Remove raises of strings from dynamic instrumentation code (#4997)

Author: p-datadog

lib/datadog/di/component.rb

@@ -29,22 +29,6 @@ def build(settings, agent_settings, logger, telemetry: nil)
           end
         end
 
-        def build!(settings, agent_settings, logger, telemetry: nil)
-          unless settings.respond_to?(:dynamic_instrumentation) && settings.dynamic_instrumentation.enabled
-            raise "Requested DI component but DI is not enabled in settings"
-          end
-
-          unless settings.respond_to?(:remote) && settings.remote.enabled
-            raise "Requested DI component but remote config is not enabled in settings"
-          end
-
-          unless environment_supported?(settings, logger)
-            raise "DI does not support the environment (development or Ruby version too low or not MRI)"
-          end
-
-          new(settings, agent_settings, logger, code_tracker: DI.code_tracker, telemetry: telemetry)
-        end
-
         # Checks whether the runtime environment is supported by
         # dynamic instrumentation. Currently we only require that, if Rails
         # is used, that Rails environment is not development because

lib/datadog/di/error.rb

@@ -10,6 +10,10 @@ module DI
     #
     # @api private
     class Error < StandardError
+      # Internal Dynamic Instrumentation error ("should never happen").
+      class InternalError < Error
+      end
+
       # Probe does not contain a line number (i.e., is not a line probe).
       class MissingLineNumber < Error
       end

lib/datadog/di/instrumenter.rb

@@ -409,9 +409,11 @@ def hook_line(probe, &block)
           # TODO test this path
         end
 
-        # TODO internal check - remove or use a proper exception
+        # Internal sanity check - untargeted trace points create a huge
+        # performance impact, and we absolutely do not want to set them
+        # accidentally.
         if !iseq && !permit_untargeted_trace_points
-          raise "Trying to use an untargeted trace point when user did not permit it"
+          raise Error::InternalError, "Trying to use an untargeted trace point when user did not permit it"
         end
 
         lock.synchronize do

sig/datadog/di/component.rbs

@@ -27,7 +27,6 @@ module Datadog
 
       def self.build: (untyped settings, untyped agent_settings, Core::Logger logger, ?telemetry: untyped?) -> (nil | untyped)
 
-      def self.build!: (untyped settings, untyped agent_settings, Core::Logger logger, ?telemetry: untyped?) -> untyped
       def self.environment_supported?: (untyped settings, Core::Logger logger) -> (false | true)
 
       def initialize: (untyped settings, untyped agent_settings, Core::Logger logger, ?code_tracker: untyped?, ?telemetry: untyped?) -> void

sig/datadog/di/error.rbs

@@ -1,6 +1,8 @@
 module Datadog
   module DI
     class Error < StandardError
+      class InternalError < Error
+      end
       class MissingLineNumber < Error
       end
       class AgentCommunicationError < Error

spec/datadog/di/integration/everything_from_remote_config_spec.rb

@@ -61,7 +61,13 @@ def target_method
   let(:receiver) { remote.receivers(telemetry)[0] }
 
   let(:component) do
-    Datadog::DI::Component.build!(settings, agent_settings, logger)
+    # TODO should this use Component.new? We have to manually pass in
+    # the code tracker in that case.
+    Datadog::DI::Component.build(settings, agent_settings, logger).tap do |component|
+      if component.nil?
+        raise "Component failed to create - unsuitable environment? Check log entries"
+      end
+    end
   end
 
   let(:propagate_all_exceptions) { true }

spec/datadog/di/integration/instrumentation_spec.rb

@@ -90,7 +90,13 @@ def exception_method
   end
 
   let(:component) do
-    Datadog::DI::Component.build!(settings, agent_settings, logger)
+    # TODO should this use Component.new? We have to manually pass in
+    # the code tracker in that case.
+    Datadog::DI::Component.build(settings, agent_settings, logger).tap do |component|
+      if component.nil?
+        raise "Component failed to create - unsuitable environment? Check log entries"
+      end
+    end
   end
 
   let(:expected_installed_payload) do