Bulk update/delete returns incomplete IDs for composite primary keys

[8dazo]

Summary

updateMany / deleteMany return only the first column of a composite primary key (e.g. "1") instead of the pipe-joined ID used everywhere else (e.g. "1|2").

This is a regression/gap in the compound-key support from #769, not a new feature request. Single-record endpoints already implement "col1|col2" correctly. Bulk endpoints do not.

Expected

react-admin requires updateMany / deleteMany to return the same record IDs used by getList / getOne / getMany:

{"data": ["1|2", "1|3"]}

That format is the contract from #769 and from _convert_record():

"id": "|".join(str(record[pk]) for pk in self.primary_key)

Actual (reproduced on current master)

Against a table with PK (id, other) and rows (1, 2), (1, 3), (4, 5):

Endpoint	Status	IDs
GET …/list	200	["1|2", "1|3", "4|5"]
GET …/one?id=1|2	200	"1|2"
GET …/many?ids=["1|2","1|3"]	200	"1|2", "1|3"
PUT …/update_many?ids=["1|2","1|3"]	200	["1", "1"]
DELETE …?ids=["4|5"]	200	["4"]

The bulk writes succeed (incoming "1|2" is parsed correctly and the rows are updated/deleted). Only the response IDs are wrong. Two different rows both come back as "1", so react-admin’s cache / selection / unselect after a bulk action will desync.

Why this is a bug, not intentional

1. Compound primary keys #769 defined "first|second" as the ID format for compound keys and was closed as implemented.
2. List/get-one/get-many already return that format; bulk is inconsistent with the same resource.
3. _convert_ids() is documented as converting IDs to the “correct output format”, but it does str(i) instead of the same "|".join(...) as _convert_record().
4. SAResource.update_many / delete_many are typed as returning list[tuple[Any, ...]] (full PK tuples) but call Result.scalars(), which only yields the first RETURNING column.

Root cause

1. SQLAlchemy backend drops extra PK columns (aiohttp_admin/backends/sqlalchemy.py):

stmt = stmt.values(data).returning(*(self._table.c[pk] for pk in self.primary_key))
return list(await conn.scalars(stmt))  # first column only

Same pattern in delete_many.

2. ID encoding does not pipe-join (aiohttp_admin/backends/abc.py):

def _convert_ids(self, ids: Sequence[_ID]) -> tuple[str, ...]:
    return tuple(str(i) for i in ids)  # "1" or "(1, 2)", never "1|2"

Even if (1) returned full tuples, str((1, 2)) would be "(1, 2)", not "1|2".

Test gap (no existing coverage)

Test	What it covers	Composite PK bulk?
tests/test_backends_sqlalchemy.py::test_id_nonpk	Schema only: primary_key == ("id", "other")	No HTTP
tests/test_backends_sqlalchemy.py::test_nonid_pk_api	list/one/many/create/update for a single non-id PK	No
tests/test_views.py::test_update_many / test_delete_many	Dummy2Model integer PK, expects {"data": ["1", "2"]}	No
admin-js/tests/relationships.test.js	Composite foreign keys, not composite PKs	No

That is why this slipped through: compound PK support was implemented and tested for get/create/update-one, never for bulk.

Suggested fix

1. Return full PK tuples from RETURNING ([tuple(row) for row in await conn.execute(stmt)]) instead of scalars().
2. Encode with the same helper as records: "|".join(str(part) for part in i).
3. Add an API test for composite PK update_many / delete_many asserting {"data": ["1|2", "1|3"]}.

Single-column PKs stay "1" / "2" because (1,) joins to "1".

[8dazo]

@Dreamsorcerer please check this out.