From 3fa0afc12a0dc24c2721ebaf35ff324b0031221e Mon Sep 17 00:00:00 2001
From: Kris Nye <krisnye@gmail.com>
Date: Mon, 8 Jun 2026 11:52:30 -0700
Subject: [PATCH] feat(ecs): merge `imports` plugins at runtime (types still
 exclude them)
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Previously `imports` was type-only: the imported plugins' members were visible
to local declarations but contributed nothing at runtime, so a consumer that
forgot to re-list them in the top-level combine got `undefined` transactions/
resources at runtime despite a clean compile.

Now `imports` merges into the assembled plugin at runtime exactly like
`extends` (order: imports, then extends, then local — preserving service init
order). This is a pure runtime change: the result TYPE is unchanged and still
excludes the imported members, so the quadratic-killing property is preserved
(imports do not propagate through downstream result types). No type-signature
changes.

Adds "imports runtime behavior" tests proving imported members exist on the
assembled plugin and on a database built from it alone (no separate combine).
Updates docs that incorrectly stated the consumer must re-list imports.

Bump to 0.9.65.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 package.json                                  |  2 +-
 packages/data-lit-tictactoe/package.json      |  2 +-
 packages/data-lit-todo/package.json           |  2 +-
 packages/data-lit/package.json                |  2 +-
 packages/data-p2p-tictactoe/package.json      |  2 +-
 packages/data-persistence/package.json        |  2 +-
 packages/data-react-hello/package.json        |  2 +-
 packages/data-react-pixie/package.json        |  2 +-
 packages/data-react/package.json              |  2 +-
 packages/data-solid-dashboard/package.json    |  2 +-
 packages/data-solid/package.json              |  2 +-
 packages/data-sync/package.json               |  2 +-
 packages/data/package.json                    |  2 +-
 packages/data/scripts/typeperf/README.md      |  9 ++--
 .../src/ecs/database/create-plugin.test.ts    | 52 +++++++++++++++++++
 .../data/src/ecs/database/create-plugin.ts    | 20 ++++---
 .../ecs/database/imports-chain.type-test.ts   | 22 ++++----
 17 files changed, 94 insertions(+), 35 deletions(-)

diff --git a/package.json b/package.json
index 1079731..1e604b8 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "data-monorepo",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "private": true,
   "scripts": {
     "build": "pnpm -r run build",
diff --git a/packages/data-lit-tictactoe/package.json b/packages/data-lit-tictactoe/package.json
index 8b24078..c36aae6 100644
--- a/packages/data-lit-tictactoe/package.json
+++ b/packages/data-lit-tictactoe/package.json
@@ -1,6 +1,6 @@
 {
   "name": "data-lit-tictactoe",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "Tic-Tac-Toe sample - Lit web components with @adobe/data-lit and AgenticService",
   "type": "module",
   "private": true,
diff --git a/packages/data-lit-todo/package.json b/packages/data-lit-todo/package.json
index 1545f58..08fecab 100644
--- a/packages/data-lit-todo/package.json
+++ b/packages/data-lit-todo/package.json
@@ -1,6 +1,6 @@
 {
   "name": "data-lit-todo",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "Todo sample app demonstrating @adobe/data with Lit",
   "type": "module",
   "private": true,
diff --git a/packages/data-lit/package.json b/packages/data-lit/package.json
index ede5322..2f4271d 100644
--- a/packages/data-lit/package.json
+++ b/packages/data-lit/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@adobe/data-lit",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "Adobe data Lit bindings - hooks, elements, decorators",
   "type": "module",
   "private": false,
diff --git a/packages/data-p2p-tictactoe/package.json b/packages/data-p2p-tictactoe/package.json
index a4e15f4..a29b85c 100644
--- a/packages/data-p2p-tictactoe/package.json
+++ b/packages/data-p2p-tictactoe/package.json
@@ -1,6 +1,6 @@
 {
   "name": "data-p2p-tictactoe",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "Serverless P2P tic-tac-toe — WebRTC DataChannel + @adobe/data-sync",
   "type": "module",
   "private": true,
diff --git a/packages/data-persistence/package.json b/packages/data-persistence/package.json
index 5fd5d27..689bc70 100644
--- a/packages/data-persistence/package.json
+++ b/packages/data-persistence/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@adobe/data-persistence",
-    "version": "0.9.64",
+    "version": "0.9.65",
     "description": "Worker-based incremental persistence layer for @adobe/data ECS over OPFS (browser) and node:fs (server).",
     "type": "module",
     "sideEffects": false,
diff --git a/packages/data-react-hello/package.json b/packages/data-react-hello/package.json
index 4d2d39d..55248eb 100644
--- a/packages/data-react-hello/package.json
+++ b/packages/data-react-hello/package.json
@@ -1,6 +1,6 @@
 {
   "name": "data-react-hello",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "Hello World sample - click counter using @adobe/data-react",
   "type": "module",
   "private": true,
diff --git a/packages/data-react-pixie/package.json b/packages/data-react-pixie/package.json
index a8b5592..12308c1 100644
--- a/packages/data-react-pixie/package.json
+++ b/packages/data-react-pixie/package.json
@@ -1,6 +1,6 @@
 {
   "name": "data-react-pixie",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "PixiJS React sample - ECS sprites (bunny, fox) with @adobe/data-react",
   "type": "module",
   "private": true,
diff --git a/packages/data-react/package.json b/packages/data-react/package.json
index 96fa02d..fbf1b6a 100644
--- a/packages/data-react/package.json
+++ b/packages/data-react/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@adobe/data-react",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "Adobe data React bindings — hooks and context for ECS database",
   "type": "module",
   "private": false,
diff --git a/packages/data-solid-dashboard/package.json b/packages/data-solid-dashboard/package.json
index 7d5338a..1bd17b6 100644
--- a/packages/data-solid-dashboard/package.json
+++ b/packages/data-solid-dashboard/package.json
@@ -1,6 +1,6 @@
 {
   "name": "data-solid-dashboard",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "Mini dashboard sample — multiple components sharing one @adobe/data ECS database with SolidJS",
   "type": "module",
   "private": true,
diff --git a/packages/data-solid/package.json b/packages/data-solid/package.json
index 354f07f..19de146 100644
--- a/packages/data-solid/package.json
+++ b/packages/data-solid/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@adobe/data-solid",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "Adobe data SolidJS bindings — context and provider for ECS database",
   "type": "module",
   "private": false,
diff --git a/packages/data-sync/package.json b/packages/data-sync/package.json
index 4c65738..9f0c8df 100644
--- a/packages/data-sync/package.json
+++ b/packages/data-sync/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@adobe/data-sync",
-    "version": "0.9.64",
+    "version": "0.9.65",
     "description": "Multi-user real-time synchronisation for @adobe/data ECS — server, client, and in-process loopback.",
     "type": "module",
     "sideEffects": false,
diff --git a/packages/data/package.json b/packages/data/package.json
index c9dbae2..b186331 100644
--- a/packages/data/package.json
+++ b/packages/data/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@adobe/data",
-  "version": "0.9.64",
+  "version": "0.9.65",
   "description": "Adobe data oriented programming library",
   "type": "module",
   "sideEffects": false,
diff --git a/packages/data/scripts/typeperf/README.md b/packages/data/scripts/typeperf/README.md
index 5aeed1e..a8a2518 100644
--- a/packages/data/scripts/typeperf/README.md
+++ b/packages/data/scripts/typeperf/README.md
@@ -64,10 +64,10 @@ the knee.
 ## Result — `imports` vs `extends`
 
 `imports` makes ancestor types visible to local declarations **without**
-re-exporting them into the result type. Each link's result stays
-`O(local members)`, so the chain becomes **linear**; consumers compose the
-union once via `Database.Plugin.combine(...)`. Measured (TS 5.8.3,
-`node scripts/typeperf/measure.mjs extends imports`):
+re-exporting them into the result type (it still merges them at runtime, like
+`extends` — the difference is purely in the result type). Each link's result
+type stays `O(local members)`, so the chain becomes **linear**. Measured
+(TS 5.8.3, `node scripts/typeperf/measure.mjs extends imports`):
 
 | depth | extends (inst) | imports (inst) | speedup |
 |------:|---------------:|---------------:|--------:|
@@ -94,4 +94,3 @@ several ancestors imports a combined context
 per import site over local-only (O(1)) operands, so the total stays linear in
 total members as long as authors keep result types local — which `imports`
 enforces by construction.
-</content>
diff --git a/packages/data/src/ecs/database/create-plugin.test.ts b/packages/data/src/ecs/database/create-plugin.test.ts
index 9331e69..61f89a7 100644
--- a/packages/data/src/ecs/database/create-plugin.test.ts
+++ b/packages/data/src/ecs/database/create-plugin.test.ts
@@ -675,5 +675,57 @@ describe("Database.Plugin.create", () => {
             }).not.toThrow();
         });
     });
+
+    describe("imports runtime behavior", () => {
+        // `imports` differs from `extends` ONLY in the result type (imported
+        // members are not declared there — see imports-chain.type-test.ts).
+        // At runtime, imports merge into the assembled plugin exactly like
+        // extends, so the consumer does NOT have to re-list the imported plugin
+        // in the top-level combine for its members to exist.
+        const basePlugin = createPlugin({
+            resources: { baseScale: { default: 7 as number } },
+            transactions: {
+                setBaseScale: (_t, _input: { scale: number }) => { },
+            },
+        });
+
+        it("merges imported plugin members into the runtime plugin object", () => {
+            const featurePlugin = createPlugin({
+                imports: basePlugin,
+                resources: { featureFlag: { default: true as boolean } },
+            });
+            // Imported members are present on the assembled plugin at runtime...
+            expect((featurePlugin.resources as any).baseScale).toBeDefined();
+            expect((featurePlugin.transactions as any).setBaseScale).toBeDefined();
+            // ...alongside the local ones.
+            expect((featurePlugin.resources as any).featureFlag).toBeDefined();
+        });
+
+        it("imported members are usable on a database built from the plugin alone", () => {
+            const featurePlugin = createPlugin({
+                imports: basePlugin,
+                resources: { featureFlag: { default: true as boolean } },
+            });
+            // No separate combine(basePlugin, ...) — imports already merged.
+            const db = Database.create(featurePlugin);
+            expect((db.resources as any).baseScale).toBe(7);
+            expect(() => (db.transactions as any).setBaseScale({ scale: 9 })).not.toThrow();
+        });
+
+        it("merges imports first, then extends, then local declarations", () => {
+            const extendedBase = createPlugin({
+                resources: { fromExtends: { default: 1 as number } },
+            });
+            const combined = createPlugin({
+                imports: basePlugin,
+                extends: extendedBase,
+                resources: { fromLocal: { default: 2 as number } },
+            });
+            const r = combined.resources as any;
+            expect(r.baseScale).toBeDefined();   // from imports
+            expect(r.fromExtends).toBeDefined();  // from extends
+            expect(r.fromLocal).toBeDefined();    // local
+        });
+    });
 });
 
diff --git a/packages/data/src/ecs/database/create-plugin.ts b/packages/data/src/ecs/database/create-plugin.ts
index 89c9f32..faf33a6 100644
--- a/packages/data/src/ecs/database/create-plugin.ts
+++ b/packages/data/src/ecs/database/create-plugin.ts
@@ -247,13 +247,19 @@ export function createPlugin<
         systems: plugins.systems ?? {},
     };
 
-    // `imports` is a type-only contract: it makes the imported plugins' types
-    // visible to this plugin's local declarations without re-exporting them into
-    // the result. At runtime it contributes nothing — the consumer is responsible
-    // for actually including the imported plugins in the final
-    // `Database.Plugin.combine(...)`. Only `extends` merges at runtime.
-    if (plugins.extends) {
-        return combinePlugins(plugins.extends, plugin) as any;
+    // `imports` differs from `extends` only at the TYPE level: the imported
+    // plugins' members are NOT declared in this plugin's result type, so they
+    // don't propagate through downstream result types (the source of the
+    // quadratic `extends` blowup). At RUNTIME, however, imports merge in exactly
+    // like extends — so the imported components/resources/transactions/etc. are
+    // present in the assembled database without the consumer having to re-list
+    // them in the top-level combine. Order: imports first, then extends, then
+    // this plugin's own declarations (preserves service initialization order).
+    const bases: Database.Plugin[] = [];
+    if (plugins.imports) bases.push(plugins.imports);
+    if (plugins.extends) bases.push(plugins.extends);
+    if (bases.length > 0) {
+        return combinePlugins(...bases, plugin) as any;
     }
     return plugin as any;
 }
\ No newline at end of file
diff --git a/packages/data/src/ecs/database/imports-chain.type-test.ts b/packages/data/src/ecs/database/imports-chain.type-test.ts
index a26ed1d..2386a42 100644
--- a/packages/data/src/ecs/database/imports-chain.type-test.ts
+++ b/packages/data/src/ecs/database/imports-chain.type-test.ts
@@ -13,18 +13,18 @@ import type { True, False } from "../../types/types.js";
  *   - `extends`  — base types are visible to local declarations AND
  *                  re-exported into the result plugin's type.
  *   - `imports`  — base types are visible to local declarations ONLY;
- *                  they do NOT flow into the result plugin's type.
+ *                  they do NOT flow into the result plugin's TYPE.
  *
- * The result-type asymmetry is what keeps deep dependency graphs cheap: an
- * `imports` link's result stays O(local members) instead of accumulating the
- * full chain (see scripts/typeperf — `imports` is linear where `extends` is
- * quadratic in chain depth). The consumer reconstitutes the union once, at the
- * top, via `Database.Plugin.combine(...)`.
- *
- * These tests verify BOTH halves of that contract:
+ * The two merge identically at RUNTIME (both pull the base's members into the
+ * assembled plugin); they differ only in the result TYPE. That result-type
+ * asymmetry is what keeps deep dependency graphs cheap: an `imports` link's
+ * result type stays O(local members) instead of accumulating the full chain
+ * (see scripts/typeperf — `imports` is linear where `extends` is quadratic in
+ * chain depth). Runtime-merge behavior is covered by create-plugin.test.ts
+ * ("imports runtime behavior"); this file covers the type contract:
  *   1. Visibility — a plugin that `imports` a base gets FULL type safety on the
  *      base's components/resources/transactions (no weakening vs `extends`).
- *   2. Non-export — the imported members are absent from the result type.
+ *   2. Non-export — the imported members are absent from the result TYPE.
  */
 
 // ============================================================================
@@ -106,7 +106,9 @@ type _ExtendsReExportsComponent = True<'baseColor' extends keyof ExtendedResult[
 type _ExtendsReExportsTx = True<'setBaseColor' extends keyof ExtendedResult['transactions'] ? true : false>;
 
 // ============================================================================
-// 3. Consumer reconstitutes the union via combine — full DB is type-safe
+// 3. To regain the imported members in the TYPE, combine the base back in
+//    explicitly (runtime already merged them — this is purely to surface the
+//    base's members on the database type for the consumer).
 // ============================================================================
 
 function testCombinedUsage() {