fix: record operation duration when trackMetricsOf extractor throws

Author: mattrmc1

lib/sdk/server-ai/src/main/java/com/launchdarkly/sdk/server/ai/internal/LDAIConfigTrackerImpl.java

@@ -318,9 +318,16 @@ public <T> T trackMetricsOf(
     // Capture operation duration immediately so a slow extractor does not inflate the metric.
     long operationElapsedMs = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - start);
 
-    // Extractor exceptions propagate to the caller — do NOT catch them here.
-    // Do NOT call trackError() on extractor failure; the AI operation itself succeeded.
-    AIMetrics metrics = Objects.requireNonNull(metricsExtractor.apply(result), "metricsExtractor returned null");
+    // Extractor exceptions propagate to the caller, but the operation's duration must still be
+    // recorded — the AI operation itself succeeded, only the user-supplied extractor failed.
+    // Do NOT call trackError(); that signals the operation failed, which is not what happened.
+    AIMetrics metrics;
+    try {
+      metrics = Objects.requireNonNull(metricsExtractor.apply(result), "metricsExtractor returned null");
+    } catch (RuntimeException e) {
+      trackDuration(Duration.ofMillis(operationElapsedMs));
+      throw e;
+    }
 
     // Duration: prefer runner-reported value (§1.1.13.2), fall back to wall-clock.
     if (metrics.getDurationMs() != null) {

lib/sdk/server-ai/src/test/java/com/launchdarkly/sdk/server/ai/internal/LDAIConfigTrackerImplTest.java

@@ -545,6 +545,18 @@ public void trackMetricsOfExtractorExceptionPropagatesAndDoesNotCallTrackError()
     verify(client, never()).trackMetric(eq("$ld:ai:generation:success"), any(), any(), anyDouble());
   }
 
+  @Test
+  public void trackMetricsOfRecordsDurationWhenExtractorThrows() {
+    try {
+      tracker.trackMetricsOf(
+          r -> { throw new RuntimeException("extractor failed"); },
+          () -> "ok");
+    } catch (Exception e) {
+      // expected; we care that duration was recorded before the throw
+    }
+    verify(client).trackMetric(eq("$ld:ai:duration:total"), any(), any(), anyDouble());
+  }
+
   @Test
   public void trackMetricsOfTracksToolCalls() throws Exception {
     AIMetrics metrics = AIMetrics.builder()