fix: use :peer for cluster tests

.github/workflows/ci.yml

@@ -1,56 +1,77 @@
-name: Tests
+name: CI
 
 on:
-  pull_request:
   push:
-
-env:
-  ACTIONS_RUNNER_FORCED_INTERNAL_NODE_VERSION: node16
-  ACTIONS_RUNNER_FORCE_ACTIONS_NODE_VERSION: node16
-  ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
+  pull_request:
+    branches:
+      - main
 
 jobs:
-  tests:
-    name: Run tests (${{ matrix.image }})
-
-    # prevent workflow jobs run twice on push and pull_request event
-    # see https://github.com/orgs/community/discussions/57827
-    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
+  mix_test:
+    name: mix test (OTP ${{matrix.otp}} | Elixir ${{matrix.elixir}})
 
     strategy:
       fail-fast: false
       matrix:
         include:
-          - image: 1.6.6-erlang-21.3.8.24-debian-buster-20210902-slim
-          - image: 1.19.3-erlang-28.1.1-debian-bullseye-20251103-slim
+          - elixir: 1.13.4
+            otp: 25.3
+
+          - elixir: 1.16.3
+            otp: 26.2
+
+          - elixir: 1.18.4
+            otp: 27.3
+
+          - elixir: 1.19.4
+            otp: 28.1
+            lint: lint
+
+          # run against latest Elixir to catch warnings early
+          - elixir: main-otp-28
+            otp: maint-28
 
     runs-on: ubuntu-latest
-    container:
-      image: hexpm/elixir:${{ matrix.image }}
 
     steps:
-    - name: Checkout
-      uses: actions/checkout@v5
-
-    - name: Hex and Rebar setup
-      run: |
-        mix local.hex --force
-        mix local.rebar --force
-
-    - name: Restore deps and _build cache
-      uses: actions/cache@v4
-      with:
-        path: |
-          deps
-          _build
-        key: deps-${{ runner.os }}-${{ matrix.image }}-${{ hashFiles('**/mix.lock') }}
-        restore-keys: |
-          deps-${{ runner.os }}-${{ matrix.image }}
-
-    - name: Install dependencies
-      run: mix deps.get --only test
-
-    - name: Run tests
-      run: |
-        epmd -daemon
-        mix test
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Elixir
+        uses: erlef/setup-beam@v1
+        with:
+          elixir-version: ${{ matrix.elixir }}
+          otp-version: ${{ matrix.otp }}
+
+      - name: Restore deps and _build cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            deps
+            _build
+          key: deps-${{ runner.os }}-${{ matrix.otp }}-${{ matrix.elixir }}-${{ hashFiles('**/mix.lock') }}
+          restore-keys: |
+            deps-${{ runner.os }}-${{ matrix.otp }}-${{ matrix.elixir }}
+
+      - name: Install dependencies
+        run: mix deps.get
+
+      - name: Remove compiled application files
+        run: mix clean
+
+      - name: Compile dependencies
+        run: mix compile
+        if: ${{ !matrix.lint }}
+        env:
+          MIX_ENV: test
+
+      - name: Compile & lint dependencies
+        run: mix compile --warnings-as-errors
+        if: ${{ matrix.lint }}
+        env:
+          MIX_ENV: test
+
+      - name: Run tests
+        run: |
+          epmd -daemon
+          mix test

mix.exs

@@ -7,7 +7,7 @@ defmodule Phoenix.PubSub.Mixfile do
     [
       app: :phoenix_pubsub,
       version: @version,
-      elixir: "~> 1.6",
+      elixir: "~> 1.13",
       name: "Phoenix.PubSub",
       description: "Distributed PubSub and Presence platform",
       homepage_url: "http://www.phoenixframework.org",

test/support/cluster.ex

@@ -9,17 +9,22 @@ defmodule Phoenix.PubSub.Cluster do
     # Turn node into a distributed node with the given long name
     :net_kernel.start([:"primary@127.0.0.1"])
 
-    # Allow spawned nodes to fetch all code from this node
-    :erl_boot_server.start([])
-    allow_boot to_charlist("127.0.0.1")
-
     nodes
     |> Enum.map(&Task.async(fn -> spawn_node(&1) end))
     |> Enum.map(&Task.await(&1, 30_000))
   end
 
   defp spawn_node({node_host, opts}) do
-    {:ok, node} = :slave.start(to_charlist("127.0.0.1"), node_name(node_host), inet_loader_args())
+    cookie = :erlang.get_cookie()
+
+    {:ok, _peer, node} =
+      :peer.start(%{
+        name: node_name(node_host),
+        host: ~c"127.0.0.1",
+        env: [{~c"ERL_AFLAGS", ~c"-setcookie #{cookie}"}]
+      })
+
+    true = Node.connect(node)
     add_code_paths(node)
     transfer_configuration(node)
     ensure_applications_started(node)
@@ -34,15 +39,6 @@ defmodule Phoenix.PubSub.Cluster do
     :rpc.block_call(node, module, function, args)
   end
 
-  defp inet_loader_args do
-    to_charlist("-loader inet -hosts 127.0.0.1 -setcookie #{:erlang.get_cookie()}")
-  end
-
-  defp allow_boot(host) do
-    {:ok, ipv4} = :inet.parse_ipv4_address(host)
-    :erl_boot_server.add_slave(ipv4)
-  end
-
   defp add_code_paths(node) do
     rpc(node, :code, :add_paths, [:code.get_path()])
   end