Fix dirty mid-computation when truncate was changed causing stale refs

Author: jerelmiller

src/cache/inmemory/__tests__/cache.diff/incremental.test.ts

@@ -2985,7 +2985,7 @@ test("returns the truncated stream array with complete items when truncation is
   });
 });
 
-test("invalidates a pruned stream array when truncation state changes", () => {
+test("invalidates a pruned stream array when the stream position changes", () => {
   const cache = new InMemoryCache();
   const query = gql`
     query {
@@ -2999,16 +2999,19 @@ test("invalidates a pruned stream array when truncation state changes", () => {
   const streamEntry = streamInfo.lookupArray(["friendList"]);
   streamEntry.state.streamPosition = 1;
 
-  cache.writeQuery({
-    query,
-    data: {
-      friendList: [
-        { __typename: "Friend", id: "1", name: "Luke" },
-        { __typename: "Friend", id: "2", name: "Han" },
-        { __typename: "Friend", id: "3", name: "Leia" },
-      ],
-    },
-  });
+  {
+    using _ = spyOnConsole("error");
+    cache.writeQuery({
+      query,
+      data: {
+        friendList: [
+          { __typename: "Friend", id: "1", name: "Luke" },
+          { __typename: "Friend", id: "2", name: "Han" },
+          { __typename: "Friend", id: "3" },
+        ],
+      },
+    });
+  }
 
   const diff = () =>
     cache.diff({
@@ -3018,16 +3021,6 @@ test("invalidates a pruned stream array when truncation state changes", () => {
       [handleIncrementalSymbol]: { streamInfo },
     });
 
-  expect(diff().result).toStrictEqualTyped({
-    friendList: [
-      { __typename: "Friend", id: "1", name: "Luke" },
-      { __typename: "Friend", id: "2", name: "Han" },
-      { __typename: "Friend", id: "3", name: "Leia" },
-    ],
-  });
-
-  streamEntry.state.truncate = true;
-
   expect(diff().result).toStrictEqualTyped({
     friendList: [{ __typename: "Friend", id: "1", name: "Luke" }],
   });

src/utilities/internal/StreamArrayState.ts

@@ -3,9 +3,9 @@ import { dep } from "optimism";
 import type { Incremental } from "@apollo/client/incremental";
 
 export class StreamArrayState {
-  private _streamPosition = 0;
-  private _truncate = false;
+  truncate = false;
 
+  private _streamPosition = 0;
   private path: Incremental.Path;
   private dep = dep<Incremental.Path>();
 
@@ -28,17 +28,6 @@ export class StreamArrayState {
     }
   }
 
-  get truncate() {
-    return this._truncate;
-  }
-
-  set truncate(value) {
-    if (value !== this._truncate) {
-      this._truncate = value;
-      this.dirty();
-    }
-  }
-
   private dirty() {
     this.dep.dirty(this.path);
   }