[PATCH v2 1/1] setup: recognise extensions.objectFormat
- From
Patryk Obara <patryk.obara@gmail.com>
- Date
- Jan 28, 2018, 00:36 UTC
- Message-ID
- <e430ad029facdd6209927d352f0e7545cdd0e435.1517098675.git.patryk.obara@gmail.com>
- In-Reply-To
- <cover.1517098675.git.patryk.obara@gmail.com>
This extension selects which hashing algorithm from vtable should be used for reading and writing objects in the object store. At the moment supports only single value (sha-1).
In case value of objectFormat is an unknown hashing algorithm, Git command will fail with following message:
fatal: unknown repository extensions found: objectformat = <value>
To indicate, that this specific objectFormat value is not recognised.
The objectFormat extension is not allowed in repository marked as version 0 to prevent any possibility of accidentally writing a NewHash object in the sha-1 object store. This extension behaviour is different than preciousObjects extension (which is allowed in repo version 0).
Add tests and documentation note about new extension.
Signed-off-by: Patryk Obara <patryk.obara@gmail.com> --- Documentation/technical/repository-version.txt | 12 ++++++++++++ setup.c | 27 ++++++++++++++++++++++++++ t/t1302-repo-version.sh | 15 ++++++++++++++ 3 files changed, 54 insertions(+)
diff --git a/Documentation/technical/repository-version.txt b/Documentation/technical/repository-version.txt index 00ad37986e..7e2b832603 100644 --- a/Documentation/technical/repository-version.txt +++ b/Documentation/technical/repository-version.txt @@ -86,3 +86,15 @@ for testing format-1 compatibility. When the config key `extensions.preciousObjects` is set to `true`, objects in the repository MUST NOT be deleted (e.g., by `git-prune` or `git repack -d`). + +`objectFormat` +~~~~~~~~~~~~~~ + +This extension instructs Git to use a specific algorithm for addressing +and interpreting objects in the object store. Currently, the only +supported object format is `sha-1`. At the moment, the primary purpose +of this option is to enable Git developers to experiment with different +hashing algorithms without re-compilation of git client. + +See `hash-function-transition.txt` document for more detailed explanation. + diff --git a/setup.c b/setup.c index 8cc34186ce..9b9993a14e 100644 --- a/setup.c +++ b/setup.c @@ -405,6 +405,31 @@ void setup_work_tree(void) initialized = 1; } +static int find_object_format(const char *value) +{ + int i; + for (i = GIT_HASH_SHA1; i < GIT_HASH_NALGOS; ++i) { + if (strcmp(value, hash_algos[i].name) == 0) + return i; + } + return GIT_HASH_UNKNOWN; +} + +static void detect_object_format(struct repository_format *data, + const char *value) +{ + if (data->version == 0) + die(_("invalid repository format version '%d'"), data->version); + + data->hash_algo = find_object_format(value); + if (data->hash_algo == GIT_HASH_UNKNOWN) { + struct strbuf object_format = STRBUF_INIT; + strbuf_addf(&object_format, "objectformat = %s", value); + string_list_append(&data->unknown_extensions, object_format.buf); + strbuf_release(&object_format); + } +} + static int check_repo_format(const char *var, const char *value, void *vdata) { struct repository_format *data = vdata; @@ -422,6 +447,8 @@ static int check_repo_format(const char *var, const char *value, void *vdata) ; else if (!strcmp(ext, "preciousobjects")) data->precious_objects = git_config_bool(var, value); + else if (!strcmp(ext, "objectformat")) + detect_object_format(data, value); else string_list_append(&data->unknown_extensions, ext); } else if (strcmp(var, "core.bare") == 0) { diff --git a/t/t1302-repo-version.sh b/t/t1302-repo-version.sh index ce4cff13bb..227b397ff2 100755 --- a/t/t1302-repo-version.sh +++ b/t/t1302-repo-version.sh @@ -107,4 +107,19 @@ test_expect_success 'gc runs without complaint' ' git gc ' +test_expect_success 'object-format not allowed in repo version=0' ' + mkconfig 0 "objectFormat = sha-1" >.git/config && + check_abort +' + +test_expect_success 'object-format=sha-1 allowed' ' + mkconfig 1 "objectFormat = sha-1" >.git/config && + check_allow +' + +test_expect_success 'object-format=foo unsupported' ' + mkconfig 1 "objectFormat = foo" >.git/config && + check_abort +' + test_done
-- 2.14.3