setup aggregation number before connecting children

turbopack/crates/turbo-tasks-backend/src/backend/mod.rs

@@ -39,10 +39,10 @@ pub use self::{operation::AnyOperation, storage::TaskDataCategory};
 use crate::{
     backend::{
         operation::{
-            connect_children, get_aggregation_number, is_root_node, AggregatedDataUpdate,
-            AggregationUpdateJob, AggregationUpdateQueue, CleanupOldEdgesOperation,
-            ConnectChildOperation, ExecuteContext, ExecuteContextImpl, Operation, OutdatedEdge,
-            TaskDirtyCause, TaskGuard,
+            connect_children, get_aggregation_number, is_root_node, prepare_new_children,
+            AggregatedDataUpdate, AggregationUpdateJob, AggregationUpdateQueue,
+            CleanupOldEdgesOperation, ConnectChildOperation, ExecuteContext, ExecuteContextImpl,
+            Operation, OutdatedEdge, TaskDirtyCause, TaskGuard,
         },
         persisted_storage_log::PersistedStorageLog,
         storage::{get, get_many, get_mut, get_mut_or_insert_with, iter_many, remove, Storage},
@@ -1253,17 +1253,22 @@ impl<B: BackingStorage> TurboTasksBackendInner<B> {
         let mut removed_data = Vec::new();
         let mut old_edges = Vec::new();
 
-        // Connect children
-        {
-            for old_child in iter_many!(task, Child { task } => task) {
-                if !new_children.remove(&old_child) {
-                    old_edges.push(OutdatedEdge::Child(old_child));
-                }
-            }
+        // Prepare all new children
+        prepare_new_children(task_id, &mut task, &new_children, &mut queue);
 
-            let active_count =
-                get!(task, Activeness).map_or(0, |activeness| activeness.active_counter);
-            connect_children(task_id, &mut task, new_children, &mut queue, active_count);
+        // Filter actual new children
+        let mut kept_children = Vec::new();
+        for old_child in iter_many!(task, Child { task } => task) {
+            if !new_children.remove(&old_child) {
+                old_edges.push(OutdatedEdge::Child(old_child));
+            } else {
+                kept_children.push(old_child);
+            }
+        }
+        if !kept_children.is_empty() {
+            queue.push(AggregationUpdateJob::DecreaseActiveCounts {
+                task_ids: kept_children,
+            });
         }
 
         // Remove no longer existing cells and notify in progress cells
@@ -1323,7 +1328,7 @@ impl<B: BackingStorage> TurboTasksBackendInner<B> {
         drop(task);
 
         {
-            let _span = tracing::trace_span!("CleanupOldEdgesOperation").entered();
+            let _span = tracing::trace_span!("remove old edges and prepare new children").entered();
             // Remove outdated edges first, before removing in_progress+dirty flag.
             // We need to make sure all outdated edges are removed before the task can potentially
             // be scheduled and executed again
@@ -1334,6 +1339,52 @@ impl<B: BackingStorage> TurboTasksBackendInner<B> {
         // suspend in `CleanupOldEdgesOperation`), but that's ok as the task is still dirty and
         // would be executed again.
 
+        let mut task = ctx.task(task_id, TaskDataCategory::All);
+        let Some(in_progress) = get!(task, InProgress) else {
+            panic!("Task execution completed, but task is not in progress: {task:#?}");
+        };
+        let InProgressState::InProgress(box InProgressStateInner { stale, .. }) = in_progress
+        else {
+            panic!("Task execution completed, but task is not in progress: {task:#?}");
+        };
+
+        // If the task is stale, reschedule it
+        if *stale {
+            let Some(InProgressState::InProgress(box InProgressStateInner {
+                done_event,
+                new_children,
+                ..
+            })) = remove!(task, InProgress)
+            else {
+                unreachable!();
+            };
+            task.add_new(CachedDataItem::InProgress {
+                value: InProgressState::Scheduled { done_event },
+            });
+
+            // All `new_children` are currently hold active with an active count and we need to undo
+            // that.
+            AggregationUpdateQueue::run(
+                AggregationUpdateJob::DecreaseActiveCounts {
+                    task_ids: new_children.into_iter().collect(),
+                },
+                &mut ctx,
+            );
+            return true;
+        }
+
+        let mut queue = AggregationUpdateQueue::new();
+
+        let active_count = get!(task, Activeness).map_or(0, |activeness| activeness.active_counter);
+        connect_children(task_id, &mut task, new_children, &mut queue, active_count);
+
+        drop(task);
+
+        {
+            let _span = tracing::trace_span!("connect new children").entered();
+            queue.execute(&mut ctx);
+        }
+
         let mut task = ctx.task(task_id, TaskDataCategory::All);
         let Some(in_progress) = remove!(task, InProgress) else {
             panic!("Task execution completed, but task is not in progress: {task:#?}");

turbopack/crates/turbo-tasks-backend/src/backend/operation/connect_children.rs

@@ -1,21 +1,14 @@
-use std::{cmp::max, num::NonZeroU32};
-
 use rustc_hash::FxHashSet;
 use turbo_tasks::TaskId;
 
 use crate::{
-    backend::{
-        get,
-        operation::{
-            get_uppers, is_aggregating_node, is_root_node, AggregationUpdateJob,
-            AggregationUpdateQueue, TaskGuard,
-        },
+    backend::operation::{
+        get_aggregation_number, get_uppers, is_aggregating_node, AggregationUpdateJob,
+        AggregationUpdateQueue, TaskGuard,
     },
     data::CachedDataItem,
 };
 
-const AGGREGATION_NUMBER_BUFFER_SPACE: u32 = 3;
-
 pub fn connect_children(
     parent_task_id: TaskId,
     parent_task: &mut impl TaskGuard,
@@ -26,45 +19,8 @@ pub fn connect_children(
     if new_children.is_empty() {
         return;
     }
-    let children_count = new_children.len();
-
-    // Compute future parent aggregation number based on the number of children
-    let current_parent_aggregation = get!(parent_task, AggregationNumber)
-        .copied()
-        .unwrap_or_default();
-    let (parent_aggregation, future_parent_aggregation) =
-        if is_root_node(current_parent_aggregation.base) {
-            (u32::MAX, u32::MAX)
-        } else {
-            let target_distance = children_count.ilog2() * 2;
-            if target_distance > current_parent_aggregation.distance {
-                queue.push(AggregationUpdateJob::UpdateAggregationNumber {
-                    task_id: parent_task_id,
-                    base_aggregation_number: 0,
-                    distance: NonZeroU32::new(target_distance),
-                })
-            }
-            (
-                current_parent_aggregation.effective,
-                current_parent_aggregation
-                    .base
-                    .saturating_add(max(target_distance, current_parent_aggregation.distance)),
-            )
-        };
 
-    // When the parent is a leaf node, we need to increase the aggregation number of the children to
-    // be counting from the parent's aggregation number.
-    if !is_aggregating_node(future_parent_aggregation) {
-        let child_base_aggregation_number =
-            future_parent_aggregation + AGGREGATION_NUMBER_BUFFER_SPACE;
-        for &new_child in new_children.iter() {
-            queue.push(AggregationUpdateJob::UpdateAggregationNumber {
-                task_id: new_child,
-                base_aggregation_number: child_base_aggregation_number,
-                distance: None,
-            });
-        }
-    };
+    let parent_aggregation = get_aggregation_number(parent_task);
 
     for &new_child in new_children.iter() {
         parent_task.add_new(CachedDataItem::Child {

turbopack/crates/turbo-tasks-backend/src/backend/operation/mod.rs

@@ -3,6 +3,7 @@ mod cleanup_old_edges;
 mod connect_child;
 mod connect_children;
 mod invalidate;
+mod prepare_new_children;
 mod update_cell;
 mod update_collectible;
 mod update_output;
@@ -751,6 +752,7 @@ pub use self::{
     cleanup_old_edges::OutdatedEdge,
     connect_children::connect_children,
     invalidate::TaskDirtyCause,
+    prepare_new_children::prepare_new_children,
     update_cell::UpdateCellOperation,
     update_collectible::UpdateCollectibleOperation,
 };

turbopack/crates/turbo-tasks-backend/src/backend/operation/prepare_new_children.rs

@@ -0,0 +1,59 @@
+use std::{cmp::max, num::NonZeroU32};
+
+use rustc_hash::FxHashSet;
+use turbo_tasks::TaskId;
+
+use crate::backend::{
+    get,
+    operation::{
+        is_aggregating_node, is_root_node, AggregationUpdateJob, AggregationUpdateQueue, TaskGuard,
+    },
+};
+
+const AGGREGATION_NUMBER_BUFFER_SPACE: u32 = 3;
+
+pub fn prepare_new_children(
+    parent_task_id: TaskId,
+    parent_task: &mut impl TaskGuard,
+    new_children: &FxHashSet<TaskId>,
+    queue: &mut AggregationUpdateQueue,
+) {
+    if new_children.is_empty() {
+        return;
+    }
+    let children_count = new_children.len();
+
+    // Compute future parent aggregation number based on the number of children
+    let current_parent_aggregation = get!(parent_task, AggregationNumber)
+        .copied()
+        .unwrap_or_default();
+    let future_parent_aggregation = if is_root_node(current_parent_aggregation.base) {
+        u32::MAX
+    } else {
+        let target_distance = children_count.ilog2() * 2;
+        if target_distance > current_parent_aggregation.distance {
+            queue.push(AggregationUpdateJob::UpdateAggregationNumber {
+                task_id: parent_task_id,
+                base_aggregation_number: 0,
+                distance: NonZeroU32::new(target_distance),
+            })
+        }
+        current_parent_aggregation
+            .base
+            .saturating_add(max(target_distance, current_parent_aggregation.distance))
+    };
+
+    // When the parent is a leaf node, we need to increase the aggregation number of the children to
+    // be counting from the parent's aggregation number.
+    if !is_aggregating_node(future_parent_aggregation) {
+        let child_base_aggregation_number =
+            future_parent_aggregation + AGGREGATION_NUMBER_BUFFER_SPACE;
+        for &new_child in new_children.iter() {
+            queue.push(AggregationUpdateJob::UpdateAggregationNumber {
+                task_id: new_child,
+                base_aggregation_number: child_base_aggregation_number,
+                distance: None,
+            });
+        }
+    };
+}