fix(core): release detached location graphs after reload

package.json

@@ -182,6 +182,7 @@
     "@ff-labs/fff-bun@0.10.5": "patches/@ff-labs%2Ffff-bun@0.10.5.patch",
     "ghostty-web@github:anomalyco/ghostty-web#83c0a07": "patches/ghostty-web@0.3.0.patch",
     "vite@8.2.2": "patches/vite@8.2.2.patch",
-    "@modelcontextprotocol/client@2.0.0": "patches/@modelcontextprotocol%2Fclient@2.0.0.patch"
+    "@modelcontextprotocol/client@2.0.0": "patches/@modelcontextprotocol%2Fclient@2.0.0.patch",
+    "effect@4.0.0-rc.112": "patches/effect@4.0.0-rc.112.patch"
   }
 }

packages/core/test/location-layer.test.ts

@@ -78,6 +78,52 @@ const itWithActivity = testEffect(
 )
 
 describe("LocationServiceMap", () => {
+  testEffect(Layer.empty).live("releases a reloaded graph after its last borrower without evicting its replacement", () =>
+    Effect.gen(function* () {
+      const builds = { started: 0 }
+      const finalized: number[] = []
+      const layer = AppNodeBuilder.build(LayerNode.group([Database.node, Bus.node, LocationServiceMap.node]), [
+        Global.node.replace(tempGlobalLayer),
+        offlineModels,
+        LocationWatcher.node.replace(
+          LocationWatcher.node.mapLayer((layer) =>
+            layer.pipe(
+              Layer.tap(() =>
+                Effect.gen(function* () {
+                  const build = ++builds.started
+                  yield* Effect.addFinalizer(() => Effect.sync(() => finalized.push(build)))
+                }),
+              ),
+            ),
+          ),
+        ),
+      ])
+      yield* Effect.gen(function* () {
+        const dir = yield* tmpdirScoped()
+        const ref = Location.Ref.make({ directory: AbsolutePath.make(dir.path) })
+        const locations = yield* LocationServiceMap.Service
+        const first = yield* Scope.make()
+        const second = yield* Scope.make()
+        yield* Effect.addFinalizer(() => Scope.close(first, Exit.void))
+        yield* Effect.addFinalizer(() => Scope.close(second, Exit.void))
+        yield* locations.contextEffect(ref).pipe(Scope.provide(first))
+        yield* locations.contextEffect(ref).pipe(Scope.provide(second))
+        yield* LocationServiceMap.reload()
+        const replacement = yield* locations.contextEffect(ref)
+        expect(builds.started).toBe(2)
+        expect(finalized).toEqual([])
+        yield* Scope.close(first, Exit.void)
+        expect(finalized).toEqual([])
+        yield* Scope.close(second, Exit.void)
+        expect(finalized).toEqual([1])
+        expect(yield* locations.contextEffect(ref)).toBe(replacement)
+        expect(builds.started).toBe(2)
+      }).pipe(Effect.provide(layer))
+      expect(finalized).toEqual([1, 2])
+    }),
+    60000,
+  )
+
   for (const failure of ["file", "permissions", "config reference"] as const) {
     for (const invalidate of [false, true]) {
       // The file-path fixture boots on Windows rather than failing during

patches/effect@4.0.0-rc.112.patch

@@ -0,0 +1,42 @@
+diff --git a/dist/RcMap.js b/dist/RcMap.js
+index 6e9a9ad04ec2c0fef0852cc0e6b3b1dba530a6f4..25941ed96695ef0272c2920fd6369848cdc03b0e 100644
+--- a/dist/RcMap.js
++++ b/dist/RcMap.js
+@@ -252,10 +252,12 @@ export const getOption = /*#__PURE__*/dual(2, (self, key) => Effect.uninterrupti
+ }));
+ const release = (self, key, entry) => Effect.withFiber(fiber => {
+   entry.refCount--;
++  const current = self.state._tag === "Open" ? MutableHashMap.get(self.state.map, key) : undefined;
++  const retained = current?._tag === "Some" && current.value === entry;
+   if (entry.refCount > 0) {
+     return Effect.void;
+-  } else if (self.state._tag === "Closed" || !MutableHashMap.has(self.state.map, key) || Duration.isZero(entry.idleTimeToLive)) {
+-    if (self.state._tag === "Open") {
++  } else if (self.state._tag === "Closed" || !retained || Duration.isZero(entry.idleTimeToLive)) {
++    if (self.state._tag === "Open" && retained) {
+       MutableHashMap.remove(self.state.map, key);
+     }
+     return Scope.close(entry.scope, Exit.void);
+diff --git a/src/RcMap.ts b/src/RcMap.ts
+index 67dcc147389a8fd0e8aae21b69ef58f44c295958..9c66319ddd58b0db3f84d7e5026210061e541013 100644
+--- a/src/RcMap.ts
++++ b/src/RcMap.ts
+@@ -736,14 +736,16 @@ export const getOption: {
+ const release = <K, A, E>(self: RcMap<K, A, E>, key: K, entry: State.Entry<A, E>) =>
+   Effect.withFiber((fiber) => {
+     entry.refCount--
++    const current = self.state._tag === "Open" ? MutableHashMap.get(self.state.map, key) : undefined
++    const retained = current?._tag === "Some" && current.value === entry
+     if (entry.refCount > 0) {
+       return Effect.void
+     } else if (
+       self.state._tag === "Closed"
+-      || !MutableHashMap.has(self.state.map, key)
++      || !retained
+       || Duration.isZero(entry.idleTimeToLive)
+     ) {
+-      if (self.state._tag === "Open") {
++      if (self.state._tag === "Open" && retained) {
+         MutableHashMap.remove(self.state.map, key)
+       }
+       return Scope.close(entry.scope, Exit.void)