From cd1454ede5558385f18831fc77689e59b3fc4de3 Mon Sep 17 00:00:00 2001
From: Mukul Kumar <mukulrao6480@gmail.com>
Date: Sat, 23 Aug 2025 18:59:44 +0530
Subject: [PATCH 1/4] added news for PR 7260

---
 NEWS.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index fc69449438..8156f0eed4 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -8,6 +8,8 @@
 
 1. `data.table(x=1, <expr>)`, where `<expr>` is an expression resulting in a 1-column matrix without column names, will eventually have names `x` and `V2`, not `x` and `V1`, consistent with `data.table(x=1, <expr>)` where `<expr>` results in an atomic vector, for example `data.table(x=1, cbind(1))` and `data.table(x=1, 1)` will both have columns named `x` and `V2`. In this release, the matrix case continues to be named `V1`, but the new behavior can be activated by setting `options(datatable.old.matrix.autoname)` to `FALSE`. See point 5 under Bug Fixes for more context; this change will provide more internal consistency as well as more consistency with `data.frame()`.
 
+2. `dcast()` now errors when `fun.aggregate` returns length != 1, regardless of `fill` ([#6629](https://github.com/Rdatatable/data.table/issues/6629),[#6032](https://github.com/Rdatatable/data.table/issues/6032)). Previously, when `fill` was not `NULL`, `dcast` warned and returned an undefined result. Updated code to use a scalar-returning aggregator instead of identity or functions that return vectors.
+
 ### NEW FEATURES
 
 1. New `sort_by()` method for data.tables, [#6662](https://github.com/Rdatatable/data.table/issues/6662). It uses `forder()` to improve upon the data.frame method and also matches `DT[order(...)]` behavior with respect to locale. Thanks @rikivillalba for the suggestion and PR.

From 9dd07296ef63d32ec4e6a3b9a3334b2399e48e6e Mon Sep 17 00:00:00 2001
From: Mukul <145585624+Mukulyadav2004@users.noreply.github.com>
Date: Mon, 25 Aug 2025 22:53:41 +0530
Subject: [PATCH 2/4] Revise breaking changes news

Updated breaking changes and new features in NEWS.md.
---
 NEWS.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index 8156f0eed4..a9d3ce4292 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -8,7 +8,8 @@
 
 1. `data.table(x=1, <expr>)`, where `<expr>` is an expression resulting in a 1-column matrix without column names, will eventually have names `x` and `V2`, not `x` and `V1`, consistent with `data.table(x=1, <expr>)` where `<expr>` results in an atomic vector, for example `data.table(x=1, cbind(1))` and `data.table(x=1, 1)` will both have columns named `x` and `V2`. In this release, the matrix case continues to be named `V1`, but the new behavior can be activated by setting `options(datatable.old.matrix.autoname)` to `FALSE`. See point 5 under Bug Fixes for more context; this change will provide more internal consistency as well as more consistency with `data.frame()`.
 
-2. `dcast()` now errors when `fun.aggregate` returns length != 1, regardless of `fill` ([#6629](https://github.com/Rdatatable/data.table/issues/6629),[#6032](https://github.com/Rdatatable/data.table/issues/6032)). Previously, when `fill` was not `NULL`, `dcast` warned and returned an undefined result. Updated code to use a scalar-returning aggregator instead of identity or functions that return vectors.
+### BREAKING CHANGE
+1. `dcast()` now errors when `fun.aggregate` returns length != 1 (consistent with documentation), regardless of `fill` ([#6629](https://github.com/Rdatatable/data.table/issues/6629),[#6032](https://github.com/Rdatatable/data.table/issues/6032)). Previously, when `fill` was not `NULL`, `dcast` warned and returned an undefined result. This change has been planned since 1.16.0 (25 Aug 2024).
 
 ### NEW FEATURES
 

From 1946705861b49d7eadfe9f0e0192faad8287a30b Mon Sep 17 00:00:00 2001
From: Mukul <145585624+Mukulyadav2004@users.noreply.github.com>
Date: Tue, 26 Aug 2025 00:21:18 +0530
Subject: [PATCH 3/4] Improve news

Co-authored-by: Toby Dylan Hocking <tdhock5@gmail.com>
---
 NEWS.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/NEWS.md b/NEWS.md
index a9d3ce4292..d840aca0db 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -9,6 +9,7 @@
 1. `data.table(x=1, <expr>)`, where `<expr>` is an expression resulting in a 1-column matrix without column names, will eventually have names `x` and `V2`, not `x` and `V1`, consistent with `data.table(x=1, <expr>)` where `<expr>` results in an atomic vector, for example `data.table(x=1, cbind(1))` and `data.table(x=1, 1)` will both have columns named `x` and `V2`. In this release, the matrix case continues to be named `V1`, but the new behavior can be activated by setting `options(datatable.old.matrix.autoname)` to `FALSE`. See point 5 under Bug Fixes for more context; this change will provide more internal consistency as well as more consistency with `data.frame()`.
 
 ### BREAKING CHANGE
+
 1. `dcast()` now errors when `fun.aggregate` returns length != 1 (consistent with documentation), regardless of `fill` ([#6629](https://github.com/Rdatatable/data.table/issues/6629),[#6032](https://github.com/Rdatatable/data.table/issues/6032)). Previously, when `fill` was not `NULL`, `dcast` warned and returned an undefined result. This change has been planned since 1.16.0 (25 Aug 2024).
 
 ### NEW FEATURES

From 279b24be84e294a9e8cc1184f2c0d603c92b05f1 Mon Sep 17 00:00:00 2001
From: Mukul <145585624+Mukulyadav2004@users.noreply.github.com>
Date: Tue, 26 Aug 2025 00:51:38 +0530
Subject: [PATCH 4/4] improve NEWS.md

Co-authored-by: Toby Dylan Hocking <tdhock5@gmail.com>
---
 NEWS.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index d840aca0db..0d044632dd 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -10,7 +10,7 @@
 
 ### BREAKING CHANGE
 
-1. `dcast()` now errors when `fun.aggregate` returns length != 1 (consistent with documentation), regardless of `fill` ([#6629](https://github.com/Rdatatable/data.table/issues/6629),[#6032](https://github.com/Rdatatable/data.table/issues/6032)). Previously, when `fill` was not `NULL`, `dcast` warned and returned an undefined result. This change has been planned since 1.16.0 (25 Aug 2024).
+1. `dcast()` now errors when `fun.aggregate` returns length != 1 (consistent with documentation), regardless of `fill`, [#6629](https://github.com/Rdatatable/data.table/issues/6629). Previously, when `fill` was not `NULL`, `dcast` warned and returned an undefined result. This change has been planned since 1.16.0 (25 Aug 2024).
 
 ### NEW FEATURES
 
