Revert "Relax individual document revert constraints"

This reverts commit 6ce8ed4.

Author: wilhuff

packages/firestore/src/local/local_store.ts

@@ -458,6 +458,40 @@ export class LocalStore {
         }
       );
 
+      let changedDocKeys = documentKeySet();
+      remoteEvent.documentUpdates.forEach((key, doc) => {
+        changedDocKeys = changedDocKeys.add(key);
+        promises.push(
+          documentBuffer.getEntry(txn, key).next(existingDoc => {
+            // Make sure we don't apply an old document version to the remote
+            // cache, though we make an exception for SnapshotVersion.MIN which
+            // can happen for manufactured events (e.g. in the case of a limbo
+            // document resolution failing).
+            if (
+              existingDoc == null ||
+              doc.version.isEqual(SnapshotVersion.MIN) ||
+              doc.version.compareTo(existingDoc.version) >= 0
+            ) {
+              documentBuffer.addEntry(doc);
+            } else {
+              log.debug(
+                LOG_TAG,
+                'Ignoring outdated watch update for ',
+                key,
+                '. Current version:',
+                existingDoc.version,
+                ' Watch version:',
+                doc.version
+              );
+            }
+
+            // The document might be garbage because it was unreferenced by
+            // everything. Make sure to mark it as garbage if it is...
+            this.garbageCollector.addPotentialGarbageKey(key);
+          })
+        );
+      });
+
       // HACK: The only reason we allow a null snapshot version is so that we
       // can synthesize remote events when we get permission denied errors while
       // trying to resolve the state of a locally cached document that is in
@@ -477,13 +511,6 @@ export class LocalStore {
         );
       }
 
-      let changedDocKeys = documentKeySet();
-      remoteEvent.documentUpdates.forEach((key, doc) => {
-        changedDocKeys = changedDocKeys.add(key);
-        documentBuffer.addEntry(doc);
-        this.garbageCollector.addPotentialGarbageKey(key);
-      });
-
       let releasedWriteKeys: DocumentKeySet;
       return PersistencePromise.waitFor(promises)
         .next(() => this.releaseHeldBatchResults(txn, documentBuffer))