fix(core): harden vcs backend lifecycle

packages/core/src/vcs/backends.ts

@@ -3,7 +3,7 @@ export * as VcsBackends from "./backends"
 import { Vcs } from "@opencode-ai/plugin/v2/effect"
 import { FileDiff } from "@opencode-ai/schema/file-diff"
 import { FileStatus } from "@opencode-ai/schema/vcs"
-import { Context, Effect, Exit, Layer, Option, Schema } from "effect"
+import { Cause, Context, Effect, Exit, Layer, Option, Schema } from "effect"
 import type { Scope } from "effect"
 import { ConfigVcs } from "../config/vcs"
 import { makeLocationNode } from "../effect/app-node"
@@ -46,8 +46,12 @@ const layer = Layer.effect(
               message: `Vcs backend '${backend.type}' is already registered`,
             })
           }
-          registry.set(backend.type, { backend })
-          yield* Effect.addFinalizer(() => Effect.sync(() => registry.delete(backend.type)))
+          yield* Effect.uninterruptible(
+            Effect.gen(function* () {
+              registry.set(backend.type, { backend })
+              yield* Effect.addFinalizer(() => Effect.sync(() => registry.delete(backend.type)))
+            }),
+          )
         }),
       get: (type) => {
         const vcs = location.vcsBackend
@@ -87,6 +91,7 @@ function sanitize<A>(type: string, operation: string, decode: (input: unknown) =
       Effect.exit,
       Effect.flatMap((exit) => {
         if (Exit.isFailure(exit)) {
+          if (Cause.hasInterrupts(exit.cause)) return Effect.failCause(exit.cause)
           return Effect.logWarning("vcs backend failed", { type, operation, cause: exit.cause }).pipe(
             Effect.as([] as readonly A[]),
           )

packages/core/test/vcs-backends.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect } from "bun:test"
-import { Effect, Exit, Layer, Scope } from "effect"
+import { Cause, Effect, Exit, Fiber, Layer, Scope } from "effect"
 import { Vcs as PluginVcs } from "@opencode-ai/plugin/v2/effect"
 import { LayerNode } from "@opencode-ai/core/effect/layer-node"
 import { Location } from "@opencode-ai/core/location"
@@ -116,6 +116,18 @@ describe("VcsBackends", () => {
     }).pipe(Effect.scoped, provide),
   )
 
+  it.live("preserves adapter interruption", () =>
+    Effect.gen(function* () {
+      yield* register(backend({ status: () => Effect.never }))
+      const vcs = yield* Vcs.Service
+      const fiber = yield* Effect.forkChild(vcs.status())
+      yield* Fiber.interrupt(fiber)
+      const exit = yield* Fiber.await(fiber)
+      expect(Exit.isFailure(exit)).toBe(true)
+      if (Exit.isFailure(exit)) expect(Cause.hasInterrupts(exit.cause)).toBe(true)
+    }).pipe(Effect.scoped, provide),
+  )
+
   it.live("drops rows that fail schema validation", () =>
     Effect.gen(function* () {
       yield* register(