read-tree: add "--super-prefix" option, eliminate global

The "--super-prefix" option to "git" was initially added in [1] for
use with "ls-files"[2], and shortly thereafter "submodule--helper"[3]
and "grep"[4]. It wasn't until [5] that "read-tree" made use of it.

At the time [5] made sense, but since then we've made "ls-files"
recurse in-process in [6], "grep" in [7], and finally
"submodule--helper" in the preceding commits.

Let's also remove it from "read-tree", which allows us to remove the
option to "git" itself.

We can do this because the only remaining user of it is the submodule
API, which will now invoke "read-tree" with its new "--super-prefix"
option. It will only do so when the "submodule_move_head()" function
is called.

That "submodule_move_head()" function was then only invoked by
"read-tree" itself, but now rather than setting an environment
variable to pass "--super-prefix" between cmd_read_tree() we:

- Set a new "super_prefix" in "struct unpack_trees_options". The
  "super_prefixed()" function in "unpack-trees.c" added in [5] will now
  use this, rather than get_super_prefix() looking up the environment
  variable we set earlier in the same process.

- Add the same field to the "struct checkout", which is only needed to
  ferry the "super_prefix" in the "struct unpack_trees_options" all the
  way down to the "entry.c" callers of "submodule_move_head()".

  Those calls which used the super prefix all originated in
  "cmd_read_tree()". The only other caller is the "unlink_entry()"
  caller in "builtin/checkout.c", which now passes a "NULL".

1. 74866d7 (git: make super-prefix option, 2016-10-07)
2. e77aa33 (ls-files: optionally recurse into submodules, 2016-10-07)
3. 89c8626 (submodule helper: support super prefix, 2016-12-08)
4. 0281e48 (grep: optionally recurse into submodules, 2016-12-16)
5. 3d41542 (unpack-trees: support super-prefix option, 2017-01-17)
6. 188dce1 (ls-files: use repository object, 2017-06-22)
7. f9ee2fc (grep: recurse in-process using 'struct repository', 2017-08-02)

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

Documentation/git.txt

@@ -13,8 +13,7 @@ SYNOPSIS
     [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
     [-p|--paginate|-P|--no-pager] [--no-replace-objects] [--bare]
     [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
-    [--super-prefix=<path>] [--config-env=<name>=<envvar>]
-    <command> [<args>]
+    [--config-env=<name>=<envvar>] <command> [<args>]
 
 DESCRIPTION
 -----------
@@ -169,11 +168,6 @@ If you just want to run git as if it was started in `<path>` then use
 	details.  Equivalent to setting the `GIT_NAMESPACE` environment
 	variable.
 
---super-prefix=<path>::
-	Currently for internal use only.  Set a prefix which gives a path from
-	above a repository down to its root.  One use is to give submodules
-	context about the superproject that invoked it.
-
 --bare::
 	Treat the repository as a bare repository.  If GIT_DIR
 	environment is not set, it is set to the current working

builtin.h

@@ -51,10 +51,6 @@
  *	on bare repositories.
  *	This only makes sense when `RUN_SETUP` is also set.
  *
- * `SUPPORT_SUPER_PREFIX`:
- *
- *	The built-in supports `--super-prefix`.
- *
  * `DELAY_PAGER_CONFIG`:
  *
  *	If RUN_SETUP or RUN_SETUP_GENTLY is set, git.c normally handles

builtin/checkout.c

@@ -232,7 +232,7 @@ static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
 		pos++;
 	}
 	if (!overlay_mode) {
-		unlink_entry(ce);
+		unlink_entry(ce, NULL);
 		return 0;
 	}
 	if (stage == 2)

builtin/read-tree.c

@@ -114,6 +114,7 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
 	int prefix_set = 0;
 	struct lock_file lock_file = LOCK_INIT;
 	const struct option read_tree_options[] = {
+		OPT__SUPER_PREFIX(&opts.super_prefix),
 		OPT_CALLBACK_F(0, "index-output", NULL, N_("file"),
 		  N_("write resulting index to <file>"),
 		  PARSE_OPT_NONEG, index_output_cb),

cache.h

@@ -480,7 +480,6 @@ static inline enum object_type object_type(unsigned int mode)
 #define GIT_NAMESPACE_ENVIRONMENT "GIT_NAMESPACE"
 #define GIT_WORK_TREE_ENVIRONMENT "GIT_WORK_TREE"
 #define GIT_PREFIX_ENVIRONMENT "GIT_PREFIX"
-#define GIT_SUPER_PREFIX_ENVIRONMENT "GIT_INTERNAL_SUPER_PREFIX"
 #define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
 #define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY"
 #define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
@@ -566,7 +565,6 @@ int get_common_dir_noenv(struct strbuf *sb, const char *gitdir);
 int get_common_dir(struct strbuf *sb, const char *gitdir);
 const char *get_git_namespace(void);
 const char *strip_namespace(const char *namespaced_ref);
-const char *get_super_prefix(void);
 const char *get_git_work_tree(void);
 
 /*

entry.c

@@ -383,7 +383,7 @@ static int write_entry(struct cache_entry *ce, char *path, struct conv_attrs *ca
 			return error("cannot create submodule directory %s", path);
 		sub = submodule_from_ce(ce);
 		if (sub)
-			return submodule_move_head(ce->name,
+			return submodule_move_head(ce->name, state->super_prefix,
 				NULL, oid_to_hex(&ce->oid),
 				state->force ? SUBMODULE_MOVE_HEAD_FORCE : 0);
 		break;
@@ -476,7 +476,7 @@ int checkout_entry_ca(struct cache_entry *ce, struct conv_attrs *ca,
 			 * no pathname to return.
 			 */
 			BUG("Can't remove entry to a path");
-		unlink_entry(ce);
+		unlink_entry(ce, state->super_prefix);
 		return 0;
 	}
 
@@ -510,10 +510,10 @@ int checkout_entry_ca(struct cache_entry *ce, struct conv_attrs *ca,
 				if (!(st.st_mode & S_IFDIR))
 					unlink_or_warn(ce->name);
 
-				return submodule_move_head(ce->name,
+				return submodule_move_head(ce->name, state->super_prefix,
 					NULL, oid_to_hex(&ce->oid), 0);
 			} else
-				return submodule_move_head(ce->name,
+				return submodule_move_head(ce->name, state->super_prefix,
 					"HEAD", oid_to_hex(&ce->oid),
 					state->force ? SUBMODULE_MOVE_HEAD_FORCE : 0);
 		}
@@ -560,12 +560,12 @@ int checkout_entry_ca(struct cache_entry *ce, struct conv_attrs *ca,
 	return write_entry(ce, path.buf, ca, state, 0, nr_checkouts);
 }
 
-void unlink_entry(const struct cache_entry *ce)
+void unlink_entry(const struct cache_entry *ce, const char *super_prefix)
 {
 	const struct submodule *sub = submodule_from_ce(ce);
 	if (sub) {
 		/* state.force is set at the caller. */
-		submodule_move_head(ce->name, "HEAD", NULL,
+		submodule_move_head(ce->name, super_prefix, "HEAD", NULL,
 				    SUBMODULE_MOVE_HEAD_FORCE);
 	}
 	if (check_leading_path(ce->name, ce_namelen(ce), 1) >= 0)

entry.h

@@ -8,6 +8,7 @@ struct checkout {
 	struct index_state *istate;
 	const char *base_dir;
 	int base_dir_len;
+	const char *super_prefix;
 	struct delayed_checkout *delayed_checkout;
 	struct checkout_metadata meta;
 	unsigned force:1,
@@ -48,8 +49,11 @@ int finish_delayed_checkout(struct checkout *state, int show_progress);
 /*
  * Unlink the last component and schedule the leading directories for
  * removal, such that empty directories get removed.
+ *
+ * The "super_prefix" is either NULL, or the "--super-prefix" passed
+ * down from "read-tree" et al.
  */
-void unlink_entry(const struct cache_entry *ce);
+void unlink_entry(const struct cache_entry *ce, const char *super_prefix);
 
 void *read_blob_entry(const struct cache_entry *ce, size_t *size);
 int fstat_checkout_output(int fd, const struct checkout *state, struct stat *st);

environment.c

@@ -102,8 +102,6 @@ char *git_work_tree_cfg;
 
 static char *git_namespace;
 
-static char *super_prefix;
-
 /*
  * Repository-local GIT_* environment variables; see cache.h for details.
  */
@@ -121,7 +119,6 @@ const char * const local_repo_env[] = {
 	NO_REPLACE_OBJECTS_ENVIRONMENT,
 	GIT_REPLACE_REF_BASE_ENVIRONMENT,
 	GIT_PREFIX_ENVIRONMENT,
-	GIT_SUPER_PREFIX_ENVIRONMENT,
 	GIT_SHALLOW_FILE_ENVIRONMENT,
 	GIT_COMMON_DIR_ENVIRONMENT,
 	NULL
@@ -234,16 +231,6 @@ const char *strip_namespace(const char *namespaced_ref)
 	return NULL;
 }
 
-const char *get_super_prefix(void)
-{
-	static int initialized;
-	if (!initialized) {
-		super_prefix = xstrdup_or_null(getenv(GIT_SUPER_PREFIX_ENVIRONMENT));
-		initialized = 1;
-	}
-	return super_prefix;
-}
-
 static int git_work_tree_initialized;
 
 /*

git.c

@@ -14,9 +14,8 @@
  * RUN_SETUP for reading from the configuration file.
  */
 #define NEED_WORK_TREE		(1<<3)
-#define SUPPORT_SUPER_PREFIX	(1<<4)
-#define DELAY_PAGER_CONFIG	(1<<5)
-#define NO_PARSEOPT		(1<<6) /* parse-options is not used */
+#define DELAY_PAGER_CONFIG	(1<<4)
+#define NO_PARSEOPT		(1<<5) /* parse-options is not used */
 
 struct cmd_struct {
 	const char *cmd;
@@ -29,8 +28,7 @@ const char git_usage_string[] =
 	   "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
 	   "           [-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]\n"
 	   "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
-	   "           [--super-prefix=<path>] [--config-env=<name>=<envvar>]\n"
-	   "           <command> [<args>]");
+	   "           [--config-env=<name>=<envvar>] <command> [<args>]");
 
 const char git_more_info_string[] =
 	N_("'git help -a' and 'git help -g' list available subcommands and some\n"
@@ -226,20 +224,6 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 			setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 			if (envchanged)
 				*envchanged = 1;
-		} else if (!strcmp(cmd, "--super-prefix")) {
-			if (*argc < 2) {
-				fprintf(stderr, _("no prefix given for --super-prefix\n" ));
-				usage(git_usage_string);
-			}
-			setenv(GIT_SUPER_PREFIX_ENVIRONMENT, (*argv)[1], 1);
-			if (envchanged)
-				*envchanged = 1;
-			(*argv)++;
-			(*argc)--;
-		} else if (skip_prefix(cmd, "--super-prefix=", &cmd)) {
-			setenv(GIT_SUPER_PREFIX_ENVIRONMENT, cmd, 1);
-			if (envchanged)
-				*envchanged = 1;
 		} else if (!strcmp(cmd, "--bare")) {
 			char *cwd = xgetcwd();
 			is_bare_repository_cfg = 1;
@@ -449,11 +433,6 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 		trace_repo_setup(prefix);
 	commit_pager_choice();
 
-	if (!help && get_super_prefix()) {
-		if (!(p->option & SUPPORT_SUPER_PREFIX))
-			die(_("%s doesn't support --super-prefix"), p->cmd);
-	}
-
 	if (!help && p->option & NEED_WORK_TREE)
 		setup_work_tree();
 
@@ -504,7 +483,7 @@ static struct cmd_struct commands[] = {
 	{ "check-ref-format", cmd_check_ref_format, NO_PARSEOPT  },
 	{ "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 	{ "checkout--worker", cmd_checkout__worker,
-		RUN_SETUP | NEED_WORK_TREE | SUPPORT_SUPER_PREFIX },
+		RUN_SETUP | NEED_WORK_TREE },
 	{ "checkout-index", cmd_checkout_index,
 		RUN_SETUP | NEED_WORK_TREE},
 	{ "cherry", cmd_cherry, RUN_SETUP },
@@ -583,7 +562,7 @@ static struct cmd_struct commands[] = {
 	{ "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 	{ "push", cmd_push, RUN_SETUP },
 	{ "range-diff", cmd_range_diff, RUN_SETUP | USE_PAGER },
-	{ "read-tree", cmd_read_tree, RUN_SETUP | SUPPORT_SUPER_PREFIX},
+	{ "read-tree", cmd_read_tree, RUN_SETUP },
 	{ "rebase", cmd_rebase, RUN_SETUP | NEED_WORK_TREE },
 	{ "receive-pack", cmd_receive_pack },
 	{ "reflog", cmd_reflog, RUN_SETUP },
@@ -727,9 +706,6 @@ static void execv_dashed_external(const char **argv)
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	int status;
 
-	if (get_super_prefix())
-		die(_("%s doesn't support --super-prefix"), argv[0]);
-
 	if (use_pager == -1 && !is_builtin(argv[0]))
 		use_pager = check_pager_config(argv[0]);
 	commit_pager_choice();
@@ -799,9 +775,6 @@ static int run_argv(int *argcp, const char ***argv)
 			 */
 			trace2_cmd_name("_run_git_alias_");
 
-			if (get_super_prefix())
-				die("%s doesn't support --super-prefix", **argv);
-
 			commit_pager_choice();
 
 			strvec_push(&cmd.args, "git");

submodule.c

@@ -2054,14 +2054,6 @@ void submodule_unset_core_worktree(const struct submodule *sub)
 	strbuf_release(&config_path);
 }
 
-static const char *get_super_prefix_or_empty(void)
-{
-	const char *s = get_super_prefix();
-	if (!s)
-		s = "";
-	return s;
-}
-
 static int submodule_has_dirty_index(const struct submodule *sub)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
@@ -2080,7 +2072,7 @@ static int submodule_has_dirty_index(const struct submodule *sub)
 	return finish_command(&cp);
 }
 
-static void submodule_reset_index(const char *path)
+static void submodule_reset_index(const char *path, const char *super_prefix)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	prepare_submodule_repo_env(&cp.env);
@@ -2089,10 +2081,10 @@ static void submodule_reset_index(const char *path)
 	cp.no_stdin = 1;
 	cp.dir = path;
 
-	strvec_pushf(&cp.args, "--super-prefix=%s%s/",
-		     get_super_prefix_or_empty(), path);
 	/* TODO: determine if this might overwright untracked files */
 	strvec_pushl(&cp.args, "read-tree", "-u", "--reset", NULL);
+	strvec_pushf(&cp.args, "--super-prefix=%s%s/",
+		     (super_prefix ? super_prefix : ""), path);
 
 	strvec_push(&cp.args, empty_tree_oid_hex());
 
@@ -2105,10 +2097,9 @@ static void submodule_reset_index(const char *path)
  * For edge cases (a submodule coming into existence or removing a submodule)
  * pass NULL for old or new respectively.
  */
-int submodule_move_head(const char *path,
-			 const char *old_head,
-			 const char *new_head,
-			 unsigned flags)
+int submodule_move_head(const char *path, const char *super_prefix,
+			const char *old_head, const char *new_head,
+			unsigned flags)
 {
 	int ret = 0;
 	struct child_process cp = CHILD_PROCESS_INIT;
@@ -2146,7 +2137,7 @@ int submodule_move_head(const char *path,
 		if (old_head) {
 			if (!submodule_uses_gitfile(path))
 				absorb_git_dir_into_superproject(path,
-								 get_super_prefix());
+								 super_prefix);
 		} else {
 			struct strbuf gitdir = STRBUF_INIT;
 			submodule_name_to_gitdir(&gitdir, the_repository,
@@ -2155,7 +2146,7 @@ int submodule_move_head(const char *path,
 			strbuf_release(&gitdir);
 
 			/* make sure the index is clean as well */
-			submodule_reset_index(path);
+			submodule_reset_index(path, super_prefix);
 		}
 
 		if (old_head && (flags & SUBMODULE_MOVE_HEAD_FORCE)) {
@@ -2173,9 +2164,9 @@ int submodule_move_head(const char *path,
 	cp.no_stdin = 1;
 	cp.dir = path;
 
-	strvec_pushf(&cp.args, "--super-prefix=%s%s/",
-		     get_super_prefix_or_empty(), path);
 	strvec_pushl(&cp.args, "read-tree", "--recurse-submodules", NULL);
+	strvec_pushf(&cp.args, "--super-prefix=%s%s/",
+		     (super_prefix ? super_prefix : ""), path);
 
 	if (flags & SUBMODULE_MOVE_HEAD_DRY_RUN)
 		strvec_push(&cp.args, "-n");