[PATCH v2 0/3] Filter alternate references

[Taylor Blau <me@ttaylorr.com>]

Hi,

Attached is the second re-roll of my series to teach
"core.alternateRefsCommand" and "core.alternateRefsPrefixes".

I have included a range-diff below (which I have taught my scripts to do
by default now), but will summarize the changes as usual:

  * Clean up t5410 according to Peff's suggestions in [1]:

    * Simplify many `git update-ref -d`'s into one `git update-ref
      --stdin`.

    * Use `echo >`, instead of `printf >` to write an alternate
      repository.

    * Avoid placing Git on the left-hand side of a pipe.

    * Use 'write_script', instead of embedding the same code in a
      lengthy 'test_config'.

  * Add a motivating example in Documentation/config.txt, per Peff's
    suggestion in [1].

  * Use `printf "%s .have\n"` with many arguments instead of another
    `cat <<-EOF` block and extract it into `expect_haves`, per [2].

  * Do not use `grep -o` in `extract_haves`, thus making it portable.
    Per [3].

[1]: https://public-inbox.org/git/20180920193751.GC29603@sigill.intra.peff.net/
[2]: https://public-inbox.org/git/CAPig+cT7WTyBCQZ75WSjmBqiui383YrKqoHqbLASQkOaGVTfVA@mail.gmail.com/
[3]: https://public-inbox.org/git/xmqqlg7ux0st.fsf@gitster-ct.c.googlers.com/

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

 Documentation/config.txt | 18 ++++++++++++
 t/t5410-receive-pack.sh  | 62 ++++++++++++++++++++++++++++++++++++++++
 transport.c              | 34 ++++++++++++++++++----
 3 files changed, 108 insertions(+), 6 deletions(-)
 create mode 100755 t/t5410-receive-pack.sh

Range-diff against v1:
1:  6e3a58afe7 = 1:  6e3a58afe7 transport.c: extract 'fill_alternate_refs_command'
2:  4c4900722c ! 2:  9797f52551 transport.c: introduce core.alternateRefsCommand
    @@ -42,6 +42,11 @@
     +	the shell to execute the specified command instead of
     +	linkgit:git-for-each-ref[1]. The first argument is the path of the alternate.
     +	Output must be of the form: `%(objectname) SPC %(refname)`.
    +++
    ++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 refs/heads`.
     +
      core.bare::
      	If true this repository is assumed to be 'bare' and has no
    @@ -70,32 +75,39 @@
     +	(
     +		cd fork &&
     +		git config receive.advertisealternates true &&
    -+		git update-ref -d refs/heads/a &&
    -+		git update-ref -d refs/heads/b &&
    -+		git update-ref -d refs/heads/c &&
    -+		git update-ref -d refs/heads/master &&
    -+		git update-ref -d refs/tags/one &&
    -+		git update-ref -d refs/tags/two &&
    -+		git update-ref -d refs/tags/three &&
    -+		printf "../../.git/objects" >objects/info/alternates
    ++		cat <<-EOF | git update-ref --stdin &&
    ++		delete refs/heads/a
    ++		delete refs/heads/b
    ++		delete refs/heads/c
    ++		delete refs/heads/master
    ++		delete refs/tags/one
    ++		delete refs/tags/two
    ++		delete refs/tags/three
    ++		EOF
    ++		echo "../../.git/objects" >objects/info/alternates
     +	)
     +'
     +
    ++expect_haves () {
    ++	printf "%s .have\n" $(git rev-parse $@) >expect
    ++}
    ++
     +extract_haves () {
    -+	depacketize - | grep -o '^.* \.have'
    ++	depacketize - | grep '\.have' | sed -e 's/\\0.*$//g'
     +}
     +
     +test_expect_success 'with core.alternateRefsCommand' '
    -+	test_config -C fork core.alternateRefsCommand \
    -+		"git --git-dir=\"\$1\" for-each-ref \
    -+		--format=\"%(objectname) %(refname)\" \
    -+		refs/heads/a refs/heads/c;:" &&
    -+	cat >expect <<-EOF &&
    -+	$(git rev-parse a) .have
    -+	$(git rev-parse c) .have
    ++	write_script fork/alternate-refs <<-\EOF &&
    ++		git --git-dir="$1" for-each-ref \
    ++			--format="%(objectname) %(refname)" \
    ++			refs/heads/a \
    ++			refs/heads/c
     +	EOF
    -+	printf "0000" | git receive-pack fork | extract_haves >actual &&
    -+	test_cmp expect actual
    ++	test_config -C fork core.alternateRefsCommand alternate-refs &&
    ++	expect_haves a c >expect &&
    ++	printf "0000" | git receive-pack fork >actual &&
    ++	extract_haves <actual >actual.haves &&
    ++	test_cmp expect actual.haves
     +'
     +
     +test_done
3:  3639e90588 ! 3:  6e8f65a16d transport.c: introduce core.alternateRefsPrefixes
    @@ -40,13 +40,14 @@
      --- a/Documentation/config.txt
      +++ b/Documentation/config.txt
     @@
    - 	linkgit:git-for-each-ref[1]. The first argument is the path of the alternate.
    - 	Output must be of the form: `%(objectname) SPC %(refname)`.
    + heads, configure `core.alternateRefsCommand` to the path of a script which runs
    + `git --git-dir="$1" for-each-ref refs/heads`.

     +core.alternateRefsPrefixes::
     +	When listing references from an alternate, list only references that begin
    -+	with the given prefix. To list multiple prefixes, separate them with a
    -+	whitespace character. If `core.alternateRefsCommand` is set, setting
    ++	with the given prefix. Prefixes match as if they were given as arguments to
    ++	linkgit:git-for-each-ref[1]. To list multiple prefixes, separate them with
    ++	whitespace. If `core.alternateRefsCommand` is set, setting
     +	`core.alternateRefsPrefixes` has no effect.
     +
      core.bare::
    @@ -57,18 +58,15 @@
      --- a/t/t5410-receive-pack.sh
      +++ b/t/t5410-receive-pack.sh
     @@
    - 	test_cmp expect actual
    + 	test_cmp expect actual.haves
      '

     +test_expect_success 'with core.alternateRefsPrefixes' '
     +	test_config -C fork core.alternateRefsPrefixes "refs/tags" &&
    -+	cat >expect <<-EOF &&
    -+	$(git rev-parse one) .have
    -+	$(git rev-parse three) .have
    -+	$(git rev-parse two) .have
    -+	EOF
    -+	printf "0000" | git receive-pack fork | extract_haves >actual &&
    -+	test_cmp expect actual
    ++	expect_haves one three two >expect &&
    ++	printf "0000" | git receive-pack fork >actual &&
    ++	extract_haves <actual >actual.haves &&
    ++	test_cmp expect actual.haves
     +'
     +
      test_done
--
2.19.0.221.g150f307af