[PATCH v2 3/3] Revert "pack-objects: lazily set up "struct rev_info", don't leak"

["René Scharfe" <l.s.r@web.de>]

This reverts commit 5cb28270a1ff94a0a23e67b479bbbec3bc993518.

5cb28270a1 (pack-objects: lazily set up "struct rev_info", don't leak,
2022-03-28) avoided leaking rev_info allocations in many cases by
calling repo_init_revisions() only when the .filter member was actually
needed, but then still leaking it.  That was fixed later by 2108fe4a19
(revisions API users: add straightforward release_revisions(),
2022-04-13), making the reverted commit unnecessary.

5cb28270a1 broke support for multiple --filter options by calling
repo_init_revisions() for each one, clobbering earlier state and
leaking rev_info allocations.  Reverting it fixes that regression.
Luckily it only affects users that run pack-objects directly.  Internal
callers in bundle.c and upload-pack.c combine multiple filters into a
single option using "+".

5cb28270a1 introduced OPT_PARSE_LIST_OBJECTS_FILTER_INIT.  It relies on
being able to faithfully convert function pointers to object pointers
and back, which is undefined in C99.  The standard mentions this ability
as a common extension in its annex J (J.5.7 Function pointer casts), but
avoiding that dependency is more portable.  The macro hasn't been used
since, OPT_PARSE_LIST_OBJECTS_FILTER is enough so far.

So revert 5cb28270a1 fully to fix support for multiple --filter options
and avoid reliance on undefined behavior.  Its intent is better served
by the release_revisions() call added by 2108fe4a19 alone -- we just
need to do it unconditionally, mirroring the unconditional call of
repo_init_revisions().

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: René Scharfe <l.s.r@web.de>
---
 builtin/pack-objects.c                 | 31 +++++---------------------
 list-objects-filter-options.c          |  4 ----
 list-objects-filter-options.h          | 24 +++-----------------
 t/t5317-pack-objects-filter-objects.sh |  2 +-
 4 files changed, 10 insertions(+), 51 deletions(-)

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 573d0b20b7..3e74fbb0cd 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -4149,21 +4149,6 @@ static int option_parse_cruft_expiration(const struct option *opt,
 	return 0;
 }

-struct po_filter_data {
-	unsigned have_revs:1;
-	struct rev_info revs;
-};
-
-static struct list_objects_filter_options *po_filter_revs_init(void *value)
-{
-	struct po_filter_data *data = value;
-
-	repo_init_revisions(the_repository, &data->revs, NULL);
-	data->have_revs = 1;
-
-	return &data->revs.filter;
-}
-
 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 {
 	int use_internal_rev_list = 0;
@@ -4174,7 +4159,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 	int rev_list_index = 0;
 	int stdin_packs = 0;
 	struct string_list keep_pack_list = STRING_LIST_INIT_NODUP;
-	struct po_filter_data pfd = { .have_revs = 0 };
+	struct rev_info revs;

 	struct option pack_objects_options[] = {
 		OPT_SET_INT('q', "quiet", &progress,
@@ -4265,7 +4250,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 			      &write_bitmap_index,
 			      N_("write a bitmap index if possible"),
 			      WRITE_BITMAP_QUIET, PARSE_OPT_HIDDEN),
-		OPT_PARSE_LIST_OBJECTS_FILTER_INIT(&pfd, po_filter_revs_init),
+		OPT_PARSE_LIST_OBJECTS_FILTER(&revs.filter),
 		OPT_CALLBACK_F(0, "missing", NULL, N_("action"),
 		  N_("handling for missing objects"), PARSE_OPT_NONEG,
 		  option_parse_missing_action),
@@ -4284,6 +4269,8 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)

 	read_replace_refs = 0;

+	repo_init_revisions(the_repository, &revs, NULL);
+
 	sparse = git_env_bool("GIT_TEST_PACK_SPARSE", -1);
 	if (the_repository->gitdir) {
 		prepare_repo_settings(the_repository);
@@ -4385,7 +4372,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 	if (!rev_list_all || !rev_list_reflog || !rev_list_index)
 		unpack_unreachable_expiration = 0;

-	if (pfd.have_revs && pfd.revs.filter.choice) {
+	if (revs.filter.choice) {
 		if (!pack_to_stdout)
 			die(_("cannot use --filter without --stdout"));
 		if (stdin_packs)
@@ -4472,16 +4459,10 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 		read_cruft_objects();
 	} else if (!use_internal_rev_list) {
 		read_object_list_from_stdin();
-	} else if (pfd.have_revs) {
-		get_object_list(&pfd.revs, rp.nr, rp.v);
-		release_revisions(&pfd.revs);
 	} else {
-		struct rev_info revs;
-
-		repo_init_revisions(the_repository, &revs, NULL);
 		get_object_list(&revs, rp.nr, rp.v);
-		release_revisions(&revs);
 	}
+	release_revisions(&revs);
 	cleanup_preferred_base();
 	if (include_tag && nr_result)
 		for_each_tag_ref(add_ref_tag, NULL);
diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 5339660238..ee01bcd2cc 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -290,10 +290,6 @@ int opt_parse_list_objects_filter(const struct option *opt,
 				  const char *arg, int unset)
 {
 	struct list_objects_filter_options *filter_options = opt->value;
-	opt_lof_init init = (opt_lof_init)opt->defval;
-
-	if (init)
-		filter_options = init(opt->value);

 	if (unset || !arg)
 		list_objects_filter_set_no_filter(filter_options);
diff --git a/list-objects-filter-options.h b/list-objects-filter-options.h
index 7eeadab2dd..64af2e29e2 100644
--- a/list-objects-filter-options.h
+++ b/list-objects-filter-options.h
@@ -107,31 +107,13 @@ void parse_list_objects_filter(
 	struct list_objects_filter_options *filter_options,
 	const char *arg);

-/**
- * The opt->value to opt_parse_list_objects_filter() is either a
- * "struct list_objects_filter_option *" when using
- * OPT_PARSE_LIST_OBJECTS_FILTER().
- *
- * Or, if using no "struct option" field is used by the callback,
- * except the "defval" which is expected to be an "opt_lof_init"
- * function, which is called with the "opt->value" and must return a
- * pointer to the ""struct list_objects_filter_option *" to be used.
- *
- * The OPT_PARSE_LIST_OBJECTS_FILTER_INIT() can be used e.g. the
- * "struct list_objects_filter_option" is embedded in a "struct
- * rev_info", which the "defval" could be tasked with lazily
- * initializing. See cmd_pack_objects() for an example.
- */
 int opt_parse_list_objects_filter(const struct option *opt,
 				  const char *arg, int unset);
-typedef struct list_objects_filter_options *(*opt_lof_init)(void *);
-#define OPT_PARSE_LIST_OBJECTS_FILTER_INIT(fo, init) \
-	{ OPTION_CALLBACK, 0, "filter", (fo), N_("args"), \
-	  N_("object filtering"), 0, opt_parse_list_objects_filter, \
-	  (intptr_t)(init) }

 #define OPT_PARSE_LIST_OBJECTS_FILTER(fo) \
-	OPT_PARSE_LIST_OBJECTS_FILTER_INIT((fo), NULL)
+	OPT_CALLBACK(0, "filter", fo, N_("args"), \
+	  N_("object filtering"), \
+	  opt_parse_list_objects_filter)

 /*
  * Translates abbreviated numbers in the filter's filter_spec into their
diff --git a/t/t5317-pack-objects-filter-objects.sh b/t/t5317-pack-objects-filter-objects.sh
index 25faebaada..5b707d911b 100755
--- a/t/t5317-pack-objects-filter-objects.sh
+++ b/t/t5317-pack-objects-filter-objects.sh
@@ -265,7 +265,7 @@ test_expect_success 'verify normal and blob:limit packfiles have same commits/tr
 	test_cmp expected observed
 '

-test_expect_failure 'verify small limit and big limit results in small limit' '
+test_expect_success 'verify small limit and big limit results in small limit' '
 	git -C r2 ls-files -s large.1000 >ls_files_result &&
 	test_parse_ls_files_stage_oids <ls_files_result |
 	sort >expected &&
--
2.38.1