Re: [PATCH v2 2/2] templates: detect commit messages containing diffs

On 13/02/2026 17:59, Junio C Hamano wrote:

Phillip Wood [off-list ref] writes:

quoted

From: Phillip Wood <redacted>

If the body of a commit message contains a diff that is not indented
then "git am" will treat that diff as part of the patch rather than
as part of the commit message. This allows it to apply email messages
that were created by adding a commit message in front of a regular diff
without adding the "---" separator used by "git format-patch". This
often surprises users [1-4] so add a check to the sample "commit-msg"
hook to reject messages that would confuse "git am". Even if a project
does not use an email based workflow it is not uncommon for people
to generate patches from it and apply them with "git am". Therefore
it is still worth discouraging the creation of commit messages that
would not be applied correctly.

A further source of confusion when applying patches with "git am" is
the "---" separator that is added by "git format patch". If a commit
message body contains that line then it will be truncated by "git am".
As this is often used by patch authors to add some commentary that
they do not want to end up in the commit message when the patch is
applied, the hook does not complain about the presence of "---" lines
in the message.

"git format match" -> "git format-patch".

Thanks (I was confused for a minute because it says "format patch" above 
not "format match" but you're pointing out that it should be hypenated)

quoted

The trailing ".*" when matching commented lines
ensures that if the comment string ends with a "$" it is not treated
as an anchor.

I am not sure what this means.  Wouldn't these three

	sed -e '/^#/d'
	sed -e '/^#.*/d'
	sed -e '/^#.*$/d'

work exactly the same way?

They do, but if the comment string is '$' then these two

	sed -e '/^$/d'
	sed -e '/^$.*/d'

have different meanings

Thanks

Phillip