Accept -t/--timeout before command name [again]

There are existing users (including RabbitMQ core tests) that
use that sequence because it was previously in the docs.

This relaxes command validation so that if a command-specific
flag overrides a global, we accept it as long as their types match.

Per discussion with @hairyhum.

deps/rabbitmq_cli/lib/rabbitmq/cli/core/parser.ex

@@ -168,6 +168,7 @@ defmodule RabbitMQ.CLI.Core.Parser do
      quiet: :boolean,
      dry_run: :boolean,
      vhost: :string,
+     timeout: :integer,
      longnames: :boolean,
      formatter: :string,
      printer: :string,
@@ -186,7 +187,8 @@ defmodule RabbitMQ.CLI.Core.Parser do
     [p: :vhost,
      n: :node,
      q: :quiet,
-     l: :longnames]
+     l: :longnames,
+     t: :timeout]
   end
 
   defp build_switches(default, command) do
@@ -204,7 +206,7 @@ defmodule RabbitMQ.CLI.Core.Parser do
                         {command, {:redefining_global_aliases,
                                    command_aliases}}})
   end
-
+  
   defp apply_if_exported(mod, fun, args, default) do
     case function_exported?(mod, fun, length(args)) do
       true  -> apply(mod, fun, args);
@@ -214,8 +216,17 @@ defmodule RabbitMQ.CLI.Core.Parser do
 
   defp merge_if_different(default, specific, error) do
     case keyword_intersect(default, specific) do
-      [] -> Keyword.merge(default, specific);
-      _  -> exit(error)
+      []        -> Keyword.merge(default, specific);
+      conflicts ->
+        # if all conflicting keys are of the same type,
+        # that's acceptable
+        case Enum.all?(conflicts,
+              fn(c) ->
+                Keyword.get(default, c) == Keyword.get(specific, c)
+              end) do
+          true  -> Keyword.merge(default, specific);
+          false -> exit(error)
+        end
     end
   end
 

deps/rabbitmq_cli/test/parser_test.exs

@@ -152,6 +152,18 @@ defmodule ParserTest do
       {["seagull"], %{vhost: "my_vhost"}, []}
   end
 
+  test "--timeout can be specified before command" do
+    # for backwards compatibility
+    assert @subject.parse_global(["-n", "rabbitmq@localhost", "--timeout", "5", "sandwich", "pastrami"]) ==
+      {["sandwich", "pastrami"], %{node: :"rabbitmq@localhost", timeout: 5}, []}
+  end
+
+  test "-t can be specified before command" do
+    # for backwards compatibility
+    assert @subject.parse_global(["-n", "rabbitmq@localhost", "-t", "5", "sandwich", "pastrami"]) ==
+      {["sandwich", "pastrami"], %{node: :"rabbitmq@localhost", timeout: 5}, []}
+  end
+
   test "parse/1 returns command name" do
     command_line = ["pacific_gull", "fly", "-p", "my_vhost"]
     command = RabbitMQ.CLI.Seagull.Commands.PacificGullCommand