fix(odoo-spo): #525 codex P2 — bind no-_name _inherit to inherit[0] only

A no-_name Odoo class reopens ONE existing model in place; Odoo binds it
to _inherit[0] and treats further entries as mixins. The prior fix bound
local relational fields to the whole _inherit list, so build_relation_map()
could emit bogus target/reads_field triples for secondary parents
(e.g. _inherit = ['account.move', 'mail.thread']). Scope to inherit_models[:1],
mirroring parsers/classes.py.

Corpus byte-identical: regenerated from base 1ec76f5 (22245) with the fixed
enrich -> out=24166, target=842, inverse_name=144 (diff clean). No real
scanned-addons class triggers the secondary-mixin path scoped to a
corpus-declared model, so odoo_ontology.rs counts are unchanged.

Test: test_inherit_list_binds_field_to_first_model_only asserts only
inherit[0] is bound. 20/20 python tests green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CcpLeEC3XK8Eye53GKBVvi

Author: claude

.claude/board/AGENT_LOG.md

@@ -1,3 +1,13 @@
+## 2026-06-18 — PR #525 follow-up: `_inherit`-only binding scoped to `inherit[0]`
+
+**Main thread (Opus) — single implementer**, branch `claude/odoo-spo-fk-target-deep-reads`. Addresses the one unresolved codex P2 on #525: the prior `_inherit`-only fix bound a no-`_name` class's relational fields to the WHOLE `_inherit` list, so a multi-element `_inherit = ['a','b']` would attach local fields to every inherited mixin and let `build_relation_map()` emit bogus `target`/`reads_field` triples for secondary parents.
+
+**Fix:** `spo_enrich.py` no-`_name` case now binds to `inherit[0]` only (`inherit_models[:1]`), matching Odoo in-place extension semantics and the repo's own `parsers/classes.py` collapse. `test_inherit_list_binds_field_to_each_model` → `..._to_first_model_only` (asserts `sale_order` bound, `purchase_order` NOT). Docstrings reworded.
+
+**Corpus impact: NONE.** Regenerated from base `1ec76f5b` (22 245) with the fixed enrich → `out=24166`, `target=842`, `inverse_name=144` — **byte-identical** to the committed corpus (`diff -q` clean). No real scanned-addons class triggers the bogus secondary-mixin binding scoped to a corpus-declared model, so the Rust count assertions (24 166 / 842 / 144 / 3 030) are unchanged; no `odoo_ontology.rs` edit. The fix is defensive tooling-correctness.
+
+**Tests:** `python3 -m unittest tests.test_spo_enrich` 20/20 green.
+
 ## 2026-06-17 — PR #523 review fixes: spo_enrich multi-emitter + `_inherit`-only
 
 **Main thread (Opus) — single implementer**, branch `claude/odoo-spo-fk-target-deep-reads` (review-fix commit on top of the enrichment commit, no rebase). Addresses 4 valid review findings (codex P1 + codex P2/CodeRabbit Major + 2 CodeRabbit doc nits). Scope: the lance-graph SPO corpus + the stdlib Python extractor tooling under `tools/odoo-blueprint-extractor/` (no odoo-rs change).

tools/odoo-blueprint-extractor/odoo_blueprint_extractor/spo_enrich.py

@@ -194,12 +194,20 @@ def _scan_file(path: str, relmap: Dict[Tuple[str, str], Tuple[str, Optional[str]
                 local_fields[target_name] = (comodel, inverse)
 
         # Resolve the model name(s) this class contributes fields to: `_name`
-        # if present, else the `_inherit` target(s). A class with neither
-        # contributes nothing.
+        # if present, else the single in-place `_inherit` target. A class with
+        # neither contributes nothing.
+        #
+        # No-`_name` extension reopens ONE existing model in place. Odoo binds
+        # such a class to `_inherit[0]`; a multi-element `_inherit` adds the rest
+        # as mixins, NOT as additional homes for these local fields. Assigning
+        # the whole list here would attach the fields to every secondary mixin
+        # and let build_relation_map() emit bogus `target`/`reads_field` triples
+        # for them. `parsers/classes.py` collapses the no-name case to
+        # `inherit[0]` for the same reason; mirror it.
         if name_model is not None:
             model_names = [name_model]
         else:
-            model_names = inherit_models
+            model_names = inherit_models[:1]
 
         for model_name in model_names:
             mu = model_to_underscore(model_name)

tools/odoo-blueprint-extractor/tests/test_spo_enrich.py

@@ -295,9 +295,11 @@ class TestInheritOnlyRelationMap(unittest.TestCase):
 
     The common Odoo extension form reopens an existing model via
     `_inherit = "some.model"` (string) or `_inherit = ["a", "b"]` (list) WITHOUT
-    a `_name`; relational fields on such classes must map onto the inherited
-    model(s), or their target/inverse_name (and any deep hop through them) is
-    lost.
+    a `_name`; relational fields on such classes must map onto the single
+    in-place extension target, or their target/inverse_name (and any deep hop
+    through them) is lost. Odoo binds the no-`_name` case to `_inherit[0]`; any
+    further entries are mixins, not additional homes for the local fields, so
+    they must NOT receive the relational fields (mirrors `parsers/classes.py`).
     """
 
     def _scan_source(self, src: str):
@@ -320,7 +322,11 @@ def test_inherit_string_binds_field_to_inherited_model(self):
             ("payment.transaction", None),
         )
 
-    def test_inherit_list_binds_field_to_each_model(self):
+    def test_inherit_list_binds_field_to_first_model_only(self):
+        # No-`_name` multi-element `_inherit` extends `_inherit[0]` in place;
+        # the rest are mixins and must NOT inherit the local relational fields
+        # (otherwise build_relation_map() emits bogus target/reads_field triples
+        # for secondary parents). Matches parsers/classes.py inherit[0] collapse.
         src = (
             "from odoo import fields, models\n"
             "class Mixin(models.AbstractModel):\n"
@@ -331,9 +337,7 @@ def test_inherit_list_binds_field_to_each_model(self):
         self.assertEqual(
             relmap.get(("sale_order", "partner_id")), ("res.partner", None)
         )
-        self.assertEqual(
-            relmap.get(("purchase_order", "partner_id")), ("res.partner", None)
-        )
+        self.assertIsNone(relmap.get(("purchase_order", "partner_id")))
 
     def test_inherit_tuple_form_is_accepted(self):
         src = (