Check for imports conflicts in batches

Author: José Valim

lib/elixir/lib/module/dispatch_tracker.ex

@@ -153,6 +153,18 @@ defmodule Module.DispatchTracker do
     Enum.any?(:digraph.in_neighbours(d, mod), match?({ :import, _, _ }, &1))
   end
 
+  # Collecting all conflicting imports with the given functions
+  @doc false
+  def collect_imports_conflicts(pid, all_defined) do
+    d = :gen_server.call(to_pid(pid), :digraph, @timeout)
+
+    lc { name, arity } inlist all_defined,
+       n = :digraph.out_neighbours(d, { :import, name, arity }),
+       n != [] do
+      { n, name, arity }
+    end
+  end
+
   # Collect all unused definitions based on the private
   # given also accounting the expected amount of default
   # clauses a private function have.

lib/elixir/src/elixir_tracker.erl

@@ -69,26 +69,14 @@ if_tracker(Module, Callback) ->
 
 %% ERROR HANDLING
 
-%% Ensure no import conflicts with any of the local definitions.
-
 ensure_no_import_conflict(Meta, File, Module, AllDefined) ->
   if_tracker(Module, fun(Pid) ->
-    [do_ensure_no_import_conflict(Meta, File, Pid, X) || X  <- AllDefined]
+    [ begin
+        elixir_errors:form_error(Meta, File, ?MODULE, { import_conflict, Error })
+      end || Error <- ?tracker:collect_imports_conflicts(Pid, AllDefined) ]
   end),
   ok.
 
-do_ensure_no_import_conflict(Meta, File, Pid, { Name, Arity } = Tuple) ->
-  Matches = ?tracker:imports_with_dispatch(Pid, Tuple),
-
-  case Matches of
-    []  -> ok;
-    Key ->
-      Error = { import_conflict, { hd(Key), Name, Arity } },
-      elixir_errors:form_error(Meta, File, ?MODULE, Error)
-  end.
-
-%% Ensure all imports are used.
-
 ensure_all_imports_used(_Line, File, Module) ->
   if_tracker(Module, fun(Pid) ->
     [ begin
@@ -97,8 +85,6 @@ ensure_all_imports_used(_Line, File, Module) ->
   end),
   ok.
 
-%% Warn for unused/unreachable locals and default arguments.
-
 warn_unused_local(File, Module, Private) ->
   if_tracker(Module, fun(Pid) ->
     Args = [ { Fun, Kind, Defaults } ||
@@ -112,9 +98,9 @@ warn_unused_local(File, Module, Private) ->
       end || Error <- Unused ]
   end).
 
-format_error({import_conflict,{Receiver, Name, Arity}}) ->
+format_error({import_conflict,{Receivers, Name, Arity}}) ->
   io_lib:format("imported ~ts.~ts/~B conflicts with local function",
-    [elixir_errors:inspect(Receiver), Name, Arity]);
+    [elixir_errors:inspect(hd(Receivers)), Name, Arity]);
 
 format_error({ unused_import, Module }) ->
   io_lib:format("unused import ~ts", [elixir_errors:inspect(Module)]);

lib/elixir/test/elixir/module/dispatch_tracker_test.exs

@@ -132,4 +132,11 @@ defmodule Module.DispatchTrackerTest do
     D.add_warnable(config[:pid], Module, false, 15)
     refute { Module, 15 } in D.collect_unused_imports(config[:pid])
   end
+
+  test "find import conflicts", config do
+    refute { [Module], :conflict, 1 } in D.collect_imports_conflicts(config[:pid], [conflict: 1])
+
+    D.add_import(config[:pid], Module, { :conflict, 1 })
+    assert { [Module], :conflict, 1 } in D.collect_imports_conflicts(config[:pid], [conflict: 1])
+  end
 end