Bug: signed commits vs. git-fast-export

Some repositories contain signed commits. "git fast-export" silently skips them. This breaks "git filter-repo".

Example:

$ git cat-file -p 7657709a2600849b69307a428314a8adb1d8a7f6 tree b73dbbcb8c0bb80197d82edaaa24a383bb80833c author eadali <erkanadali91@gmail.com> 1655729676 +0300 committer GitHub <noreply@github.com> 1655729676 +0300 gpgsig -----BEGIN PGP SIGNATURE-----

  wsBcBAABCAAQBQJisG4MCRBK7hj4Ov3rIwAAAvQIAAdcfZfwI8Cm3AHQhXRjEnv3
  r6lxOPDfH7vAbMeMS6/yUEZLQI2cVnWuKzUtTytH07aaNJ6kDc4FoigRp9Cnn0OV
  3uBSnm4UcpLlq41qD328L86+qBbHWHKzKANj1nK3ZQ2eLQkDkQ+Zi0ozypvxKHDm
  K1NNAvlTIc8kczgsfH9ORUin26qgMvjAT2vzdmhKLlHVeTzVNki6kenqq3zdUBOg
  7Veonvpy3SA5LnmPkCNs9s4qFW/PauThiFQ87W1kXFbSJ8hkFYKHOScIQ2kgy/0M
  c7Fh+jxSu+HCGLc2Uv3WYhtGbQNTD5+9VDV3FxWOS8IiVuj/kbCTeEi15xQ3sfY=
  =G6dA
  -----END PGP SIGNATURE-----

Initial commit [ no trailing newline ]

$ git fast-export --no-data 7657709a2600849b69307a428314a8adb1d8a7f6 --signed-tags=verbatim reset 7657709a2600849b69307a428314a8adb1d8a7f6 commit 7657709a2600849b69307a428314a8adb1d8a7f6 mark :1 author eadali <erkanadali91@gmail.com> 1655729676 +0300 committer GitHub <noreply@github.com> 1655729676 +0300 data 14 Initial commitM 100644 b6e47617de110dea7ca47e087ff1347cc2646eda .gitignore M 100644 ccc7a8c253e40cc08d9e4d122c1585d29edfc883 LICENSE M 100644 f65e27a64885c7bf563e0b6e974c0beaec16428c README.md

Oops, I see that current git already contains an option to control that. I should have checked more closely …

NB --signed-commits should probably default to whatever --signed-tags says, unless overridden.