#
#
# add_dir "tests/p_selector"
# 
# add_file "tests/p_selector/__driver__.lua"
#  content [db1fd89811f2e462874c0d1559943b816db301e1]
# 
# patch "NEWS"
#  from [af16495a1be882a92d9ba611b1d835c5008fbb86]
#    to [bef79302404102a3c375c60857e90043e2f6d887]
# 
# patch "monotone.texi"
#  from [a198d13bb3365b7d67591144799f5330377aacc6]
#    to [5fab7072154208ae616663e4579cef644987b6bd]
# 
# patch "selectors.cc"
#  from [42d6f2ba123ad9887a14ba28d9e6bc0a0bac5148]
#    to [6ed76563cb3eb25fd04fa557b4a618a8f3b3ce3a]
# 
# patch "work.cc"
#  from [772e23f689e6523ca680a9dcd5d5889637eeb816]
#    to [de879cd6058f54689874d6e06b8f23af423193ca]
# 
# patch "work.hh"
#  from [3a96efd140b80cfafff521c5c99bb187b16faed3]
#    to [cd117c8295b2bdf48db35e92aaf29842c27a1b7f]
#
============================================================
--- tests/p_selector/__driver__.lua	db1fd89811f2e462874c0d1559943b816db301e1
+++ tests/p_selector/__driver__.lua	db1fd89811f2e462874c0d1559943b816db301e1
@@ -0,0 +1,19 @@
+
+include("common/selectors.lua")
+mtn_setup()
+
+addfile("testfile", "blah blah")
+commit()
+REV1=base_revision()
+
+writefile("testfile", "stuff stuff")
+commit()
+REV2=base_revision()
+
+-- empty parent selector
+selmap("p:", {REV1})
+-- standard selection
+selmap("p:" .. REV2, {REV1})
+-- parent of a root revision
+selmap("p:" .. REV1, {})
+
============================================================
--- NEWS	af16495a1be882a92d9ba611b1d835c5008fbb86
+++ NEWS	bef79302404102a3c375c60857e90043e2f6d887
@@ -1,13 +1,13 @@
 ??? ??? ?? ??:??:?? UTC ????
 
         0.40 release.
 
         Changes
-        
+
         - The vim merger has been improved and now uses diff3 to merge
           non-conflict changes automatically before executing vimdiff.
 
-	- Values used with the --depth option used to control recursion with
+        - Values used with the --depth option used to control recursion with
           node and path restrictions have changed. Using --depth=0 now means
           exactly the specified directories and *not* their children. Using
           --depth=1 now means the specified directories and their immediate
@@ -25,6 +25,10 @@
 
         New features
 
+        - The bare parent selector 'p:' can now be used in a workspace to
+          query the parent(s) of the workspace' base revision. This is
+          equivalent to "mtn au select p:`mtn au get_base_workspace_revision`".
+
         Internal
 
         - Update Botan to 1.7.4.
============================================================
--- monotone.texi	a198d13bb3365b7d67591144799f5330377aacc6
+++ monotone.texi	5fab7072154208ae616663e4579cef644987b6bd
@@ -2775,7 +2775,8 @@ @heading Selectors in detail
 @item Parent selection
 Uses selector type @code{p}. For example, @code{p:0f3a} matches the
 revision IDs which are the parent of the revision ID which begins with
address@hidden
address@hidden If you give a bare @code{p:}, monotone will require you to be in
+a workspace, and query the parent of the base workspace revision.
 @item Tag selection
 Uses selector type @code{t}. For example, @code{t:monotone-0.11} matches
 @code{tag} certs where the cert value begins with @code{monotone-0.11}.
============================================================
--- selectors.cc	42d6f2ba123ad9887a14ba28d9e6bc0a0bac5148
+++ selectors.cc	6ed76563cb3eb25fd04fa557b4a618a8f3b3ce3a
@@ -48,7 +48,8 @@ static void
 typedef vector<pair<selector_type, string> > selector_list;
 
 static void
-decode_selector(options const & opts,
+decode_selector(project_t & project,
+                options const & opts,
                 lua_hooks & lua,
                 string const & orig_sel,
                 selector_type & type,
@@ -140,7 +141,7 @@ decode_selector(options const & opts,
             tmp += "T00:00:00";
           N(tmp.size()==19 || sel_date==type, 
             F("selector '%s' is not a valid date (%s)") % sel % tmp);
-            
+
           if (sel != tmp)
             {
               P (F ("expanded date '%s' -> '%s'\n") % sel % tmp);
@@ -170,13 +171,35 @@ decode_selector(options const & opts,
             F("the cert selector c: may not be empty"));
           break;
 
+        case sel_parent:
+          if (sel.empty())
+            {
+              workspace work(opts, lua, F("the empty parent selector p: refers to"
+                                          "the base revision of the workspace"));
+
+              parent_map parents;
+              set<revision_id> parent_ids;
+
+              work.get_parent_rosters(project.db, parents);
+
+              for (parent_map::const_iterator i = parents.begin();
+                i != parents.end(); ++i)
+                {
+                  parent_ids.insert(i->first);
+                }
+
+              diagnose_ambiguous_expansion(project, "p:", parent_ids);
+              sel = (* parent_ids.begin()).inner()();
+            }
+          break;
         default: break;
         }
     }
 }
 
 static void 
-parse_selector(options const & opts,
+parse_selector(project_t & project,
+               options const & opts,
                lua_hooks & lua,
                string const & str, selector_list & sels)
 {
@@ -204,7 +227,7 @@ parse_selector(options const & opts,
           string sel;
           selector_type type = sel_unknown;
 
-          decode_selector(opts, lua, *i, type, sel);
+          decode_selector(project, opts, lua, *i, type, sel);
           sels.push_back(make_pair(type, sel));
         }
     }
@@ -338,7 +361,7 @@ complete(options const & opts, lua_hooks
          set<revision_id> & completions)
 {
   selector_list sels;
-  parse_selector(opts, lua, str, sels);
+  parse_selector(project, opts, lua, str, sels);
 
   // avoid logging if there's no expansion to be done
   if (sels.size() == 1
@@ -393,7 +416,7 @@ expand_selector(options const & opts, lu
                 set<revision_id> & completions)
 {
   selector_list sels;
-  parse_selector(opts, lua, str, sels);
+  parse_selector(project, opts, lua, str, sels);
 
   // avoid logging if there's no expansion to be done
   if (sels.size() == 1
============================================================
--- work.cc	772e23f689e6523ca680a9dcd5d5889637eeb816
+++ work.cc	de879cd6058f54689874d6e06b8f23af423193ca
@@ -179,6 +179,14 @@ workspace::workspace(app_state & app, i1
     set_ws_options(app.opts, false);
 }
 
+workspace::workspace(options const & opts, lua_hooks & lua, 
+                     i18n_format const & explanation, bool writeback_options)
+  : lua(lua)
+{
+  require_workspace(explanation);
+  if (writeback_options)
+    set_ws_options(opts, false);
+}
 
 // routines for manipulating the bookkeeping directory
 
============================================================
--- work.hh	3a96efd140b80cfafff521c5c99bb187b16faed3
+++ work.hh	cd117c8295b2bdf48db35e92aaf29842c27a1b7f
@@ -110,6 +110,8 @@ public:
   explicit workspace(app_state & app, bool writeback_options = true);
   explicit workspace(app_state & app, i18n_format const & explanation,
                      bool writeback_options = true);
+  explicit workspace(options const & opts, lua_hooks & lua,
+                     i18n_format const & explanation, bool writeback_options = true);
 
   // Methods for manipulating the workspace's content.
   void find_missing(roster_t const & new_roster_shape,