feat(tracing): report OTLP telemetry export status in startup log (#4056)

Add otlp_traces_export_enabled, otlp_metrics_export_enabled, and
otlp_logs_export_enabled to the "DATADOG TRACER CONFIGURATION" startup
diagnostic log, matching the shared cross-language schema.

PHP exports traces natively via the Datadog Agent (never over OTLP), so
otlp_traces_export_enabled is always false. The metrics and logs flags
reflect the existing DD_METRICS_OTEL_ENABLED / DD_LOGS_OTEL_ENABLED
configs -- the same request-scoped values the userland OpenTelemetry
resolver consults -- so the log matches actual export behavior.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Bob Weinand <bob.weinand@datadoghq.com>

Author: 3 people

tests/ext/startup_logging.phpt

@@ -53,4 +53,7 @@ enabled_from_env: true
 opcache.file_cache: null
 dynamic_instrumentation_enabled: false
 exception_replay_enabled: false
+otlp_traces_export_enabled: false
+otlp_metrics_export_enabled: false
+otlp_logs_export_enabled: false
 loaded_by_ssi: false

tests/ext/startup_logging_config.phpt

@@ -27,6 +27,8 @@ $env = [
     'DD_TRACE_REPORT_HOSTNAME' => '1',
     'DD_TRACE_TRACED_INTERNAL_FUNCTIONS' => 'array_sum,mt_rand,DateTime::add',
     'DD_TRACE_ENABLED' => '1',
+    'DD_METRICS_OTEL_ENABLED' => '1',
+    'DD_LOGS_OTEL_ENABLED' => '1',
 ];
 $logs = dd_get_startup_logs($ini, $env);
 
@@ -53,6 +55,9 @@ dd_dump_startup_logs($logs, [
     'report_hostname_on_root_span',
     'traced_internal_functions',
     'enabled_from_env',
+    'otlp_traces_export_enabled',
+    'otlp_metrics_export_enabled',
+    'otlp_logs_export_enabled',
 ]);
 ?>
 --EXPECT--
@@ -76,3 +81,6 @@ measure_compile_time: false
 report_hostname_on_root_span: true
 traced_internal_functions: "array_sum,mt_rand,DateTime::add"
 enabled_from_env: true
+otlp_traces_export_enabled: false
+otlp_metrics_export_enabled: true
+otlp_logs_export_enabled: true

tests/ext/startup_logging_json.phpt

@@ -54,5 +54,8 @@ enabled_from_env: true
 opcache.file_cache: null
 dynamic_instrumentation_enabled: false
 exception_replay_enabled: false
+otlp_traces_export_enabled: false
+otlp_metrics_export_enabled: false
+otlp_logs_export_enabled: false
 loaded_by_ssi: false
 datadog.trace.sources_path_reachable: false

tracer/tracer_startup_logging.c

@@ -60,6 +60,13 @@ void ddtrace_populate_startup_config(HashTable *ht) {
     dd_add_assoc_bool(ht, ZEND_STRL("sidecar_trace_sender"), get_global_DD_TRACE_SIDECAR_TRACE_SENDER());
     dd_add_assoc_bool(ht, ZEND_STRL("dynamic_instrumentation_enabled"), get_global_DD_DYNAMIC_INSTRUMENTATION_ENABLED());
     dd_add_assoc_bool(ht, ZEND_STRL("exception_replay_enabled"), get_global_DD_EXCEPTION_REPLAY_ENABLED());
+
+    // OTLP telemetry export status (cross-language schema). PHP exports traces natively via the
+    // Datadog Agent (never over OTLP), so otlp_traces_export_enabled is always false; the metrics
+    // and logs flags mirror DD_METRICS_OTEL_ENABLED / DD_LOGS_OTEL_ENABLED (request-scoped).
+    dd_add_assoc_bool(ht, ZEND_STRL("otlp_traces_export_enabled"), false);
+    dd_add_assoc_bool(ht, ZEND_STRL("otlp_metrics_export_enabled"), get_DD_METRICS_OTEL_ENABLED());
+    dd_add_assoc_bool(ht, ZEND_STRL("otlp_logs_export_enabled"), get_DD_LOGS_OTEL_ENABLED());
 }
 
 static bool dd_file_exists(const char *file) {