#
#
# add_dir "tests/m_selector"
# 
# add_dir "tests/u_selector"
# 
# add_file "tests/m_selector/__driver__.lua"
#  content [595d0882c8a144c189c960a4108a993a5c91cef2]
# 
# add_file "tests/u_selector/__driver__.lua"
#  content [8fe1f6a14eb1c3ce47dc753495c3b5fe1d807e97]
# 
# patch "NEWS"
#  from [730ace914a4621c491e14e302834289f77ed52de]
#    to [9cd3c7c3f2e2082f369020eb51b863462a8e584f]
# 
# patch "cmd_merging.cc"
#  from [22376019b500781e104580a1dfa1678954e15872]
#    to [24996c053cd6ce5bfbe9466e9d4bbc36fe071c3f]
# 
# patch "monotone.texi"
#  from [48bab75212b595ebbd07ce72fb3442531ed3530a]
#    to [45b376c07ebdff41d56cbf7ca055b845f0590621]
# 
# patch "selectors.cc"
#  from [cab93c9e7cfddc4e88626713b1b94f07d489924b]
#    to [91d924b52e55b60329cba63adac1af6d874014d0]
# 
# patch "work.cc"
#  from [8639fa3a282cb2ce24dd2b582d9be4ad833b43ac]
#    to [c599d6997fd914394ef1143ab131c0fc0002eeaf]
# 
# patch "work.hh"
#  from [37d90e812bd3f1eff977682b7e363036b4da4f5f]
#    to [e78bc57d1e78333c06e831ec917384eecbe3c44f]
#
============================================================
--- tests/m_selector/__driver__.lua	595d0882c8a144c189c960a4108a993a5c91cef2
+++ tests/m_selector/__driver__.lua	595d0882c8a144c189c960a4108a993a5c91cef2
@@ -0,0 +1,31 @@
+include("common/selectors.lua")
+mtn_setup()
+
+addfile("testfile", "blah blah")
+commit("testbranch", "this is revision one")
+REV1=base_revision()
+
+writefile("testfile", "stuff stuff")
+commit("testbranch", "this is revision number two")
+REV2=base_revision()
+
+writefile("testfile", "foobar")
+commit("testbranch", "this is revision number three")
+REV3=base_revision()
+
+check(mtn("comment", REV2, "revision 2 comment"), 0, true, false)
+
+-- changelogs
+
+selmap("m:*one*", {REV1})
+selmap("m:*two*", {REV2})
+selmap("m:*three*", {REV3})
+selmap("m:*revision*", {REV1, REV2, REV3})
+selmap("m:*number*", {REV2, REV3})
+selmap("m:*foobar*", {})
+
+-- comments
+
+selmap("m:revision*", {REV2})
+selmap("m:*2*", {REV2})
+selmap("m:*comment*", {REV2})
============================================================
--- tests/u_selector/__driver__.lua	8fe1f6a14eb1c3ce47dc753495c3b5fe1d807e97
+++ tests/u_selector/__driver__.lua	8fe1f6a14eb1c3ce47dc753495c3b5fe1d807e97
@@ -0,0 +1,52 @@
+include("common/selectors.lua")
+mtn_setup()
+
+addfile("testfile", "blah blah")
+commit("testbranch", "this is revision one")
+REV1=base_revision()
+
+writefile("testfile", "stuff stuff")
+commit("testbranch", "this is revision number two")
+REV2=base_revision()
+
+writefile("testfile", "foobar")
+commit("testbranch", "this is revision number three")
+REV3=base_revision()
+
+-- no updates yet
+
+check(mtn("automate", "select", "u:"), 1, true, false)
+
+-- update to rev1 from rev3
+
+check(mtn("update", "-r", REV1), 0, true, false)
+selmap("u:", {REV3})
+
+-- update to rev2 from rev1
+
+check(mtn("update", "-r", REV2), 0, true, false)
+selmap("u:", {REV1})
+
+-- update back to rev1 from rev2
+
+check(mtn("update", "-r", "u:"), 0, true, false)
+selmap("u:", {REV2})
+
+-- finally update back to rev3
+
+check(mtn("update"), 0, true, false)
+selmap("u:", {REV1})
+
+-- log the update rev
+
+check(mtn("log", "-r", "u:", "--no-graph", "--brief"), 0, true, false)
+check(qgrep(REV1, "stdout"))
+check(not qgrep(REV2, "stdout"))
+check(not qgrep(REV3, "stdout"))
+
+-- log back to the update rev
+
+check(mtn("log", "--to", "u:", "--no-graph", "--brief"), 0, true, false)
+check(not qgrep(REV1, "stdout"))
+check(qgrep(REV2, "stdout"))
+check(qgrep(REV3, "stdout"))
============================================================
--- NEWS	730ace914a4621c491e14e302834289f77ed52de
+++ NEWS	9cd3c7c3f2e2082f369020eb51b863462a8e584f
@@ -77,6 +77,10 @@
         - Additional '--revision' option for 'mtn log' allows logging of
           selected sets of revisions.
 
+        - Additional 'u:' and 'm:' selector types for selecting the revision the
+          workspace was last updated from and revisions matching specified
+          message globs in changelog and comment certs.
+
         Internal
 
         - Using 64 bit integer values to represent dates internally. This
============================================================
--- cmd_merging.cc	22376019b500781e104580a1dfa1678954e15872
+++ cmd_merging.cc	24996c053cd6ce5bfbe9466e9d4bbc36fe071c3f
@@ -300,6 +300,7 @@ CMD(update, "update", "", CMD_REF(worksp
                               merged_roster, remaining);
 
   // small race condition here... FIXME: what is it?
+  work.put_update_id(old_rid);
   work.put_work_rev(remaining);
   work.update_any_attrs(db);
   work.maybe_update_inodeprints(db);
============================================================
--- monotone.texi	48bab75212b595ebbd07ce72fb3442531ed3530a
+++ monotone.texi	45b376c07ebdff41d56cbf7ca055b845f0590621
@@ -2764,6 +2764,10 @@ @heading Selectors in detail
 Uses selector type @code{d}. For example, @code{d:2004-04} matches
 @code{date} certs where the cert value begins with
 @code{2004-04}. This selector also accepts expanded date syntax (see below).
address@hidden Message selection
+Uses selector type @code{m}. For example @code{m:*foobar*} matches
address@hidden and @code{comment} certs where the cert value
+contains the glob @code{*foobar*}.
 @item "Earlier or equal than" selection
 Uses selector type @code{e}. For example, @code{e:2004-04-25} matches
 @code{date} certs where the cert value is less or equal than
@@ -2784,6 +2788,24 @@ @heading Selectors in detail
 revision IDs which are the parent of the revision ID which begins with
 @code{0f3a}. 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.
address@hidden Update selection
+Uses selector type @code{u}. This selector must be used from within a
+workspace and must not have any associated value. It matches the base
+revision ID of the workspace before the last @command{update} command
+was executed. This can be useful for reviewing incoming
+revisions. After each update operation, or at least before the next
+update operation, run a command similar to the following:
address@hidden
+$ mtn log --to u: --diffs
address@hidden smallexample
+to log all revisions back to the last update. It can also be
+used for quickly jumping between two different revisions. For example,
+the following command:
address@hidden
+$ mtn update -r u:
address@hidden smallexample
+will update back to the previous update revision. Repeating this
+command will swap the current and previous update 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	cab93c9e7cfddc4e88626713b1b94f07d489924b
+++ selectors.cc	91d924b52e55b60329cba63adac1af6d874014d0
@@ -42,7 +42,9 @@ enum selector_type
     sel_cert,
     sel_earlier,
     sel_later,
+    sel_message,
     sel_parent,
+    sel_update,
     sel_unknown
   };
 
@@ -105,9 +107,15 @@ decode_selector(project_t & project,
         case 'e':
           type = sel_earlier;
           break;
+        case 'm':
+          type = sel_message;
+          break;
         case 'p':
           type = sel_parent;
           break;
+        case 'u':
+          type = sel_update;
+          break;
         default:
           W(F("unknown selector type: %c") % sel[0]);
           break;
@@ -194,6 +202,19 @@ decode_selector(project_t & project,
                                   origin::internal);
             }
           break;
+        case sel_update:
+          E(sel.empty(), origin::user,
+            F("no value is allowed with the update selector u:"));
+          {
+            workspace work(opts, lua, F("the update selector u: refers to the "
+                                        "revision before the last update in the "
+                                        "workspace"));
+            revision_id update_id;
+            work.get_update_id(update_id);
+            sel = encode_hexenc(update_id.inner()(), origin::internal);
+          }
+          break;
+
         default: break;
         }
     }
@@ -251,6 +272,10 @@ complete_one_selector(project_t & projec
       project.db.select_parent(value, completions);
       break;
 
+    case sel_update:
+      project.db.complete(value, completions);
+      break;
+
     case sel_author:
       project.db.select_cert(author_cert_name(), value, completions);
       break;
@@ -280,6 +305,16 @@ complete_one_selector(project_t & projec
       project.db.select_date(value, ">", completions);
       break;
 
+    case sel_message:
+      {
+        set<revision_id> changelogs, comments;
+        project.db.select_cert(changelog_cert_name(), value, changelogs);
+        project.db.select_cert(comment_cert_name(), value, comments);
+        completions.insert(changelogs.begin(), changelogs.end());
+        completions.insert(comments.begin(), comments.end());
+      }
+      break;
+
     case sel_cert:
       {
         I(!value.empty());
============================================================
--- work.cc	8639fa3a282cb2ce24dd2b582d9be4ad833b43ac
+++ work.cc	c599d6997fd914394ef1143ab131c0fc0002eeaf
@@ -53,6 +53,7 @@ static char const revision_file_name[] =
 static char const options_file_name[] = "options";
 static char const user_log_file_name[] = "log";
 static char const revision_file_name[] = "revision";
+static char const update_file_name[] = "update";
 
 static void
 get_revision_path(bookkeeping_path & m_path)
@@ -89,6 +90,13 @@ get_user_log_path(bookkeeping_path & ul_
   L(FL("user log path is %s") % ul_path);
 }
 
+static void
+get_update_path(bookkeeping_path & update_path)
+{
+  update_path = bookkeeping_root / update_file_name;
+  L(FL("update path is %s") % update_path);
+}
+
 //
 
 bool
@@ -230,6 +238,33 @@ workspace::put_work_rev(revision_t const
   write_data(rev_path, rev_data);
 }
 
+void
+workspace::get_update_id(revision_id & update_id)
+{
+  data update_data;
+  bookkeeping_path update_path;
+  get_update_path(update_path);
+  E(file_exists(update_path), origin::user,
+    F("no update has occurred in this workspace"));
+
+  read_data(update_path, update_data);
+
+  update_id = revision_id(decode_hexenc(update_data(), origin::internal),
+                          origin::internal);
+  E(!null_id(update_id), origin::internal,
+    F("no update revision available"));
+}
+
+void
+workspace::put_update_id(revision_id const & update_id)
+{
+  data update_data(encode_hexenc(update_id.inner()(), origin::internal), 
+                   origin::internal);
+  bookkeeping_path update_path;
+  get_update_path(update_path);
+  write_data(update_path, update_data);
+}
+
 // structures derived from the work revision, the database, and possibly
 // the workspace
 
============================================================
--- work.hh	37d90e812bd3f1eff977682b7e363036b4da4f5f
+++ work.hh	e78bc57d1e78333c06e831ec917384eecbe3c44f
@@ -169,6 +169,14 @@ public:
   // read the (partial) revision describing the current workspace.
   void get_work_rev(revision_t & rev);
 
+  // read the revision id that was the parent of this workspace before
+  // the last update occured. this is used for the u: (update) selector
+  void get_update_id(revision_id & update_id);
+
+  // write the revision id that was the parent of this workspace before
+  // update completes. this is used for the u: (update) selector
+  void put_update_id(revision_id const & update_id);
+
   // convenience wrappers around the above functions.
 
   // This returns the current roster, except it does not bother updating the