[PATCH 1 of 5] resolve: when pats do not match, hint about path: [RFC]

[timeless]

# HG changeset patch
# User timeless <timeless at mozdev.org>
# Date 1450931494 0
#      Thu Dec 24 04:31:34 2015 +0000
# Node ID 99bb0f0a91660f1ec6aa355221c64e6349a1836a
# Parent  e2aa9c4030c4109e5efa50462ffc6048ca30106f
resolve: when pats do not match, hint about path: [RFC]

--tear here--
I don't really like resolve's output at all...

1. If none of the arguments match, it seems to me that the exit
code should be non-zero to hint to users that things didn't
go as expected.

That's a behavior change, and I'm not sure people
would really benefit from it.

2. It's not very helpful. This commit would at least
have it suggest what command the user could use to
try again.

3. When you're done resolving, it really should tell you
what command to do next, e.g. "use `hg commit` to finalize
your merge", or "`hg graft/rebase/histedit --cont` to continue"

This commit covers #2
The remainder of this series covers #3

diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -5979,7 +5979,17 @@
         ms.recordactions()
 
         if not didwork and pats:
+            hint = None
+            if not any([p for p in pats if p.find(':') >= 0]):
+                pats = ['path:%s' % p for p in pats]
+                m = scmutil.match(wctx, pats, opts)
+                for f in ms:
+                    if not m(f):
+                        continue
+                    hint = _("try: hg resolve ... path:...'\n")
             ui.warn(_("arguments do not match paths that need resolving\n"))
+            if hint:
+                ui.warn(hint)
         elif ms.mergedriver and ms.mdstate() != 's':
             # run conclude step when either a driver-resolved file is requested
             # or there are no driver-resolved files
diff --git a/tests/test-resolve.t b/tests/test-resolve.t
--- a/tests/test-resolve.t
+++ b/tests/test-resolve.t
@@ -53,6 +53,16 @@
   arguments do not match paths that need resolving
   $ hg resolve -l does-not-exist
 
+tell users how they could have used resolve
+
+  $ mkdir nested
+  $ cd nested
+  $ hg resolve -m file1
+  arguments do not match paths that need resolving
+  try: hg resolve ... path:...'
+  $ cd ..
+  $ rmdir nested
+
 don't allow marking or unmarking driver-resolved files
 
   $ cat > $TESTTMP/markdriver.py << EOF