On Sun, Oct 01, 2023 at 09:40:07PM -0500, Eric W. Biederman wrote:
> From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
>
> Support short oids encoded in any algorithm, while ensuring enough of
> the oid is specified to disambiguate between all of the oids in the
> repository encoded in any algorithm.
>
> By default have the code continue to only accept oids specified in the
> storage hash algorithm of the repository, but when something is
> ambiguous display all of the possible oids from any accepted oid
> encoding.
>
> A new flag is added GET_OID_HASH_ANY that when supplied causes the
> code to accept oids specified in any hash algorithm, and to return the
> oids that were resolved.
>
> This implements the functionality that allows both SHA-1 and SHA-256
> object names, from the "Object names on the command line" section of
> the hash function transition document.
>
> Care is taken in get_short_oid so that when the result is ambiguous
> the output remains the same if GIT_OID_HASH_ANY was not supplied. If
> GET_OID_HASH_ANY was supplied objects of any hash algorithm that match
> the prefix are displayed.
>
> This required updating repo_for_each_abbrev to give it a parameter so
> that it knows to look at all hash algorithms.
>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> ---
> builtin/rev-parse.c | 2 +-
> hash-ll.h | 1 +
> object-name.c | 46 ++++++++++++++++++++++++++++++++++-----------
> object-name.h | 3 ++-
> 4 files changed, 39 insertions(+), 13 deletions(-)
>
> diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
> index fde8861ca4e0..43e96765400c 100644
> --- a/builtin/rev-parse.c
> +++ b/builtin/rev-parse.c
> @@ -882,7 +882,7 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
> continue;
> }
> if (skip_prefix(arg, "--disambiguate=", &arg)) {
> - repo_for_each_abbrev(the_repository, arg,
> + repo_for_each_abbrev(the_repository, arg, the_hash_algo,
> show_abbrev, NULL);
> continue;
> }
> diff --git a/hash-ll.h b/hash-ll.h
> index 10d84cc20888..2cfde63ae1cf 100644
> --- a/hash-ll.h
> +++ b/hash-ll.h
> @@ -145,6 +145,7 @@ struct object_id {
> #define GET_OID_RECORD_PATH 0200
> #define GET_OID_ONLY_TO_DIE 04000
> #define GET_OID_REQUIRE_PATH 010000
> +#define GET_OID_HASH_ANY 020000
>
> #define GET_OID_DISAMBIGUATORS \
> (GET_OID_COMMIT | GET_OID_COMMITTISH | \
> diff --git a/object-name.c b/object-name.c
> index 0bfa29dbbfe9..7dd6e5e47566 100644
> --- a/object-name.c
> +++ b/object-name.c
> @@ -25,6 +25,7 @@
> #include "midx.h"
> #include "commit-reach.h"
> #include "date.h"
> +#include "object-file-convert.h"
>
> static int get_oid_oneline(struct repository *r, const char *, struct object_id *, struct commit_list *);
>
> @@ -49,6 +50,7 @@ struct disambiguate_state {
>
> static void update_candidates(struct disambiguate_state *ds, const struct object_id *current)
> {
> + /* The hash algorithm of current has already been filtered */
> if (ds->always_call_fn) {
> ds->ambiguous = ds->fn(ds->repo, current, ds->cb_data) ? 1 : 0;
> return;
> @@ -134,6 +136,8 @@ static void unique_in_midx(struct multi_pack_index *m,
> {
> uint32_t num, i, first = 0;
> const struct object_id *current = NULL;
> + int len = ds->len > ds->repo->hash_algo->hexsz ?
> + ds->repo->hash_algo->hexsz : ds->len;
`hexsz` is not an `int`, but a `size_t`. `match_hash()` of course uses
a third type `unsigned` instead, adding to the confusion.
> num = m->num_objects;
>
> if (!num)
> @@ -149,7 +153,7 @@ static void unique_in_midx(struct multi_pack_index *m,
> for (i = first; i < num && !ds->ambiguous; i++) {
> struct object_id oid;
> current = nth_midxed_object_oid(&oid, m, i);
> - if (!match_hash(ds->len, ds->bin_pfx.hash, current->hash))
> + if (!match_hash(len, ds->bin_pfx.hash, current->hash))
> break;
> update_candidates(ds, current);
> }
> @@ -159,6 +163,8 @@ static void unique_in_pack(struct packed_git *p,
> struct disambiguate_state *ds)
> {
> uint32_t num, i, first = 0;
> + int len = ds->len > ds->repo->hash_algo->hexsz ?
> + ds->repo->hash_algo->hexsz : ds->len;
>
> if (p->multi_pack_index)
> return;
> @@ -177,7 +183,7 @@ static void unique_in_pack(struct packed_git *p,
> for (i = first; i < num && !ds->ambiguous; i++) {
> struct object_id oid;
> nth_packed_object_id(&oid, p, i);
> - if (!match_hash(ds->len, ds->bin_pfx.hash, oid.hash))
> + if (!match_hash(len, ds->bin_pfx.hash, oid.hash))
> break;
> update_candidates(ds, &oid);
> }
> @@ -188,6 +194,10 @@ static void find_short_packed_object(struct disambiguate_state *ds)
> struct multi_pack_index *m;
> struct packed_git *p;
>
> + /* Skip, unless oids from the storage hash algorithm are wanted */
> + if (ds->bin_pfx.algo && (&hash_algos[ds->bin_pfx.algo] != ds->repo->hash_algo))
> + return;
> +
> for (m = get_multi_pack_index(ds->repo); m && !ds->ambiguous;
> m = m->next)
> unique_in_midx(m, ds);
> @@ -326,11 +336,12 @@ int set_disambiguate_hint_config(const char *var, const char *value)
>
> static int init_object_disambiguation(struct repository *r,
> const char *name, int len,
> + const struct git_hash_algo *algo,
> struct disambiguate_state *ds)
> {
> int i;
>
> - if (len < MINIMUM_ABBREV || len > the_hash_algo->hexsz)
> + if (len < MINIMUM_ABBREV || len > GIT_MAX_HEXSZ)
> return -1;
Isn't this loosening things up a bit too much? I'd have expected that we
would compare with `algo->hexsz`, unless `GET_OID_HASH_ANY` is set and
thus `algo == NULL`.
Patrick
> memset(ds, 0, sizeof(*ds));
> @@ -357,6 +368,7 @@ static int init_object_disambiguation(struct repository *r,
> ds->len = len;
> ds->hex_pfx[len] = '\0';
> ds->repo = r;
> + ds->bin_pfx.algo = algo ? hash_algo_by_ptr(algo) : GIT_HASH_UNKNOWN;
> prepare_alt_odb(r);
> return 0;
> }
> @@ -491,9 +503,10 @@ static int repo_collect_ambiguous(struct repository *r UNUSED,
> return collect_ambiguous(oid, data);
> }
>
> -static int sort_ambiguous(const void *a, const void *b, void *ctx)
> +static int sort_ambiguous(const void *va, const void *vb, void *ctx)
> {
> struct repository *sort_ambiguous_repo = ctx;
> + const struct object_id *a = va, *b = vb;
> int a_type = oid_object_info(sort_ambiguous_repo, a, NULL);
> int b_type = oid_object_info(sort_ambiguous_repo, b, NULL);
> int a_type_sort;
> @@ -503,8 +516,12 @@ static int sort_ambiguous(const void *a, const void *b, void *ctx)
> * Sorts by hash within the same object type, just as
> * oid_array_for_each_unique() would do.
> */
> - if (a_type == b_type)
> - return oidcmp(a, b);
> + if (a_type == b_type) {
> + if (a->algo == b->algo)
> + return oidcmp(a, b);
> + else
> + return a->algo > b->algo ? 1 : -1;
> + }
>
> /*
> * Between object types show tags, then commits, and finally
> @@ -533,8 +550,12 @@ static enum get_oid_result get_short_oid(struct repository *r,
> int status;
> struct disambiguate_state ds;
> int quietly = !!(flags & GET_OID_QUIETLY);
> + const struct git_hash_algo *algo = r->hash_algo;
> +
> + if (flags & GET_OID_HASH_ANY)
> + algo = NULL;
>
> - if (init_object_disambiguation(r, name, len, &ds) < 0)
> + if (init_object_disambiguation(r, name, len, algo, &ds) < 0)
> return -1;
>
> if (HAS_MULTI_BITS(flags & GET_OID_DISAMBIGUATORS))
> @@ -588,7 +609,7 @@ static enum get_oid_result get_short_oid(struct repository *r,
> if (!ds.ambiguous)
> ds.fn = NULL;
>
> - repo_for_each_abbrev(r, ds.hex_pfx, collect_ambiguous, &collect);
> + repo_for_each_abbrev(r, ds.hex_pfx, algo, collect_ambiguous, &collect);
> sort_ambiguous_oid_array(r, &collect);
>
> if (oid_array_for_each(&collect, show_ambiguous_object, &out))
> @@ -610,13 +631,14 @@ static enum get_oid_result get_short_oid(struct repository *r,
> }
>
> int repo_for_each_abbrev(struct repository *r, const char *prefix,
> + const struct git_hash_algo *algo,
> each_abbrev_fn fn, void *cb_data)
> {
> struct oid_array collect = OID_ARRAY_INIT;
> struct disambiguate_state ds;
> int ret;
>
> - if (init_object_disambiguation(r, prefix, strlen(prefix), &ds) < 0)
> + if (init_object_disambiguation(r, prefix, strlen(prefix), algo, &ds) < 0)
> return -1;
>
> ds.always_call_fn = 1;
> @@ -787,10 +809,12 @@ void strbuf_add_unique_abbrev(struct strbuf *sb, const struct object_id *oid,
> int repo_find_unique_abbrev_r(struct repository *r, char *hex,
> const struct object_id *oid, int len)
> {
> + const struct git_hash_algo *algo =
> + oid->algo ? &hash_algos[oid->algo] : r->hash_algo;
> struct disambiguate_state ds;
> struct min_abbrev_data mad;
> struct object_id oid_ret;
> - const unsigned hexsz = r->hash_algo->hexsz;
> + const unsigned hexsz = algo->hexsz;
>
> if (len < 0) {
> unsigned long count = repo_approximate_object_count(r);
> @@ -826,7 +850,7 @@ int repo_find_unique_abbrev_r(struct repository *r, char *hex,
>
> find_abbrev_len_packed(&mad);
>
> - if (init_object_disambiguation(r, hex, mad.cur_len, &ds) < 0)
> + if (init_object_disambiguation(r, hex, mad.cur_len, algo, &ds) < 0)
> return -1;
>
> ds.fn = repo_extend_abbrev_len;
> diff --git a/object-name.h b/object-name.h
> index 9ae522307148..064ddc97d1fe 100644
> --- a/object-name.h
> +++ b/object-name.h
> @@ -67,7 +67,8 @@ enum get_oid_result get_oid_with_context(struct repository *repo, const char *st
>
>
> typedef int each_abbrev_fn(const struct object_id *oid, void *);
> -int repo_for_each_abbrev(struct repository *r, const char *prefix, each_abbrev_fn, void *);
> +int repo_for_each_abbrev(struct repository *r, const char *prefix,
> + const struct git_hash_algo *algo, each_abbrev_fn, void *);
>
> int set_disambiguate_hint_config(const char *var, const char *value);
>
> --
> 2.41.0
>
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