diff --git a/src/rebar_core.erl b/src/rebar_core.erl
index fcfa62a..863d1d5 100644
--- a/src/rebar_core.erl
+++ b/src/rebar_core.erl
@@ -172,8 +172,9 @@ skip_or_process_dir1(AppFile, ModuleSet, Config, CurrentCodePath,
                          CurrentCodePath, ModuleSet)
     end.
 
-process_dir1(Dir, Command, DirSet, Config0, CurrentCodePath,
+process_dir1(Dir, Command, DirSet, Config, CurrentCodePath,
              {DirModules, ModuleSetFile}) ->
+    Config0 = rebar_config:set(Config, command, Command),
     %% Get the list of modules for "any dir". This is a catch-all list
     %% of modules that are processed in addition to modules associated
     %% with this directory type. These any_dir modules are processed
diff --git a/src/rebar_deps.erl b/src/rebar_deps.erl
index be6283d..82c5061 100644
--- a/src/rebar_deps.erl
+++ b/src/rebar_deps.erl
@@ -97,8 +97,22 @@ preprocess(Config, _) ->
     %% deps-related can be executed on their directories.
     NonRawAvailableDeps = [D || D <- AvailableDeps, not D#dep.is_raw],
 
-    %% Return all the available dep directories for process
-    {ok, NewConfig, dep_dirs(NonRawAvailableDeps)}.
+    case rebar_config:get(Config, command, undefined) of
+        'update-deps' ->
+            %% Skip ALL of the dep folders, we do this because we don't want
+            %% any other calls to preprocess() for update-deps beyond the
+            %% toplevel directory. They aren't actually harmful, but they slow
+            %% things down unnecessarily.
+            NewConfig2 = lists:foldl(fun(D, Acc) ->
+                                             rebar_config:set_skip_dir(Acc, D#dep.dir)
+                                     end, NewConfig, collect_deps(rebar_utils:get_cwd(),NewConfig)),
+            %% Return the empty list, as we don't want anything processed before
+            %% us.
+            {ok, NewConfig2, []};
+        _ ->
+            %% Return all the available dep directories for process
+            {ok, NewConfig, dep_dirs(NonRawAvailableDeps)}
+    end.
 
 postprocess(Config, _) ->
     case rebar_config:get_xconf(Config, ?MODULE, undefined) of
@@ -169,17 +183,23 @@ do_check_deps(Config) ->
     {ok, save_dep_dirs(Config2, lists:reverse(PulledDeps))}.
 
 'update-deps'(Config, _) ->
-    %% Determine what deps are required
-    RawDeps = rebar_config:get_local(Config, deps, []),
-    {Config1, Deps} = find_deps(Config, read, RawDeps),
+    {Config2, UpdatedDeps} = update_deps_int(rebar_config:set(Config, depowner, dict:new()), []),
+    DepOwners = rebar_config:get(Config2, depowner, dict:new()),
 
-    %% Update each dep
-    UpdatedDeps = [update_source(Config1, D)
-                   || D <- Deps, D#dep.source =/= undefined],
+    %% check for conflicting deps
+    [?ERROR("Conflicting dependencies for ~p: ~p~n", [K,
+                                                      [{"From: " ++ string:join(dict:fetch(D,
+                                                                               DepOwners),
+                                                                               ", "),
+                                                        {D#dep.vsn_regex,
+                                                         D#dep.source}} || D <- V]]) ||
+           {K, V} <- dict:to_list(lists:foldl(fun(Dep, Acc) ->
+                                                      dict:append(Dep#dep.app, Dep, Acc)
+                                              end, dict:new(), UpdatedDeps)), length(V) > 1],
 
     %% Add each updated dep to our list of dirs for post-processing. This yields
     %% the necessary transitivity of the deps
-    {ok, save_dep_dirs(Config1, UpdatedDeps)}.
+    {ok, save_dep_dirs(Config, UpdatedDeps)}.
 
 'delete-deps'(Config, _) ->
     %% Delete all the available deps in our deps/ directory, if any
@@ -566,6 +586,64 @@ update_source1(AppDir, {fossil, _Url, Version}) ->
     rebar_utils:sh("fossil pull", [{cd, AppDir}]),
     rebar_utils:sh(?FMT("fossil update ~s", [Version]), []).
 
+%% Recursively update deps, this is not done via rebar's usual dep traversal as
+%% that is the wrong order (tips are updated before branches). Instead we do a
+%% traverse the deps at each level completely before traversing *their* deps.
+%% This allows updates to actually propogate down the tree, rather than fail to
+%% flow up the tree, which was the previous behaviour.
+update_deps_int(Config0, UDD) ->
+    %% Determine what deps are required
+    ConfDir = filename:basename(rebar_utils:get_cwd()),
+    RawDeps = rebar_config:get_local(Config0, deps, []),
+    {Config1, Deps} = find_deps(Config0, read, RawDeps),
+
+    %% Update each dep
+    UpdatedDeps = [update_source(Config1, D)
+                   || D <- Deps, D#dep.source =/= undefined, not lists:member(D, UDD)],
+
+    lists:foldl(fun(Dep, {Config, Updated}) ->
+                        {true, AppDir} = get_deps_dir(Config, Dep#dep.app),
+                        Config2 = case has_vcs_dir(element(1, Dep#dep.source), AppDir) of
+                            false ->
+                                %% If the dep did not exist (maybe it was added)
+                                %% clone it. We'll traverse ITS deps below. and
+                                %% clone them if needed.
+                                {C1, _D1} = use_source(Config, Dep),
+                                C1;
+                            true ->
+                                Config
+                        end,
+                        ok = file:set_cwd(AppDir),
+                        Config3 = rebar_config:new(Config2),
+                        %% track where a dep comes from...
+                        Config4 = rebar_config:set(Config3, depowner,
+                                                   dict:append(Dep, ConfDir,
+                                                               rebar_config:get(Config3,
+                                                                                depowner,
+                                                                                dict:new()))),
+
+                        {Config5, Res} = update_deps_int(Config4, Updated),
+                        {Config5, lists:umerge(lists:sort(Res),
+                                               lists:sort(Updated))}
+                end, {Config1, lists:umerge(lists:sort(UpdatedDeps),
+                                            lists:sort(UDD))}, UpdatedDeps).
+
+%% Recursively walk the deps and build a list of them.
+collect_deps(Dir, C) ->
+    case file:set_cwd(Dir) of
+        ok ->
+            Config = rebar_config:new(C),
+            RawDeps = rebar_config:get_local(Config, deps, []),
+            {Config1, Deps} = find_deps(Config, read, RawDeps),
+
+            lists:flatten(Deps ++ [begin
+                                       {true, AppDir} = get_deps_dir(Config1, Dep#dep.app),
+                                       collect_deps(AppDir, C)
+                                   end || Dep <- Deps]);
+        _ ->
+            []
+    end.
+
 
 %% ===================================================================
 %% Source helper functions