Merge branch 'tb/filter-alternate-refs'

When pushing into a repository that borrows its objects from an
alternate object store, "git receive-pack" that responds to the
push request on the other side lists the tips of refs in the
alternate to reduce the amount of objects transferred.  This
sometimes is detrimental when the number of refs in the alternate
is absurdly large, in which case the bandwidth saved in potentially
fewer objects transferred is wasted in excessively large ref
advertisement.  The alternate refs that are advertised are now
configurable with a pair of configuration variables.

* tb/filter-alternate-refs:
  transport.c: introduce core.alternateRefsPrefixes
  transport.c: introduce core.alternateRefsCommand
  transport.c: extract 'fill_alternate_refs_command'
  transport: drop refnames from for_each_alternate_ref
This commit is contained in:
Junio C Hamano 2018-10-19 13:34:08 +09:00
commit 465e73fff3
6 changed files with 92 additions and 13 deletions

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@ -616,6 +616,24 @@ core.preferSymlinkRefs::
This is sometimes needed to work with old scripts that
expect HEAD to be a symbolic link.
core.alternateRefsCommand::
When advertising tips of available history from an alternate, use the shell to
execute the specified command instead of linkgit:git-for-each-ref[1]. The
first argument is the absolute path of the alternate. Output must contain one
hex object id per line (i.e., the same as produce by `git for-each-ref
--format='%(objectname)'`).
+
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.alternateRefsPrefixes::
When listing references from an alternate, list only references that begin
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::
If true this repository is assumed to be 'bare' and has no
working directory associated with it. If this is the case a

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@ -281,8 +281,7 @@ static int show_ref_cb(const char *path_full, const struct object_id *oid,
return 0;
}
static void show_one_alternate_ref(const char *refname,
const struct object_id *oid,
static void show_one_alternate_ref(const struct object_id *oid,
void *data)
{
struct oidset *seen = data;

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@ -76,8 +76,7 @@ struct alternate_object_cache {
size_t nr, alloc;
};
static void cache_one_alternate(const char *refname,
const struct object_id *oid,
static void cache_one_alternate(const struct object_id *oid,
void *vcache)
{
struct alternate_object_cache *cache = vcache;

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@ -0,0 +1,41 @@
#!/bin/sh
test_description='git receive-pack with alternate ref filtering'
. ./test-lib.sh
test_expect_success 'setup' '
test_commit base &&
git clone -s --bare . fork &&
git checkout -b public/branch master &&
test_commit public &&
git checkout -b private/branch master &&
test_commit private
'
extract_haves () {
depacketize | perl -lne '/^(\S+) \.have/ and print $1'
}
test_expect_success 'with core.alternateRefsCommand' '
write_script fork/alternate-refs <<-\EOF &&
git --git-dir="$1" for-each-ref \
--format="%(objectname)" \
refs/heads/public/
EOF
test_config -C fork core.alternateRefsCommand alternate-refs &&
git rev-parse public/branch >expect &&
printf "0000" | git receive-pack fork >actual &&
extract_haves <actual >actual.haves &&
test_cmp expect actual.haves
'
test_expect_success 'with core.alternateRefsPrefixes' '
test_config -C fork core.alternateRefsPrefixes "refs/heads/private" &&
git rev-parse private/branch >expect &&
printf "0000" | git receive-pack fork >actual &&
extract_haves <actual >actual.haves &&
test_cmp expect actual.haves
'
test_done

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@ -1370,6 +1370,33 @@ literal_copy:
return xstrdup(url);
}
static void fill_alternate_refs_command(struct child_process *cmd,
const char *repo_path)
{
const char *value;
if (!git_config_get_value("core.alternateRefsCommand", &value)) {
cmd->use_shell = 1;
argv_array_push(&cmd->args, value);
argv_array_push(&cmd->args, repo_path);
} else {
cmd->git_cmd = 1;
argv_array_pushf(&cmd->args, "--git-dir=%s", repo_path);
argv_array_push(&cmd->args, "for-each-ref");
argv_array_push(&cmd->args, "--format=%(objectname)");
if (!git_config_get_value("core.alternateRefsPrefixes", &value)) {
argv_array_push(&cmd->args, "--");
argv_array_split(&cmd->args, value);
}
}
cmd->env = local_repo_env;
cmd->out = -1;
}
static void read_alternate_refs(const char *path,
alternate_ref_fn *cb,
void *data)
@ -1378,12 +1405,7 @@ static void read_alternate_refs(const char *path,
struct strbuf line = STRBUF_INIT;
FILE *fh;
cmd.git_cmd = 1;
argv_array_pushf(&cmd.args, "--git-dir=%s", path);
argv_array_push(&cmd.args, "for-each-ref");
argv_array_push(&cmd.args, "--format=%(objectname) %(refname)");
cmd.env = local_repo_env;
cmd.out = -1;
fill_alternate_refs_command(&cmd, path);
if (start_command(&cmd))
return;
@ -1393,13 +1415,13 @@ static void read_alternate_refs(const char *path,
struct object_id oid;
if (get_oid_hex(line.buf, &oid) ||
line.buf[GIT_SHA1_HEXSZ] != ' ') {
line.buf[GIT_SHA1_HEXSZ]) {
warning(_("invalid line while parsing alternate refs: %s"),
line.buf);
break;
}
cb(line.buf + GIT_SHA1_HEXSZ + 1, &oid, data);
cb(&oid, data);
}
fclose(fh);

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@ -261,6 +261,6 @@ int transport_refs_pushed(struct ref *ref);
void transport_print_push_status(const char *dest, struct ref *refs,
int verbose, int porcelain, unsigned int *reject_reasons);
typedef void alternate_ref_fn(const char *refname, const struct object_id *oid, void *);
typedef void alternate_ref_fn(const struct object_id *oid, void *);
extern void for_each_alternate_ref(alternate_ref_fn, void *);
#endif