diff --git a/poky/bitbake/lib/bb/command.py b/poky/bitbake/lib/bb/command.py
index 3902ccc..805ed92 100644
--- a/poky/bitbake/lib/bb/command.py
+++ b/poky/bitbake/lib/bb/command.py
@@ -396,7 +396,7 @@
         def sortkey(x):
             vfn, _ = x
             realfn, _, mc = bb.cache.virtualfn2realfn(vfn)
-            return (-command.cooker.collections[mc].calc_bbfile_priority(realfn), vfn)
+            return (-command.cooker.collections[mc].calc_bbfile_priority(realfn)[0], vfn)
 
         skipdict = OrderedDict(sorted(command.cooker.skiplist.items(), key=sortkey))
         return list(skipdict.items())
diff --git a/poky/bitbake/lib/bb/cooker.py b/poky/bitbake/lib/bb/cooker.py
index effd024..f6abc63 100644
--- a/poky/bitbake/lib/bb/cooker.py
+++ b/poky/bitbake/lib/bb/cooker.py
@@ -626,6 +626,7 @@
         current = 0
         runlist = []
         for k in fulltargetlist:
+            origk = k
             mc = ""
             if k.startswith("mc:"):
                 mc = k.split(":")[1]
@@ -635,6 +636,10 @@
                 k2 = k.split(":do_")
                 k = k2[0]
                 ktask = k2[1]
+
+            if mc not in self.multiconfigs:
+                 bb.fatal("Multiconfig dependency %s depends on nonexistent multiconfig configuration named %s" % (origk, mc))
+
             taskdata[mc].add_provider(localdata[mc], self.recipecaches[mc], k)
             current += 1
             if not ktask.startswith("do_"):
@@ -670,7 +675,7 @@
                         l = k.split(':')
                         depmc = l[2]
                         if depmc not in self.multiconfigs:
-                            bb.fatal("Multiconfig dependency %s depends on nonexistent mc configuration %s" % (k,depmc))
+                            bb.fatal("Multiconfig dependency %s depends on nonexistent multiconfig configuration named configuration %s" % (k,depmc))
                         else:
                             logger.debug(1, "Adding providers for multiconfig dependency %s" % l[3])
                             taskdata[depmc].add_provider(localdata[depmc], self.recipecaches[depmc], l[3])
@@ -1588,7 +1593,7 @@
             self.show_appends_with_no_recipes()
             self.handlePrefProviders()
             for mc in self.multiconfigs:
-                self.recipecaches[mc].bbfile_priority = self.collections[mc].collection_priorities(self.recipecaches[mc].pkg_fn, self.data)
+                self.recipecaches[mc].bbfile_priority = self.collections[mc].collection_priorities(self.recipecaches[mc].pkg_fn, self.parser.mcfilelist[mc], self.data)
             self.state = state.running
 
             # Send an event listing all stamps reachable after parsing
@@ -1609,7 +1614,7 @@
             raise NothingToBuild
 
         ignore = (self.data.getVar("ASSUME_PROVIDED") or "").split()
-        for pkg in pkgs_to_build:
+        for pkg in pkgs_to_build.copy():
             if pkg in ignore:
                 parselog.warning("Explicit target \"%s\" is in ASSUME_PROVIDED, ignoring" % pkg)
             if pkg.startswith("multiconfig:"):
@@ -1704,14 +1709,11 @@
         # the shortest.  This allows nested layers to be properly evaluated.
         self.bbfile_config_priorities = sorted(priorities, key=lambda tup: tup[1], reverse=True)
 
-    def calc_bbfile_priority( self, filename, matched = None ):
+    def calc_bbfile_priority(self, filename):
         for _, _, regex, pri in self.bbfile_config_priorities:
             if regex.match(filename):
-                if matched is not None:
-                    if not regex in matched:
-                        matched.add(regex)
-                return pri
-        return 0
+                return pri, regex
+        return 0, None
 
     def get_bbfiles(self):
         """Get list of default .bb files by reading out the current directory"""
@@ -1744,7 +1746,7 @@
         config.setVar("BBFILES", " ".join(files))
 
         # Sort files by priority
-        files.sort( key=lambda fileitem: self.calc_bbfile_priority(fileitem) )
+        files.sort( key=lambda fileitem: self.calc_bbfile_priority(fileitem)[0] )
 
         if not len(files):
             files = self.get_bbfiles()
@@ -1866,39 +1868,62 @@
                 filelist.append(filename)
         return tuple(filelist)
 
-    def collection_priorities(self, pkgfns, d):
+    def collection_priorities(self, pkgfns, fns, d):
+        # Return the priorities of the entries in pkgfns
+        # Also check that all the regexes in self.bbfile_config_priorities are used
+        # (but to do that we need to ensure skipped recipes aren't counted, nor
+        # collections in BBFILE_PATTERN_IGNORE_EMPTY)
 
         priorities = {}
+        seen = set()
+        matched = set()
+
+        matched_regex = set()
+        unmatched_regex = set()
+        for _, _, regex, _ in self.bbfile_config_priorities:
+            unmatched_regex.add(regex)
 
         # Calculate priorities for each file
-        matched = set()
         for p in pkgfns:
             realfn, cls, mc = bb.cache.virtualfn2realfn(p)
-            priorities[p] = self.calc_bbfile_priority(realfn, matched)
+            priorities[p], regex = self.calc_bbfile_priority(realfn)
+            if regex in unmatched_regex:
+                matched_regex.add(regex)
+                unmatched_regex.remove(regex)
+            seen.add(realfn)
+            if regex:
+                matched.add(realfn)
 
-        unmatched = set()
-        for _, _, regex, pri in self.bbfile_config_priorities:
-            if not regex in matched:
-                unmatched.add(regex)
-
-        # Don't show the warning if the BBFILE_PATTERN did match .bbappend files
-        def find_bbappend_match(regex):
+        if unmatched_regex:
+            # Account for bbappend files
             for b in self.bbappends:
                 (bbfile, append) = b
-                if regex.match(append):
-                    # If the bbappend is matched by already "matched set", return False
-                    for matched_regex in matched:
-                        if matched_regex.match(append):
-                            return False
-                    return True
-            return False
+                seen.add(append)
 
-        for unmatch in unmatched.copy():
-            if find_bbappend_match(unmatch):
-                unmatched.remove(unmatch)
+            # Account for skipped recipes
+            seen.update(fns)
+
+            seen.difference_update(matched)
+
+            def already_matched(fn):
+                for regex in matched_regex:
+                    if regex.match(fn):
+                        return True
+                return False
+
+            for unmatch in unmatched_regex.copy():
+                for fn in seen:
+                    if unmatch.match(fn):
+                        # If the bbappend or file was already matched by another regex, skip it
+                        # e.g. for a layer within a layer, the outer regex could match, the inner
+                        # regex may match nothing and we should warn about that
+                        if already_matched(fn):
+                            continue
+                        unmatched_regex.remove(unmatch)
+                        break
 
         for collection, pattern, regex, _ in self.bbfile_config_priorities:
-            if regex in unmatched:
+            if regex in unmatched_regex:
                 if d.getVar('BBFILE_PATTERN_IGNORE_EMPTY_%s' % collection) != '1':
                     collectlog.warning("No bb files in %s matched BBFILE_PATTERN_%s '%s'" % (self.mc if self.mc else 'default',
                                                                                              collection, pattern))
diff --git a/poky/bitbake/lib/bb/fetch2/git.py b/poky/bitbake/lib/bb/fetch2/git.py
index dbf8715..644ba92 100644
--- a/poky/bitbake/lib/bb/fetch2/git.py
+++ b/poky/bitbake/lib/bb/fetch2/git.py
@@ -355,7 +355,7 @@
               runfetchcmd("%s remote rm origin" % ud.basecmd, d, workdir=ud.clonedir)
 
             runfetchcmd("%s remote add --mirror=fetch origin %s" % (ud.basecmd, repourl), d, workdir=ud.clonedir)
-            fetch_cmd = "LANG=C %s fetch -f --prune --progress %s refs/*:refs/*" % (ud.basecmd, repourl)
+            fetch_cmd = "LANG=C %s fetch -f --progress %s refs/*:refs/*" % (ud.basecmd, repourl)
             if ud.proto.lower() != 'file':
                 bb.fetch2.check_network_access(d, fetch_cmd, ud.url)
             progresshandler = GitProgressHandler(d)
diff --git a/poky/bitbake/lib/bb/parse/ast.py b/poky/bitbake/lib/bb/parse/ast.py
index 785aa97..0714296 100644
--- a/poky/bitbake/lib/bb/parse/ast.py
+++ b/poky/bitbake/lib/bb/parse/ast.py
@@ -244,12 +244,14 @@
         bb.build.addtask(self.func, self.before, self.after, data)
 
 class DelTaskNode(AstNode):
-    def __init__(self, filename, lineno, func):
+    def __init__(self, filename, lineno, tasks):
         AstNode.__init__(self, filename, lineno)
-        self.func = func
+        self.tasks = tasks
 
     def eval(self, data):
-        bb.build.deltask(self.func, data)
+        tasks = data.expand(self.tasks).split()
+        for task in tasks:
+            bb.build.deltask(task, data)
 
 class BBHandlerNode(AstNode):
     def __init__(self, filename, lineno, fns):
@@ -305,7 +307,7 @@
     statements.append(AddTaskNode(filename, lineno, func, before, after))
 
 def handleDelTask(statements, filename, lineno, m):
-    func = m.group("func")
+    func = m.group(1)
     if func is None:
         return
 
diff --git a/poky/bitbake/lib/bb/parse/parse_py/BBHandler.py b/poky/bitbake/lib/bb/parse/parse_py/BBHandler.py
index 6e216ef..215f940 100644
--- a/poky/bitbake/lib/bb/parse/parse_py/BBHandler.py
+++ b/poky/bitbake/lib/bb/parse/parse_py/BBHandler.py
@@ -26,7 +26,7 @@
 __inherit_regexp__       = re.compile(r"inherit\s+(.+)" )
 __export_func_regexp__   = re.compile(r"EXPORT_FUNCTIONS\s+(.+)" )
 __addtask_regexp__       = re.compile(r"addtask\s+(?P<func>\w+)\s*((before\s*(?P<before>((.*(?=after))|(.*))))|(after\s*(?P<after>((.*(?=before))|(.*)))))*")
-__deltask_regexp__       = re.compile(r"deltask\s+(?P<func>\w+)(?P<ignores>.*)")
+__deltask_regexp__       = re.compile(r"deltask\s+(.+)")
 __addhandler_regexp__    = re.compile(r"addhandler\s+(.+)" )
 __def_regexp__           = re.compile(r"def\s+(\w+).*:" )
 __python_func_regexp__   = re.compile(r"(\s+.*)|(^$)|(^#)" )
@@ -238,9 +238,6 @@
 
     m = __deltask_regexp__.match(s)
     if m:
-        # Check and warn "for deltask task1 task2"
-        if m.group('ignores'):
-            logger.warning('deltask ignored: "%s"' % m.group('ignores'))
         ast.handleDelTask(statements, fn, lineno, m)
         return
 
diff --git a/poky/bitbake/lib/bb/pysh/pyshyacc.py b/poky/bitbake/lib/bb/pysh/pyshyacc.py
index de565dc..924860a 100644
--- a/poky/bitbake/lib/bb/pysh/pyshyacc.py
+++ b/poky/bitbake/lib/bb/pysh/pyshyacc.py
@@ -570,6 +570,7 @@
 
 def p_separator_op(p):                 
     """separator_op : COMMA
+                    | COMMA COMMA
                     | AMP"""
     p[0] = p[1]
 
diff --git a/poky/bitbake/lib/bb/server/process.py b/poky/bitbake/lib/bb/server/process.py
index 83385ba..9ec79f5 100644
--- a/poky/bitbake/lib/bb/server/process.py
+++ b/poky/bitbake/lib/bb/server/process.py
@@ -48,7 +48,7 @@
 
         self.event_handle = None
         self.haveui = False
-        self.lastui = False
+        self.maxuiwait = 30
         self.xmlrpc = False
 
         self._idlefuns = {}
@@ -155,6 +155,7 @@
                 print("No timeout, exiting.")
                 self.quit = True
 
+        self.lastui = time.time()
         while not self.quit:
             if self.sock in ready:
                 while select.select([self.sock],[],[],0)[0]:
@@ -191,11 +192,18 @@
                 except (EOFError, OSError):
                     disconnect_client(self, fds)
 
-            if not self.timeout == -1.0 and not self.haveui and self.lastui and self.timeout and \
+            if not self.timeout == -1.0 and not self.haveui and self.timeout and \
                     (self.lastui + self.timeout) < time.time():
                 print("Server timeout, exiting.")
                 self.quit = True
 
+            # If we don't see a UI connection within maxuiwait, its unlikely we're going to see
+            # one. We have had issue with processes hanging indefinitely so timing out UI-less
+            # servers is useful.
+            if not self.haveui and not self.timeout and (self.lastui + self.maxuiwait) < time.time():
+                print("No UI connection within max timeout, exiting to avoid infinite loop.")
+                self.quit = True
+
             if self.command_channel in ready:
                 try:
                     command = self.command_channel.get()
@@ -220,10 +228,13 @@
 
         print("Exiting")
         # Remove the socket file so we don't get any more connections to avoid races
-        os.unlink(self.sockname)
+        try:
+            os.unlink(self.sockname)
+        except:
+            pass
         self.sock.close()
 
-        try: 
+        try:
             self.cooker.shutdown(True)
             self.cooker.notifier.stop()
             self.cooker.confignotifier.stop()
@@ -243,7 +254,7 @@
                 lock = bb.utils.lockfile(lockfile, shared=False, retry=False, block=True)
                 if lock:
                     # We hold the lock so we can remove the file (hide stale pid data)
-                    bb.utils.remove(lockfile)
+                    # via unlockfile.
                     bb.utils.unlockfile(lock)
                     return
 
@@ -331,7 +342,7 @@
     def runCommand(self, command):
         self.connection.send(command)
         if not self.recv.poll(30):
-            logger.note("No reply from server in 30s")
+            logger.info("No reply from server in 30s")
             if not self.recv.poll(30):
                 raise ProcessTimeout("Timeout while waiting for a reply from the bitbake server (60s)")
         return self.recv.get()
diff --git a/poky/bitbake/lib/bb/tests/cooker.py b/poky/bitbake/lib/bb/tests/cooker.py
index 74c903f..c82d4b7 100644
--- a/poky/bitbake/lib/bb/tests/cooker.py
+++ b/poky/bitbake/lib/bb/tests/cooker.py
@@ -60,7 +60,7 @@
         log_handler = LogHandler()
         logger.addHandler(log_handler)
         collection = bb.cooker.CookerCollectFiles(bbfile_config_priorities)
-        collection.collection_priorities(pkgfns, self.d)
+        collection.collection_priorities(pkgfns, pkgfns, self.d)
         logger.removeHandler(log_handler)
 
         # Should be empty (no generated messages)
diff --git a/poky/bitbake/lib/bb/tests/parse.py b/poky/bitbake/lib/bb/tests/parse.py
index 9afd1b2..9e21e18 100644
--- a/poky/bitbake/lib/bb/tests/parse.py
+++ b/poky/bitbake/lib/bb/tests/parse.py
@@ -178,7 +178,10 @@
 addtask do_patch after do_foo after do_unpack before do_configure before do_compile
 addtask do_fetch do_patch
 
-deltask do_fetch do_patch
+MYVAR = "do_patch"
+EMPTYVAR = ""
+deltask do_fetch ${MYVAR} ${EMPTYVAR}
+deltask ${EMPTYVAR}
 """
     def test_parse_addtask_deltask(self):
         import sys
@@ -189,6 +192,5 @@
         self.assertTrue("addtask contained multiple 'before' keywords" in stdout)
         self.assertTrue("addtask contained multiple 'after' keywords" in stdout)
         self.assertTrue('addtask ignored: " do_patch"' in stdout)
-        self.assertTrue('deltask ignored: " do_patch"' in stdout)
         #self.assertTrue('dependent task do_foo for do_patch does not exist' in stdout)