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[PATCH v4 4/9] submodule--helper: don't use global --super-prefix in "absorbgitdirs"

From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date
Dec 15, 2022, 09:32 UTC
Message-ID
<patch-v4-4.9-bde9038c4e3-20221215T083502Z-avarab@gmail.com>
In-Reply-To
<cover-v4-0.9-00000000000-20221215T083502Z-avarab@gmail.com>

The "--super-prefix" facility was introduced in [1] has always been a transitory hack, which is why we've made it an error to supply it as an option to "git" to commands that don't know about it.

That's been a good goal, as it has a global effect we haven't wanted calls to get_super_prefix() from built-ins we didn't expect.

But it has meant that when we've had chains of different built-ins using it all of the processes in that "chain" have needed to support it, and worse processes that don't need it have needed to ask for "SUPPORT_SUPER_PREFIX" because their parent process needs it.

That's how "fsmonitor--daemon" ended up with it, per [2] it's called from (among other things) "submodule--helper absorbgitdirs", but as we declared "submodule--helper" as "SUPPORT_SUPER_PREFIX" we needed to declare "fsmonitor--daemon" as accepting it too, even though it doesn't care about it.

But in the case of "absorbgitdirs" it only needed "--super-prefix" to invoke itself recursively, and we'd never have another "in-between" process in the chain. So we didn't need the bigger hammer of "git --super-prefix", and the "setenv(GIT_SUPER_PREFIX_ENVIRONMENT, ...)" that it entails.

Let's instead accept a hidden "--super-prefix" option to "submodule--helper absorbgitdirs" itself.

Eventually (as with all other "--super-prefix" users) we'll want to clean this code up so that this all happens in-process. I.e. needing any variant of "--super-prefix" is itself a hack around our various global state, and implicit reliance on "the_repository". This stepping stone makes such an eventual change easier, as we'll need to deal with less global state at that point.

The "fsmonitor--daemon" test adjusted here was added in [3]. To assert that it didn't run into the "--super-prefix" message it was asserting the output it didn't have. Let's instead assert the full output that we *do* have, which we can do here as this is based on a change[4] to make it predictable (until [4] it contained absolute paths).

We could also remove the test entirely (as [5] did), but even though the initial reason for having it is gone we're still getting some marginal benefit from testing the "fsmonitor" and "submodule absorbgitdirs" interaction, so let's keep it.

The change here to have either a NULL or non-"" string as a "super_prefix" instead of the previous arrangement of "" or non-"" is somewhat arbitrary. We could also decide to never have to check for NULL.

As we'll be changing the rest of the "git --super-prefix" users to the same pattern, leaving them all consistent makes sense. Why not pick "" over NULL? Because that's how the "prefix" works[6], and having "prefix" and "super_prefix" work the same way will be less confusing. That "prefix" picked NULL instead of "" is itself arbitrary, but as it's easy to make this small bit of our overall API consistent, let's go with that.

1. 74866d75793 (git: make super-prefix option, 2016-10-07)
2. 53fcfbc84f6 (fsmonitor--daemon: allow --super-prefix argument,
   2022-05-26)
3. 53fcfbc84f6 (fsmonitor--daemon: allow --super-prefix argument,
   2022-05-26)
4. https://lore.kernel.org/git/patch-1.1-34b54fdd9bb-20221109T020347Z-avarab@gmail.com/
5. https://lore.kernel.org/git/20221109004708.97668-5-chooglen@google.com/
6. 9725c8dda20 (built-ins: trust the "prefix" from run_builtin(),
   2022-02-16)
Signed-off-by: Glen Choo <chooglen@google.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 builtin/submodule--helper.c  |  7 +++----
 git.c                        |  2 +-
 parse-options.h              |  4 ++++
 submodule.c                  | 12 +++++++-----
 t/t7527-builtin-fsmonitor.sh | 36 ++++++++++++++----------------------
 5 files changed, 29 insertions(+), 32 deletions(-)
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index da844cad5ce..b8b2bc776d1 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -2834,8 +2834,9 @@ static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
 	int i;
 	struct pathspec pathspec = { 0 };
 	struct module_list list = MODULE_LIST_INIT;
-	const char *super_prefix;
+	const char *super_prefix = NULL;
 	struct option embed_gitdir_options[] = {
+		OPT__SUPER_PREFIX(&super_prefix),
 		OPT_END()
 	};
 	const char *const git_submodule_helper_usage[] = {
@@ -2850,7 +2851,6 @@ static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
 	if (module_list_compute(argv, prefix, &pathspec, &list) < 0)
 		goto cleanup;
 
-	super_prefix = get_super_prefix();
 	for (i = 0; i < list.nr; i++)
 		absorb_git_dir_into_superproject(list.entries[i]->name,
 						 super_prefix);
@@ -3391,8 +3391,7 @@ int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
 
 	if (strcmp(subcmd, "clone") && strcmp(subcmd, "update") &&
 	    strcmp(subcmd, "foreach") && strcmp(subcmd, "status") &&
-	    strcmp(subcmd, "sync") && strcmp(subcmd, "absorbgitdirs") &&
-	    get_super_prefix())
+	    strcmp(subcmd, "sync") && get_super_prefix())
 		/*
 		 * xstrfmt() rather than "%s %s" to keep the translated
 		 * string identical to git.c's.
diff --git a/git.c b/git.c
index 277a8cce840..e473b4b7d72 100644
--- a/git.c
+++ b/git.c
@@ -539,7 +539,7 @@ static struct cmd_struct commands[] = {
 	{ "format-patch", cmd_format_patch, RUN_SETUP },
 	{ "fsck", cmd_fsck, RUN_SETUP },
 	{ "fsck-objects", cmd_fsck, RUN_SETUP },
-	{ "fsmonitor--daemon", cmd_fsmonitor__daemon, SUPPORT_SUPER_PREFIX | RUN_SETUP },
+	{ "fsmonitor--daemon", cmd_fsmonitor__daemon, RUN_SETUP },
 	{ "gc", cmd_gc, RUN_SETUP },
 	{ "get-tar-commit-id", cmd_get_tar_commit_id, NO_PARSEOPT },
 	{ "grep", cmd_grep, RUN_SETUP_GENTLY },
diff --git a/parse-options.h b/parse-options.h
index b6ef86e0d15..50d852f2991 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -369,6 +369,10 @@ int parse_opt_tracking_mode(const struct option *, const char *, int);
 	{ OPTION_CALLBACK, 0, "abbrev", (var), N_("n"),	\
 	  N_("use <n> digits to display object names"),	\
 	  PARSE_OPT_OPTARG, &parse_opt_abbrev_cb, 0 }
+#define OPT__SUPER_PREFIX(var) \
+	OPT_STRING_F(0, "super-prefix", (var), N_("prefix"), \
+		N_("prefixed path to initial superproject"), PARSE_OPT_HIDDEN)
+
 #define OPT__COLOR(var, h) \
 	OPT_COLOR_FLAG(0, "color", (var), (h))
 #define OPT_COLUMN(s, l, v, h) \
diff --git a/submodule.c b/submodule.c
index bf19598b8c2..46a03473195 100644
--- a/submodule.c
+++ b/submodule.c
@@ -2275,7 +2275,8 @@ int validate_submodule_git_dir(char *git_dir, const char *submodule_name)
  * Embeds a single submodules git directory into the superprojects git dir,
  * non recursively.
  */
-static void relocate_single_git_dir_into_superproject(const char *path)
+static void relocate_single_git_dir_into_superproject(const char *path,
+						      const char *super_prefix)
 {
 	char *old_git_dir = NULL, *real_old_git_dir = NULL, *real_new_git_dir = NULL;
 	struct strbuf new_gitdir = STRBUF_INIT;
@@ -2305,7 +2306,7 @@ static void relocate_single_git_dir_into_superproject(const char *path)
 	real_new_git_dir = real_pathdup(new_gitdir.buf, 1);
 
 	fprintf(stderr, _("Migrating git directory of '%s%s' from\n'%s' to\n'%s'\n"),
-		get_super_prefix_or_empty(), path,
+		super_prefix ? super_prefix : "", path,
 		real_old_git_dir, real_new_git_dir);
 
 	relocate_gitdir(path, real_old_git_dir, real_new_git_dir);
@@ -2325,10 +2326,11 @@ static void absorb_git_dir_into_superproject_recurse(const char *path,
 	cp.dir = path;
 	cp.git_cmd = 1;
 	cp.no_stdin = 1;
-	strvec_pushf(&cp.args, "--super-prefix=%s%s/", super_prefix ?
-		     super_prefix : "", path);
 	strvec_pushl(&cp.args, "submodule--helper",
 		     "absorbgitdirs", NULL);
+	strvec_pushf(&cp.args, "--super-prefix=%s%s/", super_prefix ?
+		     super_prefix : "", path);
+
 	prepare_submodule_repo_env(&cp.env);
 	if (run_command(&cp))
 		die(_("could not recurse into submodule '%s'"), path);
@@ -2382,7 +2384,7 @@ void absorb_git_dir_into_superproject(const char *path,
 		char *real_common_git_dir = real_pathdup(get_git_common_dir(), 1);
 
 		if (!starts_with(real_sub_git_dir, real_common_git_dir))
-			relocate_single_git_dir_into_superproject(path);
+			relocate_single_git_dir_into_superproject(path, super_prefix);
 
 		free(real_sub_git_dir);
 		free(real_common_git_dir);
diff --git a/t/t7527-builtin-fsmonitor.sh b/t/t7527-builtin-fsmonitor.sh
index 4abc74db2bb..76d0220daa0 100755
--- a/t/t7527-builtin-fsmonitor.sh
+++ b/t/t7527-builtin-fsmonitor.sh
@@ -866,27 +866,9 @@ test_expect_success 'submodule always visited' '
 # the submodule, and someone does a `git submodule absorbgitdirs`
 # in the super, Git will recursively invoke `git submodule--helper`
 # to do the work and this may try to read the index.  This will
-# try to start the daemon in the submodule *and* pass (either
-# directly or via inheritance) the `--super-prefix` arg to the
-# `git fsmonitor--daemon start` command inside the submodule.
-# This causes a warning because fsmonitor--daemon does take that
-# global arg (see the table in git.c)
-#
-# This causes a warning when trying to start the daemon that is
-# somewhat confusing.  It does not seem to hurt anything because
-# the fsmonitor code maps the query failure into a trivial response
-# and does the work anyway.
-#
-# It would be nice to silence the warning, however.
-
-have_t2_error_event () {
-	log=$1
-	msg="fsmonitor--daemon doesnQt support --super-prefix" &&
-
-	tr '\047' Q <$1 | grep -e "$msg"
-}
+# try to start the daemon in the submodule.
 
-test_expect_success "stray submodule super-prefix warning" '
+test_expect_success "submodule absorbgitdirs implicitly starts daemon" '
 	test_when_finished "rm -rf super; \
 			    rm -rf sub;   \
 			    rm super-sub.trace" &&
@@ -904,10 +886,20 @@ test_expect_success "stray submodule super-prefix warning" '
 
 	test_path_is_dir super/dir_1/dir_2/sub/.git &&
 
+	cwd="$(cd super && pwd)" &&
+	cat >expect <<-EOF &&
+	Migrating git directory of '\''dir_1/dir_2/sub'\'' from
+	'\''$cwd/dir_1/dir_2/sub/.git'\'' to
+	'\''$cwd/.git/modules/dir_1/dir_2/sub'\''
+	EOF
 	GIT_TRACE2_EVENT="$PWD/super-sub.trace" \
-		git -C super submodule absorbgitdirs &&
+		git -C super submodule absorbgitdirs >out 2>actual &&
+	test_cmp expect actual &&
+	test_must_be_empty out &&
 
-	! have_t2_error_event super-sub.trace
+	# Confirm that the trace2 log contains a record of the
+	# daemon starting.
+	test_subcommand git fsmonitor--daemon start <super-sub.trace
 '
 
 # On a case-insensitive file system, confirm that the daemon

-- 
2.39.0.rc2.1048.g0e5493b8d5b
Previous: Ævar Arnfjörð BjarmasonNext: Glen Choo
Message 83 of 105 in “git: remove --super-prefix”
  1. 0/4 git: remove --super-prefixGlen Choo, Nov 9, 2022
  2. 1/4 submodule--helper: teach --toplevel-cwd-prefixGlen Choo, Nov 9, 2022
  3. Ævar Arnfjörð BjarmasonNov 9, 2022
  4. 2/4 fetch: refactor --submodule-prefixGlen Choo, Nov 9, 2022
  5. Ævar Arnfjörð BjarmasonNov 9, 2022
  6. 3/4 read-tree: teach --submodule-prefixGlen Choo, Nov 9, 2022
  7. Ævar Arnfjörð BjarmasonNov 9, 2022
  8. 4/4 git: remove --super-prefixGlen Choo, Nov 9, 2022
  9. 0/8 Get rid of "git --super-prefix"Ævar Arnfjörð Bjarmason, Nov 9, 2022
  10. 1/8 submodule--helper: don't use global --super-prefix in "absorbgitdirs"Ævar Arnfjörð Bjarmason, Nov 9, 2022
  11. Glen ChooNov 11, 2022
  12. 2/8 submodule--helper: "deinit" has never used "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 9, 2022
  13. 3/8 submodule--helper: convert "foreach" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 9, 2022
  14. 4/8 submodule--helper: convert "sync" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 9, 2022
  15. 5/8 submodule--helper: convert "status" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 9, 2022
  16. 6/8 submodule--helper: convert "{update,clone}" to their own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 9, 2022
  17. 7/8 submodule tests: test "git branch -t" output and stderrÆvar Arnfjörð Bjarmason, Nov 9, 2022
  18. 8/8 read-tree: add "--super-prefix" option, eliminate globalÆvar Arnfjörð Bjarmason, Nov 9, 2022
  19. Glen ChooNov 11, 2022
  20. Taylor BlauNov 9, 2022
  21. Ævar Arnfjörð BjarmasonNov 9, 2022
  22. Taylor BlauNov 9, 2022
  23. Ævar Arnfjörð BjarmasonNov 9, 2022
  24. Glen ChooNov 10, 2022
  25. Ævar Arnfjörð BjarmasonNov 10, 2022
  26. Glen ChooNov 11, 2022
  27. Glen ChooNov 11, 2022
  28. Ævar Arnfjörð BjarmasonNov 11, 2022
  29. Taylor BlauNov 11, 2022
  30. Glen ChooNov 12, 2022
  31. Ævar Arnfjörð BjarmasonNov 14, 2022
  32. Glen ChooNov 14, 2022
  33. Ævar Arnfjörð BjarmasonNov 15, 2022
  34. 00/10 Get rid of "git --super-prefix"Ævar Arnfjörð Bjarmason, Nov 14, 2022
  35. 01/10 read-tree + fetch tests: test failing "--super-prefix" interactionÆvar Arnfjörð Bjarmason, Nov 14, 2022
  36. Glen ChooNov 14, 2022
  37. Ævar Arnfjörð BjarmasonNov 14, 2022
  38. Glen ChooNov 14, 2022
  39. 02/10 submodule--helper: don't use global --super-prefix in "absorbgitdirs"Ævar Arnfjörð Bjarmason, Nov 14, 2022
  40. Glen ChooNov 14, 2022
  41. Ævar Arnfjörð BjarmasonNov 17, 2022
  42. 03/10 submodule--helper: "deinit" has never used "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 14, 2022
  43. 04/10 submodule--helper: convert "foreach" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 14, 2022
  44. Glen ChooNov 14, 2022
  45. Ævar Arnfjörð BjarmasonNov 17, 2022
  46. 05/10 submodule--helper: convert "sync" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 14, 2022
  47. 06/10 submodule--helper: convert "status" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 14, 2022
  48. 07/10 submodule--helper: convert "{update,clone}" to their own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 14, 2022
  49. Glen ChooNov 14, 2022
  50. 08/10 submodule tests: test "git branch -t" output and stderrÆvar Arnfjörð Bjarmason, Nov 14, 2022
  51. Glen ChooNov 14, 2022
  52. 10/10 fetch: rename "--submodule-prefix" to "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 14, 2022
  53. Glen ChooNov 14, 2022
  54. 09/10 read-tree: add "--super-prefix" option, eliminate globalÆvar Arnfjörð Bjarmason, Nov 14, 2022
  55. Glen ChooNov 14, 2022
  56. Taylor BlauNov 14, 2022
  57. Glen ChooNov 14, 2022
  58. Glen ChooNov 14, 2022
  59. Ævar Arnfjörð BjarmasonNov 15, 2022
  60. Glen ChooNov 16, 2022
  61. Ævar Arnfjörð BjarmasonNov 17, 2022
  62. Glen ChooNov 21, 2022
  63. 0/9 Get rid of "git --super-prefix"Ævar Arnfjörð Bjarmason, Nov 19, 2022
  64. 1/9 read-tree + fetch tests: test failing "--super-prefix" interactionÆvar Arnfjörð Bjarmason, Nov 19, 2022
  65. 3/9 submodule--helper: don't use global --super-prefix in "absorbgitdirs"Ævar Arnfjörð Bjarmason, Nov 19, 2022
  66. Glen ChooNov 22, 2022
  67. 2/9 submodule.c & submodule--helper: pass along "super_prefix" paramÆvar Arnfjörð Bjarmason, Nov 19, 2022
  68. 4/9 submodule--helper: convert "foreach" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 19, 2022
  69. 6/9 submodule--helper: convert "status" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 19, 2022
  70. 5/9 submodule--helper: convert "sync" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 19, 2022
  71. 7/9 submodule--helper: convert "{update,clone}" to their own "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 19, 2022
  72. 9/9 fetch: rename "--submodule-prefix" to "--super-prefix"Ævar Arnfjörð Bjarmason, Nov 19, 2022
  73. 8/9 read-tree: add "--super-prefix" option, eliminate globalÆvar Arnfjörð Bjarmason, Nov 19, 2022
  74. Glen ChooNov 22, 2022
  75. Glen ChooNov 22, 2022
  76. 0/9 Get rid of "git --super-prefix"Ævar Arnfjörð Bjarmason, Dec 15, 2022
  77. 2/9 read-tree + fetch tests: test failing "--super-prefix" interactionÆvar Arnfjörð Bjarmason, Dec 15, 2022
  78. 1/9 submodule absorbgitdirs tests: add missing "Migrating git..." testsÆvar Arnfjörð Bjarmason, Dec 15, 2022
  79. Glen ChooDec 15, 2022
  80. Ævar Arnfjörð BjarmasonDec 20, 2022
  81. 3/9 submodule.c & submodule--helper: pass along "super_prefix" paramÆvar Arnfjörð Bjarmason, Dec 15, 2022
  82. 5/9 submodule--helper: convert "foreach" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Dec 15, 2022
  83. 4/9 submodule--helper: don't use global --super-prefix in "absorbgitdirs"Ævar Arnfjörð Bjarmason, Dec 15, 2022
  84. Glen ChooDec 15, 2022
  85. 6/9 submodule--helper: convert "sync" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Dec 15, 2022
  86. 7/9 submodule--helper: convert "status" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Dec 15, 2022
  87. 8/9 submodule--helper: convert "{update,clone}" to their own "--super-prefix"Ævar Arnfjörð Bjarmason, Dec 15, 2022
  88. 9/9 read-tree: add "--super-prefix" option, eliminate globalÆvar Arnfjörð Bjarmason, Dec 15, 2022
  89. Glen ChooDec 15, 2022
  90. Junio C HamanoDec 15, 2022
  91. Junio C HamanoDec 15, 2022
  92. 0/9 Get rid of "git --super-prefix"Ævar Arnfjörð Bjarmason, Dec 20, 2022
  93. 2/9 read-tree + fetch tests: test failing "--super-prefix" interactionÆvar Arnfjörð Bjarmason, Dec 20, 2022
  94. 1/9 submodule absorbgitdirs tests: add missing "Migrating git..." testsÆvar Arnfjörð Bjarmason, Dec 20, 2022
  95. 3/9 submodule.c & submodule--helper: pass along "super_prefix" paramÆvar Arnfjörð Bjarmason, Dec 20, 2022
  96. 5/9 submodule--helper: convert "foreach" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Dec 20, 2022
  97. 4/9 submodule--helper: don't use global --super-prefix in "absorbgitdirs"Ævar Arnfjörð Bjarmason, Dec 20, 2022
  98. 6/9 submodule--helper: convert "sync" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Dec 20, 2022
  99. 7/9 submodule--helper: convert "status" to its own "--super-prefix"Ævar Arnfjörð Bjarmason, Dec 20, 2022
  100. 8/9 submodule--helper: convert "{update,clone}" to their own "--super-prefix"Ævar Arnfjörð Bjarmason, Dec 20, 2022
  101. 9/9 read-tree: add "--super-prefix" option, eliminate globalÆvar Arnfjörð Bjarmason, Dec 20, 2022
  102. Taylor BlauNov 9, 2022
  103. Glen ChooNov 9, 2022
  104. Taylor BlauNov 10, 2022
  105. Glen ChooNov 10, 2022

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