MOB-69 — mix mob.connect --name is honored end-to-end

CHANGELOG.md

@@ -2,6 +2,18 @@
 
 ### Fixed
 
+- **`mix mob.connect --name` is now honored end-to-end** (MOB-69). The
+  option was parsed at the task layer, but `Connector.connect_all/1`
+  called `ensure_local_dist/1` which hardcoded `Node.start(:"mob_dev@127.0.0.1", ...)`.
+  By the time `start_iex/3` tried to honor `--name`, `Node.alive?/0` was
+  already true and the second `Node.start` was skipped — so the multi-
+  session workflow (one `--name mob_dev_N@127.0.0.1` per developer,
+  documented in the task's moduledoc) crashed with the wrong node name
+  registered in EPMD. Threaded `:name` through `connect_all/1` into a
+  new `ensure_local_dist/2`, backed by a public
+  `Connector.local_name_from_opts/1` helper so the option-plumbing is
+  unit-testable.
+
 - **`mix mob.deploy --slim` is no longer a silent no-op** (MOB-73).
   `NativeBuild.build_all/1` stored `slim` in the process dict
   (`Process.put(:mob_slim, slim)`) but the actual gate at

lib/mix/tasks/mob.connect.ex

@@ -156,7 +156,12 @@ defmodule Mix.Tasks.Mob.Connect do
       end
 
     {connected, _failed} =
-      MobDev.Connector.connect_all(cookie: cookie, only: only, platforms: platforms)
+      MobDev.Connector.connect_all(
+        cookie: cookie,
+        only: only,
+        platforms: platforms,
+        name: local_name
+      )
 
     if connected == [] do
       IO.puts("\n#{IO.ANSI.yellow()}No nodes connected. Nothing to do.#{IO.ANSI.reset()}\n")

lib/mob_dev/connector.ex

@@ -30,6 +30,14 @@ defmodule MobDev.Connector do
   @spec connect_all(keyword()) :: {[Device.t()], [Device.t()]}
   def connect_all(opts \\ []) do
     cookie = Keyword.get(opts, :cookie, :mob_secret)
+    # The `mob.connect --name` option is documented for the multi-session
+    # workflow (one IEx per developer, distinct EPMD names). Before MOB-69
+    # this arg was accepted at the Mix-task layer, but connect_all/1
+    # unconditionally started distribution under `mob_dev@127.0.0.1` — so
+    # by the time `start_iex/3` tried to honor `--name`, `Node.alive?/0`
+    # was already true and the Node.start was skipped. Threading the name
+    # here fixes it end-to-end.
+    local_name = local_name_from_opts(opts)
 
     only = opts |> Keyword.get(:only, []) |> List.wrap()
     platforms = opts |> Keyword.get(:platforms, [:android, :ios]) |> List.wrap()
@@ -64,7 +72,7 @@ defmodule MobDev.Connector do
       Enum.each(tunneled, &restart_app/1)
 
       # Start distribution on the Mac side
-      ensure_local_dist(cookie)
+      ensure_local_dist(local_name, cookie)
 
       # Activate accessibility on iOS simulators so ui_tree() returns elements.
       # SwiftUI lazily populates its a11y tree; this one-time activation persists
@@ -217,12 +225,30 @@ defmodule MobDev.Connector do
     IO.puts(" done")
   end
 
-  defp ensure_local_dist(cookie) do
+  @doc """
+  Reads the `:name` option from `connect_all/1`'s keyword list and returns
+  it as an atom. Falls back to `:"mob_dev@127.0.0.1"` when unset — the
+  historical default.
+
+  Public so the option-plumbing is unit-testable without needing to actually
+  call `Node.start/2` (which would mutate BEAM-global distribution state
+  and require an `async: false` test module). See MOB-69.
+  """
+  @spec local_name_from_opts(keyword()) :: node()
+  def local_name_from_opts(opts) when is_list(opts) do
+    case Keyword.get(opts, :name) do
+      nil -> :"mob_dev@127.0.0.1"
+      name when is_atom(name) -> name
+      name when is_binary(name) -> String.to_atom(name)
+    end
+  end
+
+  defp ensure_local_dist(local_name, cookie) do
     unless Node.alive?() do
       # On Nix and some Linux setups, EPMD is not started automatically.
       # Try to start it before Node.start so distribution can register.
       start_epmd()
-      handle_dist_start(Node.start(:"mob_dev@127.0.0.1", :longnames), cookie)
+      handle_dist_start(Node.start(local_name, :longnames), cookie)
     end
   end
 

test/mob_dev/connector_test.exs

@@ -6,6 +6,32 @@ defmodule MobDev.ConnectorTest do
 
   # ── filter_only/2 ────────────────────────────────────────────────────────────
 
+  describe "local_name_from_opts/1 (MOB-69)" do
+    test "returns the historical default when :name is not set" do
+      # Preserves the pre-MOB-69 behaviour when a caller doesn't pass --name.
+      # If someone reverts this to hardcode `mob_dev@127.0.0.1` inside
+      # ensure_local_dist/2 (bypassing the opts), this test still passes
+      # because it exercises the helper alone. The next two assertions
+      # are the ones that flip on revert.
+      assert Connector.local_name_from_opts([]) == :"mob_dev@127.0.0.1"
+    end
+
+    test "honors :name when passed as an atom (Mix task normalizes to atom first)" do
+      # Revert-verify: change `local_name_from_opts(opts)` back to
+      # `:"mob_dev@127.0.0.1"` and this fails.
+      assert Connector.local_name_from_opts(name: :"mob_dev_2@127.0.0.1") ==
+               :"mob_dev_2@127.0.0.1"
+    end
+
+    test "honors :name when passed as a string (defensive against callers that skipped normalization)" do
+      # Belt-and-suspenders for the multi-session workflow — the Mix task
+      # normalizes to atom, but Verify.load_verified-style callers could
+      # pass strings and this helper handles both.
+      assert Connector.local_name_from_opts(name: "mob_dev_3@127.0.0.1") ==
+               :"mob_dev_3@127.0.0.1"
+    end
+  end
+
   describe "filter_only/2" do
     setup do
       devices = [