[PATCH v3 0/2] Add mailmap mechanism in cat-file options

Thanks a lot Avar for the review :) I have made the suggested changes.

= Description

At present, `git-cat-file` command with `--batch-check` and `-s` options does not complain when `--use-mailmap` option is given. The latter option is just ignored. Instead, for commit/tag objects, the command should compute the size of the object after replacing the idents and report it. So, this patch series makes `-s` and `--batch-check` options of `git-cat-file` honor mailmap when used with `--use-mailmap` option.

In this patch series we didn't want to change that '%(objectsize)' always shows the size of the original object even when `--use-mailmap` is set because first we have the long term plan to unify how the formats for `git cat-file` and other commands works. And second existing formats like the "pretty formats" used bt `git log` have different options for fields respecting mailmap or not respecting it (%an is for author name while %aN for author name respecting mailmap).

I would like to thank my mentors, Christian Couder and John Cai, for all of their help! Looking forward to the reviews!

= Patch Organization

- The first patch makes `-s` option to return updated size of the
  <commit/tag> object, when combined with `--use-mailmap` option, after
  replacing the idents using the mailmap mechanism.
- The second patch makes `--batch-check` option to return updated size of
  the <commit/tag> object, when combined with `--use-mailmap` option,
  after replacing the idents using the mailmap mechanism.

= Changes in v2:

- The commit messages of both the patches have been improved.
- In the second patch, we were populating the `contentp` field of the
  `object_info` structure when `--batch-check` was combined with
  `--use-mailmap`. Which made us read the contents of tree and blob
  object types as well, which affected the performance. We should only
  be reading the contents for commit or tag object types. The second
  patch has been updated to do just that.

= Changes in v3:

- Make the tests a bit more self documenting by running commands in test
  without using mailmap flag.
- In the first patch added the test for tag objects as well.

Siddharth Asthana (2):
  cat-file: add mailmap support to -s option
  cat-file: add mailmap support to --batch-check option

 Documentation/git-cat-file.txt |  6 +++-
 builtin/cat-file.c             | 27 ++++++++++++++++
 t/t4203-mailmap.sh             | 59 ++++++++++++++++++++++++++++++++++
 3 files changed, 91 insertions(+), 1 deletion(-)

Range-diff against v2:
-:  ---------- > 1:  4b0231504b cat-file: add mailmap support to -s option
1:  0e142beb2b ! 2:  2e87897fbb cat-file: add mailmap support to --batch-check option
    @@ builtin/cat-file.c: static void batch_object_write(const char *obj_name,
      	strbuf_reset(scratch);
     
      ## t/t4203-mailmap.sh ##
    -@@ t/t4203-mailmap.sh: test_expect_success 'git cat-file -s returns correct size with --use-mailmap' '
    +@@ t/t4203-mailmap.sh: test_expect_success 'git cat-file -s returns correct size with --use-mailmap for
      	test_cmp expect actual
      '
      
     +test_expect_success 'git cat-file --batch-check returns correct size with --use-mailmap' '
     +	test_when_finished "rm .mailmap" &&
    -+	cat >.mailmap <<-EOF &&
    ++	cat >.mailmap <<-\EOF &&
     +	C O Mitter <committer@example.com> Orig <orig@example.com>
     +	EOF
    -+	echo "92d99959b011b1cd69fe7be5315d6732fe302575 commit 220" >expect &&
    ++	cat >expect <<-\EOF &&
    ++	92d99959b011b1cd69fe7be5315d6732fe302575 commit 209
    ++	92d99959b011b1cd69fe7be5315d6732fe302575 commit 220
    ++	EOF
     +	echo "HEAD" >in &&
    -+	git cat-file --use-mailmap --batch-check <in >actual &&
    ++	git cat-file --batch-check <in >actual &&
    ++	git cat-file --use-mailmap --batch-check <in >>actual &&
     +	test_cmp expect actual
     +'
     +
     +test_expect_success 'git cat-file --batch-command returns correct size with --use-mailmap' '
     +	test_when_finished "rm .mailmap" &&
    -+	cat >.mailmap <<-EOF &&
    ++	cat >.mailmap <<-\EOF &&
     +	C O Mitter <committer@example.com> Orig <orig@example.com>
     +	EOF
    -+	echo "92d99959b011b1cd69fe7be5315d6732fe302575 commit 220" >expect &&
    ++	cat >expect <<-\EOF &&
    ++	92d99959b011b1cd69fe7be5315d6732fe302575 commit 209
    ++	92d99959b011b1cd69fe7be5315d6732fe302575 commit 220
    ++	EOF
     +	echo "info HEAD" >in &&
    -+	git cat-file --use-mailmap --batch-command <in >actual &&
    ++	git cat-file --batch-command <in >actual &&
    ++	git cat-file --use-mailmap --batch-command <in >>actual &&
     +	test_cmp expect actual
     +'
     +
2:  e95cbd7932 < -:  ---------- Add Test