pack-objects: lazily set up "struct rev_info", don't leak
In the preceding [1] (pack-objects: move revs out of
get_object_list(), 2022-03-22) the "repo_init_revisions()" was moved
to cmd_pack_objects() so that it unconditionally took place for all
invocations of "git pack-objects".
We'd thus start leaking memory, which is easily reproduced in
e.g. git.git by feeding e83c5163316 (Initial revision of "git", the
information manager from hell, 2005-04-07) to "git pack-objects";
$ echo e83c5163316f89bfbde7d9ab23ca2e25604af290 | ./git pack-objects initial
[...]
==19130==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 7120 byte(s) in 1 object(s) allocated from:
#0 0x455308 in __interceptor_malloc (/home/avar/g/git/git+0x455308)
#1 0x75b399 in do_xmalloc /home/avar/g/git/wrapper.c:41:8
#2 0x75b356 in xmalloc /home/avar/g/git/wrapper.c:62:9
#3 0x5d7609 in prep_parse_options /home/avar/g/git/diff.c:5647:2
#4 0x5d415a in repo_diff_setup /home/avar/g/git/diff.c:4621:2
#5 0x6dffbb in repo_init_revisions /home/avar/g/git/revision.c:1853:2
#6 0x4f599d in cmd_pack_objects /home/avar/g/git/builtin/pack-objects.c:3980:2
#7 0x4592ca in run_builtin /home/avar/g/git/git.c:465:11
#8 0x457d81 in handle_builtin /home/avar/g/git/git.c:718:3
#9 0x458ca5 in run_argv /home/avar/g/git/git.c:785:4
#10 0x457b40 in cmd_main /home/avar/g/git/git.c:916:19
#11 0x562259 in main /home/avar/g/git/common-main.c:56:11
#12 0x7fce792ac7ec in __libc_start_main csu/../csu/libc-start.c:332:16
#13 0x4300f9 in _start (/home/avar/g/git/git+0x4300f9)
SUMMARY: LeakSanitizer: 7120 byte(s) leaked in 1 allocation(s).
Aborted
Narrowly fixing that commit would have been easy, just add call
repo_init_revisions() right before get_object_list(), which is
effectively what was done before that commit.
But an unstated constraint when setting it up early is that it was
needed for the subsequent [2] (pack-objects: parse --filter directly
into revs.filter, 2022-03-22), i.e. we might have a --filter
command-line option, and need to either have the "struct rev_info"
setup when we encounter that option, or later.
Let's just change the control flow so that we'll instead set up the
"struct rev_info" only when we need it. Doing so leads to a bit more
verbosity, but it's a lot clearer what we're doing and why.
An earlier version of this commit[3] went behind
opt_parse_list_objects_filter()'s back by faking up a "struct option"
before calling it. Let's avoid that and instead create a blessed API
for this pattern.
We could furthermore combine the two get_object_list() invocations
here by having repo_init_revisions() invoked on &pfd.revs, but I think
clearly separating the two makes the flow clearer. Likewise
redundantly but explicitly (i.e. redundant v.s. a "{ 0 }") "0" to
"have_revs" early in cmd_pack_objects().
While we're at it add parentheses around the arguments to the OPT_*
macros in in list-objects-filter-options.h, as we need to change those
lines anyway. It doesn't matter in this case, but is good general
practice.
1. https://lore.kernel.org/git/619b757d98465dbc4995bdc11a5282fbfcbd3daa.1647970119.git.gitgitgadget@gmail.com
2. https://lore.kernel.org/git/97de926904988b89b5663bd4c59c011a1723a8f5.1647970119.git.gitgitgadget@gmail.com
3. https://lore.kernel.org/git/patch-1.1-193534b0f07-20220325T121715Z-avarab@gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/list-objects-filter-options.h b/list-objects-filter-options.h
index 90e4bc9..ffc02d7 100644
--- a/list-objects-filter-options.h
+++ b/list-objects-filter-options.h
@@ -104,13 +104,31 @@ 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_CALLBACK(0, "filter", fo, N_("args"), \
- N_("object filtering"), \
- opt_parse_list_objects_filter)
+ OPT_PARSE_LIST_OBJECTS_FILTER_INIT((fo), NULL)
/*
* Translates abbreviated numbers in the filter's filter_spec into their
