Filter alternate references

Hi,

Attached is (what I anticipate to be) the final re-roll of my series to introduce 'core.alternateRefsCommand' and 'core.alternateRefsPrefixes' in order to limit the ".have" advertisement when pushing over protocol v1 to a repository with configured alternates.

Not much has changed from last time, expect for:

- Taking a documentation suggestion from Peff (in 3/4), and

- Fixing a typo pointed out by Ramsay (in 4/4).

I believe that this series is otherwise ready for queueing, if everyone else feels sufficiently OK about the changes.

Thanks in advance for your review.

Thanks,
Taylor

Jeff King (1):
transport: drop refnames from for_each_alternate_ref

Taylor Blau (3):
transport.c: extract 'fill_alternate_refs_command' transport.c: introduce core.alternateRefsCommand transport.c: introduce core.alternateRefsPrefixes

 Documentation/config.txt           | 18 +++++++++++++
 builtin/receive-pack.c             |  3 +--
 fetch-pack.c                       |  3 +--
 t/t5410-receive-pack-alternates.sh | 41 ++++++++++++++++++++++++++++++
 transport.c                        | 38 +++++++++++++++++++++------
 transport.h                        |  2 +-
 6 files changed, 92 insertions(+), 13 deletions(-)
 create mode 100755 t/t5410-receive-pack-alternates.sh

Range-diff against v4:

1:  76482a7eba = 1:  e4947f557b transport: drop refnames from for_each_alternate_ref
2:  120df009df = 2:  3d77a46c61 transport.c: extract 'fill_alternate_refs_command'
3:  c63864c89a ! 3:  7451b4872a transport.c: introduce core.alternateRefsCommand

@@ -42,14 +42,9 @@
+ hex object id per line (i.e., the same as produce by `git for-each-ref
+ --format='%(objectname)'`).
++
-+This is useful when a repository only wishes to advertise some of its -+alternate's references as .have's. For example, to only advertise branch -+heads, configure core.alternateRefsCommand to the path of a script which runs -+git --git-dir="$1" for-each-ref --format='%(objectname)' refs/heads.
-++
-+Note that the configured value is executed in a shell, and thus -+linkgit:git-for-each-ref[1] by itself does not work, as scripts have to handle -+the path argument specially.
++Note that you cannot generally put git for-each-ref directly into the config ++value, as it does not take a repository path as an argument (but you can wrap ++the command above in a shell script).
+
core.bare::
If true this repository is assumed to be 'bare' and has no
4: 0f6cdc7ea4 ! 4: 28cbbe63f7 transport.c: introduce core.alternateRefsPrefixes

    @@ -39,8 +39,8 @@
      --- a/Documentation/config.txt
      +++ b/Documentation/config.txt
     @@
    - linkgit:git-for-each-ref[1] by itself does not work, as scripts have to handle
    - the path argument specially.
    + value, as it does not take a repository path as an argument (but you can wrap
    + the command above in a shell script).

     +core.alternateRefsPrefixes::
     +	When listing references from an alternate, list only references that begin
    @@ -62,7 +62,7 @@

     +test_expect_success 'with core.alternateRefsPrefixes' '
     +	test_config -C fork core.alternateRefsPrefixes "refs/heads/private" &&
    -+	git rev-parse private/branch expect &&
    ++	git rev-parse private/branch >expect &&
     +	printf "0000" | git receive-pack fork >actual &&
     +	extract_haves <actual >actual.haves &&
     +	test_cmp expect actual.haves

--
2.19.0.221.g150f307af