fix(retry): make trigger one-shot to prevent rapid retry exhaustion

retry_trigger_task recursively re-triggered itself on network failure,
bypassing exponential backoff (UINT64_MAX skips the backoff check) and
burning through all 5 retry attempts in milliseconds.

Since sentry__retry_send already processes all cached envelopes in a
single call, the re-trigger is only ever reached on network failure —
exactly the case where it's harmful. Make the trigger one-shot; failed
items are left for the regular poll task which respects backoff.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jpnurmi

src/sentry_retry.c

@@ -360,10 +360,7 @@ retry_trigger_task(void *_retry, void *_state)
 {
     (void)_state;
     sentry_retry_t *retry = _retry;
-    if (sentry__retry_send(
-            retry, UINT64_MAX, retry->send_cb, retry->send_data)) {
-        sentry__retry_trigger(retry);
-    }
+    sentry__retry_send(retry, UINT64_MAX, retry->send_cb, retry->send_data);
 }
 
 void

tests/unit/test_retry.c

@@ -357,3 +357,44 @@ SENTRY_TEST(retry_backoff)
     sentry__retry_free(retry);
     sentry_close();
 }
+
+SENTRY_TEST(retry_trigger)
+{
+    SENTRY_TEST_OPTIONS_NEW(options);
+    sentry_options_set_dsn(options, "https://foo@sentry.invalid/42");
+    sentry_options_set_http_retry(options, true);
+    sentry_init(options);
+
+    sentry_retry_t *retry = sentry__retry_new(options);
+    TEST_ASSERT(!!retry);
+
+    const sentry_path_t *cache_path = options->run->cache_path;
+    sentry__path_remove_all(cache_path);
+    sentry__path_create_dir_all(cache_path);
+
+    uint64_t old_ts
+        = sentry__usec_time() / 1000 - 10 * sentry__retry_backoff(0);
+    sentry_uuid_t event_id = sentry_uuid_new_v4();
+    write_retry_file(retry, old_ts, 0, &event_id);
+
+    // UINT64_MAX (trigger mode) bypasses backoff: bumps count
+    retry_test_ctx_t ctx = { -1, 0 };
+    sentry__retry_send(retry, UINT64_MAX, test_send_cb, &ctx);
+    TEST_CHECK_INT_EQUAL(ctx.count, 1);
+    TEST_CHECK_INT_EQUAL(find_envelope_attempt(cache_path), 1);
+
+    // second call: bumps again because UINT64_MAX skips backoff
+    ctx = (retry_test_ctx_t) { -1, 0 };
+    sentry__retry_send(retry, UINT64_MAX, test_send_cb, &ctx);
+    TEST_CHECK_INT_EQUAL(ctx.count, 1);
+    TEST_CHECK_INT_EQUAL(find_envelope_attempt(cache_path), 2);
+
+    // before=0 (poll mode) respects backoff: item is skipped
+    ctx = (retry_test_ctx_t) { -1, 0 };
+    sentry__retry_send(retry, 0, test_send_cb, &ctx);
+    TEST_CHECK_INT_EQUAL(ctx.count, 0);
+    TEST_CHECK_INT_EQUAL(find_envelope_attempt(cache_path), 2);
+
+    sentry__retry_free(retry);
+    sentry_close();
+}

tests/unit/tests.inc

@@ -169,6 +169,7 @@ XX(retry_cache)
 XX(retry_result)
 XX(retry_session)
 XX(retry_throttle)
+XX(retry_trigger)
 XX(ringbuffer_append)
 XX(ringbuffer_append_invalid_decref_value)
 XX(ringbuffer_append_null_decref_value)