fix: stop reporting an edited record as its own duplicate

[66Ton99]

Problem

Found while running a single page CRUD against the bundle: every edit of a record whose entity carries a UniqueEntity constraint is blocked in the browser, even when the value was not changed.

An edit form submits the value the record already holds, so checkUniqueEntityAction finds that record and answers false. The browser shows "This value is already used." and refuses to send the form. Symfony's own UniqueEntityValidator does not do this — it compares the found entity with the one it is validating and skips it — so the client refuses a submit the server would have accepted.

Reproduced end to end: a Product with #[UniqueEntity(fields: ['sku'])], opened from an edit route, name changed, SKU untouched. The only request made was the uniqueness check; the form POST never went out and the field showed the duplicate message.

Change

The browser already sends the identifier of the object the form is bound to as entityId — Form\Constraint\UniqueEntity fills it from getId(), constraints/UniqueEntity.js puts it in the request, and src/Resources/doc/3_9.md already documents it and tells custom controllers to use it to exclude the edited entity. The default controller now does the same: the value is free when every record holding it is the one that identifier names.

The identifier of a match is read from Doctrine's class metadata when a manager knows the class, and falls back to getId(); a composite key, or a match whose identifier cannot be read, is never taken for the edited record. A request with no entityId — a create form — behaves exactly as before.

toList() was added because a constraint may declare a repositoryMethod that answers with a single entity or with null rather than a list; the previous empty() check accepted all three shapes and this keeps that.

Trust

entityId is the one part of the lookup the request decides, so a caller can ask "is this value free if we ignore record N?" and get true for a value record N holds. It changes an answer, never data, and the server side validator is unaffected. The route remains the unauthenticated existence check 3_9.md already documents and asks applications to restrict; this does not widen what it can be asked about — the field combination and repository method still have to match a declared constraint. Noted in 3_9.md and in the design risks in AGENTS.md.

Tests

Four tests in Tests/Controller/AjaxControllerTest.php: the edited record is not its own duplicate, another record holding the value still is, an existing value with no entityId still is, and a match whose identifier cannot be read still is. The first fails on main.

Verified in the Nix shell on PHP 8.5.6: composer test 99 tests / 272 assertions, composer phpstan no errors, composer coverage 95.85% lines.

🤖 Generated with Claude Code

[66Ton99]

The two red jobs here are not from this change — it touches PHP only. main itself fails one Jest test: registerForm() now sweeps the registrations whose markup has left the document, and the removeDetachedForms test builds its two registrations in a way that sweep passes over. Every open pull request is red for the same reason.

#26 repairs it and is green on all six jobs. Re-running the checks here after that lands should turn this one green; nothing in this branch needs to change.