tracked files in a given directory which also
-        includes files which were removed or deleted. Considers ignored files
-        if ignore argument is True or 'i' is present in status argument.
+    represents a directory in user working copy
+
+    stores information which is required for purpose of tersing the status
+
+    path is the path to the directory
+
+    statuses is a set of statuses of all files in this directory (this includes
+    all the files in all the subdirectories too)
+
+    files is a list of files which are direct child of this directory
+
+    subdirs is a dictionary of sub-directory name as the key and it's own
+    dirnode object as the value
+    """
+
+    def __init__(self, dirpath):
+        self.path = dirpath
+        self.statuses = set([])
+        self.files = []
+        self.subdirs = {}
+
+    def _addfileindir(self, filename, status):
+        """ adds a file in this directory as the direct child """
+        self.files.append((filename, status))
+
+    def addfile(self, filename, status):
         """
-        if lencache.get(dirname):
-            return lencache[dirname]
-        if 'i' in status or ignore:
-            def match(localpath):
-                absolutepath = os.path.join(root, localpath)
-                if os.path.isdir(absolutepath) and isemptydir(absolutepath):
-                    return True
-                return False
-        else:
-            def match(localpath):
-                # there can be directory whose all the files are ignored and
-                # hence the drectory should also be ignored while counting
-                # number of files or subdirs in it's parent directory. This
-                # checks the same.
-                # XXX: We need a better logic here.
-                if os.path.isdir(os.path.join(root, localpath)):
-                    return isignoreddir(localpath)
-                else:
-                    # XXX: there can be files which have the ignored pattern but
-                    # are not ignored. That leads to bug in counting number of
-                    # tracked files in the directory.
-                    return ignorefn(localpath)
-        lendir = 0
-        abspath = os.path.join(root, dirname)
-        # There might be cases when a directory does not exists as the whole
-        # directory can be removed and/or deleted.
-        try:
-            for f in os.listdir(abspath):
-                localpath = os.path.join(dirname, f)
-                if not match(localpath):
-                    lendir += 1
-        except OSError:
-            pass
-        lendir += len(absentdir.get(dirname, []))
-        lencache[dirname] = lendir
-        return lendir
-
-    def isemptydir(abspath):
-        """
-        Check whether a directory is empty or not, i.e. there is no files in the
-        directory and all its subdirectories.
-        """
-        for f in os.listdir(abspath):
-            fullpath = os.path.join(abspath, f)
-            if os.path.isdir(fullpath):
-                # recursion here
-                ret = isemptydir(fullpath)
-                if not ret:
-                    return False
-            else:
-                return False
-        return True
-
-    def isignoreddir(localpath):
-        """Return True if `localpath` directory is ignored or contains only
-        ignored files and should hence be considered ignored.
-        """
-        dirpath = os.path.join(root, localpath)
-        if ignorefn(dirpath):
-            return True
-        for f in os.listdir(dirpath):
-            filepath = os.path.join(dirpath, f)
-            if os.path.isdir(filepath):
-                # recursion here
-                ret = isignoreddir(os.path.join(localpath, f))
-                if not ret:
-                    return False
-            else:
-                if not ignorefn(os.path.join(localpath, f)):
-                    return False
-        return True
-
-    def absentones(removedfiles, missingfiles):
+        adds a file which is present in this directory to its direct parent
+        dirnode object
+
+        if the file is not direct child of this directory, we traverse to the
+        directory of which this file is a direct child of and add the file there
         """
-        Returns a dictionary of directories with files in it which are either
-        removed or missing (deleted) in them.
-        """
-        absentdir = {}
-        absentfiles = removedfiles + missingfiles
-        while absentfiles:
-            f = absentfiles.pop()
-            par = os.path.dirname(f)
-            if par == '':
-                continue
-            # we need to store files rather than number of files as some files
-            # or subdirectories in a directory can be counted twice. This is
-            # also we have used sets here.
-            try:
-                absentdir[par].add(f)
-            except KeyError:
-                absentdir[par] = set([f])
-            absentfiles.append(par)
-        return absentdir
-
-    indexes = {'m': 0, 'a': 1, 'r': 2, 'd': 3, 'u': 4, 'i': 5, 'c': 6}
-    # get a dictonary of directories and files which are missing as os.listdir()
-    # won't be able to list them.
-    absentdir = absentones(statlist[2], statlist[3])
-    finalrs = [[]] * len(indexes)
-    didsomethingchanged = False
-    # dictionary to store number of files and subdir in a directory so that we
-    # don't compute that again.
-    lencache = {}
-
-    for st in pycompat.bytestr(status):
-
-        try:
-            ind = indexes[st]
-        except KeyError:
-            # TODO: Need a better error message here
-            raise error.Abort("'%s' not recognized" % st)
-
-        sfiles = statlist[ind]
-        if not sfiles:
-            continue
-        pardict = {}
-        for a in sfiles:
-            par = os.path.dirname(a)
-            pardict.setdefault(par, []).append(a)
-
-        rs = []
-        newls = []
-        for par, files in sorted(pardict.iteritems()):
-            lenpar = numfiles(par)
-            if lenpar == len(files):
-                newls.append(par)
-
-        if not newls:
-            continue
-
-        while newls:
-            newel = newls.pop()
-            if newel == '':
-                continue
-            parn = os.path.dirname(newel)
-            pardict[newel] = []
-            # Adding pycompat.ossep as newel is a directory.
-            pardict.setdefault(parn, []).append(newel + pycompat.ossep)
-            lenpar = numfiles(parn)
-            if lenpar == len(pardict[parn]):
-                newls.append(parn)
-
-        # dict.values() for Py3 compatibility
-        for files in pardict.values():
-            rs.extend(files)
-
-        rs.sort()
-        finalrs[ind] = rs
-        didsomethingchanged = True
-
-    # If nothing is changed, make sure the order of files is preserved.
-    if not didsomethingchanged:
-        return statlist
-
-    for x in xrange(len(indexes)):
-        if not finalrs[x]:
-            finalrs[x] = statlist[x]
-
-    return finalrs
+
+        # the filename contains a path separator, it means it's not the direct
+        # child of this directory
+        if pathsep in filename:
+            subdir, filep = filename.split(pathsep, 1)
+
+            # does the dirnode object for subdir exists
+            if subdir not in self.subdirs:
+                subdirpath = os.path.join(self.path, subdir)
+                self.subdirs[subdir] = dirnode(subdirpath)
+
+            # try adding the file in subdir
+            self.subdirs[subdir].addfile(filep, status)
+
+        else:
+            self._addfileindir(filename, status)
+
+        if status not in self.statuses:
+            self.statuses.add(status)
+
+def _addfilestotersed(path, files, tersedict):
+    """ adds files to the their respective status list in the final tersed list
+
+    path is the path of parent directory of the file
+    files is a list of tuple where each tuple is (filename, status)
+    tersedict is a dictonary which contains each status abbreviation as key and
+    list of files and tersed dirs in that status as value
+    """
+    for f, st in files:
+        tersedict[st].append(os.path.join(path, f))
+
+def _processtersestatus(subdir, tersedict, terseargs):
+    """a recursive function which process status for a certain directory.
+
+    subdir is an oject of dirnode class defined below. each object of dirnode
+    class has a set of statuses which files in that directory has. This ease our
+    check whether we can terse that directory or not.
+
+    tersedict is a dictonary which contains each status abbreviation as key and
+    list of files and tersed dirs in that status as value. In each function call
+    we are passing the same dict and adding files and dirs to it.
+
+    terseargs is the string of arguments passed by the user with `--terse` flag.
+
+    Following are the cases which can happen:
+
+    1) All the files in the directory (including all the files in its
+    subdirectories) share the same status and the user has asked us to terse
+    that status. -> we add the directory name to status list and return
+
+    2) If '1)' does not happen, we do following:
+
+            a) Add all the files which are in this directory (only the ones in
+                this directory, not the subdirs) to their respective status list
+
+            b) Recurse the function on all the subdirectories of this directory
+    """
+
+    if len(subdir.statuses) == 1:
+        onlyst = subdir.statuses.pop()
+
+        # Making sure we terse only when the status abbreviation is passed as
+        # terse argument
+        if onlyst in terseargs:
+            tersedict[onlyst].append(subdir.path + pycompat.ossep)
+            return
+
+    # add the files to status list
+    _addfilestotersed(subdir.path, subdir.files, tersedict)
+
+    #recurse on the subdirs
+    for dirobj in subdir.subdirs.values():
+        _processtersestatus(dirobj, tersedict, terseargs)
+
+def tersedir(statuslist, terseargs):
+    """
+    terses the status if all the files in a directory shares the same status
+
+    statuslist is scmutil.status() object which contains a list of files for
+    each status.
+    terseargs is string which is passed by the user as the argument to `--terse`
+    flag.
+
+    The function makes a tree of objects of dirnode class, and at each node it
+    stores the information required to know whether we can terse a certain
+    directory or not.
+
+    tersedict (defined in the function) is a dictionary which has one word key
+    for each status and a list of files and dir in that status as the respective
+    value. The dictionary is passed to other helper functions which builds it.
+    """
+    # the order matters here as that is used to produce final list
+    allst = ('m', 'a', 'r', 'd', 'u', 'i', 'c')
+
+    # checking the argument validity
+    for s in terseargs:
+        if s not in allst:
+            raise error.Abort(_("'%s' not recognized") % s)
+
+    # creating a dirnode object for the root of the repo
+    rootobj = dirnode('')
+    pstatus = ('modified', 'added', 'deleted', 'clean', 'unknown',
+               'ignored', 'removed')
+
+    tersedict = {}
+    for attrname in pstatus:
+        for f in getattr(statuslist, attrname):
+            rootobj.addfile(f, attrname[0])
+        tersedict[attrname[0]] = []
+
+    # we won't be tersing the root dir, so add files in it
+    _addfilestotersed(rootobj.path, rootobj.files, tersedict)
+
+    # process each sub-directory and build tersedict
+    for subdir in rootobj.subdirs.values():
+        _processtersestatus(subdir, tersedict, terseargs)
+
+    tersedlist = []
+    for st in allst:
+        tersedict[st].sort()
+        tersedlist.append(tersedict[st])
+
+    return tersedlist
 
 def _commentlines(raw):
     '''Surround lineswith a comment char and a new line'''

mercurial/commands.py

@@ -4805,12 +4805,18 b' def status(ui, repo, *pats, **opts):'
             show = states[:5]
 
     m = scmutil.match(repo[node2], pats, opts)
-    stat = repo.status(node1, node2, m,
-                       'ignored' in show, 'clean' in show, 'unknown' in show,
-                       opts.get('subrepos'))
     if terse:
-        stat = cmdutil.tersestatus(repo.root, stat, terse,
-                                    repo.dirstate._ignore, opts.get('ignored'))
+        # we need to compute clean and unknown to terse
+        stat = repo.status(node1, node2, m,
+                           'ignored' in show or 'i' in terse,
+                            True, True, opts.get('subrepos'))
+
+        stat = cmdutil.tersedir(stat, terse)
+    else:
+        stat = repo.status(node1, node2, m,
+                           'ignored' in show, 'clean' in show,
+                           'unknown' in show, opts.get('subrepos'))
+
     changestates = zip(states, pycompat.iterbytestr('MAR!?IC'), stat)
 
     if (opts.get('all') or opts.get('copies')