Merge branch 'jk/trailers-placeholder-in-pretty'

In addition to %(subject), %(body), "log --pretty=format:..."
learned a new placeholder %(trailers).

* jk/trailers-placeholder-in-pretty:
ref-filter: add support to display trailers as part of contents
pretty: add %(trailers) format for displaying trailers of a commit message

diff --cc Documentation/git-for-each-ref.txt
Simple merge

diff --cc ref-filter.c
Simple merge

diff --cc t/t6300-for-each-ref.sh
index 039509a9cb94ef5c653df09e0453ac83157bf184,eb4bac0fe47785164e0f0bc3d1d0ea4aa5f452ff..aea1dfc7148e4885e52a579ca60ee622c49b5693
--- 1/t/t6300-for-each-ref.sh
--- 2/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@@ -554,13 -554,29 +554,38 @@@ test_expect_success 'Verify sort with m
        test_cmp expected actual
  '
  
 +test_expect_success 'do not dereference NULL upon %(HEAD) on unborn branch' '
 +      test_when_finished "git checkout master" &&
 +      git for-each-ref --format="%(HEAD) %(refname:short)" refs/heads/ >actual &&
 +      sed -e "s/^\* /  /" actual >expect &&
 +      git checkout --orphan HEAD &&
 +      git for-each-ref --format="%(HEAD) %(refname:short)" refs/heads/ >actual &&
 +      test_cmp expect actual
 +'
 +
+ cat >trailers <<EOF
+ Reviewed-by: A U Thor <author@example.com>
+ Signed-off-by: A U Thor <author@example.com>
+ EOF
+ 
+ test_expect_success 'basic atom: head contents:trailers' '
+       echo "Some contents" > two &&
+       git add two &&
+       git commit -F - <<-EOF &&
+       trailers: this commit message has trailers
+ 
+       Some message contents
+ 
+       $(cat trailers)
+       EOF
+       git for-each-ref --format="%(contents:trailers)" refs/heads/master >actual &&
+       sanitize_pgp <actual >actual.clean &&
+       # git for-each-ref ends with a blank line
+       cat >expect <<-EOF &&
+       $(cat trailers)
+ 
+       EOF
+       test_cmp expect actual.clean
+ '
+ 
  test_done