Currently we detect the hash algorithm in use by the length of the
object ID. This is inelegant and prevents us from using a different
hash algorithm that is also 256 bits in length.
Since we cannot extend the v2 format in a backward-compatible way, let's
add a v3 format, which is identical, except for the addition of
capabilities, which are prefixed by an at sign. We add "object-format"
as the only capability and reject unknown capabilities, since we do not
have a network connection and therefore cannot negotiate with the other
side.
For compatibility, default to the v2 format for SHA-1 and require v3
for SHA-256.
In t5510, always use format v3 so we can be sure we produce consistent
results across hash algorithms. Since head -n N lists the top N lines
instead of the Nth line, let's run our output through sed to normalize
it and compare it against a fixed value, which will make sure we get
exactly what we're expecting.
Signed-off-by: brian m. carlson <sandals@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/git-bundle.txt | 9 ++-
Documentation/technical/bundle-format.txt | 30 +++++++-
builtin/bundle.c | 5 +-
bundle.c | 85 +++++++++++++++++------
bundle.h | 4 +-
t/t5510-fetch.sh | 15 ++--
t/t5607-clone-bundle.sh | 31 +++++++++
7 files changed, 148 insertions(+), 31 deletions(-)
diff --git a/Documentation/git-bundle.txt b/Documentation/git-bundle.txt
index d34b0964be..53804cad4b 100644
--- a/Documentation/git-bundle.txt
+++ b/Documentation/git-bundle.txt
@@ -9,7 +9,8 @@ git-bundle - Move objects and refs by archive
SYNOPSIS
--------
[verse]
-'git bundle' create [-q | --quiet | --progress | --all-progress] [--all-progress-implied] <file> <git-rev-list-args>
+'git bundle' create [-q | --quiet | --progress | --all-progress] [--all-progress-implied]
+ [--version=<version>] <file> <git-rev-list-args>
'git bundle' verify [-q | --quiet] <file>
'git bundle' list-heads <file> [<refname>...]
'git bundle' unbundle <file> [<refname>...]
@@ -102,6 +103,12 @@ unbundle <file>::
is activated. Unlike --all-progress this flag doesn't actually
force any progress display by itself.
+--version=<version>::
+ Specify the bundle version. Version 2 is the older format and can only be
+ used with SHA-1 repositories; the newer version 3 contains capabilities that
+ permit extensions. The default is the oldest supported format, based on the
+ hash algorithm in use.
+
-q::
--quiet::
This flag makes the command not to report its progress
diff --git a/Documentation/technical/bundle-format.txt b/Documentation/technical/bundle-format.txt
index 0e828151a5..bac558d049 100644
--- a/Documentation/technical/bundle-format.txt
+++ b/Documentation/technical/bundle-format.txt
@@ -7,6 +7,8 @@ The Git bundle format is a format that represents both refs and Git objects.
We will use ABNF notation to define the Git bundle format. See
protocol-common.txt for the details.
+A v2 bundle looks like this:
+
----
bundle = signature *prerequisite *reference LF pack
signature = "# v2 git bundle" LF
@@ -18,9 +20,28 @@ reference = obj-id SP refname LF
pack = ... ; packfile
----
+A v3 bundle looks like this:
+
+----
+bundle = signature *capability *prerequisite *reference LF pack
+signature = "# v3 git bundle" LF
+
+capability = "@" key ["=" value] LF
+prerequisite = "-" obj-id SP comment LF
+comment = *CHAR
+reference = obj-id SP refname LF
+key = 1*(ALPHA / DIGIT / "-")
+value = *(%01-09 / %0b-FF)
+
+pack = ... ; packfile
+----
+
== Semantics
-A Git bundle consists of three parts.
+A Git bundle consists of several parts.
+
+* "Capabilities", which are only in the v3 format, indicate functionality that
+ the bundle requires to be read properly.
* "Prerequisites" lists the objects that are NOT included in the bundle and the
reader of the bundle MUST already have, in order to use the data in the
@@ -46,3 +67,10 @@ put any string here. The reader of the bundle MUST ignore the comment.
Note that the prerequisites does not represent a shallow-clone boundary. The
semantics of the prerequisites and the shallow-clone boundaries are different,
and the Git bundle v2 format cannot represent a shallow clone repository.
+
+== Capabilities
+
+Because there is no opportunity for negotiation, unknown capabilities cause 'git
+bundle' to abort. The only known capability is `object-format`, which specifies
+the hash algorithm in use, and can take the same values as the
+`extensions.objectFormat` configuration value.
diff --git a/builtin/bundle.c b/builtin/bundle.c
index f049d27a14..e1a85e7dcc 100644
--- a/builtin/bundle.c
+++ b/builtin/bundle.c
@@ -60,6 +60,7 @@ static int cmd_bundle_create(int argc, const char **argv, const char *prefix) {
int all_progress_implied = 0;
int progress = isatty(STDERR_FILENO);
struct argv_array pack_opts;
+ int version = -1;
struct option options[] = {
OPT_SET_INT('q', "quiet", &progress,
@@ -71,6 +72,8 @@ static int cmd_bundle_create(int argc, const char **argv, const char *prefix) {
OPT_BOOL(0, "all-progress-implied",
&all_progress_implied,
N_("similar to --all-progress when progress meter is shown")),
+ OPT_INTEGER(0, "version", &version,
+ N_("specify bundle format version")),
OPT_END()
};
const char* bundle_file;
@@ -91,7 +94,7 @@ static int cmd_bundle_create(int argc, const char **argv, const char *prefix) {
if (!startup_info->have_repository)
die(_("Need a repository to create a bundle."));
- return !!create_bundle(the_repository, bundle_file, argc, argv, &pack_opts);
+ return !!create_bundle(the_repository, bundle_file, argc, argv, &pack_opts, version);
}
static int cmd_bundle_verify(int argc, const char **argv, const char *prefix) {
diff --git a/bundle.c b/bundle.c
index 2a0d744d3f..5c1cc8f4a8 100644
--- a/bundle.c
+++ b/bundle.c
@@ -12,7 +12,16 @@
#include "refs.h"
#include "argv-array.h"
-static const char bundle_signature[] = "# v2 git bundle\n";
+
+static const char v2_bundle_signature[] = "# v2 git bundle\n";
+static const char v3_bundle_signature[] = "# v3 git bundle\n";
+static struct {
+ int version;
+ const char *signature;
+} bundle_sigs[] = {
+ { 2, v2_bundle_signature },
+ { 3, v3_bundle_signature },
+};
static void add_to_ref_list(const struct object_id *oid, const char *name,
struct ref_list *list)
@@ -23,15 +32,30 @@ static void add_to_ref_list(const struct object_id *oid, const char *name,
list->nr++;
}
-static const struct git_hash_algo *detect_hash_algo(struct strbuf *buf)
+static int parse_capability(struct bundle_header *header, const char *capability)
{
- size_t len = strcspn(buf->buf, " \n");
- int algo;
+ const char *arg;
+ if (skip_prefix(capability, "object-format=", &arg)) {
+ int algo = hash_algo_by_name(arg);
+ if (algo == GIT_HASH_UNKNOWN)
+ return error(_("unable to detect hash algorithm"));
+ header->hash_algo = &hash_algos[algo];
+ return 0;
+ }
+ return error(_("unknown capability '%s'"), capability);
+}
- algo = hash_algo_by_length(len / 2);
- if (algo == GIT_HASH_UNKNOWN)
- return NULL;
- return &hash_algos[algo];
+static int parse_bundle_signature(struct bundle_header *header, const char *line)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(bundle_sigs); i++) {
+ if (!strcmp(line, bundle_sigs[i].signature)) {
+ header->version = bundle_sigs[i].version;
+ return 0;
+ }
+ }
+ return -1;
}
static int parse_bundle_header(int fd, struct bundle_header *header,
@@ -42,14 +66,16 @@ static int parse_bundle_header(int fd, struct bundle_header *header,
/* The bundle header begins with the signature */
if (strbuf_getwholeline_fd(&buf, fd, '\n') ||
- strcmp(buf.buf, bundle_signature)) {
+ parse_bundle_signature(header, buf.buf)) {
if (report_path)
- error(_("'%s' does not look like a v2 bundle file"),
+ error(_("'%s' does not look like a v2 or v3 bundle file"),
report_path);
status = -1;
goto abort;
}
+ header->hash_algo = the_hash_algo;
+
/* The bundle header ends with an empty line */
while (!strbuf_getwholeline_fd(&buf, fd, '\n') &&
buf.len && buf.buf[0] != '\n') {
@@ -57,21 +83,21 @@ static int parse_bundle_header(int fd, struct bundle_header *header,
int is_prereq = 0;
const char *p;
+ if (header->version == 3 && *buf.buf == '@') {
+ buf.buf[--buf.len] = '\0';
+ if (parse_capability(header, buf.buf + 1)) {
+ status = -1;
+ break;
+ }
+ continue;
+ }
+
if (*buf.buf == '-') {
is_prereq = 1;
strbuf_remove(&buf, 0, 1);
}
strbuf_rtrim(&buf);
- if (!header->hash_algo) {
- header->hash_algo = detect_hash_algo(&buf);
- if (!header->hash_algo) {
- error(_("unknown hash algorithm length"));
- status = -1;
- break;
- }
- }
-
/*
* Tip lines have object name, SP, and refname.
* Prerequisites have object name that is optionally
@@ -449,13 +475,14 @@ static int write_bundle_refs(int bundle_fd, struct rev_info *revs)
}
int create_bundle(struct repository *r, const char *path,
- int argc, const char **argv, struct argv_array *pack_options)
+ int argc, const char **argv, struct argv_array *pack_options, int version)
{
struct lock_file lock = LOCK_INIT;
int bundle_fd = -1;
int bundle_to_stdout;
int ref_count = 0;
struct rev_info revs;
+ int default_version = the_hash_algo == &hash_algos[GIT_HASH_SHA1] ? 2 : 3;
bundle_to_stdout = !strcmp(path, "-");
if (bundle_to_stdout)
@@ -464,8 +491,22 @@ int create_bundle(struct repository *r, const char *path,
bundle_fd = hold_lock_file_for_update(&lock, path,
LOCK_DIE_ON_ERROR);
- /* write signature */
- write_or_die(bundle_fd, bundle_signature, strlen(bundle_signature));
+ if (version == -1)
+ version = default_version;
+
+ if (version < 2 || version > 3) {
+ die(_("unsupported bundle version %d"), version);
+ } else if (version < default_version) {
+ die(_("cannot write bundle version %d with algorithm %s"), version, the_hash_algo->name);
+ } else if (version == 2) {
+ write_or_die(bundle_fd, v2_bundle_signature, strlen(v2_bundle_signature));
+ } else {
+ const char *capability = "@object-format=";
+ write_or_die(bundle_fd, v3_bundle_signature, strlen(v3_bundle_signature));
+ write_or_die(bundle_fd, capability, strlen(capability));
+ write_or_die(bundle_fd, the_hash_algo->name, strlen(the_hash_algo->name));
+ write_or_die(bundle_fd, "\n", 1);
+ }
/* init revs to list objects for pack-objects later */
save_commit_buffer = 0;
diff --git a/bundle.h b/bundle.h
index 2dc9442024..70c84cab08 100644
--- a/bundle.h
+++ b/bundle.h
@@ -13,6 +13,7 @@ struct ref_list {
};
struct bundle_header {
+ unsigned version;
struct ref_list prerequisites;
struct ref_list references;
const struct git_hash_algo *hash_algo;
@@ -21,7 +22,8 @@ struct bundle_header {
int is_bundle(const char *path, int quiet);
int read_bundle_header(const char *path, struct bundle_header *header);
int create_bundle(struct repository *r, const char *path,
- int argc, const char **argv, struct argv_array *pack_options);
+ int argc, const char **argv, struct argv_array *pack_options,
+ int version);
int verify_bundle(struct repository *r, struct bundle_header *header, int verbose);
#define BUNDLE_VERBOSE 1
int unbundle(struct repository *r, struct bundle_header *header,
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index a66dbe0bde..a4988784af 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -281,15 +281,20 @@ test_expect_success 'create bundle 1' '
cd "$D" &&
echo >file updated again by origin &&
git commit -a -m "tip" &&
- git bundle create bundle1 master^..master
+ git bundle create --version=3 bundle1 master^..master
'
test_expect_success 'header of bundle looks right' '
head -n 4 "$D"/bundle1 &&
- head -n 1 "$D"/bundle1 | grep "^#" &&
- head -n 2 "$D"/bundle1 | grep "^-$OID_REGEX " &&
- head -n 3 "$D"/bundle1 | grep "^$OID_REGEX " &&
- head -n 4 "$D"/bundle1 | grep "^$"
+ cat >expect <<-EOF &&
+ # v3 git bundle
+ @object-format=$(test_oid algo)
+ -OID message
+ OID message
+
+ EOF
+ sed -e "s/$OID_REGEX .*/OID message/g" -e "5q" "$D"/bundle1 >actual &&
+ test_cmp expect actual
'
test_expect_success 'create bundle 2' '
diff --git a/t/t5607-clone-bundle.sh b/t/t5607-clone-bundle.sh
index 6d5a977fcb..26985f4b44 100755
--- a/t/t5607-clone-bundle.sh
+++ b/t/t5607-clone-bundle.sh
@@ -4,6 +4,10 @@ test_description='some bundle related tests'
. ./test-lib.sh
test_expect_success 'setup' '
+ test_oid_cache <<-EOF &&
+ version sha1:2
+ version sha256:3
+ EOF
test_commit initial &&
test_tick &&
git tag -m tag tag &&
@@ -94,4 +98,31 @@ test_expect_success 'fetch SHA-1 from bundle' '
git fetch --no-tags foo/tip.bundle "$(cat hash)"
'
+test_expect_success 'git bundle uses expected default format' '
+ git bundle create bundle HEAD^.. &&
+ head -n1 bundle | grep "^# v$(test_oid version) git bundle$"
+'
+
+test_expect_success 'git bundle v3 has expected contents' '
+ git branch side HEAD &&
+ git bundle create --version=3 bundle HEAD^..side &&
+ head -n2 bundle >actual &&
+ cat >expect <<-EOF &&
+ # v3 git bundle
+ @object-format=$(test_oid algo)
+ EOF
+ test_cmp expect actual &&
+ git bundle verify bundle
+'
+
+test_expect_success 'git bundle v3 rejects unknown capabilities' '
+ cat >new <<-EOF &&
+ # v3 git bundle
+ @object-format=$(test_oid algo)
+ @unknown=silly
+ EOF
+ test_must_fail git bundle verify new 2>output &&
+ test_i18ngrep "unknown capability .unknown=silly." output
+'
+
test_done
