Hi,

Recently when I was submitting doc fixes to linux-doc mailing list [1]
using git-send-email(1), I got perl-related error:

Use of uninitialized value $address in sprintf at /home/bagas/.app/git/dist/v2.42.0/libexec/git-core/git-send-email line 1172.
error: unable to extract a valid address from:

My linux.git clone has sendemail-validate hook which uses patatt (from b4
package). The hook is:

#!/bin/sh
# installed by patatt install-hook
patatt sign --hook "${1}"

This issue occurs on Git v2.41.0 but not in v2.40.0. Bisecting, the culprit is
commit a8022c5f7b67 (send-email: expose header information to git-send-email's
sendemail-validate hook, 2023-04-19). Emily's earlier report [2] also points to
the same culprit, but with different bug.

I triggered this issue on patch series with cover letter. To reproduce:

1. Clone git.git repo, then branch off:

   $ git clone https://github.com/git/git.git && cd git
   $ git checkout -b test

2. Make two dummy signed-off commits:

   $ echo test > test && git add test && git commit -s -m "test"
   $ echo "test test" >> test && git commit -a -s -m "test test"

3. Generate patch series:

   $ mkdir /tmp/test
   $ git format-patch -o /tmp/test --cover-letter main

4. Send the series to dummy address:

   $ git send-email --to="pi <pi@pi>" /tmp/test/*.patch

git-send-email(1) trips on the cover letter since there is no recipient
addresses detected. It also errored out on patches without Signed-off-by
trailer. When the command should have been succeeded, I expected that it
asked me whether to send each patch or not.

My system runs Debian testing (trixie/sid) with perl 5.36.0.

Thanks.

[1]: https://lore.kernel.org/linux-doc/20230918093240.29824-1-bagasdotme@gmail.com/ (local)
[2]: https://lore.kernel.org/git/CAJoAoZ=GGgjGOeaeo6RFBO7=6msdRf-Ze6XcnL04K5ugupLUJA@mail.gmail.com/ (local)

-- 
An old man doll... just what I always wanted! - Clara