Merge branch 'hi/gpg-prefer-check-signature'

The code to interface with GnuPG has been refactored.

* hi/gpg-prefer-check-signature:
  gpg-interface: prefer check_signature() for GPG verification
  t: increase test coverage of signature verification output

diff --cc log-tree.c
Simple merge

diff --cc t/t4202-log.sh
index 0f766ba65f598c105bbce6f8f3aa2d4cda1c0de3,28145fe92638cfe6b1e372e19ea06971f539b5dc..5eeb739f3ed4bb44a8951fb223445ead15dc61c8
--- 1/t/t4202-log.sh
--- 2/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@@ -1607,26 -1607,66 +1607,86 @@@ test_expect_success GPG 'log --graph --
        grep "^| | gpg: Good signature" actual
  '
  
 +test_expect_success GPG 'log --graph --show-signature for merged tag in shallow clone' '
 +      test_when_finished "git reset --hard && git checkout master" &&
 +      git checkout -b plain-shallow master &&
 +      echo aaa >bar &&
 +      git add bar &&
 +      git commit -m bar_commit &&
 +      git checkout --detach master &&
 +      echo bbb >baz &&
 +      git add baz &&
 +      git commit -m baz_commit &&
 +      git tag -s -m signed_tag_msg signed_tag_shallow &&
 +      hash=$(git rev-parse HEAD) &&
 +      git checkout plain-shallow &&
 +      git merge --no-ff -m msg signed_tag_shallow &&
 +      git clone --depth 1 --no-local . shallow &&
 +      test_when_finished "rm -rf shallow" &&
 +      git -C shallow log --graph --show-signature -n1 plain-shallow >actual &&
 +      grep "tag signed_tag_shallow names a non-parent $hash" actual
 +'
 +
+ test_expect_success GPG 'log --graph --show-signature for merged tag with missing key' '
+       test_when_finished "git reset --hard && git checkout master" &&
+       git checkout -b plain-nokey master &&
+       echo aaa >bar &&
+       git add bar &&
+       git commit -m bar_commit &&
+       git checkout -b tagged-nokey master &&
+       echo bbb >baz &&
+       git add baz &&
+       git commit -m baz_commit &&
+       git tag -s -m signed_tag_msg signed_tag_nokey &&
+       git checkout plain-nokey &&
+       git merge --no-ff -m msg signed_tag_nokey &&
+       GNUPGHOME=. git log --graph --show-signature -n1 plain-nokey >actual &&
+       grep "^|\\\  merged tag" actual &&
+       grep "^| | gpg: Signature made" actual &&
+       grep "^| | gpg: Can'"'"'t check signature: \(public key not found\|No public key\)" actual
+ '
+ 
+ test_expect_success GPG 'log --graph --show-signature for merged tag with bad signature' '
+       test_when_finished "git reset --hard && git checkout master" &&
+       git checkout -b plain-bad master &&
+       echo aaa >bar &&
+       git add bar &&
+       git commit -m bar_commit &&
+       git checkout -b tagged-bad master &&
+       echo bbb >baz &&
+       git add baz &&
+       git commit -m baz_commit &&
+       git tag -s -m signed_tag_msg signed_tag_bad &&
+       git cat-file tag signed_tag_bad >raw &&
+       sed -e "s/signed_tag_msg/forged/" raw >forged &&
+       git hash-object -w -t tag forged >forged.tag &&
+       git checkout plain-bad &&
+       git merge --no-ff -m msg "$(cat forged.tag)" &&
+       git log --graph --show-signature -n1 plain-bad >actual &&
+       grep "^|\\\  merged tag" actual &&
+       grep "^| | gpg: Signature made" actual &&
+       grep "^| | gpg: BAD signature from" actual
+ '
+ 
+ test_expect_success GPG 'log --show-signature for merged tag with GPG failure' '
+       test_when_finished "git reset --hard && git checkout master" &&
+       git checkout -b plain-fail master &&
+       echo aaa >bar &&
+       git add bar &&
+       git commit -m bar_commit &&
+       git checkout -b tagged-fail master &&
+       echo bbb >baz &&
+       git add baz &&
+       git commit -m baz_commit &&
+       git tag -s -m signed_tag_msg signed_tag_fail &&
+       git checkout plain-fail &&
+       git merge --no-ff -m msg signed_tag_fail &&
+       TMPDIR="$(pwd)/bogus" git log --show-signature -n1 plain-fail >actual &&
+       grep "^merged tag" actual &&
+       grep "^No signature" actual &&
+       ! grep "^gpg: Signature made" actual
+ '
+ 
  test_expect_success GPGSM 'log --graph --show-signature for merged tag x509' '
        test_when_finished "git reset --hard && git checkout master" &&
        test_config gpg.format x509 &&