*.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 c90be786da9 (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>

13 files changed, 42 insertions, 18 deletions

diff --git a/add-interactive.c b/add-interactive.c
index 36ebdbdf7e..6498ae196f 100644
--- a/add-interactive.c
+++ b/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 \
-	{ STRING_LIST_INIT_DUP, STRING_LIST_INIT_NODUP, NULL, 1, 4 }
+#define PREFIX_ITEM_LIST_INIT { \
+	.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)
 {
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index deca75c83e..57f0992515 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -1647,8 +1647,9 @@ struct submodule_alternate_setup {
 	} error_mode;
 	struct string_list *reference;
 };
-#define SUBMODULE_ALTERNATE_SETUP_INIT { NULL, \
-	SUBMODULE_ALTERNATE_ERROR_IGNORE, NULL }
+#define SUBMODULE_ALTERNATE_SETUP_INIT { \
+	.error_mode = SUBMODULE_ALTERNATE_ERROR_IGNORE, \
+}
 
 static const char alternate_error_advice[] = N_(
 "An alternate computed from a superproject's alternate is invalid.\n"
diff --git a/cache.h b/cache.h
index 25c6b0b120..794237515b 100644
--- a/cache.h
+++ b/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);
diff --git a/entry.h b/entry.h
index 7c889e58fd..2254c62727 100644
--- a/entry.h
+++ b/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
 /*
diff --git a/list.h b/list.h
index eb601192f4..362a4cd7f5 100644
--- a/list.h
+++ b/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)
diff --git a/sequencer.h b/sequencer.h
index 2088344cb3..259d4eb4a8 100644
--- a/sequencer.h
+++ b/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);
diff --git a/shallow.h b/shallow.h
index 5b4a96dcd6..aba6ff5829 100644
--- a/shallow.h
+++ b/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);
diff --git a/strvec.h b/strvec.h
index a10aad5f64..9f55c8766b 100644
--- a/strvec.h
+++ b/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
diff --git a/submodule.c b/submodule.c
index 78aed03d92..03cf36707a 100644
--- a/submodule.c
+++ b/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, \
-		  STRING_LIST_INIT_DUP, \
-		  NULL, 0, 0, STRBUF_INIT}
+#define SPF_INIT { \
+	.args = STRVEC_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)
diff --git a/submodule.h b/submodule.h
index 35d18c7868..6bd2c99fd9 100644
--- a/submodule.h
+++ b/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);
diff --git a/t/helper/test-run-command.c b/t/helper/test-run-command.c
index 50bb98b7e0..3c4fb86223 100644
--- a/t/helper/test-run-command.c
+++ b/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 \
-	{ STRING_LIST_INIT_DUP, STRING_LIST_INIT_DUP }
+#define TESTSUITE_INIT { \
+	.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)
diff --git a/trace.h b/trace.h
index 74f62919c5..e25984051a 100644
--- a/trace.h
+++ b/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;
 
diff --git a/transport.h b/transport.h
index 1cbab11373..8bb4c8bbc8 100644
--- a/transport.h
+++ b/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.