From 61f024157f39808a2ff45789cf26742817e89d2b Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Tue, 31 Mar 2026 01:14:58 +0000
Subject: [PATCH 1/2] perf: reuse ResizeArray buffer in chunkBy and
 chunkByAsync

Previously, each time a new chunk was started in chunkBy/chunkByAsync,
a fresh ResizeArray was allocated. Since ToArray() already captures an
independent copy of the data, the internal buffer can be safely reused
by calling Clear() instead of constructing a new ResizeArray.

This eliminates one heap allocation per chunk boundary, reducing GC
pressure for sequences with many distinct runs.

5017 tests pass, 2 skipped.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 release-notes.txt                             | 1 +
 src/FSharp.Control.TaskSeq/TaskSeqInternal.fs | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/release-notes.txt b/release-notes.txt
index 7078840..9fb0961 100644
--- a/release-notes.txt
+++ b/release-notes.txt
@@ -2,6 +2,7 @@
 Release notes:
 
 1.0.0
+    - perf: TaskSeq.chunkBy and chunkByAsync reuse the ResizeArray buffer between chunks, reducing allocations on sequences with many chunk boundaries
     - fixes: TaskSeq.insertAt, insertManyAt, removeAt, removeManyAt, updateAt now raise ArgumentNullException (not NullReferenceException) when given a null source; insertManyAt also validates the values argument
     - refactor: simplify lengthBy and lengthBeforeMax to use while! and remove the redundant mutable 'go' and initial MoveNextAsync
     - adds TaskSeq.distinctUntilChangedWith and TaskSeq.distinctUntilChangedWithAsync, #345
diff --git a/src/FSharp.Control.TaskSeq/TaskSeqInternal.fs b/src/FSharp.Control.TaskSeq/TaskSeqInternal.fs
index cc279c1..261dbba 100644
--- a/src/FSharp.Control.TaskSeq/TaskSeqInternal.fs
+++ b/src/FSharp.Control.TaskSeq/TaskSeqInternal.fs
@@ -1754,7 +1754,7 @@ module internal TaskSeqInternal =
                         currentChunk.Add item
                     else
                         yield prevKey, currentChunk.ToArray()
-                        currentChunk <- ResizeArray<'T>()
+                        currentChunk.Clear() // reuse backing array; ToArray() already captured a snapshot
                         currentChunk.Add item
                         maybeCurrentKey <- ValueSome key
 
@@ -1782,7 +1782,7 @@ module internal TaskSeqInternal =
                         currentChunk.Add item
                     else
                         yield prevKey, currentChunk.ToArray()
-                        currentChunk <- ResizeArray<'T>()
+                        currentChunk.Clear() // reuse backing array; ToArray() already captured a snapshot
                         currentChunk.Add item
                         maybeCurrentKey <- ValueSome key
 

From 4ce009ba7f5eb2e7cc75353f8420fd5816677ac5 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Tue, 31 Mar 2026 01:15:01 +0000
Subject: [PATCH 2/2] ci: trigger checks