From a21e315a1a4393e2a21528e23a2eb1de12ac5bde Mon Sep 17 00:00:00 2001
From: Felipe Fumero <ffumero@backblaze.com>
Date: Mon, 28 Sep 2026 11:27:55 -0600
Subject: [PATCH] fix: retry request timeout upload responses

---
 b2sdk/_internal/exception.py | 6 ++++++
 changelog.d/605.fixed.md     | 1 +
 test/unit/test_exception.py  | 8 +++++++-
 3 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 changelog.d/605.fixed.md

diff --git a/b2sdk/_internal/exception.py b/b2sdk/_internal/exception.py
index aef410f37..15bf2d899 100644
--- a/b2sdk/_internal/exception.py
+++ b/b2sdk/_internal/exception.py
@@ -434,6 +434,10 @@ class ServiceError(TransientErrorMixin, B2Error):
     """
 
 
+class RequestTimeout(TransientErrorMixin, B2Error):
+    """Used for HTTP status code 408 (request timeout)."""
+
+
 class CapExceeded(B2Error):
     def __str__(self):
         return 'Cap exceeded.'
@@ -750,6 +754,8 @@ def interpret_b2_error(
         return Conflict()
     elif status == 416 and code == 'range_not_satisfiable':
         return UnsatisfiableRange()
+    elif status == 408:
+        return RequestTimeout('%d %s %s' % (status, code, message))
     elif status == 429:
         return TooManyRequests(retry_after_seconds=response_headers.get('retry-after'))
     elif 500 <= status < 600:
diff --git a/changelog.d/605.fixed.md b/changelog.d/605.fixed.md
new file mode 100644
index 000000000..47d11f87e
--- /dev/null
+++ b/changelog.d/605.fixed.md
@@ -0,0 +1 @@
+Retry uploads after a B2 request-timeout response (HTTP 408).
diff --git a/test/unit/test_exception.py b/test/unit/test_exception.py
index 258e301a4..19e2ce819 100644
--- a/test/unit/test_exception.py
+++ b/test/unit/test_exception.py
@@ -35,7 +35,7 @@
     interpret_b2_error,
 )
 
-from b2sdk._internal.exception import ResourceNotFound
+from b2sdk._internal.exception import RequestTimeout, ResourceNotFound
 
 
 class TestB2Error:
@@ -161,6 +161,12 @@ def test_service_error(self):
         assert isinstance(error, ServiceError)
         assert '500 code message' == str(error)
 
+    def test_request_timeout(self):
+        error = interpret_b2_error(408, 'request_timeout', 'request timeout', {})
+        assert isinstance(error, RequestTimeout)
+        assert error.should_retry_upload()
+        assert error.should_retry_http()
+
     def test_unknown_error(self):
         error = interpret_b2_error(499, 'code', 'message', {})
         assert isinstance(error, UnknownError)