*.h: move some *_INIT to designated initializers

Move various *_INIT macros to use designated initializers. This helps
readability. I've only picked those leftover macros that were not
touched by another in-flight series of mine which changed others, but
also how initialization was done.

In the case of SUBMODULE_ALTERNATE_SETUP_INIT I've left an explicit
initialization of "error_mode", even though
SUBMODULE_ALTERNATE_ERROR_IGNORE itself is defined as "0". Let's not
peek under the hood and assume that enum fields we know the value of
will stay at "0".

The change to "TESTSUITE_INIT" in "t/helper/test-run-command.c" was
part of an earlier on-list version[1] of c90be786da (test-tool
run-command: fix flip-flop init pattern, 2021-09-11).

1. https://lore.kernel.org/git/patch-1.1-0aa4523ab6e-20210909T130849Z-avarab@gmail.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

add-interactive.c

@@ -102,8 +102,12 @@ struct prefix_item_list {
 	int *selected; /* for multi-selections */
 	size_t min_length, max_length;
 };
-#define PREFIX_ITEM_LIST_INIT \
+#define PREFIX_ITEM_LIST_INIT { \
-	{ STRING_LIST_INIT_DUP, STRING_LIST_INIT_NODUP, NULL, 1, 4 }
+	.items = STRING_LIST_INIT_DUP, \
+	.sorted = STRING_LIST_INIT_NODUP, \
+	.min_length = 1, \
+	.max_length = 4, \
+}
 
 static void prefix_item_list_clear(struct prefix_item_list *list)
 {

builtin/submodule--helper.c

@@ -1647,8 +1647,9 @@ struct submodule_alternate_setup {
 	} error_mode;
 	struct string_list *reference;
 };
-#define SUBMODULE_ALTERNATE_SETUP_INIT { NULL, \
+#define SUBMODULE_ALTERNATE_SETUP_INIT { \
-	SUBMODULE_ALTERNATE_ERROR_IGNORE, NULL }
+	.error_mode = SUBMODULE_ALTERNATE_ERROR_IGNORE, \
+}
 
 static const char alternate_error_advice[] = N_(
 "An alternate computed from a superproject's alternate is invalid.\n"

cache.h

@@ -1668,7 +1668,9 @@ struct cache_def {
 	int track_flags;
 	int prefix_len_stat_func;
 };
-#define CACHE_DEF_INIT { STRBUF_INIT }
+#define CACHE_DEF_INIT { \
+	.path = STRBUF_INIT, \
+}
 static inline void cache_def_clear(struct cache_def *cache)
 {
 	strbuf_release(&cache->path);

entry.h

@@ -16,7 +16,7 @@ struct checkout {
 		 clone:1,
 		 refresh_cache:1;
 };
-#define CHECKOUT_INIT { NULL, "" }
+#define CHECKOUT_INIT { .base_dir = "" }
 
 #define TEMPORARY_FILENAME_LENGTH 25
 /*

list.h

@@ -46,7 +46,10 @@ struct list_head {
 #define INIT_LIST_HEAD(ptr) \
 	(ptr)->next = (ptr)->prev = (ptr)
 
-#define LIST_HEAD_INIT(name) { &(name), &(name) }
+#define LIST_HEAD_INIT(name) { \
+	.next = &(name), \
+	.prev = &(name), \
+}
 
 /* Add new element at the head of the list. */
 static inline void list_add(struct list_head *newp, struct list_head *head)

sequencer.h

@@ -119,7 +119,9 @@ struct todo_list {
 	struct stat_data stat;
 };
 
-#define TODO_LIST_INIT { STRBUF_INIT }
+#define TODO_LIST_INIT { \
+	.buf = STRBUF_INIT, \
+}
 
 int todo_list_parse_insn_buffer(struct repository *r, char *buf,
 				struct todo_list *todo_list);

shallow.h

@@ -23,7 +23,9 @@ int is_repository_shallow(struct repository *r);
 struct shallow_lock {
 	struct lock_file lock;
 };
-#define SHALLOW_LOCK_INIT { LOCK_INIT }
+#define SHALLOW_LOCK_INIT { \
+	.lock = LOCK_INIT, \
+}
 
 /* commit $GIT_DIR/shallow and reset stat-validity checks */
 int commit_shallow_file(struct repository *r, struct shallow_lock *lk);

strvec.h

@@ -33,7 +33,9 @@ struct strvec {
 	size_t alloc;
 };
 
-#define STRVEC_INIT { empty_strvec }
+#define STRVEC_INIT { \
+	.v = empty_strvec, \
+}
 
 /**
  * Initialize an array. This is no different than assigning from

submodule.c

@@ -1321,9 +1321,11 @@ struct submodule_parallel_fetch {
 
 	struct strbuf submodules_with_errors;
 };
-#define SPF_INIT {0, STRVEC_INIT, NULL, NULL, 0, 0, 0, 0, \
+#define SPF_INIT { \
-		  STRING_LIST_INIT_DUP, \
+	.args = STRVEC_INIT, \
-		  NULL, 0, 0, STRBUF_INIT}
+	.changed_submodule_names = STRING_LIST_INIT_DUP, \
+	.submodules_with_errors = STRBUF_INIT, \
+}
 
 static int get_fetch_recurse_config(const struct submodule *submodule,
 				    struct submodule_parallel_fetch *spf)

submodule.h

@@ -37,7 +37,9 @@ struct submodule_update_strategy {
 	enum submodule_update_type type;
 	const char *command;
 };
-#define SUBMODULE_UPDATE_STRATEGY_INIT {SM_UPDATE_UNSPECIFIED}
+#define SUBMODULE_UPDATE_STRATEGY_INIT { \
+	.type = SM_UPDATE_UNSPECIFIED, \
+}
 
 int is_gitmodules_unmerged(struct index_state *istate);
 int is_writing_gitmodules_ok(void);

t/helper/test-run-command.c

@@ -60,8 +60,10 @@ struct testsuite {
 	int next;
 	int quiet, immediate, verbose, verbose_log, trace, write_junit_xml;
 };
-#define TESTSUITE_INIT \
+#define TESTSUITE_INIT { \
-	{ STRING_LIST_INIT_DUP, STRING_LIST_INIT_DUP }
+	.tests = STRING_LIST_INIT_DUP, \
+	.failed = STRING_LIST_INIT_DUP, \
+}
 
 static int next_test(struct child_process *cp, struct strbuf *err, void *cb,
 		     void **task_cb)

trace.h

@@ -89,7 +89,7 @@ struct trace_key {
 
 extern struct trace_key trace_default_key;
 
-#define TRACE_KEY_INIT(name) { "GIT_TRACE_" #name }
+#define TRACE_KEY_INIT(name) { .key = "GIT_TRACE_" #name }
 extern struct trace_key trace_perf_key;
 extern struct trace_key trace_setup_key;
 

transport.h

@@ -262,7 +262,9 @@ struct transport_ls_refs_options {
 	 */
 	char *unborn_head_target;
 };
-#define TRANSPORT_LS_REFS_OPTIONS_INIT { STRVEC_INIT }
+#define TRANSPORT_LS_REFS_OPTIONS_INIT { \
+	.ref_prefixes = STRVEC_INIT, \
+}
 
 /*
  * Retrieve refs from a remote.