fix: comparison and source pages accept the sources: cite add writes; sources may cite sources (#173)

Files changed:
- CHANGES.md
- VERSION
- instructions/wiki-ingest/SKILL.md
- kb/CONTRACT.md
- tools/CONTRACT.md
- tools/chemenu/commands/cite_cmd.py
- tools/chemenu/commands/xref.py
- tools/chemenu/tests/test_cite_cmd.py
- tools/chemenu/tests/test_page_ops.py
- tools/chemenu/tests/test_type_resolver.py
- tools/chemenu/tests/test_xref.py
- types/comparison.md
- types/comparison.schema.yaml
- types/source.md
- types/source.schema.yaml

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SnAJ7Z3CpVD3PRbN73QtU2

tools/chemenu/tests/test_cite_cmd.py

@@ -203,3 +203,121 @@ def test_cite_sync_command_over_kb(kb_dir, raw_dir, monkeypatch):
     result = runner.invoke(app, ["cite", "sync", "--all", "--dry-run"])
     assert result.exit_code == 0, result.output
     assert "No pages needed a Footnotes block change." in result.output
+
+
+# --- citing on comparison and source pages ----------------------------------
+#
+# Both types once declared no `sources:` field, while `cite add` wrote one onto
+# every page it touched - so a correctly cited comparison or source page failed
+# `lint` with `'sources' was unexpected`, under `additionalProperties: false`.
+
+
+def _write_source(kb_dir, title, raw_file):
+    """A source page the shipped schema accepts as it stands - the fixture's own
+    `Source - Aurora` carries a stray `source:` key and would mask the finding."""
+    from chemenu.frontmatter_io import write_page
+
+    path = kb_dir / "sources/notes" / f"{title}.md"
+    write_page(
+        path,
+        {
+            "type": "types/source.md", "source_type": "notes", "author": "Fixture Author",
+            "raw_files": [raw_file], "date": "2026-08-02", "summary": f"{title} summary",
+        },
+        f"\n# Source: {title}\n\n## Summary\n\nNotes.\n",
+    )
+    return path
+
+
+def _schema_errors_for(kb_dir, title):
+    from chemenu.lint_core import run_lint
+
+    return [e for e in run_lint(kb_dir)["schema_validation_errors"] if e["page"] == title]
+
+
+def test_cite_add_on_a_comparison_page_keeps_it_schema_valid(kb_dir, raw_dir):
+    from chemenu.cli import app
+    from chemenu.frontmatter_io import write_page
+
+    path = kb_dir / "comparisons/aurora vs Borealis.md"
+    write_page(
+        path,
+        {
+            "type": "types/comparison.md", "created": "2026-08-02",
+            "entities": ["aurora", "Borealis"], "summary": "Server against workstation",
+        },
+        "\n# Comparison: aurora vs Borealis\n\n## Überblick\n\nTwo machines.\n",
+    )
+    assert _schema_errors_for(kb_dir, "aurora vs Borealis") == []
+
+    result = runner.invoke(
+        app, ["cite", "add", "--page", "aurora vs Borealis", "--source", "Source - Aurora"]
+    )
+    assert result.exit_code == 0, result.output
+    fm, _body = read_page(path)
+    assert fm["sources"] == ["Source - Aurora"]
+    assert _schema_errors_for(kb_dir, "aurora vs Borealis") == []
+
+
+def test_a_source_page_may_cite_another_source_page(kb_dir, raw_dir):
+    """The citation lands on the citing side only, in the direction it was made."""
+    from chemenu.cli import app
+    from chemenu.provenance import citing_pages
+
+    path_a = _write_source(kb_dir, "Source - A", "raw/notes/Aurora.md")
+    path_b = _write_source(kb_dir, "Source - B", "raw/notes/Uningested.md")
+    before_b = path_b.read_bytes()
+
+    result = runner.invoke(app, ["cite", "add", "--page", "Source - A", "--source", "Source - B"])
+    assert result.exit_code == 0, result.output
+
+    fm_a, _body = read_page(path_a)
+    assert fm_a["sources"] == ["Source - B"]
+    assert path_b.read_bytes() == before_b
+    assert _schema_errors_for(kb_dir, "Source - A") == []
+    assert "Source - A" in citing_pages(load_kb_pages(kb_dir), "Source - B")
+
+
+def test_a_source_citing_its_own_file_writes_no_sources_entry(kb_dir, raw_dir):
+    """A self-citation names one of the page's own raw files. The definition is
+    written; `sources:` is left exactly as it was - not even an empty list."""
+    path = _write_source(kb_dir, "Source - A", "raw/notes/Aurora.md")
+    page = _reload(kb_dir, "Source - A")
+    assert "sources" not in page.frontmatter
+
+    marker_id, body, changed = upsert_citation(page, "Source - A", "Aurora.md")
+    assert changed is True
+    assert "sources" not in page.frontmatter
+    assert f"[^{marker_id}]: [[Source - A|Aurora.md]]" in body
+
+    page.body = body
+    _id, _body, changed_again = upsert_citation(page, "Source - A", "Aurora.md")
+    assert changed_again is False
+    assert path.exists()
+
+
+def test_a_self_citation_leaves_an_existing_sources_list_unchanged(kb_dir, raw_dir):
+    _write_source(kb_dir, "Source - A", "raw/notes/Aurora.md")
+    page = _reload(kb_dir, "Source - A")
+    page.frontmatter["sources"] = ["Source - Aurora"]
+
+    upsert_citation(page, "Source - A", "Aurora.md")
+    assert page.frontmatter["sources"] == ["Source - Aurora"]
+
+
+def test_cite_add_self_citation_on_disk(kb_dir, raw_dir):
+    from chemenu.cli import app
+
+    path = _write_source(kb_dir, "Source - A", "raw/notes/Aurora.md")
+    args = ["cite", "add", "--page", "Source - A", "--source", "Source - A", "--file", "Aurora.md"]
+    result = runner.invoke(app, args)
+    assert result.exit_code == 0, result.output
+
+    fm, body = read_page(path)
+    assert "sources" not in fm
+    assert f"[^{cite_id('Source - A', 'Aurora.md')}]: [[Source - A|Aurora.md]]" in body
+    assert _schema_errors_for(kb_dir, "Source - A") == []
+
+    again = runner.invoke(app, args)
+    assert again.exit_code == 0, again.output
+    assert "Already up to date" in again.output

tools/chemenu/tests/test_page_ops.py

@@ -193,6 +193,36 @@ def test_rename_fixes_a_dangling_source_reference(patched_wiki):
     assert frontmatter["sources"] == ["Source - Aurora Notes"]
 
 
+def test_rename_carries_sources_on_comparison_and_source_pages(patched_wiki):
+    """Both types declare `sources` in `page_ref_fields:`. A schema-only fix
+    would have let them validate, but a rename would then have left a dead
+    `sources:` entry behind on each - unreported, since `lint` resolves only
+    the declared fields too."""
+    from chemenu.lint_core import run_lint
+
+    write_page(
+        patched_wiki / "comparisons/aurora vs Borealis.md",
+        {"type": "types/comparison.md", "created": "2026-08-02",
+         "entities": ["aurora", "Borealis"], "sources": ["Source - Aurora"],
+         "summary": "Server against workstation"},
+        "\n# Comparison: aurora vs Borealis\n",
+    )
+    write_page(
+        patched_wiki / "sources/notes/Source - B.md",
+        {"type": "types/source.md", "source_type": "notes", "author": "Fixture Author",
+         "raw_files": ["raw/notes/Uningested.md"], "date": "2026-08-02",
+         "sources": ["Source - Aurora"], "summary": "B"},
+        "\n# Source: B\n",
+    )
+    page_ops.rename_command(old="Source - Aurora", new="Source - Aurora Notes", dry_run=False)
+
+    for path in ("comparisons/aurora vs Borealis.md", "sources/notes/Source - B.md"):
+        frontmatter, _body = read_page(patched_wiki / path)
+        assert frontmatter["sources"] == ["Source - Aurora Notes"]
+    dangling = {e["page"] for e in run_lint(patched_wiki)["dangling_frontmatter_refs"]}
+    assert not dangling & {"aurora vs Borealis", "Source - B"}
+
+
 def test_rename_stops_before_renaming_the_file_if_a_reference_write_fails(patched_wiki, monkeypatch):
     """A write failing partway through must not still rename the target file -
     that would leave some references pointing at the new title and others

tools/chemenu/tests/test_type_resolver.py

@@ -45,8 +45,8 @@ def test_get_page_ref_fields_reads_the_type_spec():
     so `lint`/`rename`/`rm` need no hardcoded list to update for a new type."""
     assert resolver.get_page_ref_fields("types/entity.md") == ["related", "sources"]
     assert resolver.get_page_ref_fields("types/concept.md") == ["related", "sources"]
-    assert resolver.get_page_ref_fields("types/source.md") == ["entities", "concepts"]
-    assert resolver.get_page_ref_fields("types/comparison.md") == ["entities", "related"]
+    assert resolver.get_page_ref_fields("types/source.md") == ["entities", "concepts", "sources"]
+    assert resolver.get_page_ref_fields("types/comparison.md") == ["entities", "related", "sources"]
 
 
 def test_page_ref_fields_exist_in_the_type_schema():

tools/chemenu/tests/test_xref.py

@@ -482,6 +482,38 @@ def test_xref_link_source_dry_run_leaves_the_source_page_alone(kb_dir):
     assert path.read_text(encoding="utf-8") == before
 
 
+def test_xref_link_source_refuses_a_target_that_is_itself_a_source(kb_dir):
+    """`link-source` means "A mentions X" and writes `X.sources += A`; for X =
+    another source that claims "B cites A", and the back-reference would add
+    `A.sources += B` too. A citation between sources has a direction, and only
+    `cite add` says which one - so the target is refused, the rest still linked."""
+    from chemenu.frontmatter_io import write_page
+
+    runner, app = _runner_env(kb_dir)
+    path_b = kb_dir / "sources/notes/Source - B.md"
+    write_page(
+        path_b,
+        {"type": "types/source.md", "source_type": "notes", "author": "Fixture Author",
+         "raw_files": ["raw/notes/Uningested.md"], "date": "2026-08-02", "summary": "B"},
+        "\n# Source: B\n",
+    )
+    result = runner.invoke(
+        app,
+        ["xref", "link-source", "--source", "Source - Aurora", "--entities", "gdeploy,Source - B"],
+    )
+    assert result.exit_code == 1
+    assert "Source - B" in result.output
+    assert 'cite add --page "Source - Aurora" --source "Source - B"' in result.output
+
+    pages = load_kb_pages(kb_dir)
+    assert "Source - Aurora" in pages["gdeploy"].frontmatter["sources"]
+    source_a = pages["Source - Aurora"].frontmatter
+    source_b = pages["Source - B"].frontmatter
+    for field in ("sources", "entities", "concepts"):
+        assert "Source - B" not in (source_a.get(field) or [])
+        assert "Source - Aurora" not in (source_b.get(field) or [])
+
+
 # --- the inbound view ------------------------------------------------------