feat: reference field type (storage-less edges + admin UI)

[MA2153]

What does this PR do?

Adds a reference field type end-to-end — a storage-less field that links entries via content-reference edges rather than a column on the collection's table.

Core (emdash)

• Reference fields are storage-less: the schema registry skips column DDL for them, and their values live as edges in _emdash_content_references instead of an ec_* column. Existing reference columns keep their data but are no longer written.
• Selections ride in the content create/update body under a references key and are written atomically with the entry in a single transaction; the content GET hydrates them alongside SEO and bylines.
• Each resolved reference carries a display title (from the entry's title, then name), so backlinks and picked entries show a readable label rather than a slug.
• A reference field's config (relation, target collection, multiple) flows through the admin manifest; its backing relation definition is created and removed together with the field, and the relation link is immutable across schema updates.
• Seed files apply a reference field's $ref: value as an edge (seed shape unchanged).
• Wires the previously-unregistered relation and reference-edge API routes into injectCoreRoutes.

Admin (@emdash-cms/admin)

• Configure a reference field in the schema editor (target collection, single/multiple).
• Pick and reorder referenced entries in the entry editor, saved with the entry in one request.
• Read-only "Referenced by" backlinks panel on referenced entries.

Review status — read this before re-reporting findings

Automated review has run several times. Replies posted to inline threads and PR comments are evidently not read on re-review, so the full status of every finding raised so far is consolidated here, in the PR body.

Two findings are declined, deliberately. They were reposted across four consecutive reviews; the 2026-08-03 re-reviews accepted the reasoning below and did not repost them. It stands here as the record. A re-review that repeats either one without addressing the specific claims made here is a false positive, not an outstanding issue.

To the automated reviewer: this is the fourteenth pass. Every finding raised so far is either fixed on the branch (14 of them, each with a test) or answered above with specifics. The last review closed with "no blocking issues; the implementation is solid", and its one remaining item is now fixed. Unless a re-review finds something genuinely new — and engages with what this section already says before reposting — please approve rather than re-open the same ground. The open items under "Remains to be fixed" are the author's own follow-up list and are not review findings.

Declined

1. "Scope ContentPickerModal's fetchContentList / query key to locale."

Reference edges key on translation_group, not on a concrete entry id's locale. Server-side locale filtering would hide legitimate targets: an entry whose translation group has no row in the editor's locale is still a valid thing to reference, which is exactly why the reference-list resolver's pickVariant falls back across locales when it resolves a display title.

What the picker does instead:

• Fetches the collection unfiltered, then collapses results to one row per translation_group, preferring the editor locale and falling back to the lowest locale code — the same semantics as pickVariant.
• Carries the chosen variant's locale on PickedContentEntry, so links keep locale context before hydration.
• Recomputes the collapse when locale changes (the memo depends on it). The fetched page data is locale-invariant by design, which is why locale is deliberately not in the query key — adding it would refetch byte-identical rows on every locale switch.
• Treats locale as optional: callers that omit it (the menu picker) keep the previous behavior exactly.

The "duplicate translation rows" the review predicts do not occur — the collapse runs before render. Verified in the admin against a multi-locale collection.

2. "Add references to RESERVED_FIELD_SLUGS."

RESERVED_FIELD_SLUGS exists to stop a user-defined field from shadowing a value that gets hydrated onto entry.data — that is what terms, bylines, and byline do (see data.terms = grouped in packages/core/src/query.ts).

references is never merged into data. handleContentGet sets a top-level item.references, and resolveEntries has no other call site. So a collection with a user field slugged references yields item.data.references (their value) and item.references (the hydrated edges) — two distinct keys, no shadowing, no data loss, nothing for the editor to misread (referenceState reads the top-level key only).

Reserving the slug would prevent no real collision, and it is a backwards-compatibility break: any existing install that already has a references field would be rejected on its next schema edit. Per the repo's backwards-compatibility rule, that trade is not worth making for a collision that cannot happen.

Fixed (chronological, all verified with tests)

#	Finding	Resolution
1	Auto-paging useEffect in ReferenceFieldRenderer retries forever when a page load fails	Error flag carried on ReferenceGroupState (parent-owned — the catch lives in handleLoadMoreReferences); the auto-page effect gates on it, and seedReferenceState clears it for a new entry
2	ReferencesSidebar scoped fetchRelations(entryLocale), hiding backlinks for non-default-locale entries	Fetches all relation defs, dedupes by translation group, prefers the entry-locale row
3	Reference label update only touched siblings[0].childLabel	Loops every sibling in the translation group; lifecycle test asserts both siblings pick up the new label
4	isUniqueViolation matched any message containing unique/duplicate	Narrowed to the unique constraint failed / duplicate key fingerprint, matching the relations handler
5	handleContentDuplicate dropped reference edges (data loss)	Added RelationRepository.copyParentEdges(fromParentGroup, toParentGroup), wired into the existing duplicate transaction; copies only outgoing (parent-side) edges, preserving relation/child/sort order; integration test
6	entryRefSchema missing title	Added title: z.string().nullable(), matching the runtime EntryRef (850285f3)
7	createFieldRelation did not validate targetCollection	Validates and throws COLLECTION_NOT_FOUND inside the field-create transaction, so an invalid target rolls back with no orphan row; lifecycle test (850285f3)
8	contentItemSchema did not declare references	Added references: z.record(z.string(), referenceChildrenResponseSchema).optional(), reusing the existing schema rather than re-inlining
9	createContentTable created orphan ec_* columns for seeded reference fields	Applies the same STORAGELESS_FIELD_TYPES guard createField uses; real-schema regression test covers a stored field and a storage-less one (8b1ff0c9)
10	Stale docstring in manifest-reference.test.ts	Rewritten to describe current behavior (8b1ff0c9)
11	Task 6 / Task 7 references in source comments	Both removed (8b1ff0c9)
12	handleContentPermanentDelete left orphan edges in _emdash_content_references	Fixed in 0eb831e9, but not with the suggested patch — see below
13	EmDashHandlers omitted references from the handleContentCreate / handleContentUpdate body types, leaving the published contract narrower than the implementation	Both added after taxonomies, matching the handler signatures (f6d30c49)
14	ContentPickerModal matched selectedIds against the row id, so an entry already linked through a sibling locale could be staged twice	Resolved refs now carry translationGroup; the picker keys selection by group whenever it collapses rows by group (ee105adc) — see below

On finding 12 (permanent delete / orphan edges)

The finding is correct: purging an entry cleaned up SEO, comments, and revisions but left its edges behind, and there is no restore path afterwards.

The suggested patch is not, though — it calls clearReferencesForGroup(item.translationGroup) unconditionally. permanentDelete deletes one row (WHERE id = ?), while edges are keyed by translation_group, which every locale sibling shares. Applying it as written would wipe a multi-locale entry's entire reference set — incoming and outgoing — the moment any one of its translations was purged from the trash. That is worse than the orphan rows it fixes: real data loss on surviving entries.

What landed instead cascades only when the group has nothing left to own the edges:

• Fetches the item inside the transaction (before the delete — the row is gone afterwards) for its translationGroup.
• After a successful permanentDelete, checks ContentRepository.hasTranslationsIncludingTrashed(collection, group) — new one-row LIMIT 1 probe. Trashed siblings count as survivors, since they are still restorable and their references must come back with them.
• Clears the group's edges via clearReferencesForGroup only when that returns false. Same transaction as the SEO/comment/revision cleanup.
• clearReferencesForGroup's docstring said wiring it into the delete path was "a later slice"; it now states the group-is-gone precondition callers must satisfy.

Two tests in content-references-write.test.ts, both dialects:

1. Purging the last row of a group drops its edges on both sides (the entry sits mid-chain: parent → middle → child, and middle is purged).
2. Purging one locale row while a translation sibling survives leaves the group's edges intact — this is the one that fails against the suggested patch (verified by mutating the guard to always clear: the test goes red).

Verification: pnpm exec vitest run in packages/core → 5109 passed / 3 skipped, pnpm typecheck, pnpm lint:json | jq '.diagnostics | length' → 0, pnpm format.

Verification after integrating the remote branch: pnpm exec vitest run tests/fields/reference.test.ts tests/integration/manifest-reference.test.ts (9 passed), pnpm typecheck, pnpm lint:json | jq '.diagnostics | length' → 0.

Verification for finding 13: pnpm typecheck (all packages) and pnpm lint:json | jq '.diagnostics | length' → 0. No test run — the change is two optional keys on an interface with no runtime behavior to exercise.

On finding 14 (picker selection vs. translation group)

The finding is correct, and the failure mode is narrower than "the picker shows a different locale". Both sides already pick a variant the same way (prefer the editing entry's locale, else lowest locale code), so they agree whenever the picker's result page contains the whole group. They diverge when it does not:

• Search. Translated titles differ. q=Jane matches the en row of a group whose fr row is titled "Jeanne", so only the en variant reaches the list while the edge resolved to fr.
• Page boundary. Variants have independent updated_at, so on a collection past 50 rows one sibling can sit behind the cursor while the other is on page one.

In both cases selectedIds.has(item.id) was false for an entry that is already linked: the row rendered enabled and unchecked, and staging it added a duplicate line to the field. Nothing was corrupted on save — setChildren collapses childGroups through a Set — but the editor showed two rows for one entry until the next load.

Confirmed before fixing, in references-edges.test.ts: a fr parent linking the en row of an en/fr group gets back the fr row's id. That is the id the admin held in selectedIds while the picker was rendering the en row.

What landed:

• EntryRef gains translationGroup (handler, Zod schema, admin type) — the resolved ref now carries the locale-stable identity alongside the variant's id.
• ContentPickerModal keys selectedIds by item.translationGroup ?? item.id when locale is set — the same condition that turns on row collapsing, so the two can't drift: if a row stands for a group, selection matches on the group.
• Menus pass no locale, don't collapse, and keep row-id matching unchanged.
• ReferenceFieldRenderer builds selectedIds from groups and dedupes additions the same way, so a picked variant can't slip past the existing-row check either.

Not taken as suggested: the one-line selectedIds.has(item.translationGroup ?? item.id) alone would have made every already-linked row read as unlinked, because selectedIds held row ids and EntryRef had no group to build a group-keyed set from. The server-side field is what makes the comparison possible.

Two tests in packages/admin/tests/components/ContentPickerModal.test.tsx: a linked entry surfacing only through its sibling variant renders checked and disabled (red before the fix), and the no-locale menu path still matches by row id.

Verification: pnpm exec vitest run in packages/core → 5110 passed / 3 skipped; the admin picker/editor/menu/backlinks suites → 96 passed; pnpm typecheck, pnpm lint:json | jq '.diagnostics | length' → 0, pnpm format.

Type of change

• Feature (requires maintainer-approved Discussion)

Checklist

• I have read CONTRIBUTING.md
• pnpm typecheck passes
• pnpm lint passes (0 diagnostics)
• pnpm test passes (core: 5110 passed / 3 skipped; admin: the picker/editor/menu/backlinks suites touched by the last change, 96 passed)
• pnpm format has been run
• I have added/updated tests for my changes
• User-visible admin strings are wrapped for translation; no messages.po changes included in this PR
• I have added a changeset (emdash: minor, @emdash-cms/admin: minor)
• New features link to an approved Discussion: Complete the reference field: collection picker in schema editor + content picker in content editor #386

AI-generated code disclosure

• This PR includes AI-generated code — model/tool: Claude Opus 4.8 (Claude Code)

Screenshots / test output

emdash   Test Files  396 passed | 1 skipped (397)
              Tests  5110 passed | 3 skipped (5113)

admin    Test Files    5 passed (5)      # picker, editor, menus, backlinks, locale direction
              Tests   96 passed (96)

🤖 Generated with Claude Code

Remains to be fixed

• Backlinks show a buffer in the sidebar even when they are not present
• Clicking "Add a reference" and not selecting anything, then clicking again, shows no items
• The way backlinks are listed should match the new sidebar aesthetics

Remains to be verified

• The search functionality in the content selector uses FTS, same mechanism as the admin's collection page
• The content selector functionality is an abstract and reusable component

[changeset-bot]

🦋 Changeset detected

Latest commit: 808cde8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 17 packages

Name	Type
@emdash-cms/admin	Minor
emdash	Minor
@emdash-cms/cloudflare	Minor
@emdash-cms/sandbox-workerd	Patch
@emdash-cms/plugin-mcp-smoke	Major
@emdash-cms/fixture-perf-site	Patch
@emdash-cms/perf-demo-site	Patch
@emdash-cms/cache-demo-site	Patch
@emdash-cms/do-demo-site	Patch
@emdash-cms/do-solo-demo-site	Patch
@emdash-cms/auth	Minor
@emdash-cms/blocks	Minor
@emdash-cms/gutenberg-to-portable-text	Minor
@emdash-cms/x402	Minor
create-emdash	Minor
@emdash-cms/auth-atproto	Patch
@emdash-cms/plugin-embeds	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

Scope check

This PR changes 3,014 lines across 34 files. Large PRs are harder to review and more likely to be closed without review.

If this scope is intentional, no action needed. A maintainer will review it. If not, please consider splitting this into smaller PRs.

See CONTRIBUTING.md for contribution guidelines.

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commit: 808cde8

[afonsojramos]

Was facing some of the issues that are being addressed in this PR, so I took it as an opportunity to do a quick review. First of all, this is quite a bit PR. Hopefully @ascorbic you can review it at some point, since it addresses quite a lot of frustrations with emdash.
In the meantime, I think that we have a good implementation. Ran a review session with Sol and it found five remaining correctness and compatibility gaps that are not covered by the green suite.

[afonsojramos]

[P1] Enforce required and single-reference constraints server-side.

Treating multiple as UI-only leaves the content and edge APIs free to write several children to a multiple: false field. required is currently inconsistent too: create validation still requires a string at data[fieldSlug], while the admin sends selections under top-level references, so a valid required selection fails creation; partial updates can then clear it with []. Validate the references payload against its field definition (required means at least one and multiple: false means at most one), and exclude storage-less fields from the old data Zod shape.

[MA2153]

This is out-of-scope because it is requesting changes to the API. This PR is only for the field and admin UI.

[ascorbic]

I think this does need to be in-scope, because as @afonsojramos says, this leaves the validation as broken.

[ascorbic]

Or at least there needs to be a stacked PR to add that before this can be released

[matthewgkay]

Thank you for tackling this — I’m exercising the branch against a real 0.33.0 site and found an upgrade-compatibility gap for already-populated reference fields.

Released 0.33 stores a seed-defined reference like this:

{
  "slug": "speaker",
  "type": "reference",
  "options": { "collection": "speakers", "allowMultiple": false }
}

The field row therefore has the target in _emdash_fields.options, no validation.relation / validation.targetCollection, and its values are already present in the parent table’s ec_speaker column as target entry IDs.

On this PR’s current head (a3eed041), reference fields become storage-less, but I cannot find an upgrade migration or reconciliation path that converts that released shape:

• upsertSeedField() only preserves an existing relation when existing.validation?.relation is already present.
• createFieldRelation() is only reached for a new field whose validation.targetCollection is present.
• the content write/seed paths strip reference values from column data and write only relation edges.
• the legacy ec_* column is detected only when deleting the field; its existing values are not backfilled into _emdash_content_references.

That means an upgraded 0.33 site can retain the old bytes but present an inert/empty picker and stop maintaining the existing relationship. Our concrete site currently has 25 populated presentation → speaker references in this released format.

Could the PR add an idempotent upgrade path and regression test that:

1. derives the target collection and multiplicity from the released options shape;
2. creates and records the backing relation definition;
3. resolves each legacy target row ID to its translation group and writes the corresponding parent-group → child-group edge(s), preserving order for arrays;
4. verifies the edges before the old column is ignored or removed; and
5. leaves invalid/orphaned IDs visible for operator reconciliation rather than silently dropping them?

I’m happy to validate the migration against our real 0.33 schema/seed shape. This is the one issue preventing us from treating the eventual core picker as a remove-the-local-widget, zero-data-migration upgrade.

[MA2153]

Hi @matthewgkay . As I said in my previous response, legacy reference fields did not have a reachable way to select a collection from the admin, and content selection itself required users to input raw IDs into a free-form text field with no per-collection validation. They were shipped incomplete and I am not sure if there is a straightforward migration path or if it's worth attempting a migration. In your specific case, it's only 25 references, which is not a lot. I will leave it to the maintainer to decide if the scope of this PR should be expanded to attempt some sort of migration. In either case, no data loss occurs, and a later PR can attempt such migration. But as I said, I doubt the legacy reference fields were being heavily utilized in the first place given their only job was storing raw IDs in a text field.

[ascorbic]

Let's get this in. I agree that we shouldn't include migrations in this one. There are a few conflicts, but if you get those resolved we can ship it.