[wangbill (YunchuWang)]

Summary

What changed?

• Add the optional Azure Blob provider package with credential-free v2 writes and legacy v1 reads, UTF-8/gzip representation, private container initialization and ownership metadata.
• Preserve credentials/pipelines across same-service containers and path-style Azurite URLs; require identity for cross-account routing instead of forwarding configured account keys/SAS.
• Retain single-flight initialization cancellation/generation recovery and explicit ownership/ETag/snapshot deletion safety.
• Carry 39 offline Azure SDK/provider tests, seven actual .NET gzip vectors and 10 opt-in real Azurite tests. Add only the package workspace lock entry and exact Jest/TypeScript mappings.

Why is this change needed?

• Phase 3/6 of the requested large-payload implementation split. This PR's base is phase 2's branch, so its diff excludes previously reviewed phases.
• Behavioral reference: durabletask-dotnet 91739687. The stack also inherits the reviewed JavaScript carryover and whole-message size-preflight repairs described below; it does not claim unchanged .NET failure-priority semantics.

Issues / work items

• Resolves: N/A (user-requested phased feature review).
• Related: original oversized PR #387. It is closed without merging; its original branch/history remain preserved.

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Project checklist

• Release notes are not required for the next release
  • Otherwise: Notes added to CHANGELOG.md
• Backport is not required
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• All required tests have been added/updated (unit tests, E2E tests)
• Breaking change?
  • If yes:
    • Impact: No intentional API break in this phase; the payload feature remains opt-in.
    • Migration guidance: Do not release partial phases. Merge the stack in order and publish the completed core before dependent packages.

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AI-assisted code disclosure (required)

Was an AI tool used? (select one)

• No
• Yes, AI helped write parts of this PR (e.g., GitHub Copilot)
• Yes, an AI agent generated most of this PR

If AI was used:

• Tool(s): GitHub Copilot.
• AI-assisted areas/files: This phase's source, regression tests, and directly related metadata/documentation.
• What you changed after AI output: Split the implementation along independently buildable boundaries; retained focused regression evidence and removed unrelated formatting-only changes. Human review is still required.

AI verification (required if AI was used):

• I understand the code and can explain it
• I verified referenced APIs/types exist and are correct
• I reviewed edge cases/failure paths (timeouts, retries, cancellation, exceptions)
• I reviewed concurrency/async behavior
• I checked for unintended breaking or behavior changes

These human attestations are intentionally left unchecked.

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Testing

Automated tests

• Current review head: 71633cd8f81e2fc3153f2e35a71cb57e3992748d.
• This merge hop used exact approved source/test blob, ancestry and stable-patch checks, commit-hook ESLint and whitespace checks. No redundant phase-local transport suite or all-workspace build is claimed.
• Shared-call owning evidence is pinned to PR389 f3ea69fc79eb594961ab4d57651f5e1360fb9127: 233 tests / 8 suites plus core build/lint passed.
• git diff --check origin/yunchuwang-payload-phase-2-sdk...HEAD — passed. Prior heads remain ancestors; predecessor bases, phase-local review scopes, release/cleanup/version notes and ready-for-review state are preserved.
• Combined final on exact ae63cab8ecb6ec6b2b3e0e15067091a5b8a6b24e: npm run test:unit — 3,180 tests / 133 suites passed (core 2,028; Functions 226; Blob 39; Azure-managed 821; export-history 66). Ten opt-in service tests are skipped by this unit command.
• On the same final head, npm run build passed all five workspaces and npm run lint passed. This is the true final aggregate containing both approved commits; the earlier stopped pre-lifecycle run is not a final pass.
• Final structural/blob audit passed: one unary transport site and one upload/resolve site in _call; all five semantic callers delegate; phase4–6 client/lifecycle fixtures match the approved runner fix, and PR1 processor plus existing public-loopback fixtures are unchanged.
• Final DTS live run: 39837123528 on exact ae63cab8ecb6ec6b2b3e0e15067091a5b8a6b24e — PENDING (in_progress) at 2026-10-22T19:07:38.5343134Z. The link is authoritative for later completion; no early pass is claimed.
• PR388 source/body remain unchanged at 137bb547e8781fd84c2738c3e13ae0f65cd66174; its separately verified hosted evidence is 30 SUCCESS / 1 SKIPPED. Review approval is still required. Main-base-only PR filters are unchanged; absent stacked-PR jobs are not passes.
• Historical unchanged-provider receipt on 39cebd7651a669b50cdd73fdcc5e394344e08fa4: npm run test:azurite -w @microsoft/durabletask-js-azureblob — all 10 real local-Azurite/.NET-gzip fixture checks passed. This was not rerun or relabeled as current-head service evidence.
• Scope limits remain: no live storage-outage or mixed .NET/JavaScript execution, no transactional rollback or generic orphan collector. Tombstone cleanup cannot discover blobs without a backend-recorded reference.

Manual validation (only if runtime/behavior changed)

• Environment (OS, Node.js version, components): Windows, Node.js v24.14.0; Azure Storage Blob SDK 12.31.0. Historical 39cebd7 service receipts used isolated loopback Azurite 3.37.0; no new-head service rerun is claimed.
• Steps + observed results:
  1. Materialized this phase on its declared predecessor, with no future-phase imports.
  2. Ran the exact owning checks above and inspected the incremental patch.
  3. Verified .NET-produced compressed bytes, UTF-8 and uncompressed round trips, token routing and owned/unowned blob/snapshot deletion against real Azurite.
• Evidence (optional): Full local logs are session artifacts, not repository changes.

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Notes for reviewers

Shared unary boundary correction

• f3ea69fc79eb594961ab4d57651f5e1360fb9127 restores one private _call pipeline: combine cancellation once; externalize once; generate fresh metadata outside each RPC catch; invoke only the operation's RPC policy; hydrate once after success. true retries the RPC, false rethrows unchanged, and throwing maps a genuine RPC error with its cause. The no-metadata path preserves its original dispatch timing.
• Scheduling and completion waits no longer inline separate pipelines; rewind/restart mappings use the same RPC-only boundary. Errors are not mutated or tagged and no public API, helper signature, dependency or middleware framework was added.
• The separate auto-purge runner dedupe follow-up belongs to #391, not this phase.
• All earlier reviewed carryover, UTF-8 preflight, token/cancellation, rewind mapping and worker-release repairs remain ancestors. No PR merge, package publication or history rewrite was performed.

Merge order	Phase	PR	Base branch
1	Core contracts	#388	main
2	SDK integration	#389	yunchuwang-payload-phase-1-core
3	Azure Blob provider	#390	yunchuwang-payload-phase-2-sdk
4	Purge protocol/client	#391	yunchuwang-payload-phase-3-blob
5	Purge worker	#392	yunchuwang-payload-phase-4-client
6	Release/usage/consumers	#393	yunchuwang-payload-phase-5-worker

Merge 1 → 2 → 3 → 4 → 5 → 6. Each PR targets its predecessor; retarget the next PR only after its prerequisite merges. Do not publish packages or describe a partial phase as the complete feature.

• The provider supports explicit safe deletion, but does not register or expose scheduler-driven auto-purge in this phase.
• Provider documentation describes only APIs present in phases 1–3; client cleanup protocol and worker runner follow separately.
• Core >=0.4.1 remains mandatory; package installation metadata must not accept published 0.4.0.
• Full live DTS/mixed-.NET execution has not been run locally (Docker daemon unavailable). The final phase records aggregate local Blob/Azurite, source/wire interoperability and packed-consumer evidence without claiming absent hosted checks.