Bound complete encoded Python failure reports

CHANGELOG.md

@@ -6,6 +6,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.11.0] - Unreleased
+
+### Fixed
+
+- Bound failure messages, stacks and diagnostic payloads before reporting them.
+  The complete encoded request defaults to 1 MiB, including JSON escaping and
+  markers, and respects lower configured or discovered limits. Preserve failure
+  type, retry policy and claim identity; refuse an identity that cannot fit.
+
 ## [2.10.1] - Unreleased
 
 ### Fixed

docs/reference/worker.md

@@ -29,6 +29,48 @@ isolated worker processes and their resource limits. The separately
 negotiated cooperative-cancellation capability retains its supervised process
 execution; selecting a default thread does not enable that protocol.
 
+## Bounded failure reports
+
+This behavior is available in unreleased SDK source. Published packages still
+need the compatible release before these limits apply.
+
+Failure reports retain at most 62 KiB of UTF-8 message text, 128 KiB of stack
+text and 64 KiB of serialized details and diagnostics. These budgets include
+truncation markers. The complete encoded JSON request body defaults to at most
+1 MiB, counting JSON escaping, claim identities, command batches and metadata.
+The message budget reserves 2 KiB below the original 64 KiB ceiling for
+runtime-derived summaries.
+A lower discovered Server `limits.max_payload_bytes` also applies. Configure
+`Client(..., failure_report_limit_bytes=...)` when a proxy or transport has a
+lower request limit. This option can lower the default cap; it cannot raise it.
+Query-client clones inherit it. Payload warning thresholds remain advisory.
+
+Oversized diagnostics produce a visible `[truncated ...]` message marker with
+structured omitted-field names and original byte sizes. Activity failures also
+carry this information in `failure.diagnostics.failure_report`; terminal
+workflow failures use `exception.diagnostics.failure_report`. Other existing
+report shapes keep the diagnostic JSON in the message marker. Unknown sizes
+are `null` when optional details could not be encoded. Avro details are kept as
+an intact valid envelope or omitted whole, before an unnecessary payload upload.
+
+The original failure type, retry/non-retryable choice, authored retry delay and
+claim identity remain exact. Activity, workflow-task, query and update rejection
+reports, terminal workflow/update failures and local-activity attempt reports
+share the complete-request bound. A workflow-task replay failure still leaves
+the run open for repair; it does not become a terminal workflow failure.
+
+A local activity's failure is bounded before workflow code observes it. First
+execution and cold replay therefore see the same persisted message. If a later
+command batch or newly discovered lower limit cannot fit that observed value,
+reporting fails explicitly rather than changing a value already used by the
+workflow. Prepared local activities observe the runtime's canonical history.
+
+If essential identity or semantic fields cannot fit even without optional
+text, the client raises `FailureReportTooLarge` before sending the report.
+This reporting refusal is separate from the application failure. The worker's
+existing reporting-error log identifies it; shortening a task ID or replacing
+the application type would change which failure the runtime records.
+
 ## Poll failures and recovery
 
 This backoff requires Python SDK 2.10.0 or later. Earlier packages use a fixed

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "durable-workflow"
-version = "2.10.1"
+version = "2.11.0"
 description = "Python client and worker SDK for Durable Workflow Cloud and self-hosted Server"
 readme = "README.md"
 requires-python = ">=3.10"
@@ -76,8 +76,8 @@ durable-workflow-replay-conformance = "durable_workflow.replay_conformance:main"
 durable-workflow-workflow-updates-conformance = "durable_workflow.workflow_updates_conformance:main"
 
 [tool.durable-workflow]
-product-train = "2.10.1"
-registry-version = "2.10.1"
+product-train = "2.11.0"
+registry-version = "2.11.0"
 supported-server-versions = "2.8.0"
 worker-protocol-version = "1.20"
 control-plane-version = "2"

src/durable_workflow/__init__.py

@@ -81,6 +81,7 @@
     ExternalPayloadUnauthorized,
     ExternalPayloadUnavailable,
     ExternalPayloadUnsupported,
+    FailureReportTooLarge,
     InvalidArgument,
     InvalidWorkflowDefinition,
     NamespaceNotFound,
@@ -334,6 +335,7 @@
     "testing",
     "workflow",
     "DurableWorkflowError",
+    "FailureReportTooLarge",
     "EXTERNAL_PAYLOAD_REFERENCE_SCHEMA",
     "RUNTIME_EXTERNAL_PAYLOAD_REFERENCE_SCHEMA",
     "AzureBlobExternalStorage",