remove: rewrite to be ~400x faster, bit more friendly

old remove code called localrepo.changes for each file.
was very expensive:

  $ hg --time rm arch>/dev/null
  Time: real 1066.120 secs (user 1014.450+0.000 sys 18.090+0.000)

new code, same files:

  $ hg --time rm arch>/dev/null
  Time: real 2.770 secs (user 2.190+0.000 sys 0.580+0.000)

also mention "-f" if not removing files. also allow "-f" to forget
added files.

make test a bit better.

mercurial/commands.py

@@ -2189,34 +2189,42 b' def remove(ui, repo, *pats, **opts):'
     entire project history.  If the files still exist in the working
     directory, they will be deleted from it.  If invoked with --after,
     files that have been manually deleted are marked as removed.
+
+    Modified files and added files are not removed by default.  To
+    remove them, use the -f/--force option.
     """
     names = []
     if not opts['after'] and not pats:
         raise util.Abort(_('no files specified'))
-    def okaytoremove(abs, rel, exact):
-        modified, added, removed, deleted, unknown = repo.changes(files=[abs])
+    files, matchfn, anypats = matchpats(repo, pats, opts)
+    exact = dict.fromkeys(files)
+    mardu = map(dict.fromkeys, repo.changes(files=files, match=matchfn))
+    modified, added, removed, deleted, unknown = mardu
+    remove, forget = [], []
+    for src, abs, rel, exact in walk(repo, pats, opts):
         reason = None
-        if not deleted and opts['after']:
+        if abs not in deleted and opts['after']:
             reason = _('is still present')
-        elif modified and not opts['force']:
-            reason = _('is modified')
-        elif added:
-            reason = _('has been marked for add')
-        elif unknown:
+        elif abs in modified and not opts['force']:
+            reason = _('is modified (use -f to force removal)')
+        elif abs in added:
+            if opts['force']:
+                forget.append(abs)
+                continue
+            reason = _('has been marked for add (use -f to force removal)')
+        elif abs in unknown:
             reason = _('is not managed')
-        elif removed:
-            return False
+        elif abs in removed:
+            continue
         if reason:
             if exact:
                 ui.warn(_('not removing %s: file %s\n') % (rel, reason))
         else:
-            return True
-    for src, abs, rel, exact in walk(repo, pats, opts):
-        if okaytoremove(abs, rel, exact):
             if ui.verbose or not exact:
                 ui.status(_('removing %s\n') % rel)
-            names.append(abs)
-    repo.remove(names, unlink=not opts['after'])
+            remove.append(abs)
+    repo.forget(forget)
+    repo.remove(remove, unlink=not opts['after'])
 
 def rename(ui, repo, *pats, **opts):
     """rename files; equivalent of copy + remove

tests/test-remove

@@ -3,6 +3,7 b''
 hg init a
 cd a
 echo a > foo
+hg rm foo
 hg add foo
 hg commit -m 1 -d "1000000 0"
 hg remove
@@ -17,5 +18,15 b' hg export 1'
 hg log -p -r 0
 hg log -p -r 1
 
+echo a > a
+hg add a
+hg rm a
+hg rm -f a
+echo b > b
+hg ci -A -m 3 -d "1000001 0"
+echo c >> b
+hg rm b
+hg rm -f b
+
 cd ..
 hg clone a b

tests/test-remove.out

@@ -1,3 +1,4 b''
+not removing foo: file is not managed
 abort: no files specified
 undeleting foo
 removing foo
@@ -50,4 +51,8 b' diff -r 8ba83d44753d -r a1fce69c50d9 foo'
 -a
 
 
-0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+not removing a: file has been marked for add (use -f to force removal)
+adding a
+adding b
+not removing b: file is modified (use -f to force removal)
+2 files updated, 0 files merged, 0 files removed, 0 files unresolved