git-commit-vandalism/list-objects-filter-options.c
Jeff King 4c96a77594 list-objects-filter: delay parsing of sparse oid
The list-objects-filter code has two steps to its initialization:

  1. parse_list_objects_filter() makes sure the spec is a filter we know
     about and is syntactically correct. This step is done by "rev-list"
     or "upload-pack" that is going to apply a filter, but also by "git
     clone" or "git fetch" before they send the spec across the wire.

  2. list_objects_filter__init() runs the type-specific initialization
     (using function pointers established in step 1). This happens at
     the start of traverse_commit_list_filtered(), when we're about to
     actually use the filter.

It's a good idea to parse as much as we can in step 1, in order to catch
problems early (e.g., a blob size limit that isn't a number). But one
thing we _shouldn't_ do is resolve any oids at that step (e.g., for
sparse-file contents specified by oid). In the case of a fetch, the oid
has to be resolved on the remote side.

The current code does resolve the oid during the parse phase, but
ignores any error (which we must do, because we might just be sending
the spec across the wire). This leads to two bugs:

  - if we're not in a repository (e.g., because it's git-clone parsing
    the spec), then we trigger a BUG() trying to resolve the name

  - if we did hit the error case, we still have to notice that later and
    bail. The code path in rev-list handles this, but the one in
    upload-pack does not, leading to a segfault.

We can fix both by moving the oid resolution into the sparse-oid init
function. At that point we know we have a repository (because we're
about to traverse), and handling the error there fixes the segfault.

As a bonus, we can drop the NULL sparse_oid_value check in rev-list,
since this is now handled in the sparse-oid-filter init function.

Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-09-16 12:47:37 -07:00

177 lines
4.7 KiB
C

#include "cache.h"
#include "commit.h"
#include "config.h"
#include "revision.h"
#include "argv-array.h"
#include "list-objects.h"
#include "list-objects-filter.h"
#include "list-objects-filter-options.h"
/*
* Parse value of the argument to the "filter" keyword.
* On the command line this looks like:
* --filter=<arg>
* and in the pack protocol as:
* "filter" SP <arg>
*
* The filter keyword will be used by many commands.
* See Documentation/rev-list-options.txt for allowed values for <arg>.
*
* Capture the given arg as the "filter_spec". This can be forwarded to
* subordinate commands when necessary (although it's better to pass it through
* expand_list_objects_filter_spec() first). We also "intern" the arg for the
* convenience of the current command.
*/
static int gently_parse_list_objects_filter(
struct list_objects_filter_options *filter_options,
const char *arg,
struct strbuf *errbuf)
{
const char *v0;
if (filter_options->choice) {
if (errbuf) {
strbuf_addstr(
errbuf,
_("multiple filter-specs cannot be combined"));
}
return 1;
}
filter_options->filter_spec = strdup(arg);
if (!strcmp(arg, "blob:none")) {
filter_options->choice = LOFC_BLOB_NONE;
return 0;
} else if (skip_prefix(arg, "blob:limit=", &v0)) {
if (git_parse_ulong(v0, &filter_options->blob_limit_value)) {
filter_options->choice = LOFC_BLOB_LIMIT;
return 0;
}
} else if (skip_prefix(arg, "tree:", &v0)) {
if (!git_parse_ulong(v0, &filter_options->tree_exclude_depth)) {
if (errbuf) {
strbuf_addstr(
errbuf,
_("expected 'tree:<depth>'"));
}
return 1;
}
filter_options->choice = LOFC_TREE_DEPTH;
return 0;
} else if (skip_prefix(arg, "sparse:oid=", &v0)) {
filter_options->sparse_oid_name = xstrdup(v0);
filter_options->choice = LOFC_SPARSE_OID;
return 0;
} else if (skip_prefix(arg, "sparse:path=", &v0)) {
if (errbuf) {
strbuf_addstr(
errbuf,
_("sparse:path filters support has been dropped"));
}
return 1;
}
/*
* Please update _git_fetch() in git-completion.bash when you
* add new filters
*/
if (errbuf)
strbuf_addf(errbuf, _("invalid filter-spec '%s'"), arg);
memset(filter_options, 0, sizeof(*filter_options));
return 1;
}
int parse_list_objects_filter(struct list_objects_filter_options *filter_options,
const char *arg)
{
struct strbuf buf = STRBUF_INIT;
if (gently_parse_list_objects_filter(filter_options, arg, &buf))
die("%s", buf.buf);
return 0;
}
int opt_parse_list_objects_filter(const struct option *opt,
const char *arg, int unset)
{
struct list_objects_filter_options *filter_options = opt->value;
if (unset || !arg) {
list_objects_filter_set_no_filter(filter_options);
return 0;
}
return parse_list_objects_filter(filter_options, arg);
}
void expand_list_objects_filter_spec(
const struct list_objects_filter_options *filter,
struct strbuf *expanded_spec)
{
strbuf_init(expanded_spec, strlen(filter->filter_spec));
if (filter->choice == LOFC_BLOB_LIMIT)
strbuf_addf(expanded_spec, "blob:limit=%lu",
filter->blob_limit_value);
else if (filter->choice == LOFC_TREE_DEPTH)
strbuf_addf(expanded_spec, "tree:%lu",
filter->tree_exclude_depth);
else
strbuf_addstr(expanded_spec, filter->filter_spec);
}
void list_objects_filter_release(
struct list_objects_filter_options *filter_options)
{
free(filter_options->filter_spec);
free(filter_options->sparse_oid_name);
memset(filter_options, 0, sizeof(*filter_options));
}
void partial_clone_register(
const char *remote,
const struct list_objects_filter_options *filter_options)
{
/*
* Record the name of the partial clone remote in the
* config and in the global variable -- the latter is
* used throughout to indicate that partial clone is
* enabled and to expect missing objects.
*/
if (repository_format_partial_clone &&
*repository_format_partial_clone &&
strcmp(remote, repository_format_partial_clone))
die(_("cannot change partial clone promisor remote"));
git_config_set("core.repositoryformatversion", "1");
git_config_set("extensions.partialclone", remote);
repository_format_partial_clone = xstrdup(remote);
/*
* Record the initial filter-spec in the config as
* the default for subsequent fetches from this remote.
*/
core_partial_clone_filter_default =
xstrdup(filter_options->filter_spec);
git_config_set("core.partialclonefilter",
core_partial_clone_filter_default);
}
void partial_clone_get_default_filter_spec(
struct list_objects_filter_options *filter_options)
{
/*
* Parse default value, but silently ignore it if it is invalid.
*/
if (!core_partial_clone_filter_default)
return;
gently_parse_list_objects_filter(filter_options,
core_partial_clone_filter_default,
NULL);
}