Release Python SDK 2.0 with asyncio and Python 3.12+

[kvz]

Why

Python SDK 2.0 gives asyncio applications a native client and raises the supported runtime floor to Python 3.12+. The existing handwritten sync client surface stays available. The dependency refresh already shipped in 1.0.4; users on Python 3.9–3.11 can keep pytransloadit<2.

Closes #9.

Changes

• Prepared package/module/request-header version 2.0.0 and Sphinx 2.0/2.0.0, enforced Requires-Python: >=3.12, and updated Poetry metadata/tooling, CI, Docker and tox to Python 3.12/3.13/3.14.
• Added AsyncTransloadit and matching handwritten Assembly/Template/billing helpers by squash-merging Add asyncio support to the Python SDK #57. Async polling uses asyncio.sleep; tuspy uploads run in workers with file/session cleanup.
• README, Sphinx and CHANGELOG document migration, request handling, canonical response fields and recovery through AssemblyPollingError.
• Aligned Read the Docs installation and release instructions; the release helper rejects an Unreleased changelog for publication while allowing dry-run builds.

Contract-generated endpoints are outside 2.0. #61 preserves that deferred work and links #60. It waits for API2-owned SDK emitters in api2#9252, owned by the existing studio1 ~/code/api2 session.

Validation and review

• The combined tree is identical to reviewed Add asyncio support to the Python SDK #57 head 3c0a3a3: 167 tests pass on each Python 3.12/3.13/3.14, with 12 opt-in skips, 94.22% coverage and Node CLI signature parity.
• All 24 live upload, Template lifecycle and runnable-example checks pass.
• Poetry metadata, strict Sphinx, wheel/sdist build/scope checks, release-helper dry run, shell syntax and diff checks pass. The runtime preparation also passed installed-wheel/minimum-dependency/build-backend and Python 3.11 rejection checks.
• Runtime council rounds fixed the RST heading and prepared-release publication guard. Three final narrowed council rounds reviewed both the stacked and combined diff: repaired polling/query/response behavior and migration notes, then preserved error recovery/query formats and serialization. The last arbitration returned No issues found. Details and fail-first evidence are in Add asyncio support to the Python SDK #57.
• Add asyncio support to the Python SDK #57 passed all seven Ubuntu/Windows/live jobs at CI 38162453747. Combined Release Python SDK 2.0 with asyncio and Python 3.12+ #56 CI passed all seven jobs at 38162905479, including Windows and live E2E. tim-kos remains requested.

Release

Released on 2026-10-11 after the approved squash sequence #57 → #56 → main. The release commit and v2.0.0 tag are 46a98f3bf48762839b7f14a378beb359d74c0a8e.

• GitHub release and PyPI 2.0.0 are published. Both uploaded artifacts match local SHA-256 hashes. A clean Python 3.12 install from PyPI passed sync/async surface, session/factory and polling-recovery serialization checks.
• Release-commit CI passed all seven jobs, including Windows 3.12/3.13/3.14 and live E2E.
• Read the Docs built the release commit successfully for both latest and stable; the served docs include 2.0.0, asyncio and the Python 3.12+ floor.
• The required Dependabot check fell from 64 to 29 open alerts; one critical development-only anyio alert remains, with an automated update PR already open. The fresh PyPI install resolved patched runtime dependencies (aiohttp 3.14.5, urllib3 2.8.0). Existing dependency follow-ups remain outside this release-scope change.

tim-kos remains requested; both cards are Done. Contract generation remains deferred in #61, blocked by api2#9252 and linked to #60.

Friction: council found polling/query recovery gaps that needed behavioral fixes and fresh CI batches. Restricted review sandboxes could not run all network tests; the local Docker/live suite and real seven-job CI supply that runtime validation.

_{🤖 Claimed by kvz on framework1/python-sdk since 2026-10-11 · resume: codex resume 01a12c04-6ff8-7a91-9987-654db44d852e}

[codecov-commenter]

Codecov Report

❌ Patch coverage is 95.49437% with 36 lines in your changes missing coverage. Please review.
✅ Project coverage is 95.71%. Comparing base (a9f606d) to head (eecb1cc).

Files with missing lines	Patch %	Lines
transloadit/assembly.py	88.65%	11 Missing ⚠️
transloadit/async_request.py	95.81%	9 Missing ⚠️
transloadit/async_client.py	95.12%	4 Missing ⚠️
transloadit/client.py	91.48%	4 Missing ⚠️
transloadit/api_url.py	94.11%	2 Missing ⚠️
transloadit/request.py	93.54%	2 Missing ⚠️
transloadit/upload.py	93.10%	2 Missing ⚠️
transloadit/async_template.py	94.11%	1 Missing ⚠️
transloadit/template.py	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #56      +/-   ##
==========================================
+ Coverage   86.60%   95.71%   +9.10%     
==========================================
  Files           7       15       +8     
  Lines         209      933     +724     
  Branches       19      130     +111     
==========================================
+ Hits          181      893     +712     
- Misses         28       40      +12     

Flag	Coverage Δ
unittests	95.71% <95.49%> (+9.10%)	⬆️

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