[PATCH v4 00/12] submodule: make "git submodule--helper" behave like "git submodule"

These are preparatory changes to make "git submodule--helper"'s behavior align with that of "git submodule". The next step after this is to get rid of git-submodule.sh entirely, and make "git submodule" a built-in.

The last two patches here are post-cleanup of related submodule code that isn't strictly necessary, but good to do. Similarly this starts with the removal of some dead code in the area.

The goal is to make these changes as small as possible, and as obviously correct as possible. This will help to make the meaty changes that follow easier to review.

Changes since v3:

 * Leave the --super-prefix changes aside for now. As discussed in the
   v3 follow-up, now we're only removing the unused $prefix variable.

   Since the v2 was submitted Glen's submitted a series of his own. I
   think any non-trivial updates to --super-prefix are better done
   there, as noted in:
   https://lore.kernel.org/git/220628.86wnd1f9t1.gmgdl@evledraar.gmail.com/

   The overall diffstat is much smaller as a result, and I think this
   series should be ready for "next" now, as the remaining changes are
   well-revieweda at this point, with no outstanding issues.

Glen Choo (1):
  submodule--helper: eliminate internal "--update" option

Ævar Arnfjörð Bjarmason (11):
  git-submodule.sh: remove unused sanitize_submodule_env()
  git-submodule.sh: remove unused $prefix variable
  git-submodule.sh: make the "$cached" variable a boolean
  git-submodule.sh: remove unused top-level "--branch" argument
  submodule--helper: have --require-init imply --init
  submodule update: remove "-v" option
  submodule--helper: rename "absorb-git-dirs" to "absorbgitdirs"
  submodule--helper: report "submodule" as our name in some "-h" output
  submodule--helper: understand --checkout, --merge and --rebase
    synonyms
  git-submodule.sh: use "$quiet", not "$GIT_QUIET"
  git-sh-setup.sh: remove "say" function, change last users

 builtin/submodule--helper.c    | 74 ++++++++++++++++++----------
 contrib/subtree/git-subtree.sh | 15 ++++--
 git-instaweb.sh                |  2 +-
 git-sh-setup.sh                | 16 -------
 git-submodule.sh               | 88 ++++++++++++----------------------
 submodule.c                    |  2 +-
 t/t7406-submodule-update.sh    |  2 +-
 7 files changed, 96 insertions(+), 103 deletions(-)

Range-diff against v3:
 1:  ed487469d62 =  1:  63150b4091c git-submodule.sh: remove unused sanitize_submodule_env()
 2:  082e015781e !  2:  7bf62497c54 git-submodule.sh: remove unused $prefix var and --super-prefix
    @@ Metadata
     Author: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
     
      ## Commit message ##
    -    git-submodule.sh: remove unused $prefix var and --super-prefix
    +    git-submodule.sh: remove unused $prefix variable
     
         Remove the $prefix variable which isn't used anymore, and hasn't been
         since b3c5f5cb048 (submodule: move core cmd_update() logic to C,
    @@ Commit message
         "--recursive-prefix" option, but since b3c5f5cb048 that "git
         submodule--helper" option is only used when it invokes itself.
     
    -    Since we haven't used it since then we haven't been passing the
    -    --super-prefix option to "git submodule--helper", and can therefore
    -    remove the handling of it from builtin/submodule--helper.c as well.
    -
    -    Note also that the still-existing code in builtin/submodule--helper.c
    -    to invoke other "git submodule--helper" processes with
    -    "--super-prefix" is not passing the option to
    -    "cmd_submodule__helper()", rather it's an argument to "git" itself.
    -
    -    One way to verify that this is indeed dead code is to try to check out
    -    b3c5f5cb048^ and apply this change to a part of the code being removed
    -    here:
    -
    -            -#define SUPPORT_SUPER_PREFIX (1<<0)
    -            +#define SUPPORT_SUPER_PREFIX 0
    -
    -    Doing that will cause t7406-submodule-update.sh to fail with errors
    -    such as:
    -
    -            -Submodule path '../super': checked out 'e1c658656b91df52a4634fbffeaa739807ce3521'
    -            +Submodule path 'super': checked out 'e1c658656b91df52a4634fbffeaa739807ce3521'
    -
    -    I.e. the removal of the --super-prefix handling broke those cases, but
    -    when doing the same ad-hoc test with b3c5f5cb048 all of our tests will
    -    pass, since the "--super-prefix" will now be handled by earlier by
    -    "git" itself.
    -
    -    So this is just one of the things that were overly complex in "git
    -    submodule--helper", because parts of it had to bridge the gap between
    -    *.sh and *.c land, but once we moved more parts to C we ended up
    -    getting that for free.
    +    So the "--recursive-prefix" option is still in use, but at this point
    +    only when the helper invokes itself during submodule recursion. See
    +    the "--recursive-prefix" option added in
    +    c51f8f94e5b (submodule--helper: run update procedures from C,
    +    2021-08-24).
     
         Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
     
    - ## builtin/submodule--helper.c ##
    -@@ builtin/submodule--helper.c: static int module_add(int argc, const char **argv, const char *prefix)
    - 	return 0;
    - }
    - 
    --#define SUPPORT_SUPER_PREFIX (1<<0)
    --
    - struct cmd_struct {
    - 	const char *cmd;
    - 	int (*fn)(int, const char **, const char *);
    --	unsigned option;
    - };
    - 
    - static struct cmd_struct commands[] = {
    --	{"list", module_list, 0},
    --	{"name", module_name, 0},
    --	{"clone", module_clone, 0},
    --	{"add", module_add, SUPPORT_SUPER_PREFIX},
    --	{"update", module_update, 0},
    --	{"resolve-relative-url-test", resolve_relative_url_test, 0},
    --	{"foreach", module_foreach, SUPPORT_SUPER_PREFIX},
    --	{"init", module_init, SUPPORT_SUPER_PREFIX},
    --	{"status", module_status, SUPPORT_SUPER_PREFIX},
    --	{"sync", module_sync, SUPPORT_SUPER_PREFIX},
    --	{"deinit", module_deinit, 0},
    --	{"summary", module_summary, SUPPORT_SUPER_PREFIX},
    --	{"push-check", push_check, 0},
    --	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
    --	{"is-active", is_active, 0},
    --	{"check-name", check_name, 0},
    --	{"config", module_config, 0},
    --	{"set-url", module_set_url, 0},
    --	{"set-branch", module_set_branch, 0},
    --	{"create-branch", module_create_branch, 0},
    -+	{"list", module_list},
    -+	{"name", module_name},
    -+	{"clone", module_clone},
    -+	{"add", module_add},
    -+	{"update", module_update},
    -+	{"resolve-relative-url-test", resolve_relative_url_test},
    -+	{"foreach", module_foreach},
    -+	{"init", module_init},
    -+	{"status", module_status},
    -+	{"sync", module_sync},
    -+	{"deinit", module_deinit},
    -+	{"summary", module_summary},
    -+	{"push-check", push_check},
    -+	{"absorb-git-dirs", absorb_git_dirs},
    -+	{"is-active", is_active},
    -+	{"check-name", check_name},
    -+	{"config", module_config},
    -+	{"set-url", module_set_url},
    -+	{"set-branch", module_set_branch},
    -+	{"create-branch", module_create_branch},
    - };
    - 
    - int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
    -@@ builtin/submodule--helper.c: int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
    - 	if (argc < 2 || !strcmp(argv[1], "-h"))
    - 		usage("git submodule--helper <command>");
    - 
    --	for (i = 0; i < ARRAY_SIZE(commands); i++) {
    --		if (!strcmp(argv[1], commands[i].cmd)) {
    --			if (get_super_prefix() &&
    --			    !(commands[i].option & SUPPORT_SUPER_PREFIX))
    --				die(_("%s doesn't support --super-prefix"),
    --				    commands[i].cmd);
    -+	for (i = 0; i < ARRAY_SIZE(commands); i++)
    -+		if (!strcmp(argv[1], commands[i].cmd))
    - 			return commands[i].fn(argc - 1, argv + 1, prefix);
    --		}
    --	}
    - 
    - 	die(_("'%s' is not a valid submodule--helper "
    - 	      "subcommand"), argv[1]);
    -
      ## git-submodule.sh ##
     @@ git-submodule.sh: files=
      remote=
 3:  3948aa5d782 =  3:  e4750f190f8 git-submodule.sh: make the "$cached" variable a boolean
 4:  b5967afd59f =  4:  52d97fd4c36 git-submodule.sh: remove unused top-level "--branch" argument
 5:  64e4aa41d21 =  5:  a4632f00a4a submodule--helper: have --require-init imply --init
 6:  b82faad77bb =  6:  ad5aad8fed7 submodule update: remove "-v" option
 7:  ff557f3c81a !  7:  9c8a102acc0 submodule--helper: rename "absorb-git-dirs" to "absorbgitdirs"
    @@ builtin/submodule--helper.c: static int absorb_git_dirs(int argc, const char **a
      	};
      
     @@ builtin/submodule--helper.c: static struct cmd_struct commands[] = {
    - 	{"deinit", module_deinit},
    - 	{"summary", module_summary},
    - 	{"push-check", push_check},
    --	{"absorb-git-dirs", absorb_git_dirs},
    -+	{"absorbgitdirs", absorb_git_dirs},
    - 	{"is-active", is_active},
    - 	{"check-name", check_name},
    - 	{"config", module_config},
    + 	{"deinit", module_deinit, 0},
    + 	{"summary", module_summary, SUPPORT_SUPER_PREFIX},
    + 	{"push-check", push_check, 0},
    +-	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
    ++	{"absorbgitdirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
    + 	{"is-active", is_active, 0},
    + 	{"check-name", check_name, 0},
    + 	{"config", module_config, 0},
     
      ## git-submodule.sh ##
     @@ git-submodule.sh: cmd_sync()
 8:  bb1310b9abe =  8:  b8a9b085633 submodule--helper: report "submodule" as our name in some "-h" output
 9:  e251fc115e1 =  9:  e8ddb95dcbf submodule--helper: understand --checkout, --merge and --rebase synonyms
10:  66a229227a1 = 10:  abb5cb499aa submodule--helper: eliminate internal "--update" option
11:  f8219cd461d = 11:  c7eac40a0f2 git-submodule.sh: use "$quiet", not "$GIT_QUIET"
12:  ecdd8c6ed28 = 12:  f8f332f3c0a git-sh-setup.sh: remove "say" function, change last users