From 845ebe569bbc830bdc977ff239b720697a76de65 Mon Sep 17 00:00:00 2001
From: "omegent-app[bot]" <306514130+omegent-app[bot]@users.noreply.github.com>
Date: Tue, 4 Aug 2026 10:30:28 +0000
Subject: [PATCH] fix(query): keep tag-aware guard on projectComputed only

`project()` is used for view DTOs that intentionally reshape domain fields.
Tag-scoped ProjectableFromDomain stays on projectComputed (overview path).

Co-authored-by: Patrick Roza <42661+patroza@users.noreply.github.com>
---
 .changeset/projectable-key-guard-project.md |  8 ++++++++
 packages/effect-app/src/Model/query/dsl.ts  | 16 +++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/projectable-key-guard-project.md

diff --git a/.changeset/projectable-key-guard-project.md b/.changeset/projectable-key-guard-project.md
new file mode 100644
index 000000000..45052bae9
--- /dev/null
+++ b/.changeset/projectable-key-guard-project.md
@@ -0,0 +1,8 @@
+---
+"effect-app": patch
+"@effect-app/infra": patch
+"@effect-app/vue": patch
+"@effect-app/vue-components": patch
+---
+
+Keep tag-aware `ProjectableFromDomain` for `projectComputed` only; restore loose key-presence guard for `project()` so view DTOs with reshaped fields keep typechecking.
diff --git a/packages/effect-app/src/Model/query/dsl.ts b/packages/effect-app/src/Model/query/dsl.ts
index 86a1c8d60..8cbd7b166 100644
--- a/packages/effect-app/src/Model/query/dsl.ts
+++ b/packages/effect-app/src/Model/query/dsl.ts
@@ -153,6 +153,16 @@ export type ProjectableFromDomain<
   ExtraKeys extends PropertyKey = never
 > = ProjectableGuard<ProjectionEncoded, DomainEncoded, ExtraKeys>
 
+/**
+ * Loose key-presence guard for {@link project}: every projection key must exist
+ * on *some* domain member (`KeysOfUnion`). Does **not** enforce per-tag
+ * ownership — views may reshape freely. Use {@link ProjectableFromDomain} /
+ * `projectComputed` when tag-scoped ownership matters.
+ */
+type ProjectableKeyGuard<I, From> = [I] extends [FieldValues]
+  ? (Exclude<keyof I, KeysOfUnion<From> | "_tag"> extends never ? unknown : never)
+  : unknown
+
 export type RelationDirection = "some" | "every"
 export type Relation = { relation: RelationDirection }
 export type Query<TFieldValues extends FieldValues> = QueryTogether<TFieldValues, TFieldValues>
@@ -606,7 +616,7 @@ export const project: {
   >(
     schema:
       & S.Codec<Option.Option<A>, I, R>
-      & ProjectableGuard<I, ExtractFieldValues<Q>>,
+      & ProjectableKeyGuard<I, ExtractFieldValues<Q>>,
     mode: "collect"
   ): (
     current: Q
@@ -621,7 +631,7 @@ export const project: {
   >(
     schema:
       & S.Codec<A, I, R>
-      & ProjectableGuard<I, ExtractFieldValues<Q>>,
+      & ProjectableKeyGuard<I, ExtractFieldValues<Q>>,
     mode: "project"
   ): (
     current: Q
@@ -635,7 +645,7 @@ export const project: {
   >(
     schema:
       & S.Codec<A, I, R>
-      & ProjectableGuard<I, ExtractFieldValues<Q>>
+      & ProjectableKeyGuard<I, ExtractFieldValues<Q>>
   ): (
     current: Q
   ) => QueryProjection<ExtractFieldValuesRefined<Q>, A, R, ExtractTType<Q>, E>