feat(core): persist v2 session context epochs (#30789)

packages/core/src/instruction-context.ts

@@ -0,0 +1,91 @@
+export * as InstructionContext from "./instruction-context"
+
+import { Array, Effect, Layer, Schema } from "effect"
+import { isAbsolute, join, relative, sep } from "path"
+import { FSUtil } from "./fs-util"
+import { Flag } from "./flag/flag"
+import { Global } from "./global"
+import { Location } from "./location"
+import { AbsolutePath } from "./schema"
+import { SystemContext } from "./system-context"
+import { SystemContextRegistry } from "./system-context-registry"
+
+class File extends Schema.Class<File>("InstructionContext.File")({
+  path: AbsolutePath,
+  content: Schema.String,
+}) {}
+
+const Files = Schema.Array(File)
+const key = SystemContext.Key.make("core/instructions")
+
+export const layer = Layer.effectDiscard(
+  Effect.gen(function* () {
+    const fs = yield* FSUtil.Service
+    const global = yield* Global.Service
+    const location = yield* Location.Service
+    const registry = yield* SystemContextRegistry.Service
+
+    const source = (value: ReadonlyArray<File> | SystemContext.Unavailable) =>
+      SystemContext.make({
+        key,
+        codec: Schema.toCodecJson(Files),
+        load: Effect.succeed(value),
+        baseline: render,
+        update: (_previous, current) => `These instructions replace all previously loaded ambient instructions.\n\n${render(current)}`,
+        removed: () => "Previously loaded instructions no longer apply.",
+      })
+
+    const observe = Effect.fn("InstructionContext.observe")(function* () {
+      const start = FSUtil.resolve(location.directory)
+      const stop = FSUtil.resolve(location.project.directory)
+      const fromProject = relative(stop, start)
+      const insideProject =
+        fromProject === "" || (fromProject !== ".." && !fromProject.startsWith(`..${sep}`) && !isAbsolute(fromProject))
+      const discovered = new Set(
+        (Flag.OPENCODE_DISABLE_PROJECT_CONFIG || !insideProject
+          ? []
+          : yield* fs.up({
+              targets: ["AGENTS.md"],
+              start,
+              stop,
+            })
+        ).map(FSUtil.resolve),
+      )
+      const paths = Array.dedupe([FSUtil.resolve(join(global.config, "AGENTS.md")), ...discovered])
+      const files = yield* Effect.forEach(
+        paths,
+        (path) =>
+          fs
+            .readFileStringSafe(path)
+            .pipe(
+              Effect.map((content) =>
+                content === undefined ? undefined : new File({ path: AbsolutePath.make(path), content }),
+              ),
+            ),
+        { concurrency: "unbounded" },
+      )
+      if (files.some((file, index) => file === undefined && discovered.has(paths[index])))
+        return SystemContext.unavailable
+      return files.filter((file): file is File => file !== undefined)
+    })
+
+    yield* registry.contribute({
+      key,
+      load: observe().pipe(
+        Effect.map((files) =>
+          files === SystemContext.unavailable
+            ? source(files)
+            : files.length === 0
+              ? SystemContext.empty
+              : source(files),
+        ),
+        Effect.catch(() => Effect.succeed(source(SystemContext.unavailable))),
+        Effect.catchDefect(() => Effect.succeed(source(SystemContext.unavailable))),
+      ),
+    })
+  }),
+)
+
+function render(files: ReadonlyArray<File>) {
+  return files.map((file) => `Instructions from: ${file.path}\n${file.content}`).join("\n\n")
+}