fix: save() persists a non-positive TTL when the clock ticks over mid-save

src/Limit.php

@@ -372,7 +372,7 @@ public function save(RateLimitStore $store, int $resetHits = 1): static
         $successful = $store->set(
             key: $this->getName(),
             value: json_encode($data, JSON_THROW_ON_ERROR),
-            ttl: $this->getRemainingSeconds(),
+            ttl: max($this->getRemainingSeconds(), 1),
         );
 
         if ($successful === false) {

tests/Unit/LimitStoreTest.php

@@ -4,6 +4,7 @@
 
 use Saloon\RateLimitPlugin\Limit;
 use Saloon\RateLimitPlugin\Stores\MemoryStore;
+use Saloon\RateLimitPlugin\Contracts\RateLimitStore;
 use Saloon\RateLimitPlugin\Exceptions\LimitException;
 use Saloon\RateLimitPlugin\Tests\Fixtures\Connectors\TestConnector;
 
@@ -90,3 +91,35 @@
         'hits' => 1,
     ]);
 });
+
+test('the limit is not saved with a non-positive ttl when the clock ticks over mid-save', function () {
+    $store = new class implements RateLimitStore {
+        public ?int $ttl = null;
+
+        public function get(string $key): ?string
+        {
+            return null;
+        }
+
+        public function set(string $key, string $value, int $ttl): bool
+        {
+            $this->ttl = $ttl;
+
+            return true;
+        }
+    };
+
+    $limit = (new class(15) extends Limit {
+        protected int $clockReads = 0;
+
+        // The tick lands between the two reads of the remaining time inside save().
+        protected function getCurrentTimestamp(): int
+        {
+            return parent::getCurrentTimestamp() + ($this->clockReads++ > 0 ? 1 : 0);
+        }
+    })->everySeconds(1)->setPrefix('custom')->name('limit');
+
+    $limit->hit()->save($store);
+
+    expect($store->ttl)->toBe(1);
+});