Volva's code-spec review (thread 01KS4EKVKKGF) surfaced three findings
on the TDD-passing sessions module. All three addressed; one carries
a collateral contract amendment to keep INV-002 truthful.
1) drift: archived=item.get("archived", False) returned None for an
explicit "archived": null in the response. dict.get(k, default) only
fires the default when the key is absent — it does NOT default for
explicit-null values. The dataclass type is `bool` (not `bool | None`)
and INV-002 says explicit-null → False; the .get() form silently
violated both. Fixed: archived=item.get("archived") or False
(handles absent, null, false, and true cleanly).
INV-002 wording was the source of the bug — I introduced the
mis-spelled form during the Volva amendment round. Updated to spell
out the .get(default) foot-gun explicitly so future readers (and
future paraphrase rounds) don't fall back to the broken pattern.
2) test-gap: no test exercised explicit-null archived/tags. The
_list_item() helper had its own defaulting layer (tags=None →
["work"]) so a happy path test couldn't catch the underlying drift.
Added test_explicit_null_list_defaults using a raw dict to bypass
the helper. Catches the drift directly.
3) precision: message_count=body.get("message_count") could silently
default to None while POST-003 required it non-None. INV-001 prose
literally said "body['message_count']" (bracket access) so the
STEP 5 .get() was the contract's own internal inconsistency.
Aligned the code to bracket access (matches sibling required
fields like session_id) and amended STEP 5 + INV-001 to spell out
the strict semantics explicitly.
Volva's meta-note: "modest weight" — TDD caught the main surface;
this round caught a narrow Python .get() semantics edge that no
human reading would have spotted without explicit-null priors.
Still pulls real weight: that's the kind of bug that ships and
shows up months later when a server starts emitting null where
it used to omit a field.
63 tests GREEN (42 sse_client + 20 sessions + 1 boundary).
Ruff clean. Drift check still GREEN against the pinned issue body.
Implements docs/contracts/issues/2.contract.md. Two functions
(create_session, list_sessions), two frozen dataclasses (SessionInfo,
SessionPage), three exception types (AgentNotFound, InvalidCursor,
SessionApiFailed). 19 contract-listed tests cover every TESTS:
entry verbatim per the tracer-bullet vertical-slice ordering.
SessionInfo uses one shape across both endpoints with origin-
conditional defaults per INV-001 (create) and INV-002 (list). create-
origin always sets list-only fields to (name=None, archived=False,
tags=[]); list-origin reads them from the response item with
absent/null treated as those same defaults — keeps the dataclass
uniform without forcing callers to handle two types.
Spotted an internal-inconsistency in the contract at TDD start —
POST-003 and happy_create's test description still said "archived
is None, tags is None" while the freshly-applied Volva amendment
had moved INV-001 to (archived=False, tags=[]). Fixed in-place
before writing any tests so the spec stayed coherent.
SessionApiFailed.body truncates to <= 1024 bytes at construction,
matching the SseConnectFailed / CancelFailed precedent from issue #1.
No code shared with sse_client.py (convention-dependency only per
issue #2's dependencies: block). 62 tests GREEN total (42 sse_client
+ 19 sessions + 1 boundary smoke). Ruff clean.
No refactor pass — the two functions are ~25 LOC each with distinct
error-routing branches that don't naturally share more than they
already do.
vh