fix(eventstore): add owners to unique constraints (#12740)

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# Which Problems Are Solved

Bulk unique-constraint deletes (org, IDP with many links, user, project)
reconstruct every uniqueness key in Go and emit N `DELETE`s. That can
OOM on large tenants.

A one-shot owner backfill is also not enough: during a rolling deploy,
older binaries still insert `owners = '{}'`, so a later owner-only
delete would miss those rows.

Owner-only org/user/grant delete only matches rows whose `owners` bag
contains that tag. Several grant and member types stamped the aggregate
resource owner, which is not always the user’s home org or the granted
org. Username-scope rewrites also dropped `user:` tags, so owner-only
user delete could miss rewritten username rows.

Command must not switch to owner-only delete on the first 79 of a
version, because leftover `'{}'` rows from rolling-update overlap are
only backfilled on a later 79. A failed 79 must not turn owner-delete
on, and backfill joins must not stamp the wrong org (unverified domains,
org-scoped usernames colliding with instance-scoped ones).

# How the Problems Are Solved

Uniqueness stays the existing primary key `(instance_id, unique_type,
unique_field)`. `owners` is only a lifecycle bag of tags (`org:<id>`,
`user:<id>`, `idp:<id>`, `project:<id>`, `grant:<id>`).

- Add `owners TEXT[] NOT NULL DEFAULT '{}'` on
`eventstore.unique_constraints` (init SQL for greenfield, setup 78 for
existing clusters).
- Create `unique_constraints_owners_gin` with `CREATE INDEX
CONCURRENTLY` **outside a transaction** (same pattern as step 76).
Built-in `GIN (owners)` only; no `btree_gin`.
- Stamp `WithOwners` on **add** events. Field-level removes ignore
owners. `RemoveByOwner` stores the tag in `Owners` and both v1/v3 and v2
pushers run `DELETE … WHERE instance_id = $1 AND owners @>
ARRAY[$tag]::text[]`.
- Setup 79 backfills `owners` from projections via numbered
`cmd/setup/79/*.sql` files. Table names are interpolated from
`internal/query/projection` constants. Matches use `unique_field IN (x,
lower(x))` so the primary key can be used. Missing projection tables
(`42P01`) are skipped.
- Org domains are tagged only when `is_verified`. Instance-scoped
usernames join only users that are not org-scoped (organization settings
or domain policy `user_login_must_be_domain`). Every username row still
gets `org:` + `user:` of that user.
- 79 is a **repeatable** migration. `Check` re-runs when
`lastRun["version"]` changed or when setup-only `ForceFinalize` is set
and `lastRun["finalized"]` is still false. `Finalized` is written only
after Execute succeeds.
- Failed setup events keep the last successful `lastRun`. Command reads
`finalized` only from `system.migration.repeatable.done`.
- Org / user / project remove skip N-key event replay **when that
`finalized` bit is true**. Otherwise they keep today’s N-key lists
**and** still emit `RemoveByOwner`. The “ready” result is cached in
memory once true.

Setup writes `finalized` on the 79 repeatable.done payload:

- First 79 of a version: backfill only, `finalized=false` (unless
`ForceFinalize` is already set).
- Later 79: version change or
`BackfillUniqueConstraintOwners.ForceFinalize` /
`ZITADEL_BACKFILLUNIQUECONSTRAINTOWNERS_FORCEFINALIZE` after the rolling
update is done. That run backfills leftovers and writes
`finalized=true`.

Member and grant owner bags now include every org that should delete the
row:

- Instance, org, and project members also stamp
`org:<user_resource_owner>`.
- User grants stamp grant, user, project, and granted orgs.
- Project grant members stamp the project org, user org, and granted
org.
- Project grants stamp both orgs plus `grant:<id>`. Grant remove emits
`RemoveByOwner(grant)`.
- Username-scope rewrites keep `user:<id>` as well as `org:`.
- User/grant orgs are carried as unexported add-event fields (not
persisted JSON). `WithOwners` skips empty and duplicate tags.

# Additional Changes

- Table-driven owner-tag tests, including project grant (two `org:` tags
plus `grant:`), cross-org members, user grants, and username-scope
rewrite `user:` tags.
- Table-driven 79 `Check` + `finalizeAfterSuccess` tests for version
change, sequential version bumps, ForceFinalize restart, and
already-finalized skip.
- Command tests: a failed 79 event with `finalized=true` does not enable
owner-delete.
- Integration fixtures (verified vs unverified org domain;
instance-scoped `bob` vs org-scoped `bob`).
- Instance-only and global unique types stay untagged (`'{}'`). Instance
wipe still uses `UniqueConstraintInstanceRemove`.
- Pusher owner cases live in `eventstore_pusher_owners_test.go` so
`eventstore_pusher_test.go` stays under 1k lines.

# Additional Context

A later cleanup can delete the N-key replay helpers once a release that
ran 79 a second time (or an operator who set `ForceFinalize`) is in
production. That is not required for correctness.

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---------

Co-authored-by: Cursor Agent <[email protected]>
Co-authored-by: Silvan <[email protected]>

internal/command/user.go

@@ -200,7 +200,19 @@ func (c *Commands) RemoveUser(ctx context.Context, userID, resourceOwner string,
 	}
 	var events []eventstore.Command
 	userAgg := UserAggregateFromWriteModel(&existingUser.WriteModel)
-	events = append(events, user.NewUserRemovedEvent(ctx, userAgg, existingUser.UserName, existingUser.IDPLinks, domainPolicy.UserLoginMustBeDomain || orgScopedUsername))
+	userName := existingUser.UserName
+	idpLinks := existingUser.IDPLinks
+	orgScoped := domainPolicy.UserLoginMustBeDomain || orgScopedUsername
+	ownerDeleteReady, err := c.isUniqueConstraintOwnerDeleteReady(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if ownerDeleteReady {
+		userName = ""
+		idpLinks = nil
+		orgScoped = false
+	}
+	events = append(events, user.NewUserRemovedEvent(ctx, userAgg, userName, idpLinks, orgScoped))
 
 	for _, grantID := range cascadingGrantIDs {
 		removeEvent, _, err := c.removeUserGrant(ctx, grantID, "", true, false, nil)
@@ -387,6 +399,11 @@ func (c *Commands) userWriteModelByID(ctx context.Context, userID, resourceOwner
 }
 
 func ExistsUser(ctx context.Context, filter preparation.FilterToQueryReducer, id, resourceOwner string, machineOnly bool) (exists bool, err error) {
+	_, exists, err = existingUser(ctx, filter, id, resourceOwner, machineOnly)
+	return exists, err
+}
+
+func existingUser(ctx context.Context, filter preparation.FilterToQueryReducer, id, resourceOwner string, machineOnly bool) (userResourceOwner string, exists bool, err error) {
 	eventTypes := []eventstore.EventType{
 		user.MachineAddedEventType,
 		user.UserRemovedType,
@@ -408,19 +425,21 @@ func ExistsUser(ctx context.Context, filter preparation.FilterToQueryReducer, id
 		EventTypes(eventTypes...).
 		Builder())
 	if err != nil {
-		return false, err
+		return "", false, err
 	}
 
 	for _, event := range events {
 		switch event.(type) {
 		case *user.HumanRegisteredEvent, *user.HumanAddedEvent, *user.MachineAddedEvent:
 			exists = true
+			userResourceOwner = event.Aggregate().ResourceOwner
 		case *user.UserRemovedEvent:
 			exists = false
+			userResourceOwner = ""
 		}
 	}
 
-	return exists, nil
+	return userResourceOwner, exists, nil
 }
 
 func (c *Commands) newUserInitCode(ctx context.Context, filter preparation.FilterToQueryReducer, alg crypto.EncryptionAlgorithm) (*EncryptedCode, error) {