chore: provide Contexted.ignore/1

lib/contexted.ex

@@ -206,4 +206,27 @@ defmodule Contexted do
 
   See more in [Contexted.CRUD](https://hexdocs.pm/contexted/Contexted.CRUD.html).
   """
+
+  @doc ~S"""
+  Marks a module reference as intentionally ignored by the cross‑context tracer.
+
+  Wrap a cross‑context module reference with `ignore/1` when you explicitly allow
+  that call and don't want `Contexted.Tracer` to raise a compile‑time error for it.
+
+  This function is a no‑op at runtime — it simply returns the module. It only
+  serves as a hint for the tracer during compilation.
+
+  ## Examples
+
+  Usage inside a context (the cross‑context call compiles because the module is wrapped):
+
+  ```elixir
+  defmodule App.Account.UserContext do
+    def hello(id) do
+      Contexted.ignore(App.Blog.PostContext).hello(id)
+    end
+  end
+  """
+  @spec ignore(module()) :: module()
+  def ignore(module), do: module
 end

test/context_test.exs

@@ -1,4 +1,47 @@
 defmodule ContextedTest do
   use ExUnit.Case
   doctest Contexted
+
+  describe "cross-context reference checking" do
+    test "raises on cross-reference without ignore/1" do
+      code = """
+      defmodule Foo.Account.UserContext do
+        alias Foo.Blog.PostContext
+        def hello, do: PostContext.hello()
+      end
+
+      defmodule Foo.Blog.PostContext do
+        def hello, do: :ok
+      end
+      """
+
+      Application.put_env(:contexted, :contexts, [Foo.Account, Foo.Blog])
+      Code.put_compiler_option(:tracers, [Contexted.Tracer])
+
+      assert_raise RuntimeError,
+                   ~r/You can't reference Foo.Blog context within Foo.Account context\./,
+                   fn ->
+                     Code.compile_string(code, "test/foo_without_ignore.ex")
+                   end
+    end
+
+    test "does NOT raise when the call is wrapped with Contexted.ignore/1" do
+      code = """
+      defmodule Bar.Account.UserContext do
+        def hello, do: Contexted.ignore(Bar.Blog.PostContext).hello()
+      end
+
+      defmodule Bar.Blog.PostContext do
+        def hello, do: :ok
+      end
+      """
+
+      Application.put_env(:contexted, :contexts, [Bar.Account, Bar.Blog])
+      Code.put_compiler_option(:tracers, [Contexted.Tracer])
+
+      Code.compile_string(code, "test/bar_with_ignore.ex")
+      # credo:disable-for-next-line
+      assert :ok = apply(Bar.Account.UserContext, :hello, [])
+    end
+  end
 end