[PATCH v3 0/3] send-email: add --mailmap support

I recently sent a series to enable mailmap support in format patch. The discussion led me to realize that the true problem we wanted solved is to map addresses at send time, so that we do not accidentally include a dead mail address when sending an old change.

Instead of worrying about what the formatted patch has, this series implements support for mailmap at the send-email, which will translate all addresses, and not just the author/commit addresses for a patch, but also the email for any trailers.o

Since v2, we now have a configuration option (sendemail.mailmap) to enable this behavior. In addition, I enabled support for email-specific mailmap files.

The intention of these is to allow a maintainer to map the known-dead addresses of former colleagues onto a current email for an owner within the team. This would be used to update the send addresses to avoid including no-longer-valid addresses when sending patches. This is intended for cases where the original author is no longer valid such as when they are no longer employed to work on the project. While sometimes pointing to a canonical public address of that person may make sense, in other contexts, removing them from the email makes sense.

I believe this version solves the use case we have of ensuring that we stop sending emails with invalid addresses, and may be useful for others as well.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
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Changes in v3:
- Edit description of patch 1 to clarify lack of validation of email
  addresses.
- Update tests for check-mailmap, removing the bogus contact tests entirely.
- Link to v2: https://lore.kernel.org/r/20240819-jk-send-email-mailmap-support-v2-0-d212c3f9e505@gmail.com

Changes in v2:
- Loosen restriction on git check-mailmap by default, rather than
  introducing a specific --no-brackets option.
- Re-write commit message for the send-email changes.
- Add --mailmap-file and --mailmap-blob options to git check-mailmap.
- Add configuration options to git send-email for enabling mailmap support
  by default, as well as providing send-email specific mailmap files.
- Link to v1: https://lore.kernel.org/r/20240816-jk-send-email-mailmap-support-v1-0-68ca5b4a6078@gmail.com
- Link to previous "v0": https://lore.kernel.org/r/20240813-jk-support-mailmap-git-format-patch-v1-1-1aea690ea5dd@gmail.com

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Jacob Keller (3):
      check-mailmap: accept "user@host" contacts
      check-mailmap: add options for additional mailmap sources
      send-email: add mailmap support via sendemail.mailmap and --mailmap

 mailmap.h                           |   7 +++
 builtin/check-mailmap.c             |  25 +++++---
 mailmap.c                           |   9 +--
 Documentation/git-check-mailmap.txt |  18 ++++--
 git-send-email.perl                 |  20 ++++++
 t/t4203-mailmap.sh                  |  42 +++++++++++--
 t/t9001-send-email.sh               | 122 ++++++++++++++++++++++++++++++++++++
 7 files changed, 222 insertions(+), 21 deletions(-)
---
base-commit: 87a1768b93a67d0420255a43d9e07387b2e805ad
change-id: 20240816-jk-send-email-mailmap-support-1a9e86867c72

Best regards,