git-validation barfs on gpg signature verification output of git log

[cevich]

We're having a repeated problem using this tool in containers/buildah where exit-codes are being returned without any corresponding error message. For example:

+ exec git-validation -v -run DCO,short-subject -range 2b32b824f81b4397f3082ed284d26f7e04b380a8..HEAD
time="2020-09-16T08:30:49-04:00" level=error msg="mm[git] cmd: \"git --no-pager log --pretty=format:%H 2b32b824f81b4397f3082ed284d26f7e04b380a8..HEAD\""
2020/09/16 08:30:49 exit status 128

If I execute that quoted git command locally in the repo., the tool exit(0). These are terribly difficult to debug...any assistance you could provide (even a clue where to look) would be extremely helpful.

[cevich]

Update: I was able to reproduce this, and the problem appears to be caused by gpg-signed commits:

$ make validate GITVALIDATE_FLAGS="-v -D"
make -C tests/tools
make[1]: Entering directory '/home/cevich/devel/buildah/tests/tools'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/home/cevich/devel/buildah/tests/tools'

• exec git-validation -q -run DCO,short-subject -range 2b32b824f81b4397f3082ed284d26f7e04b380a8..HEAD -v -D
  2020/09/16 10:00:17 []validate.Rule{validate.Rule{Name:"DCO", Value:"", Description:"makes sure the commits are signed", Run:(func(validate.Rule, git.CommitEntry) validate.Result)(0x4ed1c0), Default:true}, validate.Rule{Name:"short-subject", Value:"", Description:"commit subjects are strictly less than 90 (github ellipsis length)", Run:(func(validate.Rule, git.CommitEntry) validate.Result)(0x4eda60), Default:true}}
  INFO[0000] [git] cmd: "git --no-pager log --pretty=format:%H 2b32b824f81b4397f3082ed284d26f7e04b380a8..HEAD"
  INFO[0000] [git] cmd: "git --no-pager log -1 --pretty=format:%GS gpg: Signature made Wed 16 Sep 2020 08:26:07 AM EDT"
  fatal: invalid object name 'gpg'.
  ERRO[0000] [git] cmd: "git --no-pager log -1 --pretty=format:%GS gpg: Signature made Wed 16 Sep 2020 08:26:07 AM EDT"
  2020/09/16 10:00:17 exit status 128
  make: *** [Makefile:97: validate] Error 1

[cevich]

Oh! There's the problem: git-validate is literally trying to execute (for example):

git --no-pager log -1 --pretty=format:%GS gpg: Signature made Wed 16 Sep 2020 08:26:07 AM EDT