[simontaurus]

Three defects in schema_to_frame, one commit and one regression test each.

• #175 is_embed counts a $ref, and reference_properties drops anything embedded_properties claims. Reference subframes are written first, embedded ones second, so a property both signals claim keeps {} instead of being overwritten with {"@embed": "@never"} and losing its nested keys. A $ref is the only trace of an embed before dereferencing, while the "@type": "@id" OO-LD requires on such a term makes it look reference-valued at the same time.
• #176 Reverse-mapped properties move from their term name to @reverse, keyed by the reverse IRI as the term writes it (new helper reverse_predicates). Two terms on one reverse IRI expanded to two subframes under that IRI, which pyld rejects with invalid frame. This changes the derived frame for every reverse term, not only colliding ones; for a single term both forms frame to the same document, checked on the Organization/worksFor shape. Derived frames carry no sub-properties, so the expanded-IRI constraint recorded in the issue does not arise.
• #177 instance_rdf_types falls back to properties.type.default where x-oold-instance-rdf-type is absent, read before the allOf walk because a schema's own spelling is nearer than an inherited one. Without that anchor the first backwards edge degenerates the framed result to @graph.

#175 is a 2.x regression, from #164 and #155 interacting rather than from either alone, and an open range such as oold[validation]>=0.20 resolves to it today. #176 and #177 are present on 0.18.1 and 0.19.0 as well.

Tests 800 passed / 10 skipped / 1 xfailed before, 804 / 10 / 1 after; each new test was confirmed to fail on the unfixed code. make check and make validate pass.

[github-actions]

Release preview

Merging this PR would release v2.3.1 (current: v2.3.0).

Changelog preview (truncated)

## v2.3.1 (2026-11-15)

### Bug Fixes

- **frame**: Anchor the frame on a type pinned as a default
  ([`fa22022`](https://github.com/OO-LD/oold-python/commit/fa220221e48feb83c26879748c317457d2484012))

- **frame**: Keep a $ref-valued embed out of the reference list
  ([`a7ac1d1`](https://github.com/OO-LD/oold-python/commit/a7ac1d1d153719258fb299c3f706a58238bbe9c4))

- **frame**: One reverse subframe per IRI, not per term
  ([`74a3adf`](https://github.com/OO-LD/oold-python/commit/74a3adf44fb647aa544c7432c0e5fd78f44949c1))

### Documentation

- **controller**: Name controller members for what they do
  ([`648018f`](https://github.com/OO-LD/oold-python/commit/648018fc480934b5b5185c6d0702860392e90c25))

_{Preview via python-semantic-release and conventional commits.}

[github-actions]

📊 Benchmark Results

Click to see benchmark comparison

📊 Benchmark Comparison (threshold: 1.3x)
============================================================

➖ Unchanged (within threshold):
  ➖ test_simple_dict_document_store: 0.0014s → 0.0014s (+0.5%)
  ➖ test_sqlite_document_store: 0.0015s → 0.0015s (-0.3%)
  ➖ test_local_sparql_store: 0.0281s → 0.0286s (+1.8%)
  ➖ test_oneof_subschema: 0.0523s → 0.0473s (-9.6%)
  ➖ test_enum_docstrings: 0.0399s → 0.0506s (+26.8%)
  ➖ test_subclass_inheritance: 0.0437s → 0.0469s (+7.5%)
  ➖ test_class_hierarchy: 0.0391s → 0.0413s (+5.5%)
  ➖ test_core[v1]: 0.0284s → 0.0266s (-6.4%)
  ➖ test_core[v2]: 0.0340s → 0.0366s (+7.8%)
  ➖ test_schema_generation[v1]: 0.0012s → 0.0012s (+1.9%)
  ➖ test_schema_generation[v2]: 0.0027s → 0.0027s (-0.7%)
  ➖ test_simple_json: 0.0004s → 0.0004s (-2.1%)
  ➖ test_complex_graph: 0.0011s → 0.0011s (-0.8%)

============================================================
Summary: 0 regressions, 0 improvements, 13 unchanged
============================================================

✅ No significant performance regressions

Threshold: 1.3x (30% slower triggers a regression warning)

Note: Benchmarks are informational only and won't fail the build.

_{💡 Tip: Download the benchmark-results artifact for detailed JSON data}

[codecov]

Codecov Report

❌ Patch coverage is 89.18919% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/oold/validation/frame.py	89.1%	2 Missing and 2 partials ⚠️

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