Copy @direction when cloning the active context; guard the @direction null reset

[skydudie]

Fixes #337.

What

Two fixes in _process_context-related direction handling, mirroring jsonld.js semantics per JSON-LD 1.1 API Context Processing:

1. _clone_active_context now copies @direction, matching the existing handling of @language/@base/@vocab. Previously any context layer processed on top of an existing active context — a second document-level layer, a property-/type-scoped context, an embedded node @context, or a remote context — silently dropped the inherited default base direction (while the default language survived), changing expanded output and, under rdfDirection, the emitted N-Quads. (Default @direction is not inherited across context layers — _clone_active_context omits @direction #337; same bug as Default @direction is not inherited across context layers — _cloneActiveContext omits @direction jsonld.js#586; matching PR Copy @direction when cloning the active context jsonld.js#587.)
2. A @direction: null context entry is now a no-op when no default direction is set (rval.pop('@direction', None) instead of an unguarded del). This mirrors JS delete semantics. Found while writing the tests: on released 3.3.0, jsonld.expand({'@context': {'@direction': None}, 'http://ex/p': 'v'}) raises KeyError: '@direction', and a legitimate scoped @direction: null reset is rejected as invalid scoped context.

Tests

• Three TestExpand methods (per AGENTS.md, added to the existing class): default @direction survival across document-level layers, inheritance into a property-scoped context, and scoped override / null reset.
• Full local run (pytest, W3C suites included via the specifications/ submodules): 1885 passed / 18 failed / 29 skipped / 1 xfailed on this branch vs 1882 / 18 / 29 / 1 on unpatched master — the failure lists are byte-identical (tests/test_cli.py JSON-decode issues and a missing aiohttp module in this environment), i.e. +3 new passing tests, zero regressions.
• make lint clean.

Compatibility note

This changes expanded output (and N-Quads under rdfDirection) for documents that combine a default @direction with multiple context layers or scoped contexts — flagging for the 4.0.0 changelog since RDFC hashes over such documents change. Related: w3c/vc-data-integrity#366.

[mielvds]

Thanks @skydudie. Could you rebase against codex/255-split-iri-and-util-tests?

[skydudie]

Thanks @skydudie. Could you rebase against codex/255-split-iri-and-util-tests?

Rebased onto codex/255-split-iri-and-util-tests and retargeted the PR to it. Moved the tests from tests/test_jsonld.py into tests/jsonld/test_expand.py

Lmk if there is anything else ya want changed😃

[mielvds]

yes, could you rebase to master? :) I had a small fix in

[skydudie]

yes, could you rebase to master? :) I had a small fix in

Rebased onto master and thanks for the schema.org fix!

[mielvds]

Thx @skydudie looks good. @anatoly-scherbakov could you have a final look at this?