Fix skip_tracing compatibility

`Trace#initialize` was incorrectly assuming that a `@Query` or
`@multiplex` was always defined. However, tracers can be instantiated
manually outside of a Query context (at least to start with).

lib/graphql/metrics/trace.rb

@@ -5,8 +5,9 @@ module Metrics
     module Trace
       def initialize(**_rest)
         super
-        context = (@multiplex || @query).context
-        @skip_tracing = context&.fetch(GraphQL::Metrics::SKIP_GRAPHQL_METRICS_ANALYSIS, false)
+
+        query_or_multiplex = @query || @multiplex
+        @skip_tracing = query_or_multiplex.context&.fetch(SKIP_GRAPHQL_METRICS_ANALYSIS, false) if query_or_multiplex
       end
 
       # NOTE: These methods come from the graphql ruby gem and are in "chronological" order based on the phases
@@ -16,60 +17,68 @@ def initialize(**_rest)
 
       # wraps everything below this line; only run once
       def execute_multiplex(multiplex:)
-        return super if @skip_tracing
+        return super if skip_tracing?(multiplex)
         capture_multiplex_start_time { super }
       end
 
       # may not trigger if the query is passed in pre-parsed
       def lex(query_string:)
-        return super if @skip_tracing
+        return super if skip_tracing?
         capture_lexing_time { super }
       end
 
       # may not trigger if the query is passed in pre-parsed
       def parse(query_string:)
-        return super if @skip_tracing
+        return super if skip_tracing?
         capture_parsing_time { super }
       end
 
       def validate(query:, validate:)
-        return super if @skip_tracing
+        return super if skip_tracing?(query)
         capture_validation_time(query.context) { super }
       end
 
       # wraps all `analyze_query`s; only run once
       def analyze_multiplex(multiplex:)
-        return super if @skip_tracing
+        return super if skip_tracing?(multiplex)
         # Ensures that we reset potentially long-lived PreContext objects between multiplexs. We reset at this point
         # since all parsing and validation will be done by this point, and a GraphQL::Query::Context will exist.
         pre_context.reset
         super
       end
 
       def analyze_query(query:)
-        return super if @skip_tracing
+        return super if skip_tracing?(query)
         capture_analysis_time(query.context) { super }
       end
 
       def execute_query(query:)
-        return super if @skip_tracing
+        return super if skip_tracing?(query)
         capture_query_start_time(query.context) { super }
       end
 
       def execute_field(field:, query:, ast_node:, arguments:, object:)
-        return super if @skip_tracing || query.context[SKIP_FIELD_AND_ARGUMENT_METRICS]
+        return super if skip_tracing?(query) || query.context[SKIP_FIELD_AND_ARGUMENT_METRICS]
         return super unless GraphQL::Metrics.timings_capture_enabled?(query.context)
         trace_field(GraphQL::Metrics::INLINE_FIELD_TIMINGS, query) { super }
       end
 
       def execute_field_lazy(field:, query:, ast_node:, arguments:, object:)
-        return super if @skip_tracing || query.context[SKIP_FIELD_AND_ARGUMENT_METRICS]
+        return super if skip_tracing?(query) || query.context[SKIP_FIELD_AND_ARGUMENT_METRICS]
         return super unless GraphQL::Metrics.timings_capture_enabled?(query.context)
         trace_field(GraphQL::Metrics::LAZY_FIELD_TIMINGS, query) { super }
       end
 
       private
 
+      def skip_tracing?(query_or_multiplex = nil)
+        if !defined?(@skip_tracing) && query_or_multiplex
+          @skip_tracing = query_or_multiplex.context&.fetch(SKIP_GRAPHQL_METRICS_ANALYSIS, false)
+        end
+
+        @skip_tracing
+      end
+
       PreContext = Struct.new(
         :multiplex_start_time,
         :multiplex_start_time_monotonic,

test/unit/graphql/metrics/trace_integration_test.rb

@@ -114,6 +114,20 @@ def self.parse_error(err, _context)
           assert query.multiplex.context[:test_trace_was_executed]
         end
 
+        test "tracing is skipped when the skip context key is set" do
+          query = GraphQL::Query.new(
+            SchemaWithFullMetrics,
+            kitchen_sink_query_document,
+            variables: { 'postId': '1', 'titleUpcase': true },
+            operation_name: 'PostDetails',
+            context: { SKIP_GRAPHQL_METRICS_ANALYSIS => true }
+          )
+          result = query.result.to_h
+
+          assert_nil query.multiplex.context.namespace(CONTEXT_NAMESPACE)[QUERY_START_TIME]
+          assert_nil query.multiplex.context.namespace(CONTEXT_NAMESPACE)[LEXING_DURATION]
+        end
+
         test 'extracts metrics from queries, as well as their fields and arguments (when using Query#result)' do
           context = {}
           query = GraphQL::Query.new(