Show correct error if mix task could not be found

Author: ericmj

lib/mix/lib/mix/cli.ex

@@ -58,11 +58,15 @@ defmodule Mix.CLI do
 
       # If the task is not available, let's try to
       # compile the repository and then run it again.
-      if Mix.Task.get(name) do
-        Mix.Task.run(name, args)
-      else
-        Mix.Task.run("compile")
-        Mix.Task.run(name, args)
+      cond do
+        Mix.Task.get(name) ->
+          Mix.Task.run(name, args)
+        Mix.Project.get ->
+          Mix.Task.run("compile")
+          Mix.Task.run(name, args)
+        true ->
+          # Raise no task error
+          Mix.Task.get!(name)
       end
     rescue
       # We only rescue exceptions in the mix namespace, all

lib/mix/test/mix/cli_test.exs

@@ -51,6 +51,13 @@ defmodule Mix.CLITest do
     end
   end
 
+  test "no task error" do
+    in_fixture "no_mixfile", fn ->
+      contents = mix("no_task")
+      assert contents =~ "** (Mix) The task no_task could not be found\n"
+    end
+  end
+
   test "--help smoke test" do
     in_fixture "only_mixfile", fn ->
       output = mix "--help"