fix(retry): prevent startup poll from re-processing same-session envelopes

The startup poll used `ts >= startup_time` to skip envelopes written
after startup. With second-precision timestamps, this also skipped
cross-session envelopes written in the same second as a fast restart.

Reset `startup_time` in `sentry__retry_enqueue` so the startup poll
falls through to the backoff path for same-session envelopes. The
bgworker processes the send task (immediate) before the startup poll
(delayed), so by the time the poll fires, `startup_time` is already 0.

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

Author: jpnurmi

src/sentry_retry.c

@@ -193,7 +193,7 @@ sentry__retry_send(sentry_retry_t *retry, uint64_t before,
 
     size_t total = 0;
     size_t eligible = 0;
-    uint64_t now = before ? 0 : (uint64_t)time(NULL);
+    uint64_t now = before > 0 ? 0 : (uint64_t)time(NULL);
 
     const sentry_path_t *p;
     while ((p = sentry__pathiter_next(piter)) != NULL) {
@@ -204,7 +204,7 @@ sentry__retry_send(sentry_retry_t *retry, uint64_t before,
         if (!sentry__retry_parse_filename(fname, &ts, &count, &uuid)) {
             continue;
         }
-        if (before && ts >= before) {
+        if (before > 0 && ts >= before) {
             continue;
         }
         total++;
@@ -279,6 +279,8 @@ void
 sentry__retry_enqueue(sentry_retry_t *retry, const sentry_envelope_t *envelope)
 {
     sentry__retry_write_envelope(retry, envelope);
+    // prevent the startup poll from re-processing this session's envelope
+    retry->startup_time = 0;
     sentry__bgworker_submit_delayed(
         retry->bgworker, retry_poll_task, NULL, retry, SENTRY_RETRY_INTERVAL);
 }

tests/unit/test_retry.c

@@ -50,7 +50,7 @@ static int
 count_eligible_files(const sentry_path_t *dir, uint64_t before)
 {
     int eligible = 0;
-    uint64_t now = before ? 0 : (uint64_t)time(NULL);
+    uint64_t now = before > 0 ? 0 : (uint64_t)time(NULL);
     sentry_pathiter_t *iter = sentry__path_iter_directory(dir);
     const sentry_path_t *file;
     while (iter && (file = sentry__pathiter_next(iter)) != NULL) {
@@ -61,7 +61,7 @@ count_eligible_files(const sentry_path_t *dir, uint64_t before)
         if (!sentry__retry_parse_filename(name, &ts, &count, &uuid)) {
             continue;
         }
-        if (before && ts >= before) {
+        if (before > 0 && ts >= before) {
             continue;
         }
         if (!before && (now - ts) < sentry__retry_backoff(count)) {