[5.1.x] Fixed #36298 -- Truncated the overwritten file content in file_move_safe().

Regression in 58cd4902a71a3695dd6c21dc957f59c333db364c.

Thanks Baptiste Mispelon for the report.

Backport of 8ad3e80e88201f4c557f6fa79fcfc0f8a0961830 from main.

3 files changed, 32 insertions, 0 deletions

diff --git a/docs/releases/4.2.21.txt b/docs/releases/4.2.21.txt
new file mode 100644
index 0000000000..36e24df12f
--- /dev/null
+++ b/docs/releases/4.2.21.txt
@@ -0,0 +1,15 @@
+===========================
+Django 4.2.21 release notes
+===========================
+
+*Expected May 7, 2025*
+
+Django 4.2.21 fixes a data loss bug in 4.2.20.
+
+Bugfixes
+========
+
+* Fixed a data corruption possibility in ``file_move_safe()`` when
+  ``allow_overwrite=True``, where leftover content from a previously larger
+  file could remain after overwriting with a smaller one due to lack of
+  truncation (:ticket:`36298`).
diff --git a/docs/releases/5.1.9.txt b/docs/releases/5.1.9.txt
new file mode 100644
index 0000000000..6847aa9a2c
--- /dev/null
+++ b/docs/releases/5.1.9.txt
@@ -0,0 +1,15 @@
+==========================
+Django 5.1.9 release notes
+==========================
+
+*Expected May 7, 2025*
+
+Django 5.1.9 fixes a data loss bug in 5.1.8.
+
+Bugfixes
+========
+
+* Fixed a data corruption possibility in ``file_move_safe()`` when
+  ``allow_overwrite=True``, where leftover content from a previously larger
+  file could remain after overwriting with a smaller one due to lack of
+  truncation (:ticket:`36298`).
diff --git a/docs/releases/index.txt b/docs/releases/index.txt
index 3f7b52d86f..9c91a0a6f6 100644
--- a/docs/releases/index.txt
+++ b/docs/releases/index.txt
@@ -25,6 +25,7 @@ versions of the documentation contain the release notes for any later releases.
 .. toctree::
    :maxdepth: 1
 
+   5.1.9
    5.1.8
    5.1.7
    5.1.6
@@ -62,6 +63,7 @@ versions of the documentation contain the release notes for any later releases.
 .. toctree::
    :maxdepth: 1
 
+   4.2.21
    4.2.20
    4.2.19
    4.2.18