feat(core): add session snapshot and revert system (#33226)

packages/schema/src/index.ts

@@ -12,6 +12,7 @@ export { Permission } from "./permission"
 export { Project } from "./project"
 export { Provider } from "./provider"
 export { Reference } from "./reference"
+export { Revert } from "./revert"
 export { Session } from "./session"
 export { SessionInput } from "./session-input"
 export { SessionMessage } from "./session-message"

packages/schema/src/revert.ts

@@ -0,0 +1,23 @@
+export * as Revert from "./revert"
+
+import { Schema } from "effect"
+import { NonNegativeInt, RelativePath } from "./schema"
+import { SessionMessageID } from "./session-message-id"
+
+export const FileDiff = Schema.Struct({
+  path: RelativePath,
+  status: Schema.Literals(["added", "modified", "deleted"]),
+  additions: NonNegativeInt,
+  deletions: NonNegativeInt,
+  patch: Schema.String,
+}).annotate({ identifier: "File.Diff" })
+export type FileDiff = typeof FileDiff.Type
+
+export const State = Schema.Struct({
+  messageID: SessionMessageID.ID,
+  partID: Schema.String.pipe(Schema.optional),
+  snapshot: Schema.String.pipe(Schema.optional),
+  diff: Schema.String.pipe(Schema.optional),
+  files: Schema.Array(FileDiff).pipe(Schema.optional),
+})
+export type State = typeof State.Type

packages/schema/src/session-event.ts

@@ -11,6 +11,7 @@ import { SessionID } from "./session-id"
 import { Location } from "./location"
 import { SessionMessageID } from "./session-message-id"
 import { SessionMessage } from "./session-message"
+import { Revert } from "./revert"
 
 export { FileAttachment }
 
@@ -176,6 +177,7 @@ export namespace Step {
         }),
       }),
       snapshot: Schema.String.pipe(Schema.optional),
+      files: Schema.Array(RelativePath).pipe(Schema.optional),
     },
   })
   export type Ended = typeof Ended.Type
@@ -429,6 +431,20 @@ export namespace Compaction {
   export type Ended = typeof Ended.Type
 }
 
+export namespace RevertEvent {
+  export const Staged = Event.define({
+    type: "session.next.revert.staged",
+    ...options,
+    schema: { ...Base, revert: Revert.State },
+  })
+  export const Cleared = Event.define({ type: "session.next.revert.cleared", ...options, schema: Base })
+  export const Committed = Event.define({
+    type: "session.next.revert.committed",
+    ...options,
+    schema: { ...Base, messageID: SessionMessageID.ID },
+  })
+}
+
 export const DurableDefinitions = Event.inventory(
   AgentSwitched,
   ModelSwitched,
@@ -455,6 +471,9 @@ export const DurableDefinitions = Event.inventory(
   Retried,
   Compaction.Started,
   Compaction.Ended,
+  RevertEvent.Staged,
+  RevertEvent.Cleared,
+  RevertEvent.Committed,
 )
 
 export const Definitions = Event.inventory(
@@ -487,6 +506,9 @@ export const Definitions = Event.inventory(
   Compaction.Started,
   Compaction.Delta,
   Compaction.Ended,
+  RevertEvent.Staged,
+  RevertEvent.Cleared,
+  RevertEvent.Committed,
 )
 
 export const Durable = Schema.Union(DurableDefinitions, { mode: "oneOf" }).pipe(Schema.toTaggedUnion("type"))

packages/schema/src/session-message.ts

@@ -4,7 +4,7 @@ import { Schema } from "effect"
 import { ProviderMetadata, ToolContent } from "./llm"
 import { Model } from "./model"
 import { FileAttachment, Prompt } from "./prompt"
-import { DateTimeUtcFromMillis } from "./schema"
+import { DateTimeUtcFromMillis, RelativePath } from "./schema"
 import { SessionID } from "./session-id"
 import { SessionMessageID } from "./session-message-id"
 
@@ -163,6 +163,7 @@ export const Assistant = Schema.Struct({
   snapshot: Schema.Struct({
     start: Schema.String.pipe(Schema.optional),
     end: Schema.String.pipe(Schema.optional),
+    files: Schema.Array(RelativePath).pipe(Schema.optional),
   }).pipe(Schema.optional),
   finish: Schema.String.pipe(Schema.optional),
   cost: Schema.Finite.pipe(Schema.optional),

packages/schema/src/session.ts

@@ -8,6 +8,7 @@ import { Project } from "./project"
 import { DateTimeUtcFromMillis, optionalOmitUndefined, RelativePath } from "./schema"
 import { SessionEvent } from "./session-event"
 import { SessionID } from "./session-id"
+import { Revert } from "./revert"
 
 export const ID = SessionID
 export type ID = SessionID
@@ -39,6 +40,7 @@ export const Info = Schema.Struct({
   title: Schema.String,
   location: Location.Ref,
   subpath: RelativePath.pipe(Schema.optional),
+  revert: Revert.State.pipe(Schema.optional),
 }).annotate({ identifier: "SessionV2.Info" })
 
 export const ListAnchor = Schema.Struct({