forget: support forgetting explicit paths in subrepos

Change the behavior of the forget command such that explicit paths in
subrepos are handled by forgetting the file in the subrepo. This eliminates the
previous behavior where if you called "hg forget" for an explicit path in a
subrepo, it would state that the file is already untracked.

mercurial/commands.py

@@ -13,6 +13,7 b' import hg, scmutil, util, revlog, extens'
 import patch, help, url, encoding, templatekw, discovery
 import archival, changegroup, cmdutil, hbisect
 import sshserver, hgweb, hgweb.server, commandserver
+import match as matchmod
 import merge as mergemod
 import minirst, revset, fileset
 import dagparser, context, simplemerge
@@ -2432,23 +2433,45 b' def forget(ui, repo, *pats, **opts):'
     if not pats:
         raise util.Abort(_('no files specified'))
 
-    m = scmutil.match(repo[None], pats, opts)
+    wctx = repo[None]
+    m = scmutil.match(wctx, pats, opts)
     s = repo.status(match=m, clean=True)
     forget = sorted(s[0] + s[1] + s[3] + s[6])
+    subforget = {}
     errs = 0
 
+    for subpath in wctx.substate:
+        sub = wctx.sub(subpath)
+        try:
+            submatch = matchmod.narrowmatcher(subpath, m)
+            for fsub in sub.walk(submatch):
+                if submatch.exact(fsub):
+                    subforget[os.path.join(subpath, fsub)] = (fsub, sub)
+        except error.LookupError:
+            ui.status(_("skipping missing subrepository: %s\n") % subpath)
+
     for f in m.files():
         if f not in repo.dirstate and not os.path.isdir(m.rel(f)):
-            if os.path.exists(m.rel(f)):
-                ui.warn(_('not removing %s: file is already untracked\n')
-                        % m.rel(f))
-            errs = 1
+            if f not in subforget:
+                if os.path.exists(m.rel(f)):
+                    ui.warn(_('not removing %s: file is already untracked\n')
+                            % m.rel(f))
+                errs = 1
 
     for f in forget:
         if ui.verbose or not m.exact(f):
             ui.status(_('removing %s\n') % m.rel(f))
 
-    repo[None].forget(forget)
+    if ui.verbose:
+        for f in sorted(subforget.keys()):
+            ui.status(_('removing %s\n') % m.rel(f))
+
+    wctx.forget(forget)
+
+    for f in sorted(subforget.keys()):
+        fsub, sub = subforget[f]
+        sub.forget([fsub])
+
     return errs
 
 @command(

mercurial/help/subrepos.txt

@@ -95,6 +95,9 b' Interaction with Mercurial Commands'
     elements. Git and Subversion subrepositories are currently
     silently ignored.
 
+:forget: forget currently only handles exact file matches in subrepos.
+    Git and Subversion subrepositories are currently silently ignored.
+
 :incoming: incoming does not recurse in subrepos unless -S/--subrepos
     is specified. Git and Subversion subrepositories are currently
     silently ignored.

mercurial/subrepo.py

@@ -360,6 +360,9 b' class abstractsubrepo(object):'
         '''
         pass
 
+    def forget(self, files):
+        pass
+
 class hgsubrepo(abstractsubrepo):
     def __init__(self, ctx, path, state):
         self._path = path
@@ -553,6 +556,10 b' class hgsubrepo(abstractsubrepo):'
         ctx = self._repo[None]
         return ctx.walk(match)
 
+    def forget(self, files):
+        ctx = self._repo[None]
+        ctx.forget(files)
+
 class svnsubrepo(abstractsubrepo):
     def __init__(self, ctx, path, state):
         self._path = path

tests/test-subrepo.t

@@ -1006,12 +1006,12 b' Adding with a pattern with -S also adds '
   committing subrepository s
 
 Test behavior of forget for explicit path in subrepo:
-Forgetting an explicit path in a subrepo currently gives a file untracked warn
+Forgetting an explicit path in a subrepo untracks the file
   $ echo c19 > s/f19
   $ hg add s/f19
   $ hg st -S
   A s/f19
   $ hg forget s/f19
-  not removing s/f19: file is already untracked
-  [1]
+  $ hg st -S
+  ? s/f19
   $ rm s/f19