[pietechsolution]

Season seats for seatlayer (Python), part of the 0.9.0 release. One release, 0.9.0, carries season 2a (#12) and this PR (decided 10 Nov).

• Versions: old 0.8.0 (published) → new 0.9.0 (with season-2a, Season 2a server operations (part A) #12). Nothing is published yet: PyPI stops at 0.8.0 (checked 10 Nov).
• 0.8.0 has the 48 season operations from 0.7.0/0.8.0. It has none of the season-2a calls and none of these.
• The branch is cut from season-2a-server so it builds on the season-2a methods. Its name still says 0.10.0, from before the decision: renaming a head branch would close the PR.
• No version bump, tag or publish is in this PR. pyproject.toml and __version__ are untouched.

A webhook problem 0.9.0 ships fixed

webhooks.create(...) and webhooks.update(...) check names against Webhooks._EVENT_NAMES, and raise ValueError for any other.

• 0.8.0's list has 8 names and no season name. On season-2a-server it is a hand list of 18, with only the three season.ticket.transfer_* season names, so season.plan.published and the rest are refused.
• WebhookEventName types all of these names, and the API accepts all of them (KNOWN_EVENTS in the app repo's workers/api/src/webhooks.ts).
• Here _EVENT_NAMES = frozenset(get_args(WebhookEventName)), with a test that every typed name is accepted.
• Every name WebhookEventName types is one the API accepts (checked against the API's list: 58 of its 63; the 5 guest.* names aren't typed here yet).
• If the season-2a PR fixes this first, this hunk falls away at the rebase.

What it adds

Built to docs/season-block-2026-11-08/contract.md in the app repo (§2, §5, §6, and §8 "Amendments, 9 Nov"). Method names are the operationIds, snake_cased (AGENTS.md).

• Methods:

  • seasons.set_aside_season_block(season_key, expected_revision, keep_for_single_tickets=None, idempotency_key=None);
  • seasons.retrieve_season_block(season_key);
  • seasons.release_season_block(season_key, expected_revision, scope, event_keys=None, at=None, reason=None, idempotency_key=None).

  Both writes use header replay, so an Idempotency-Key is generated when none is given, as on refund_season_performance. Each write answers {"job": ..., "block": ...}; follow the job with retrieve_season_bulk_job.

• inventory_mode ("block" | "per_hold") on create_season and update_season, sent as inventoryMode only when given. "block" opts the season into season seats; the default stays per_hold. Every Season answer carries inventoryMode.

• Types: SeasonSeatSelection, SeasonBlockReleaseScope, SeasonDateLeavePending. The webhook names are season.block.ready and season.block.released.

• The 202 while a date leaves every season seat (create_season_amendment cancel, mark_season_performance_past): is_season_date_leave_pending(result). The return types are unchanged (Any).

• Errors: no new classes or constants. The new codes come through SeatLayerError and its subclasses with code (§8 item 4). The CHANGELOG lists them, now including every code the 3 calls and inventoryMode can send (SEASON_BLOCK_API_BUSINESS_ERRORS in the app repo).

• Docs: a "Season seats" section at the end of the README's "Fixed Renewable Seasons": opt in with inventory_mode, set the seats aside, follow the job, read the block, release to single sale (now or at a set time), the two webhook names, the 202 guard, refusals through SeatLayerError with code, and partner seats staying out of the block.

• CHANGELOG: the "Next: 0.9.0" section. The version PR joins it with the season-2a section under ## 0.9.0. Its webhook line now says what 0.8.0 did (it had said "0.9.0 refused…", which stops being true once both ship as 0.9.0).

Files changed

CHANGELOG.md, README.md, src/seatlayer/__init__.py, src/seatlayer/resources.py, src/seatlayer/types.py, tests/test_client.py, tests/test_seasons.py (7 files, +413 −29).

Checks

• The repo's gate (ruff check src tests, mypy, pytest -q) on Python 3.14, re-run 10 Nov on this commit: green. ruff: all checks passed; mypy: no issues in 7 source files; pytest 133/133.
  • The operation map test goes 87 → 90: paths, bodies, the caller's key and the generated replay key on both writes.
  • A test sends the phase 4 answers through the transport: the 202s, a job of a new kind, and the 409 codes, each a SeatLayerConflictError with its code.
  • inventory_mode on create and update.
  • A webhook test checks that every typed name is accepted.
• Mutation check (run before this amend; the code is unchanged since): 8 mutants (the 3 paths, both bodies, header replay, the guard, the event names): 8/8 killed.
• The README sample isn't run by the repo. Its syntax was checked once (ast.parse), and the calls by hand against the signatures in resources.py.
• Compat matrix: the same fixtures, shaped as the phase 4 API answers, through a stub transport. The script is season-phase4-python-compat.py in the app session's notes; nothing is sent.

Build	Result
published 0.8.0 (the PyPI wheel, pip download seatlayer==0.8.0 --no-deps, re-run 10 Nov)	all PASS where the method exists, 4 of 14: the 409 code and the 202 on create_season_amendment, a Season answer carrying inventoryMode, and 409 season_block_packages on update_season. The other 10 are n/a: 0.8.0 has neither the season-2a calls nor these
season-2a-server head e3ab392	all PASS (10 Nov run, not re-run): jobs of both new kinds, a mixed job list, the three new 409 codes, the 202 on a cancel and on a past date, inventoryMode and 409 season_block_packages
this build (0.9.0)	all PASS, 14/14 (re-run 10 Nov on this commit's src/), including the 3 new calls and 409 season_block_not_enabled

• Not done yet: a live dev smoke of the 3 calls with the dev test key. The phase 4 API isn't on dev until the stack merges; it is step 3 below.

Release steps for the owner

1. The season-2a PR (Season 2a server operations (part A) #12) merges to main, with no tag.
2. Rebase this PR onto main and retarget it to main; the gate green; merge.
3. Compat matrix again, once the phase 4 API is on dev:
   • run the compat script against published 0.8.0 and against main's src/: both all PASS;
   • the live dev smoke of the 3 calls with the dev test key: opt in, set aside, follow the job to completed, read, release with at, read the release job.
4. Version PR: 0.9.0 in both pyproject.toml and src/seatlayer/__init__.py, which must agree. Join the CHANGELOG's season-2a section ("Unreleased") and "Next: 0.9.0" under a dated ## 0.9.0. Merge to main.
5. Publish: only after the phase 4 API (paiteq/seatmap #2059 → #2086 → #2061 → #2062 → #2063 → #2066 → #2092) is live on production and the owner says yes: git tag v0.9.0 && git push origin v0.9.0. release.yml publishes through PyPI Trusted Publishing, and refuses if the tag and either version disagree.
6. Live re-check:
   • https://pypi.org/pypi/seatlayer/json reads 0.9.0;
   • in a fresh venv, pip install seatlayer==0.9.0 and python -c "import seatlayer; print(seatlayer.__version__)";
   • run the dev smoke again from the installed package.
7. Rollback (0.9.0 only adds, apart from the webhook names fix): yank 0.9.0 in the PyPI web UI (project › Manage › Releases › Yank). New installs get 0.8.0 again, and exact pins keep working. PyPI never takes the same version twice, so a fix ships as 0.9.1. A rollback also withdraws season-2a: both ship in 0.9.0.

Failure modes

• Publishing before the phase 4 API is on production: the 3 calls would answer 404, and inventory_mode would be ignored. Step 5 waits for production.
• A caller skipping is_season_date_leave_pending: it would read the 202 body as the amendment. The return type is Any, so the README and the docstrings point at the guard.
• Webhook names: with the list built from WebhookEventName, a name typed here but unknown to the API would reach the API and be refused there. Today every typed name is one the API accepts.
• Old SDKs: 0.8.0 reads the new answers through its generic error and ignores inventoryMode (compat matrix). It can't call the 3 new routes.
• README drift: the sample isn't run. A later signature change would leave it stale.

Open risks

• No live dev smoke yet (step 3).
• The README links to the docs' "Season seats" section (/server-api/seasons/#season-seats), which goes live with paiteq/seatmap #2063. Until then the link lands on the top of the Seasons page.
• The README's season intro still counts 87 operations (it is 90 with this PR); it was left as it was.
• A code comment on _EVENT_NAMES still says "0.9.0 listed 18 by hand"; it means the season-2a branch. This amend touched only the README and CHANGELOG.