From 6e4f70f1550cb074ec7beab53eb30ed59bc9f33b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=96=E7=95=8C?= <i@sekai.icu>
Date: Fri, 17 Apr 2026 16:26:51 +0800
Subject: [PATCH] Defer implicit default HTTP client fallback to first use

---
 common/httpclient/manager.go | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/common/httpclient/manager.go b/common/httpclient/manager.go
index 2b4f9d5be..614e4f83b 100644
--- a/common/httpclient/manager.go
+++ b/common/httpclient/manager.go
@@ -69,21 +69,25 @@ func (m *Manager) Start(stage adapter.StartStage) error {
 			return E.Cause(err, "resolve default http client")
 		}
 		m.defaultTransport = sharedTransport
-	} else if m.defaultTransportFallback != nil {
-		transport, err := m.defaultTransportFallback()
-		if err != nil {
-			return E.Cause(err, "create default http client")
-		}
-		m.trackTransport(transport)
-		m.defaultTransport = &sharedManagedTransport{
-			managed: transport,
-			shared:  &sharedState{},
-		}
 	}
 	return nil
 }
 
 func (m *Manager) DefaultTransport() adapter.HTTPTransport {
+	m.access.Lock()
+	defer m.access.Unlock()
+	if m.defaultTransport == nil && m.defaultTransportFallback != nil {
+		transport, err := m.defaultTransportFallback()
+		if err != nil {
+			m.logger.Error(E.Cause(err, "create default http client"))
+			return nil
+		}
+		m.managedTransports = append(m.managedTransports, transport)
+		m.defaultTransport = &sharedManagedTransport{
+			managed: transport,
+			shared:  &sharedState{},
+		}
+	}
 	if m.defaultTransport == nil {
 		return nil
 	}