Exit function early on QUIC_BUG. Verified to fix the repro.

Code is not in production.

PiperOrigin-RevId: 600538023

quiche/quic/load_balancer/load_balancer_config.cc

diff --git a/quiche/quic/load_balancer/load_balancer_config.cc b/quiche/quic/load_balancer/load_balancer_config.cc
index b4b989e..6dfb30c 100644
--- a/quiche/quic/load_balancer/load_balancer_config.cc
+++ b/quiche/quic/load_balancer/load_balancer_config.cc
@@ -92,8 +92,11 @@
 bool LoadBalancerConfig::FourPassDecrypt(
     absl::Span<const uint8_t> ciphertext,
     LoadBalancerServerId& server_id) const {
-  QUIC_BUG_IF(quic_bug_599862571_02, ciphertext.size() < plaintext_len())
-      << "Called FourPassDecrypt with a short Connection ID";
+  if (ciphertext.size() < plaintext_len()) {
+    QUIC_BUG(quic_bug_599862571_02)
+        << "Called FourPassDecrypt with a short Connection ID";
+    return false;
+  }
   if (!key_.has_value()) {
     return false;
   }
@@ -129,8 +132,11 @@
 
 QuicConnectionId LoadBalancerConfig::FourPassEncrypt(
     absl::Span<uint8_t> plaintext) const {
-  QUIC_BUG_IF(quic_bug_599862571_03, plaintext.size() < total_len())
-      << "Called FourPassEncrypt with a short Connection ID";
+  if (plaintext.size() < total_len()) {
+    QUIC_BUG(quic_bug_599862571_03)
+        << "Called FourPassEncrypt with a short Connection ID";
+    return QuicConnectionId();
+  }
   if (!key_.has_value()) {
     return QuicConnectionId();
   }

quiche/quic/load_balancer/load_balancer_config_test.cc

diff --git a/quiche/quic/load_balancer/load_balancer_config_test.cc b/quiche/quic/load_balancer/load_balancer_config_test.cc
index 0e1b2f6..dd34fb1 100644
--- a/quiche/quic/load_balancer/load_balancer_config_test.cc
+++ b/quiche/quic/load_balancer/load_balancer_config_test.cc
@@ -253,13 +253,17 @@
       LoadBalancerConfig::Create(0, 3, 4, absl::string_view(raw_key, 16));
   uint8_t input[] = {0x0d, 0xd2, 0xd0, 0x5a, 0x7b, 0x0d, 0xe9};
   LoadBalancerServerId answer;
+  bool decrypt_result;
   EXPECT_QUIC_BUG(
-      config->FourPassDecrypt(
+      decrypt_result = config->FourPassDecrypt(
           absl::Span<const uint8_t>(input, sizeof(input) - 1), answer),
       "Called FourPassDecrypt with a short Connection ID");
-  EXPECT_QUIC_BUG(
-      config->FourPassEncrypt(absl::Span<uint8_t>(input, sizeof(input))),
-      "Called FourPassEncrypt with a short Connection ID");
+  EXPECT_FALSE(decrypt_result);
+  QuicConnectionId encrypt_result;
+  EXPECT_QUIC_BUG(encrypt_result = config->FourPassEncrypt(
+                      absl::Span<uint8_t>(input, sizeof(input))),
+                  "Called FourPassEncrypt with a short Connection ID");
+  EXPECT_TRUE(encrypt_result.IsEmpty());
 }
 
 }  // namespace