[v3,5/5] list-objects-filter: remove OPT_PARSE_LIST_OBJECTS_FILTER_INIT()

Commit Message

René Scharfe Nov. 29, 2022, 12:26 p.m. UTC

OPT_PARSE_LIST_OBJECTS_FILTER_INIT() with a non-NULL second argument
passes a function pointer via an object pointer, which is undefined.  It
may work fine on platforms that implement C99 extension J.5.7 (Function
pointer casts).  Remove the unused macro and avoid the dependency on
that extension.

Signed-off-by: René Scharfe <[e-mail]>
---
 list-objects-filter-options.c |  4 ----
 list-objects-filter-options.h | 18 ++----------------
 2 files changed, 2 insertions(+), 20 deletions(-)

--
2.38.1

Comments

Junio C Hamano Nov. 30, 2022, 1:20 a.m. UTC | #1

René Scharfe <[e-mail]> writes:

> OPT_PARSE_LIST_OBJECTS_FILTER_INIT() with a non-NULL second argument
> passes a function pointer via an object pointer, which is undefined.  It
> may work fine on platforms that implement C99 extension J.5.7 (Function
> pointer casts).  Remove the unused macro and avoid the dependency on
> that extension.

Makes sense.  Some of us may consider that no platform of importance
exists in practice that breaks with such a cast, but our opinion
does not matter at all, while opinion of those who supply compilers
and checkers to us do---they may decide to flag such a use with a
warning and that would break our build with the -Werror option.  If
we do not have to rely on the extension, we should.

Thanks.

Patch

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..1fe393f447 100644
--- a/list-objects-filter-options.h
+++ b/list-objects-filter-options.h
@@ -111,27 +111,13 @@  void parse_list_objects_filter(
  * 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