Split single step instrument entry point

lib-injection/host_inject.rb

@@ -197,7 +197,7 @@ def bundler_supported?
 
           bundle_add_cmd = "bundle add #{gem} --skip-install --version #{gem_version_mapping[gem]} "
           bundle_add_cmd << ' --verbose ' if ENV['DD_TRACE_DEBUG'] == 'true'
-          bundle_add_cmd << '--require datadog/auto_instrument' if gem == 'datadog'
+          bundle_add_cmd << '--require datadog/single_step_instrument' if gem == 'datadog'
 
           utils.debug "Injection with `#{bundle_add_cmd}`"
 

lib/datadog/single_step_instrument.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+#
+# Entrypoint file for single step instrumentation.
+#
+# This file's path is private. Do not reference this file.
+#
+begin
+  require_relative 'auto_instrument'
+rescue StandardError, LoadError => e
+  warn "Single step instrumentation failed: #{e.class}, #{e.message}"
+end

spec/datadog/single_step_instrument_spec.rb

@@ -0,0 +1,23 @@
+RSpec.describe 'Single step instrument' do
+  it do
+    expect_in_fork do
+      expect_any_instance_of(Object)
+        .to receive(:require_relative).with('auto_instrument').and_raise(LoadError)
+
+      expect do
+        load 'datadog/single_step_instrument.rb'
+      end.to output(/Single step instrumentation failed/).to_stderr
+    end
+  end
+
+  it do
+    expect_in_fork do
+      expect_any_instance_of(Object)
+        .to receive(:require_relative).with('auto_instrument').and_raise(StandardError)
+
+      expect do
+        load 'datadog/single_step_instrument.rb'
+      end.to output(/Single step instrumentation failed/).to_stderr
+    end
+  end
+end