From deca687c539112694374e1347dcd91b2fc852fa5 Mon Sep 17 00:00:00 2001
From: Felipe Fumero <ffumero@backblaze.com>
Date: Mon, 28 Sep 2026 11:27:55 -0600
Subject: [PATCH 1/2] 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)

From 4e0346a3c2b359287eaddbf21fca1b1a369365a7 Mon Sep 17 00:00:00 2001
From: Felipe Fumero <felipefumerom@gmail.com>
Date: Thu, 1 Oct 2026 11:02:47 -0600
Subject: [PATCH 2/2] fix: expose HTTP request timeout exception

---
 b2sdk/_internal/exception.py    | 6 +++++-
 b2sdk/v3/exception.py           | 2 ++
 test/unit/bucket/test_bucket.py | 9 +++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/b2sdk/_internal/exception.py b/b2sdk/_internal/exception.py
index 15bf2d899..7311ced28 100644
--- a/b2sdk/_internal/exception.py
+++ b/b2sdk/_internal/exception.py
@@ -435,7 +435,11 @@ class ServiceError(TransientErrorMixin, B2Error):
 
 
 class RequestTimeout(TransientErrorMixin, B2Error):
-    """Used for HTTP status code 408 (request timeout)."""
+    """A server HTTP 408 response, raised by :func:`interpret_b2_error` for status 408.
+
+    Unlike :class:`B2RequestTimeout`, this is not a client-side socket or connection timeout
+    raised in ``b2http.py``.
+    """
 
 
 class CapExceeded(B2Error):
diff --git a/b2sdk/v3/exception.py b/b2sdk/v3/exception.py
index 36143d567..7918e3142 100644
--- a/b2sdk/v3/exception.py
+++ b/b2sdk/v3/exception.py
@@ -63,6 +63,7 @@
     NotAllowedByAppKeyError,
     PartSha1Mismatch,
     PotentialS3EndpointPassedAsRealm,
+    RequestTimeout,
     RestrictedBucket,
     RestrictedBucketMissing,
     RetentionWriteError,
@@ -154,6 +155,7 @@
     'NotAllowedByAppKeyError',
     'PartSha1Mismatch',
     'PotentialS3EndpointPassedAsRealm',
+    'RequestTimeout',
     'RestrictedBucket',
     'RestrictedBucketMissing',
     'RetentionWriteError',
diff --git a/test/unit/bucket/test_bucket.py b/test/unit/bucket/test_bucket.py
index ead9a449a..f140a6612 100644
--- a/test/unit/bucket/test_bucket.py
+++ b/test/unit/bucket/test_bucket.py
@@ -43,6 +43,7 @@
     InvalidRange,
     InvalidUploadSource,
     MaxRetriesExceeded,
+    RequestTimeout,
     RestrictedBucketMissing,
     SourceReplicationConflict,
     SSECKeyError,
@@ -2102,6 +2103,14 @@ def test_upload_timeout(self):
         data = b'hello world'
         self.bucket.upload_bytes(data, 'file1')
 
+    def test_upload_http_request_timeout(self):
+        self.simulator.set_upload_errors([RequestTimeout('408 request_timeout request timeout')])
+        data = b'hello world'
+
+        self.bucket.upload_bytes(data, 'file1')
+
+        self._check_file_contents('file1', data)
+
     def test_upload_file_one_fatal_error(self):
         self.simulator.set_upload_errors([CanRetry(False)])
         data = b'hello world'