Logger logs :process_label if present

lib/logger/lib/logger.ex

@@ -119,6 +119,10 @@ defmodule Logger do
 
     * `:registered_name` - the process registered name as an atom
 
+    * `:process_label` - (available from Erlang/OTP 27+) an arbitrary term
+      which can be added to a process with `:proc_lib.set_label/1` for
+      debugging purposes
+
     * `:domain` - a list of domains for the logged message. For example,
       all Elixir reports default to `[:elixir]`. Erlang reports may start
       with `[:otp]` or `[:sasl]`

lib/logger/lib/logger/translator.ex

@@ -459,10 +459,14 @@ defmodule Logger.Translator do
     [prefix, "Ancestors: ", inspect(ancestors) | crash_info(min_level, debug, prefix)]
   end
 
-  defp crash_info(min_level, [{:process_label, _} | info], prefix) do
+  defp crash_info(min_level, [{:process_label, :undefined} | info], prefix) do
     crash_info(min_level, info, prefix)
   end
 
+  defp crash_info(min_level, [{:process_label, label} | debug], prefix) do
+    [prefix, "Process Label: ", inspect(label) | crash_info(min_level, debug, prefix)]
+  end
+
   defp crash_info(:debug, debug, prefix) do
     for {key, value} <- debug do
       crash_debug(key, value, prefix)

lib/logger/test/logger/translator_test.exs

@@ -530,6 +530,33 @@ defmodule Logger.TranslatorTest do
     assert {%RuntimeError{message: "oops"}, [_ | _]} = process_metadata[:crash_reason]
   end
 
+  @tag skip: System.otp_release() < "27"
+  test "translates :proc_lib crashes with :process_label" do
+    fun = fn ->
+      :proc_lib.set_label({:any, "term"})
+      raise "oops"
+    end
+
+    pid = :proc_lib.spawn_link(__MODULE__, :task, [self(), fun])
+
+    assert capture_log(:info, fn ->
+             ref = Process.monitor(pid)
+             send(pid, :message)
+             send(pid, :go)
+             receive do: ({:DOWN, ^ref, _, _, _} -> :ok)
+           end) =~ ~r"""
+           \[error\] Process #PID<\d+\.\d+\.\d+> terminating
+           \*\* \(RuntimeError\) oops
+           .*
+           Initial Call: Logger.TranslatorTest.task/2
+           Process Label: {:any, \"term\"}
+           Ancestors: \[#PID<\d+\.\d+\.\d+>\]
+           """s
+
+    assert_receive {:event, {:string, ["Process " | _]}, process_metadata}
+    assert {%RuntimeError{message: "oops"}, [_ | _]} = process_metadata[:crash_reason]
+  end
+
   test "translates :proc_lib crashes without initial call" do
     fun = fn ->
       Process.delete(:"$initial_call")