Commit message differs after applying a patch

[douniii]

• I was not able to find an open or closed issue matching what I'm seeing

Setup

• Which version of Git for Windows are you using? Is it 32-bit or 64-bit?

$ git --version --build-options

git version 2.31.1.windows.1
cpu: x86_64
built from commit: c5f0be26a7e3846e3b6268d1c6c4800d838c6bbb
sizeof-long: 4
sizeof-size_t: 8
shell-path: /bin/sh
feature: fsmonitor--daemon

• Which version of Windows are you running? Vista, 7, 8, 10? Is it 32-bit or 64-bit?

$ cmd.exe /c ver

Microsoft Windows [Version 10.0.19041.928]

• What options did you set as part of the installation? Or did you choose the
  defaults?

# One of the following:
> type "C:\Program Files\Git\etc\install-options.txt"
> type "C:\Program Files (x86)\Git\etc\install-options.txt"
> type "%USERPROFILE%\AppData\Local\Programs\Git\etc\install-options.txt"
$ cat /etc/install-options.txt

Editor Option: VIM
Custom Editor Path: 
Default Branch Option:  
Path Option: Cmd
SSH Option: OpenSSH
Tortoise Option: false
CURL Option: OpenSSL
CRLF Option: CRLFAlways
Bash Terminal Option: MinTTY
Git Pull Behavior Option: Merge
Use Credential Manager: Core
Performance Tweaks FSCache: Enabled
Enable Symlinks: Disabled
Enable Pseudo Console Support: Disabled

• Any other interesting things about your environment that might be related
  to the issue you're seeing?

None

Details

• Which terminal/shell are you running Git from? e.g Bash/CMD/PowerShell/other

Bash

• What commands did you run to trigger this issue? If you can provide a
  Minimal, Complete, and Verifiable example
  this will help us understand the issue.

In a empty folder:

git init
touch test.txt
git add *
git commit -m '[core] Adds new file'
git format-patch -M -1

Create another empty folder and copy the generated patch file in it

git init
git am *.patch
git log

• What did you expect to occur after running these commands?

In the second repository, in which the patch was applied, the commit message should be
[core] Adds new file, like in the first repository.

• What actually happened instead?

The commit message is Adds new file. So [core] was removed.

• If the problem was occurring with a specific repository, can you provide the
  URL to that repository to help us with testing?

No special repo.

[PhilipOakley]

Is this not an artefact of the [PATCH ..] application process where the initial [abcd...] is stripped from the patch subject?

[rimrul]

This is intentional behaviour. See git am --keep and git am --keep-non-patch.