fix the compat between v3 and v4

dump/src/reader/compat/snapshots/dump__reader__compat__v3_to_v4__test__compat_v3_v4-2.snap

@@ -22,7 +22,7 @@ expression: tasks
     ]
   },
   {
-    "id": 0,
+    "id": 1,
     "index_uid": "movies",
     "content": {
       "DocumentAddition": {
@@ -53,7 +53,7 @@ expression: tasks
     ]
   },
   {
-    "id": 1,
+    "id": 2,
     "index_uid": "movies",
     "content": {
       "SettingsUpdate": {
@@ -86,7 +86,7 @@ expression: tasks
     ]
   },
   {
-    "id": 2,
+    "id": 3,
     "index_uid": "movies",
     "content": {
       "SettingsUpdate": {
@@ -121,7 +121,7 @@ expression: tasks
     ]
   },
   {
-    "id": 3,
+    "id": 4,
     "index_uid": "movies",
     "content": {
       "DocumentAddition": {
@@ -152,7 +152,7 @@ expression: tasks
     ]
   },
   {
-    "id": 0,
+    "id": 5,
     "index_uid": "products",
     "content": {
       "SettingsUpdate": {
@@ -193,7 +193,7 @@ expression: tasks
     ]
   },
   {
-    "id": 1,
+    "id": 6,
     "index_uid": "products",
     "content": {
       "DocumentAddition": {
@@ -225,7 +225,7 @@ expression: tasks
     ]
   },
   {
-    "id": 2,
+    "id": 7,
     "index_uid": "products",
     "content": {
       "DocumentAddition": {
@@ -256,7 +256,7 @@ expression: tasks
     ]
   },
   {
-    "id": 0,
+    "id": 8,
     "index_uid": "dnd_spells",
     "content": {
       "DocumentAddition": {
@@ -288,7 +288,7 @@ expression: tasks
     ]
   },
   {
-    "id": 1,
+    "id": 9,
     "index_uid": "dnd_spells",
     "content": {
       "DocumentAddition": {

dump/src/reader/compat/v3_to_v4.rs

@@ -67,7 +67,10 @@ impl CompatV3ToV4 {
 
         Box::new(
             tasks
-                .map(move |task| {
+                // we need to override the old task ids that were generated
+                // by index in favor of a global unique incremental ID.
+                .enumerate()
+                .map(move |(task_id, task)| {
                     task.map(|(task, content_file)| {
                         let index_uid = indexes
                             .iter()
@@ -97,7 +100,7 @@ impl CompatV3ToV4 {
                         };
 
                         let task = v4::Task {
-                            id: task.update.id() as u32,
+                            id: task_id as u32,
                             index_uid: v4::meta::IndexUid(index_uid),
                             content: match task.update.meta() {
                                 v3::Kind::DeleteDocuments(documents) => {