Use of "iterable" Type May Need Re-Evaluation Across the Repo (#783)

* Otel-php:632 Move stack trace formatting out of Span class

* added function usages

* fix linting errors

* Added documentation for adding Span Attributes

* removing TracingUtl class

* Refactor TraceState's __toString method

* Added path with @Covers to remove warnings

* Added @coversDefaultClass annotation

* fix to check if iterable is empty

* fixed for faling test case

src/SDK/Common/Util/functions.php

@@ -5,6 +5,7 @@
 namespace OpenTelemetry\SDK\Common\Util;
 
 use Closure;
+use Exception;
 use function get_class;
 use ReflectionFunction;
 use stdClass;
@@ -50,3 +51,21 @@ function weaken(Closure $closure, ?object &$target = null): Closure
         ? static fn (...$args) => ($obj = $ref->get()) ? $closure->call($obj, ...$args) : null
         : static fn (...$args) => ($obj = $ref->get()) ? $closure->bindTo($obj)(...$args) : null;
 }
+
+/**
+ *  Returns whether an iterable is empty or not
+ */
+function isEmpty(iterable $list)
+{
+    try {
+        foreach ($list as $value) {
+            break;
+        }
+    }
+    //catch exception
+    catch (Exception $e) {
+        return true;
+    }
+
+    return empty($list);
+}

src/SDK/Metrics/Exporters/AbstractExporter.php

@@ -7,6 +7,7 @@
 use Exception;
 use InvalidArgumentException;
 use OpenTelemetry\API\Metrics as API;
+use function OpenTelemetry\SDK\Common\Util\isEmpty;
 use OpenTelemetry\SDK\Metrics\Exceptions\RetryableExportException;
 
 abstract class AbstractExporter implements API\ExporterInterface
@@ -16,7 +17,7 @@ abstract class AbstractExporter implements API\ExporterInterface
      */
     public function export(iterable $metrics): int
     {
-        if (empty($metrics)) {
+        if (isEmpty($metrics)) {
             return API\ExporterInterface::SUCCESS;
         }
 

src/SDK/Trace/Behavior/SpanExporterTrait.php

@@ -4,6 +4,7 @@
 
 namespace OpenTelemetry\SDK\Trace\Behavior;
 
+use function OpenTelemetry\SDK\Common\Util\isEmpty;
 use OpenTelemetry\SDK\Trace\SpanDataInterface;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
 
@@ -40,7 +41,7 @@ public function export(iterable $spans): int
             return SpanExporterInterface::STATUS_FAILED_NOT_RETRYABLE;
         }
 
-        if (empty($spans)) {
+        if (isEmpty($spans)) {
             return SpanExporterInterface::STATUS_SUCCESS;
         }