purge: abort with missing files avoiding problems with name-mangling fs

In a name mangling filesystem (e.g. a case insensitive one)
dirstate.walk() can yield filenames different from the ones
stored in the dirstate. This already confuses the status and
add commands, but with purge this may cause data loss.

To prevent this purge refuses to work if there are missing
files and has a 'force' option if the user knows it is safe.

Even with the force option purge checks if any of the missing
files is still available in the working dir: if so there
may be some problem with the underlying filesystem, so it
unconditionally aborts.

contrib/purge/purge.py

@@ -1,114 +1,159 b''
 # Copyright (C) 2006 - Marco Barisione <[e-mail]>
 #
 # This is a small extension for Mercurial (http://www.selenic.com/mercurial)
 # that removes files not known to mercurial
 #
 # This program was inspired by the "cvspurge" script contained in CVS utilities
 # (http://www.red-bean.com/cvsutils/).
 #
 # To enable the "purge" extension put these lines in your ~/.hgrc:
 #  [extensions]
 #  purge = /path/to/purge.py
 #
 # For help on the usage of "hg purge" use:
 #  hg help purge
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 2 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 from mercurial import hg, util
 from mercurial.i18n import _
 import os
 
-def dopurge(ui, repo, dirs=None, act=True, abort_on_err=False, eol='\n'):
+def dopurge(ui, repo, dirs=None, act=True, abort_on_err=False, eol='\n',
+            force=False):
     def error(msg):
         if abort_on_err:
             raise util.Abort(msg)
         else:
             ui.warn(_('warning: %s\n') % msg)
 
     def remove(remove_func, name):
         if act:
             try:
                 remove_func(os.path.join(repo.root, name))
             except OSError, e:
                 error(_('%s cannot be removed') % name)
         else:
             ui.write('%s%s' % (name, eol))
 
     directories = []
     files = []
+    missing = []
     roots, match, anypats = util.cmdmatcher(repo.root, repo.getcwd(), dirs)
     for src, f, st in repo.dirstate.statwalk(files=roots, match=match,
                                              ignored=True, directories=True):
         if src == 'd':
             directories.append(f)
+        elif src == 'm':
+            missing.append(f)
         elif src == 'f' and f not in repo.dirstate:
             files.append(f)
 
+    _check_missing(ui, repo, missing, force)
+
     directories.sort()
 
     for f in files:
         if f not in repo.dirstate:
             ui.note(_('Removing file %s\n') % f)
             remove(os.remove, f)
 
     for f in directories[::-1]:
         if not os.listdir(repo.wjoin(f)):
             ui.note(_('Removing directory %s\n') % f)
             remove(os.rmdir, f)
 
+def _check_missing(ui, repo, missing, force=False):
+    """Abort if there is the chance of having problems with name-mangling fs
+
+    In a name mangling filesystem (e.g. a case insensitive one)
+    dirstate.walk() can yield filenames different from the ones
+    stored in the dirstate. This already confuses the status and
+    add commands, but with purge this may cause data loss.
+    
+    To prevent this, _check_missing will abort if there are missing
+    files. The force option will let the user skip the check if he 
+    knows it is safe.
+    
+    Even with the force option this function will check if any of the 
+    missing files is still available in the working dir: if so there
+    may be some problem with the underlying filesystem, so it
+    aborts unconditionally."""
+
+    found = [f for f in missing if util.lexists(repo.wjoin(f))]
+
+    if found:
+        if not ui.quiet:
+            ui.warn(_("The following tracked files weren't listed by the "
+                      "filesystem, but could still be found:\n"))
+            for f in found:
+                ui.warn("%s\n" % f)
+            if util.checkfolding(repo.path):
+                ui.warn(_("This is probably due to a case-insensitive "
+                          "filesystem\n"))
+        raise util.Abort(_("purging on name mangling filesystems is not "
+                           "yet fully supported"))
+
+    if missing and not force:
+        raise util.Abort(_("there are missing files in the working dir and "
+                           "purge still has problems with them due to name "
+                           "mangling filesystems. "
+                           "Use --force if you know what you are doing"))
+
 
 def purge(ui, repo, *dirs, **opts):
     '''removes files not tracked by mercurial
 
     Delete files not known to mercurial, this is useful to test local and
     uncommitted changes in the otherwise clean source tree.
 
     This means that purge will delete:
      - Unknown files: files marked with "?" by "hg status"
      - Ignored files: files usually ignored by Mercurial because they match
        a pattern in a ".hgignore" file
      - Empty directories: in fact Mercurial ignores directories unless they
        contain files under source control managment
     But it will leave untouched:
      - Unmodified tracked files
      - Modified tracked files
      - New files added to the repository (with "hg add")
 
     If directories are given on the command line, only files in these
     directories are considered.
 
     Be careful with purge, you could irreversibly delete some files you
     forgot to add to the repository. If you only want to print the list of
     files that this program would delete use the --print option.
     '''
     act = not opts['print']
     abort_on_err = bool(opts['abort_on_err'])
     eol = opts['print0'] and '\0' or '\n'
     if eol == '\0':
         # --print0 implies --print
         act = False
-    dopurge(ui, repo, dirs, act, abort_on_err, eol)
+    force = bool(opts['force'])
+    dopurge(ui, repo, dirs, act, abort_on_err, eol, force)
 
 
 cmdtable = {
     'purge':
         (purge,
          [('a', 'abort-on-err', None, _('abort if an error occurs')),
+          ('f', 'force', None, _('purge even when missing files are detected')),
           ('p', 'print', None, _('print the file names instead of deleting them')),
           ('0', 'print0', None, _('end filenames with NUL, for use with xargs'
                                   ' (implies -p)'))],
          _('hg purge [OPTION]... [DIR]...'))
 }

tests/test-purge

@@ -1,76 +1,99 b''
 #!/bin/sh
 
 cat <<EOF >> $HGRCPATH
 [extensions]
 purge=${TESTDIR}/../contrib/purge/purge.py
 EOF
 
 echo % init
 hg init t
 cd t
 
 echo % setup
 echo r1 > r1
 hg ci -qAmr1 -d'0 0'
 mkdir directory
 echo r2 > directory/r2
 hg ci -qAmr2 -d'1 0'
 echo 'ignored' > .hgignore
 hg ci -qAmr3 -d'2 0'
 
 echo % delete an empty directory
 mkdir empty_dir
 hg purge -p
 hg purge -v
 ls
 
 echo % delete an untracked directory
 mkdir untracked_dir
 touch untracked_dir/untracked_file1
 touch untracked_dir/untracked_file2
 hg purge -p
 hg purge -v
 ls
 
 echo % delete an untracked file
 touch untracked_file
 hg purge -p
 hg purge -v
 ls
 
 echo % delete an untracked file in a tracked directory
 touch directory/untracked_file
 hg purge -p
 hg purge -v
 ls
 
 echo % delete nested directories
 mkdir -p untracked_directory/nested_directory
 hg purge -p
 hg purge -v
 ls
 
 echo % delete nested directories from a subdir
 mkdir -p untracked_directory/nested_directory
 cd directory
 hg purge -p
 hg purge -v
 cd ..
 ls
 
 echo % delete only part of the tree
 mkdir -p untracked_directory/nested_directory
 touch directory/untracked_file
 cd directory
 hg purge -p ../untracked_directory
 hg purge -v ../untracked_directory
 cd ..
 ls
 ls directory/untracked_file
 rm directory/untracked_file
 
 echo % delete ignored files
 touch ignored
 hg purge -p
 hg purge -v
 ls
+
+echo % abort with missing files until we support name mangling filesystems
+touch untracked_file
+rm r1
+# hide error messages to avoid changing the output when the text changes
+hg purge -p 2> /dev/null
+if [ $? -ne 0 ]; then
+    echo "refused to run"
+fi
+if [ -f untracked_file ]; then
+    echo "untracked_file still around"
+fi
+hg purge -p --force
+hg purge -v 2> /dev/null
+if [ $? -ne 0 ]; then
+    echo "refused to run"
+fi
+if [ -f untracked_file ]; then
+    echo "untracked_file still around"
+fi
+hg purge -v --force
+hg revert --all --quiet
+ls

tests/test-purge.out

@@ -1,49 +1,58 b''
 % init
 % setup
 % delete an empty directory
 empty_dir
 Removing directory empty_dir
 directory
 r1
 % delete an untracked directory
 untracked_dir/untracked_file1
 untracked_dir/untracked_file2
 Removing file untracked_dir/untracked_file1
 Removing file untracked_dir/untracked_file2
 Removing directory untracked_dir
 directory
 r1
 % delete an untracked file
 untracked_file
 Removing file untracked_file
 directory
 r1
 % delete an untracked file in a tracked directory
 directory/untracked_file
 Removing file directory/untracked_file
 directory
 r1
 % delete nested directories
 untracked_directory/nested_directory
 Removing directory untracked_directory/nested_directory
 Removing directory untracked_directory
 directory
 r1
 % delete nested directories from a subdir
 untracked_directory/nested_directory
 Removing directory untracked_directory/nested_directory
 Removing directory untracked_directory
 directory
 r1
 % delete only part of the tree
 untracked_directory/nested_directory
 Removing directory untracked_directory/nested_directory
 Removing directory untracked_directory
 directory
 r1
 directory/untracked_file
 % delete ignored files
 ignored
 Removing file ignored
 directory
 r1
+% abort with missing files until we support name mangling filesystems
+refused to run
+untracked_file still around
+untracked_file
+refused to run
+untracked_file still around
+Removing file untracked_file
+directory
+r1