purge: simplify safety net for case mangling filesystems

Relying on the exact return of statwalk would cause us to abort
when there was at least one tracked file inside an ignored directory.

This patch forces an extra walk of the whole working directory even
on sane filesystems, where it wouldn't be needed.

Fixes issue621.

hgext/purge.py

@@ -49,6 +49,9 @@ def dopurge(ui, repo, dirs=None, act=True, ignored=False,
         else:
             ui.write('%s%s' % (name, eol))
 
+    if not force:
+        _check_fs(ui, repo)
+
     directories = []
     files = []
     missing = []
@@ -63,8 +66,6 @@ def dopurge(ui, repo, dirs=None, act=True, ignored=False,
         elif src == 'f' and f not in repo.dirstate:
             files.append(f)
 
-    _check_missing(ui, repo, missing, force)
-
     directories.sort()
 
     for f in files:
@@ -77,7 +78,7 @@ def dopurge(ui, repo, dirs=None, act=True, ignored=False,
             ui.note(_('Removing directory %s\n') % f)
             remove(os.rmdir, f)
 
-def _check_missing(ui, repo, missing, force=False):
+def _check_fs(ui, repo):
     """Abort if there is the chance of having problems with name-mangling fs
 
     In a name mangling filesystem (e.g. a case insensitive one)
@@ -85,34 +86,18 @@ def _check_missing(ui, repo, missing, force=False):
     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.
+    To prevent this, this function will abort if there are uncommitted
+    changes.
+    """
 
-    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"))
+    # We can't use (files, match) to do a partial walk here - we wouldn't
+    # notice a modified README file if the user ran "hg purge readme"
+    modified, added, removed, deleted = repo.status()[:4]
+    if modified or added or removed or deleted:
+        if not util.checkfolding(repo.path) and not ui.quiet:
+            ui.warn(_("Purging on name mangling filesystems is not "
+                      "fully supported.\n"))
+        raise util.Abort(_("outstanding uncommitted changes"))
 
 
 def purge(ui, repo, *dirs, **opts):
@@ -158,7 +143,7 @@ cmdtable = {
         (purge,
          [('a', 'abort-on-err', None, _('abort if an error occurs')),
           ('',  'all', None, _('purge ignored files too')),
-          ('f', 'force', None, _('purge even when missing files are detected')),
+          ('f', 'force', None, _('purge even when there are uncommitted changes')),
           ('p', 'print', None, _('print the file names instead of deleting them')),
           ('0', 'print0', None, _('end filenames with NUL, for use with xargs'
                                   ' (implies -p)')),

tests/test-purge

@@ -101,6 +101,13 @@ hg purge -v --force
 hg revert --all --quiet
 ls
 
+echo '% tracked file in ignored directory (issue621)'
+echo directory >> .hgignore
+hg ci -m 'ignore directory'
+touch untracked_file
+hg purge -p
+hg purge -v
+
 echo % skip excluded files
 touch excluded_file
 hg purge -p -X excluded_file

tests/test-purge.out

@@ -59,6 +59,9 @@ untracked_file still around
 Removing file untracked_file
 directory
 r1
+% tracked file in ignored directory (issue621)
+untracked_file
+Removing file untracked_file
 % skip excluded files
 directory
 excluded_file