GRPC.Stub.connect basic usage does not work after upgrading from 0.10.2 to 0.11.0

[xshadowlegendx]

Describe the bug
client failed to connect in test environment and in iex

To Reproduce
on version 0.10.2, running GRPC.Stub.connect("localhost:24000") will work, when upgrade to 0.11.0 doesn't, and when downgrade back to 0.10.2 it will work as expected again

Expected behavior
return {:ok, channel}

Logs

# when running mix test --cover
** (exit) exited in: GenServer.call(GRPC.Client.Supervisor, {:start_child, {{GenServer, :start_link, [GRPC.Client.Connection, %GRPC.Client.Connection{virtual_channel: %GRPC.Channel{host: "localhost", port: 24000, scheme: "http", cred: nil, ref: #Reference<0.193739494.1766064131.16111>, adapter: GRPC.Client.Adapters.Gun, adapter_payload: %{conn_pid: #PID<0.3619.0>}, codec: GRPC.Codec.Proto, interceptors: [], compressor: nil, accepted_compressors: [], headers: []}, real_channels: %{"\"localhost\":24000" => %GRPC.Channel{host: "localhost", port: 24000, scheme: "http", cred: nil, ref: #Reference<0.193739494.1766064131.16111>, adapter: GRPC.Client.Adapters.Gun, adapter_payload: %{conn_pid: #PID<0.3619.0>}, codec: GRPC.Codec.Proto, interceptors: [], compressor: nil, accepted_compressors: [], headers: []}}, lb_mod: GRPC.Client.LoadBalancing.PickFirst, lb_state: %{current: %{port: 24000, address: "localhost"}, addresses: [%{port: 24000, address: "localhost"}]}, resolver: GRPC.Client.Resolver, adapter: GRPC.Client.Adapters.Gun}, [name: {:global, {GRPC.Client.Connection, #Reference<0.193739494.1766064131.16111>}}]]}, :transient, 5000, :worker, [GenServer]}}, :infinity)
         ** (EXIT) no process: the process is not alive or there's no process currently associated with the given name, possibly because its application isn't started

# manual test running inside iex
iex(1)> GRPC.Stub.connect("localhost:24000")
** (exit) exited in: GenServer.call(GRPC.Client.Supervisor, {:start_child, {{GenServer, :start_link, [GRPC.Client.Connection, %GRPC.Client.Connection{virtual_channel: %GRPC.Channel{host: "localhost", port: 24000, scheme: "http", cred: nil, ref: #Reference<0.2295188456.2840068099.54656>, adapter: GRPC.Client.Adapters.Gun, adapter_payload: %{conn_pid: #PID<0.12258.0>}, codec: GRPC.Codec.Proto, interceptors: [], compressor: nil, accepted_compressors: [], headers: []}, real_channels: %{"\"localhost\":24000" => %GRPC.Channel{host: "localhost", port: 24000, scheme: "http", cred: nil, ref: #Reference<0.2295188456.2840068099.54656>, adapter: GRPC.Client.Adapters.Gun, adapter_payload: %{conn_pid: #PID<0.12258.0>}, codec: GRPC.Codec.Proto, interceptors: [], compressor: nil, accepted_compressors: [], headers: []}}, lb_mod: GRPC.Client.LoadBalancing.PickFirst, lb_state: %{current: %{port: 24000, address: "localhost"}, addresses: [%{port: 24000, address: "localhost"}]}, resolver: GRPC.Client.Resolver, adapter: GRPC.Client.Adapters.Gun}, [name: {:global, {GRPC.Client.Connection, #Reference<0.2295188456.2840068099.54656>}}]]}, :transient, 5000, :worker, [GenServer]}}, :infinity)
    ** (EXIT) no process: the process is not alive or there's no process currently associated with the given name, possibly because its application isn't started
    (elixir 1.18.1) lib/gen_server.ex:1121: GenServer.call/3
    (grpc 0.11.0) lib/grpc/client/connection.ex:160: GRPC.Client.Connection.connect/2
    iex:1: (file)

Protos
If applicable, add protos to help explain your problem.

Versions:

• OS: macos 15.4.1
• Erlang: 27
• Elixir: 1.18.1
• mix.lock(grpc, gun, cowboy, cowlib): 0.11.0, 2.2.0, 2.14.2, 2.16.0

Additional context
previous working mix.lock(grpc, gun, cowboy, cowlib): 0.10.2, 2.2.0, 2.13.0, 2.15.0

[polvalente]

@sleipnir this is related to #438. I believe Connection.connect is expecting virtual_channel to always be present.

Locally I'm getting:

iex(5)> GRPC.Stub.connect("localhost:24000")
** (KeyError) key :ref not found in: nil

If you are using the dot syntax, such as map.field, make sure the left-hand side of the dot is a map
    (grpc 0.11.0) lib/grpc/client/connection.ex:102: GRPC.Client.Connection.child_spec/1
    (grpc 0.11.0) lib/grpc/client/connection.ex:160: GRPC.Client.Connection.connect/2
    iex:5: (file)

[polvalente]

0.11.1 has been released without #438 and should resolve the issue

[polvalente]

A future release will include the feature again (likely 0.11.2)

[sleipnir]

@polvalente see #450
That PR fixes this issue

[polvalente]

@xshadowlegendx 0.11.2 contains the fixed version!

Running in the helloworld example we have:

21:25:39.416 [info] Running Helloworld.Endpoint with Cowboy using http://0.0.0.0:50051
Interactive Elixir (1.18.2) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> GRPC.Stub.connect("localhost:50051")
** (RuntimeError) GRPC.Client.Supervisor is not running. Please ensure it is started as part of your
application's supervision tree:

    children = [
      {GRPC.Client.Supervisor, []}
    ]

    opts = [strategy: :one_for_one, name: MyApp.Supervisor]
    Supervisor.start_link(children, opts)

You can also start it manually in scripts or test environments:

    {:ok, _pid} = DynamicSupervisor.start_link(strategy: :one_for_one, name: GRPC.Client.Supervisor)

    lib/grpc/client/connection.ex:159: GRPC.Client.Connection.connect/2
    iex:1: (file)
iex(1)> {:ok, _pid} = DynamicSupervisor.start_link(strategy: :one_for_one, name: GRPC.Client.Supervisor)
{:ok, #PID<0.2738.0>}
iex(2)> GRPC.Stub.connect("localhost:50051")
{:ok,
 %GRPC.Channel{
   host: "localhost",
   port: 50051,
   scheme: "http",
   cred: nil,
   ref: #Reference<0.3939269630.2145910792.249449>,
   adapter: GRPC.Client.Adapters.Gun,
   adapter_payload: %{conn_pid: #PID<0.2739.0>},
   codec: GRPC.Codec.Proto,
   interceptors: [],
   compressor: nil,
   accepted_compressors: [],
   headers: []
 }}
iex(3)> {:ok, channel} = GRPC.Stub.connect("localhost:50051")
{:ok,
 %GRPC.Channel{
   host: "localhost",
   port: 50051,
   scheme: "http",
   cred: nil,
   ref: #Reference<0.3939269630.2145910788.252249>,
   adapter: GRPC.Client.Adapters.Gun,
   adapter_payload: %{conn_pid: #PID<0.2744.0>},
   codec: GRPC.Codec.Proto,
   interceptors: [],
   compressor: nil,
   accepted_compressors: [],
   headers: []
 }}
iex(4)>     req = Helloworld.HelloRequest.new(name: "grpc-elixir")
warning: Helloworld.HelloRequest.new/1 is deprecated. Build the struct by hand with %MyMessage{...} or use struct/2
└─ iex:4

%Helloworld.HelloRequest{name: "grpc-elixir", __unknown_fields__: []}

21:26:26.004 [debug] refreshing LB pick, caller=#PID<0.2743.0>

21:26:33.693 [debug] refreshing LB pick, caller=#PID<0.2745.0>
iex(5)> Helloworld.Greeter.Stub.say_hello(channel, req)

21:26:37.722 [info] Handled by Helloworld.Greeter.Server.say_hello

21:26:37.722 [info] Response :ok in 3µs
{:ok,
 %Helloworld.HelloReply{
   message: "Hello grpc-elixir",
   today: %Google.Protobuf.Timestamp{
     seconds: 1760574397,
     nanos: 722050417,
     __unknown_fields__: []
   },
   __unknown_fields__: []
 }}

As you can see, the code now guide the user as to what setup is needed (this is also documented, but we though it best to also teach per call as well).