Since the info command in cat-file --batch-command prints object
info for a given object, it is natural to add another command in
cat-file --batch-command to print object info for a given object
from a remote.
Add remote-object-info command to cat-file --batch-command.
While info takes object ids one at a time, this creates overhead when
making requests to a server. So remote-object-info instead can take
multiple object ids at once.
The cat-file --batch-command command is generally implemented in the
following manner:
- Receive and parse input from user
- Call respective function attached to command
- Get object info, print object info
In --buffer mode, this changes to:
- Receive and parse input from user
- Store respective function attached to command in a queue
- After flush, loop through commands in queue
- Call respective function attached to command
- Get object info, print object info
Notice how the getting and printing of object info is accomplished one
at a time. As described above, this creates a problem for making
requests to a server. Therefore, remote-object-info is implemented in
the following manner:
- Receive and parse input from user
If command is remote-object-info:
- Get object info from remote
- Loop through and print each object info
Else:
- Call respective function attached to command
- Parse input, get object info, print object info
And finally for --buffer mode remote-object-info:
- Receive and parse input from user
- Store respective function attached to command in a queue
- After flush, loop through commands in queue:
If command is remote-object-info:
- Get object info from remote
- Loop through and print each object info
Else:
- Call respective function attached to command
- Get object info, print object info
To summarize, remote-object-info gets object info from the remote and
then loops through the object info passed in, printing the info.
In order for remote-object-info to avoid remote communication
overhead in the non-buffer mode, the objects are passed in as such:
remote-object-info <remote> <oid> <oid> ... <oid>
rather than
remote-object-info <remote> <oid>
remote-object-info <remote> <oid>
...
remote-object-info <remote> <oid>
Placeholders in the format are validated against an allow-list of the
atoms the remote path supports: "objectname" and "objectsize".
Unsupported atoms expand to an empty string, honoring how for-each-ref
handles known but inapplicable atoms.
Without this, atoms like %(objecttype) would mark data->info.typep and
because the server only sends size, type_name() would later crash.
As extra safety, even outside of the remote path, initialize
expand_data's type to OBJ_BAD and handle type_name() returning NULL.
Helped-by: Jonathan Tan <jonathantanmy@google.com>
Helped-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Mentored-by: Chandra Pratap <chandrapratap3519@gmail.com>
Signed-off-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Eric Ju <eric.peijian@gmail.com>
[pablo: added the atom allow-list validation]
Signed-off-by: Pablo Sabater <pabloosabaterr@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Eric Ju committedJul 24, 2026 at 12:54 UTC0ae93f56ecd792d227149161b57f292a1c909d0c
6 files changed+930-7
Documentation/git-cat-file.adoc
+21-2
index 86b9181599..ac3b528c6f 100644--- a/Documentation/git-cat-file.adoc+++ b/Documentation/git-cat-file.adoc@@ -169,6 +169,13 @@ info <object>:: Print object info for object reference `<object>`. This corresponds to the output of `--batch-check`.+remote-object-info <remote> <object>...::+ Print object info for object references `<object>` at specified+ `<remote>` without downloading objects from the remote.+ Raise an error when the `object-info` capability is not supported by the remote.+ Raise an error when no object references are provided.+ This command may be combined with `--buffer`.+ flush:: Used with `--buffer` to execute all preceding commands that were issued since the beginning or since the last flush was issued. When `--buffer`@@ -301,7 +308,8 @@ one per line, and print information based on the command given. With `--batch-command`, the `info` command followed by an object will print information about the object the same way `--batch-check` would, and the `contents` command followed by an object prints contents in the same way-`--batch` would.+`--batch` would. The `remote-object-info` command followed by a remote and+object IDs prints object info from the remote without downloading the objects. You can specify the information shown for each object by using a custom `<format>`. The `<format>` is copied literally to stdout for each@@ -340,8 +348,15 @@ newline. The available atoms are: after that first run of whitespace (i.e., the "rest" of the line) are output in place of the `%(rest)` atom.+The command `remote-object-info` only supports the `%(objectname)` and+`%(objectsize)` placeholders. See `CAVEATS` below for more information.+ If no format is specified, the default format is `%(objectname)-%(objecttype) %(objectsize)`.+%(objecttype) %(objectsize)`, except for `remote-object-info` commands which+use `%(objectname) %(objectsize)` because `%(objecttype)` is not supported yet.++WARNING: When "%(objecttype)" is supported, the default format WILL be unified,+so DO NOT RELY on the current default format to stay the same!!! If `--batch` is specified, or if `--batch-command` is used with the `contents` command, the object information is followed by the object contents (consisting@@ -438,6 +453,10 @@ scripting purposes. CAVEATS -------+Note that only `%(objectname)` and `%(objectsize)` are currently+supported by the `remote-object-info` command. Using any other placeholder in+the format string will return an empty string in its position.+ Note that the sizes of objects on disk are reported accurately, but care should be taken in drawing conclusions about which refs or objects are responsible for disk usage. The size of a packed non-delta object may be
builtin/cat-file.c
+176-5
index 03afc44c5e..8994b04d15 100644--- a/builtin/cat-file.c+++ b/builtin/cat-file.c@@ -29,6 +29,22 @@ #include "promisor-remote.h" #include "mailmap.h" #include "write-or-die.h"+#include "alias.h"+#include "remote.h"+#include "transport.h"++/*+ * Maximum length for a remote URL. While no universal standard exists,+ * 8K is assumed to be a reasonable limit.+ */+#define MAX_REMOTE_URL_LEN (8 * 1024)++/* Maximum number of objects allowed in a single remote-object-info request. */+#define MAX_ALLOWED_OBJ_LIMIT 10000++/* Maximum input size permitted for the remote-object-info command. */+#define MAX_REMOTE_OBJ_INFO_LINE \+ (MAX_REMOTE_URL_LEN + MAX_ALLOWED_OBJ_LIMIT * (GIT_MAX_HEXSZ + 1)) enum batch_mode { BATCH_MODE_CONTENTS,@@ -317,8 +333,19 @@ struct expand_data { * optimized out. */ unsigned skip_object_info : 1;++ /*+ * Flags about when an object info is being fetched from remote.+ */+ unsigned is_remote:1;+};++#define EXPAND_DATA_INIT { .mode = S_IFINVALID, .type = OBJ_BAD }++static const char *remote_object_info_atoms[] = {+ "objectname",+ "objectsize", };-#define EXPAND_DATA_INIT { .mode = S_IFINVALID } static int is_atom(const char *atom, const char *s, int slen) {@@ -329,14 +356,31 @@ static int is_atom(const char *atom, const char *s, int slen) static int expand_atom(struct strbuf *sb, const char *atom, int len, struct expand_data *data) {+ if (data->is_remote) {+ size_t i, allowed_nr = ARRAY_SIZE(remote_object_info_atoms);+ for (i = 0; i < allowed_nr; i++)+ if (is_atom(remote_object_info_atoms[i], atom, len))+ break;++ /*+ * On remote, skip unsupported atoms returning an empty sb,+ * honoring how for-each-ref handles known but inapplicable+ * atoms (e.g. %(tagger)).+ */+ if (i == allowed_nr)+ return 1;+ }+ if (is_atom("objectname", atom, len)) { if (!data->mark_query) strbuf_add_oid_hex(sb, &data->oid); } else if (is_atom("objecttype", atom, len)) {- if (data->mark_query)+ if (data->mark_query) { data->info.typep = &data->type;- else- strbuf_addstr(sb, type_name(data->type));+ } else {+ const char *t = type_name(data->type);+ strbuf_addstr(sb, t ? t : "");+ } } else if (is_atom("objectsize", atom, len)) { if (data->mark_query) data->info.sizep = &data->size;@@ -636,6 +680,65 @@ out: object_context_release(&ctx); }+static int get_remote_info(int argc,+ const char **argv,+ struct object_info **remote_object_info,+ struct oid_array *object_info_oids)+{+ int retval = 0;+ struct remote *remote = NULL;+ struct object_id oid;+ struct string_list object_info_options = STRING_LIST_INIT_NODUP;+ struct transport *gtransport;++ remote = remote_get(argv[0]);+ if (!remote)+ die(_("must supply valid remote when using remote-object-info"));++ oid_array_clear(object_info_oids);+ for (size_t i = 1; i < argc; i++) {+ if (get_oid_hex(argv[i], &oid)) {+ size_t len = strlen(argv[i]);++ if (len < the_hash_algo->hexsz && len >= 4) {+ size_t j;+ for (j = 0; j < len; j++)+ if (!isxdigit(argv[i][j]))+ break;+ if (j == len)+ die(_("remote-object-info does not support "+ "short oids, %d characters required"),+ (int)the_hash_algo->hexsz);+ }+ die(_("not a valid object name '%s'"), argv[i]);+ }+ oid_array_append(object_info_oids, &oid);+ }++ if (!object_info_oids->nr)+ die(_("remote-object-info requires objects"));++ gtransport = transport_get(remote, NULL);++ if (!gtransport->smart_options) {+ retval = -1;+ goto cleanup;+ }++ CALLOC_ARRAY(*remote_object_info, object_info_oids->nr);+ gtransport->smart_options->object_info_oids = object_info_oids;++ string_list_append(&object_info_options, "size");++ gtransport->smart_options->object_info_options = &object_info_options;+ gtransport->smart_options->object_info_data = *remote_object_info;+ retval = transport_fetch_object_info(gtransport);+cleanup:+ string_list_clear(&object_info_options, 0);+ transport_disconnect(gtransport);+ return retval;+}+ struct object_cb_data { struct batch_options *opt; struct expand_data *expand;@@ -717,6 +820,73 @@ static void parse_cmd_mailmap(struct batch_options *opt UNUSED, load_mailmap(); }+static void parse_cmd_remote_object_info(struct batch_options *opt,+ const char *line, struct strbuf *output,+ struct expand_data *data)+{+ int count;+ const char **argv;+ char *line_to_split;+ struct object_info *remote_object_info = NULL;+ struct oid_array object_info_oids = OID_ARRAY_INIT;+ const char *saved_format = opt->format;++ if (strlen(line) >= MAX_REMOTE_OBJ_INFO_LINE)+ die(_("remote-object-info command too long"));+ /*+ * TODO: Use the default format once %(objecttype) is supported.+ */+ if (!opt->format)+ opt->format = "%(objectname) %(objectsize)";++ line_to_split = xstrdup(line);+ count = split_cmdline(line_to_split, &argv);+ if (count < 0)+ die(_("remote-object-info: failed to parse command line: %s"),+ split_cmdline_strerror(count));+ if (count - 1 > MAX_ALLOWED_OBJ_LIMIT)+ die(_("remote-object-info supports at most %d objects"),+ MAX_ALLOWED_OBJ_LIMIT);++ if (get_remote_info(count, argv, &remote_object_info,+ &object_info_oids))+ die(_("failed to get object info from the remote: %s"), argv[0]);++ data->skip_object_info = 1;+ for (size_t i = 0; i < object_info_oids.nr; i++) {+ data->oid = object_info_oids.oid[i];++ if (remote_object_info[i].unrecognized) {+ report_object_status(opt, oid_to_hex(&data->oid),+ &data->oid, "missing");+ continue;+ }++ if (remote_object_info[i].sizep) {+ /*+ * When reaching here, it means remote-object-info can retrieve+ * information from server without downloading them.+ */+ data->size = *remote_object_info[i].sizep;+ opt->batch_mode = BATCH_MODE_INFO;+ data->is_remote = 1;+ batch_object_write(argv[i + 1], output, opt, data, NULL, 0);+ data->is_remote = 0;+ } else {+ report_object_status(opt, oid_to_hex(&data->oid), &data->oid, "missing");+ }+ }+ data->skip_object_info = 0;+ opt->format = saved_format;++ for (size_t i = 0; i < object_info_oids.nr; i++)+ free_object_info_contents(&remote_object_info[i]);+ free(line_to_split);+ free(argv);+ free(remote_object_info);+ oid_array_clear(&object_info_oids);+}+ static void dispatch_calls(struct batch_options *opt, struct strbuf *output, struct expand_data *data,@@ -747,9 +917,10 @@ static const struct parse_cmd { unsigned takes_args; } commands[] = { { "contents", parse_cmd_contents, 1 },- { "info", parse_cmd_info, 1 }, { "flush", NULL, 0 },+ { "info", parse_cmd_info, 1 }, { "mailmap", parse_cmd_mailmap, 1 },+ { "remote-object-info", parse_cmd_remote_object_info, 1 }, }; static void batch_objects_command(struct batch_options *opt,