Merge branch 'rs/t4062-obsd' into next
[gitweb.git] / builtin / submodule--helper.c
index 3bea3aaa5029082198abab2b5a5dab838dbd6dec..0ff9dd0b85074dfe6e04b6fc56c04f2c1789f7eb 100644 (file)
 #include "builtin.h"
+#include "repository.h"
 #include "cache.h"
+#include "config.h"
 #include "parse-options.h"
 #include "quote.h"
 #include "pathspec.h"
 #include "dir.h"
-#include "utf8.h"
 #include "submodule.h"
 #include "submodule-config.h"
 #include "string-list.h"
 #include "run-command.h"
+#include "remote.h"
+#include "refs.h"
+#include "connect.h"
+
+static char *get_default_remote(void)
+{
+       char *dest = NULL, *ret;
+       unsigned char sha1[20];
+       struct strbuf sb = STRBUF_INIT;
+       const char *refname = resolve_ref_unsafe("HEAD", 0, sha1, NULL);
+
+       if (!refname)
+               die(_("No such ref: %s"), "HEAD");
+
+       /* detached HEAD */
+       if (!strcmp(refname, "HEAD"))
+               return xstrdup("origin");
+
+       if (!skip_prefix(refname, "refs/heads/", &refname))
+               die(_("Expecting a full ref name, got %s"), refname);
+
+       strbuf_addf(&sb, "branch.%s.remote", refname);
+       if (git_config_get_string(sb.buf, &dest))
+               ret = xstrdup("origin");
+       else
+               ret = dest;
+
+       strbuf_release(&sb);
+       return ret;
+}
+
+static int starts_with_dot_slash(const char *str)
+{
+       return str[0] == '.' && is_dir_sep(str[1]);
+}
+
+static int starts_with_dot_dot_slash(const char *str)
+{
+       return str[0] == '.' && str[1] == '.' && is_dir_sep(str[2]);
+}
+
+/*
+ * Returns 1 if it was the last chop before ':'.
+ */
+static int chop_last_dir(char **remoteurl, int is_relative)
+{
+       char *rfind = find_last_dir_sep(*remoteurl);
+       if (rfind) {
+               *rfind = '\0';
+               return 0;
+       }
+
+       rfind = strrchr(*remoteurl, ':');
+       if (rfind) {
+               *rfind = '\0';
+               return 1;
+       }
+
+       if (is_relative || !strcmp(".", *remoteurl))
+               die(_("cannot strip one component off url '%s'"),
+                       *remoteurl);
+
+       free(*remoteurl);
+       *remoteurl = xstrdup(".");
+       return 0;
+}
+
+/*
+ * The `url` argument is the URL that navigates to the submodule origin
+ * repo. When relative, this URL is relative to the superproject origin
+ * URL repo. The `up_path` argument, if specified, is the relative
+ * path that navigates from the submodule working tree to the superproject
+ * working tree. Returns the origin URL of the submodule.
+ *
+ * Return either an absolute URL or filesystem path (if the superproject
+ * origin URL is an absolute URL or filesystem path, respectively) or a
+ * relative file system path (if the superproject origin URL is a relative
+ * file system path).
+ *
+ * When the output is a relative file system path, the path is either
+ * relative to the submodule working tree, if up_path is specified, or to
+ * the superproject working tree otherwise.
+ *
+ * NEEDSWORK: This works incorrectly on the domain and protocol part.
+ * remote_url      url              outcome          expectation
+ * http://a.com/b  ../c             http://a.com/c   as is
+ * http://a.com/b/ ../c             http://a.com/c   same as previous line, but
+ *                                                   ignore trailing slash in url
+ * http://a.com/b  ../../c          http://c         error out
+ * http://a.com/b  ../../../c       http:/c          error out
+ * http://a.com/b  ../../../../c    http:c           error out
+ * http://a.com/b  ../../../../../c    .:c           error out
+ * NEEDSWORK: Given how chop_last_dir() works, this function is broken
+ * when a local part has a colon in its path component, too.
+ */
+static char *relative_url(const char *remote_url,
+                               const char *url,
+                               const char *up_path)
+{
+       int is_relative = 0;
+       int colonsep = 0;
+       char *out;
+       char *remoteurl = xstrdup(remote_url);
+       struct strbuf sb = STRBUF_INIT;
+       size_t len = strlen(remoteurl);
+
+       if (is_dir_sep(remoteurl[len-1]))
+               remoteurl[len-1] = '\0';
+
+       if (!url_is_local_not_ssh(remoteurl) || is_absolute_path(remoteurl))
+               is_relative = 0;
+       else {
+               is_relative = 1;
+               /*
+                * Prepend a './' to ensure all relative
+                * remoteurls start with './' or '../'
+                */
+               if (!starts_with_dot_slash(remoteurl) &&
+                   !starts_with_dot_dot_slash(remoteurl)) {
+                       strbuf_reset(&sb);
+                       strbuf_addf(&sb, "./%s", remoteurl);
+                       free(remoteurl);
+                       remoteurl = strbuf_detach(&sb, NULL);
+               }
+       }
+       /*
+        * When the url starts with '../', remove that and the
+        * last directory in remoteurl.
+        */
+       while (url) {
+               if (starts_with_dot_dot_slash(url)) {
+                       url += 3;
+                       colonsep |= chop_last_dir(&remoteurl, is_relative);
+               } else if (starts_with_dot_slash(url))
+                       url += 2;
+               else
+                       break;
+       }
+       strbuf_reset(&sb);
+       strbuf_addf(&sb, "%s%s%s", remoteurl, colonsep ? ":" : "/", url);
+       if (ends_with(url, "/"))
+               strbuf_setlen(&sb, sb.len - 1);
+       free(remoteurl);
+
+       if (starts_with_dot_slash(sb.buf))
+               out = xstrdup(sb.buf + 2);
+       else
+               out = xstrdup(sb.buf);
+       strbuf_reset(&sb);
+
+       if (!up_path || !is_relative)
+               return out;
+
+       strbuf_addf(&sb, "%s%s", up_path, out);
+       free(out);
+       return strbuf_detach(&sb, NULL);
+}
+
+static int resolve_relative_url(int argc, const char **argv, const char *prefix)
+{
+       char *remoteurl = NULL;
+       char *remote = get_default_remote();
+       const char *up_path = NULL;
+       char *res;
+       const char *url;
+       struct strbuf sb = STRBUF_INIT;
+
+       if (argc != 2 && argc != 3)
+               die("resolve-relative-url only accepts one or two arguments");
+
+       url = argv[1];
+       strbuf_addf(&sb, "remote.%s.url", remote);
+       free(remote);
+
+       if (git_config_get_string(sb.buf, &remoteurl))
+               /* the repository is its own authoritative upstream */
+               remoteurl = xgetcwd();
+
+       if (argc == 3)
+               up_path = argv[2];
+
+       res = relative_url(remoteurl, url, up_path);
+       puts(res);
+       free(res);
+       free(remoteurl);
+       return 0;
+}
+
+static int resolve_relative_url_test(int argc, const char **argv, const char *prefix)
+{
+       char *remoteurl, *res;
+       const char *up_path, *url;
+
+       if (argc != 4)
+               die("resolve-relative-url-test only accepts three arguments: <up_path> <remoteurl> <url>");
+
+       up_path = argv[1];
+       remoteurl = xstrdup(argv[2]);
+       url = argv[3];
+
+       if (!strcmp(up_path, "(null)"))
+               up_path = NULL;
+
+       res = relative_url(remoteurl, url, up_path);
+       puts(res);
+       free(res);
+       free(remoteurl);
+       return 0;
+}
 
 struct module_list {
        const struct cache_entry **entries;
@@ -24,8 +234,7 @@ static int module_list_compute(int argc, const char **argv,
        int i, result = 0;
        char *ps_matched = NULL;
        parse_pathspec(pathspec, 0,
-                      PATHSPEC_PREFER_FULL |
-                      PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP,
+                      PATHSPEC_PREFER_FULL,
                       prefix, argv);
 
        if (pathspec->nr)
@@ -61,6 +270,29 @@ static int module_list_compute(int argc, const char **argv,
        return result;
 }
 
+static void module_list_active(struct module_list *list)
+{
+       int i;
+       struct module_list active_modules = MODULE_LIST_INIT;
+
+       gitmodules_config();
+
+       for (i = 0; i < list->nr; i++) {
+               const struct cache_entry *ce = list->entries[i];
+
+               if (!is_submodule_active(the_repository, ce->name))
+                       continue;
+
+               ALLOC_GROW(active_modules.entries,
+                          active_modules.nr + 1,
+                          active_modules.alloc);
+               active_modules.entries[active_modules.nr++] = ce;
+       }
+
+       free(list->entries);
+       *list = active_modules;
+}
+
 static int module_list(int argc, const char **argv, const char *prefix)
 {
        int i;
@@ -82,10 +314,8 @@ static int module_list(int argc, const char **argv, const char *prefix)
        argc = parse_options(argc, argv, prefix, module_list_options,
                             git_submodule_helper_usage, 0);
 
-       if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0) {
-               printf("#unmatched\n");
+       if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
                return 1;
-       }
 
        for (i = 0; i < list.nr; i++) {
                const struct cache_entry *ce = list.entries[i];
@@ -93,13 +323,151 @@ static int module_list(int argc, const char **argv, const char *prefix)
                if (ce_stage(ce))
                        printf("%06o %s U\t", ce->ce_mode, sha1_to_hex(null_sha1));
                else
-                       printf("%06o %s %d\t", ce->ce_mode, sha1_to_hex(ce->sha1), ce_stage(ce));
+                       printf("%06o %s %d\t", ce->ce_mode,
+                              oid_to_hex(&ce->oid), ce_stage(ce));
 
-               utf8_fprintf(stdout, "%s\n", ce->name);
+               fprintf(stdout, "%s\n", ce->name);
        }
        return 0;
 }
 
+static void init_submodule(const char *path, const char *prefix, int quiet)
+{
+       const struct submodule *sub;
+       struct strbuf sb = STRBUF_INIT;
+       char *upd = NULL, *url = NULL, *displaypath;
+
+       /* Only loads from .gitmodules, no overlay with .git/config */
+       gitmodules_config();
+
+       if (prefix && get_super_prefix())
+               die("BUG: cannot have prefix and superprefix");
+       else if (prefix)
+               displaypath = xstrdup(relative_path(path, prefix, &sb));
+       else if (get_super_prefix()) {
+               strbuf_addf(&sb, "%s%s", get_super_prefix(), path);
+               displaypath = strbuf_detach(&sb, NULL);
+       } else
+               displaypath = xstrdup(path);
+
+       sub = submodule_from_path(&null_oid, path);
+
+       if (!sub)
+               die(_("No url found for submodule path '%s' in .gitmodules"),
+                       displaypath);
+
+       /*
+        * NEEDSWORK: In a multi-working-tree world, this needs to be
+        * set in the per-worktree config.
+        *
+        * Set active flag for the submodule being initialized
+        */
+       if (!is_submodule_active(the_repository, path)) {
+               strbuf_reset(&sb);
+               strbuf_addf(&sb, "submodule.%s.active", sub->name);
+               git_config_set_gently(sb.buf, "true");
+       }
+
+       /*
+        * Copy url setting when it is not set yet.
+        * To look up the url in .git/config, we must not fall back to
+        * .gitmodules, so look it up directly.
+        */
+       strbuf_reset(&sb);
+       strbuf_addf(&sb, "submodule.%s.url", sub->name);
+       if (git_config_get_string(sb.buf, &url)) {
+               if (!sub->url)
+                       die(_("No url found for submodule path '%s' in .gitmodules"),
+                               displaypath);
+
+               url = xstrdup(sub->url);
+
+               /* Possibly a url relative to parent */
+               if (starts_with_dot_dot_slash(url) ||
+                   starts_with_dot_slash(url)) {
+                       char *remoteurl, *relurl;
+                       char *remote = get_default_remote();
+                       struct strbuf remotesb = STRBUF_INIT;
+                       strbuf_addf(&remotesb, "remote.%s.url", remote);
+                       free(remote);
+
+                       if (git_config_get_string(remotesb.buf, &remoteurl)) {
+                               warning(_("could not lookup configuration '%s'. Assuming this repository is its own authoritative upstream."), remotesb.buf);
+                               remoteurl = xgetcwd();
+                       }
+                       relurl = relative_url(remoteurl, url, NULL);
+                       strbuf_release(&remotesb);
+                       free(remoteurl);
+                       free(url);
+                       url = relurl;
+               }
+
+               if (git_config_set_gently(sb.buf, url))
+                       die(_("Failed to register url for submodule path '%s'"),
+                           displaypath);
+               if (!quiet)
+                       fprintf(stderr,
+                               _("Submodule '%s' (%s) registered for path '%s'\n"),
+                               sub->name, url, displaypath);
+       }
+
+       /* Copy "update" setting when it is not set yet */
+       strbuf_reset(&sb);
+       strbuf_addf(&sb, "submodule.%s.update", sub->name);
+       if (git_config_get_string(sb.buf, &upd) &&
+           sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
+               if (sub->update_strategy.type == SM_UPDATE_COMMAND) {
+                       fprintf(stderr, _("warning: command update mode suggested for submodule '%s'\n"),
+                               sub->name);
+                       upd = xstrdup("none");
+               } else
+                       upd = xstrdup(submodule_strategy_to_string(&sub->update_strategy));
+
+               if (git_config_set_gently(sb.buf, upd))
+                       die(_("Failed to register update mode for submodule path '%s'"), displaypath);
+       }
+       strbuf_release(&sb);
+       free(displaypath);
+       free(url);
+       free(upd);
+}
+
+static int module_init(int argc, const char **argv, const char *prefix)
+{
+       struct pathspec pathspec;
+       struct module_list list = MODULE_LIST_INIT;
+       int quiet = 0;
+       int i;
+
+       struct option module_init_options[] = {
+               OPT__QUIET(&quiet, N_("Suppress output for initializing a submodule")),
+               OPT_END()
+       };
+
+       const char *const git_submodule_helper_usage[] = {
+               N_("git submodule--helper init [<path>]"),
+               NULL
+       };
+
+       argc = parse_options(argc, argv, prefix, module_init_options,
+                            git_submodule_helper_usage, 0);
+
+       if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
+               return 1;
+
+       /*
+        * If there are no path args and submodule.active is set then,
+        * by default, only initialize 'active' modules.
+        */
+       if (!argc && git_config_get_value_multi("submodule.active"))
+               module_list_active(&list);
+
+       for (i = 0; i < list.nr; i++)
+               init_submodule(list.entries[i]->name, prefix, quiet);
+
+       return 0;
+}
+
 static int module_name(int argc, const char **argv, const char *prefix)
 {
        const struct submodule *sub;
@@ -108,7 +476,7 @@ static int module_name(int argc, const char **argv, const char *prefix)
                usage(_("git submodule--helper name <path>"));
 
        gitmodules_config();
-       sub = submodule_from_path(null_sha1, argv[1]);
+       sub = submodule_from_path(&null_oid, argv[1]);
 
        if (!sub)
                die(_("no submodule mapping found in .gitmodules for path '%s'"),
@@ -118,20 +486,27 @@ static int module_name(int argc, const char **argv, const char *prefix)
 
        return 0;
 }
+
 static int clone_submodule(const char *path, const char *gitdir, const char *url,
-                          const char *depth, const char *reference, int quiet)
+                          const char *depth, struct string_list *reference,
+                          int quiet, int progress)
 {
-       struct child_process cp;
-       child_process_init(&cp);
+       struct child_process cp = CHILD_PROCESS_INIT;
 
        argv_array_push(&cp.args, "clone");
        argv_array_push(&cp.args, "--no-checkout");
        if (quiet)
                argv_array_push(&cp.args, "--quiet");
+       if (progress)
+               argv_array_push(&cp.args, "--progress");
        if (depth && *depth)
                argv_array_pushl(&cp.args, "--depth", depth, NULL);
-       if (reference && *reference)
-               argv_array_pushl(&cp.args, "--reference", reference, NULL);
+       if (reference->nr) {
+               struct string_list_item *item;
+               for_each_string_list_item(item, reference)
+                       argv_array_pushl(&cp.args, "--reference",
+                                        item->string, NULL);
+       }
        if (gitdir && *gitdir)
                argv_array_pushl(&cp.args, "--separate-git-dir", gitdir, NULL);
 
@@ -139,21 +514,115 @@ static int clone_submodule(const char *path, const char *gitdir, const char *url
        argv_array_push(&cp.args, path);
 
        cp.git_cmd = 1;
-       cp.env = local_repo_env;
+       prepare_submodule_repo_env(&cp.env_array);
        cp.no_stdin = 1;
 
        return run_command(&cp);
 }
 
+struct submodule_alternate_setup {
+       const char *submodule_name;
+       enum SUBMODULE_ALTERNATE_ERROR_MODE {
+               SUBMODULE_ALTERNATE_ERROR_DIE,
+               SUBMODULE_ALTERNATE_ERROR_INFO,
+               SUBMODULE_ALTERNATE_ERROR_IGNORE
+       } error_mode;
+       struct string_list *reference;
+};
+#define SUBMODULE_ALTERNATE_SETUP_INIT { NULL, \
+       SUBMODULE_ALTERNATE_ERROR_IGNORE, NULL }
+
+static int add_possible_reference_from_superproject(
+               struct alternate_object_database *alt, void *sas_cb)
+{
+       struct submodule_alternate_setup *sas = sas_cb;
+
+       /*
+        * If the alternate object store is another repository, try the
+        * standard layout with .git/(modules/<name>)+/objects
+        */
+       if (ends_with(alt->path, "/objects")) {
+               char *sm_alternate;
+               struct strbuf sb = STRBUF_INIT;
+               struct strbuf err = STRBUF_INIT;
+               strbuf_add(&sb, alt->path, strlen(alt->path) - strlen("objects"));
+
+               /*
+                * We need to end the new path with '/' to mark it as a dir,
+                * otherwise a submodule name containing '/' will be broken
+                * as the last part of a missing submodule reference would
+                * be taken as a file name.
+                */
+               strbuf_addf(&sb, "modules/%s/", sas->submodule_name);
+
+               sm_alternate = compute_alternate_path(sb.buf, &err);
+               if (sm_alternate) {
+                       string_list_append(sas->reference, xstrdup(sb.buf));
+                       free(sm_alternate);
+               } else {
+                       switch (sas->error_mode) {
+                       case SUBMODULE_ALTERNATE_ERROR_DIE:
+                               die(_("submodule '%s' cannot add alternate: %s"),
+                                   sas->submodule_name, err.buf);
+                       case SUBMODULE_ALTERNATE_ERROR_INFO:
+                               fprintf(stderr, _("submodule '%s' cannot add alternate: %s"),
+                                       sas->submodule_name, err.buf);
+                       case SUBMODULE_ALTERNATE_ERROR_IGNORE:
+                               ; /* nothing */
+                       }
+               }
+               strbuf_release(&sb);
+       }
+
+       return 0;
+}
+
+static void prepare_possible_alternates(const char *sm_name,
+               struct string_list *reference)
+{
+       char *sm_alternate = NULL, *error_strategy = NULL;
+       struct submodule_alternate_setup sas = SUBMODULE_ALTERNATE_SETUP_INIT;
+
+       git_config_get_string("submodule.alternateLocation", &sm_alternate);
+       if (!sm_alternate)
+               return;
+
+       git_config_get_string("submodule.alternateErrorStrategy", &error_strategy);
+
+       if (!error_strategy)
+               error_strategy = xstrdup("die");
+
+       sas.submodule_name = sm_name;
+       sas.reference = reference;
+       if (!strcmp(error_strategy, "die"))
+               sas.error_mode = SUBMODULE_ALTERNATE_ERROR_DIE;
+       else if (!strcmp(error_strategy, "info"))
+               sas.error_mode = SUBMODULE_ALTERNATE_ERROR_INFO;
+       else if (!strcmp(error_strategy, "ignore"))
+               sas.error_mode = SUBMODULE_ALTERNATE_ERROR_IGNORE;
+       else
+               die(_("Value '%s' for submodule.alternateErrorStrategy is not recognized"), error_strategy);
+
+       if (!strcmp(sm_alternate, "superproject"))
+               foreach_alt_odb(add_possible_reference_from_superproject, &sas);
+       else if (!strcmp(sm_alternate, "no"))
+               ; /* do nothing */
+       else
+               die(_("Value '%s' for submodule.alternateLocation is not recognized"), sm_alternate);
+
+       free(sm_alternate);
+       free(error_strategy);
+}
+
 static int module_clone(int argc, const char **argv, const char *prefix)
 {
-       const char *name = NULL, *url = NULL;
-       const char *reference = NULL, *depth = NULL;
+       const char *name = NULL, *url = NULL, *depth = NULL;
        int quiet = 0;
-       FILE *submodule_dot_git;
+       int progress = 0;
        char *p, *path = NULL, *sm_gitdir;
-       struct strbuf rel_path = STRBUF_INIT;
        struct strbuf sb = STRBUF_INIT;
+       struct string_list reference = STRING_LIST_INIT_NODUP;
+       char *sm_alternate = NULL, *error_strategy = NULL;
 
        struct option module_clone_options[] = {
                OPT_STRING(0, "prefix", &prefix,
@@ -168,31 +637,34 @@ static int module_clone(int argc, const char **argv, const char *prefix)
                OPT_STRING(0, "url", &url,
                           N_("string"),
                           N_("url where to clone the submodule from")),
-               OPT_STRING(0, "reference", &reference,
-                          N_("string"),
+               OPT_STRING_LIST(0, "reference", &reference,
+                          N_("repo"),
                           N_("reference repository")),
                OPT_STRING(0, "depth", &depth,
                           N_("string"),
                           N_("depth for shallow clones")),
                OPT__QUIET(&quiet, "Suppress output for cloning a submodule"),
+               OPT_BOOL(0, "progress", &progress,
+                          N_("force cloning progress")),
                OPT_END()
        };
 
        const char *const git_submodule_helper_usage[] = {
                N_("git submodule--helper clone [--prefix=<path>] [--quiet] "
-                  "[--reference <repository>] [--name <name>] [--url <url>]"
-                  "[--depth <depth>] [--] [<path>...]"),
+                  "[--reference <repository>] [--name <name>] [--depth <depth>] "
+                  "--url <url> --path <path>"),
                NULL
        };
 
        argc = parse_options(argc, argv, prefix, module_clone_options,
                             git_submodule_helper_usage, 0);
 
-       if (!path || !*path)
-               die(_("submodule--helper: unspecified or empty --path"));
+       if (argc || !url || !path || !*path)
+               usage_with_options(git_submodule_helper_usage,
+                                  module_clone_options);
 
        strbuf_addf(&sb, "%s/modules/%s", get_git_dir(), name);
-       sm_gitdir = xstrdup(absolute_path(sb.buf));
+       sm_gitdir = absolute_pathdup(sb.buf);
        strbuf_reset(&sb);
 
        if (!is_absolute_path(path)) {
@@ -204,7 +676,11 @@ static int module_clone(int argc, const char **argv, const char *prefix)
        if (!file_exists(sm_gitdir)) {
                if (safe_create_leading_directories_const(sm_gitdir) < 0)
                        die(_("could not create directory '%s'"), sm_gitdir);
-               if (clone_submodule(path, sm_gitdir, url, depth, reference, quiet))
+
+               prepare_possible_alternates(name, &reference);
+
+               if (clone_submodule(path, sm_gitdir, url, depth, &reference,
+                                   quiet, progress))
                        die(_("clone of '%s' into submodule path '%s' failed"),
                            url, path);
        } else {
@@ -215,57 +691,590 @@ static int module_clone(int argc, const char **argv, const char *prefix)
                strbuf_reset(&sb);
        }
 
-       /* Write a .git file in the submodule to redirect to the superproject. */
-       strbuf_addf(&sb, "%s/.git", path);
-       if (safe_create_leading_directories_const(sb.buf) < 0)
-               die(_("could not create leading directories of '%s'"), sb.buf);
-       submodule_dot_git = fopen(sb.buf, "w");
-       if (!submodule_dot_git)
-               die_errno(_("cannot open file '%s'"), sb.buf);
-
-       fprintf_or_die(submodule_dot_git, "gitdir: %s\n",
-                      relative_path(sm_gitdir, path, &rel_path));
-       if (fclose(submodule_dot_git))
-               die(_("could not close file %s"), sb.buf);
-       strbuf_reset(&sb);
-       strbuf_reset(&rel_path);
+       /* Connect module worktree and git dir */
+       connect_work_tree_and_git_dir(path, sm_gitdir);
 
-       /* Redirect the worktree of the submodule in the superproject's config */
        p = git_pathdup_submodule(path, "config");
        if (!p)
                die(_("could not get submodule directory for '%s'"), path);
-       git_config_set_in_file(p, "core.worktree",
-                              relative_path(path, sm_gitdir, &rel_path));
+
+       /* setup alternateLocation and alternateErrorStrategy in the cloned submodule if needed */
+       git_config_get_string("submodule.alternateLocation", &sm_alternate);
+       if (sm_alternate)
+               git_config_set_in_file(p, "submodule.alternateLocation",
+                                          sm_alternate);
+       git_config_get_string("submodule.alternateErrorStrategy", &error_strategy);
+       if (error_strategy)
+               git_config_set_in_file(p, "submodule.alternateErrorStrategy",
+                                          error_strategy);
+
+       free(sm_alternate);
+       free(error_strategy);
+
        strbuf_release(&sb);
-       strbuf_release(&rel_path);
        free(sm_gitdir);
        free(path);
        free(p);
        return 0;
 }
 
+struct submodule_update_clone {
+       /* index into 'list', the list of submodules to look into for cloning */
+       int current;
+       struct module_list list;
+       unsigned warn_if_uninitialized : 1;
+
+       /* update parameter passed via commandline */
+       struct submodule_update_strategy update;
+
+       /* configuration parameters which are passed on to the children */
+       int progress;
+       int quiet;
+       int recommend_shallow;
+       struct string_list references;
+       const char *depth;
+       const char *recursive_prefix;
+       const char *prefix;
+
+       /* Machine-readable status lines to be consumed by git-submodule.sh */
+       struct string_list projectlines;
+
+       /* If we want to stop as fast as possible and return an error */
+       unsigned quickstop : 1;
+
+       /* failed clones to be retried again */
+       const struct cache_entry **failed_clones;
+       int failed_clones_nr, failed_clones_alloc;
+};
+#define SUBMODULE_UPDATE_CLONE_INIT {0, MODULE_LIST_INIT, 0, \
+       SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, \
+       NULL, NULL, NULL, \
+       STRING_LIST_INIT_DUP, 0, NULL, 0, 0}
+
+
+static void next_submodule_warn_missing(struct submodule_update_clone *suc,
+               struct strbuf *out, const char *displaypath)
+{
+       /*
+        * Only mention uninitialized submodules when their
+        * paths have been specified.
+        */
+       if (suc->warn_if_uninitialized) {
+               strbuf_addf(out,
+                       _("Submodule path '%s' not initialized"),
+                       displaypath);
+               strbuf_addch(out, '\n');
+               strbuf_addstr(out,
+                       _("Maybe you want to use 'update --init'?"));
+               strbuf_addch(out, '\n');
+       }
+}
+
+/**
+ * Determine whether 'ce' needs to be cloned. If so, prepare the 'child' to
+ * run the clone. Returns 1 if 'ce' needs to be cloned, 0 otherwise.
+ */
+static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
+                                          struct child_process *child,
+                                          struct submodule_update_clone *suc,
+                                          struct strbuf *out)
+{
+       const struct submodule *sub = NULL;
+       struct strbuf displaypath_sb = STRBUF_INIT;
+       struct strbuf sb = STRBUF_INIT;
+       const char *displaypath = NULL;
+       int needs_cloning = 0;
+
+       if (ce_stage(ce)) {
+               if (suc->recursive_prefix)
+                       strbuf_addf(&sb, "%s/%s", suc->recursive_prefix, ce->name);
+               else
+                       strbuf_addstr(&sb, ce->name);
+               strbuf_addf(out, _("Skipping unmerged submodule %s"), sb.buf);
+               strbuf_addch(out, '\n');
+               goto cleanup;
+       }
+
+       sub = submodule_from_path(&null_oid, ce->name);
+
+       if (suc->recursive_prefix)
+               displaypath = relative_path(suc->recursive_prefix,
+                                           ce->name, &displaypath_sb);
+       else
+               displaypath = ce->name;
+
+       if (!sub) {
+               next_submodule_warn_missing(suc, out, displaypath);
+               goto cleanup;
+       }
+
+       if (suc->update.type == SM_UPDATE_NONE
+           || (suc->update.type == SM_UPDATE_UNSPECIFIED
+               && sub->update_strategy.type == SM_UPDATE_NONE)) {
+               strbuf_addf(out, _("Skipping submodule '%s'"), displaypath);
+               strbuf_addch(out, '\n');
+               goto cleanup;
+       }
+
+       /* Check if the submodule has been initialized. */
+       if (!is_submodule_active(the_repository, ce->name)) {
+               next_submodule_warn_missing(suc, out, displaypath);
+               goto cleanup;
+       }
+
+       strbuf_reset(&sb);
+       strbuf_addf(&sb, "%s/.git", ce->name);
+       needs_cloning = !file_exists(sb.buf);
+
+       strbuf_reset(&sb);
+       strbuf_addf(&sb, "%06o %s %d %d\t%s\n", ce->ce_mode,
+                       oid_to_hex(&ce->oid), ce_stage(ce),
+                       needs_cloning, ce->name);
+       string_list_append(&suc->projectlines, sb.buf);
+
+       if (!needs_cloning)
+               goto cleanup;
+
+       child->git_cmd = 1;
+       child->no_stdin = 1;
+       child->stdout_to_stderr = 1;
+       child->err = -1;
+       argv_array_push(&child->args, "submodule--helper");
+       argv_array_push(&child->args, "clone");
+       if (suc->progress)
+               argv_array_push(&child->args, "--progress");
+       if (suc->quiet)
+               argv_array_push(&child->args, "--quiet");
+       if (suc->prefix)
+               argv_array_pushl(&child->args, "--prefix", suc->prefix, NULL);
+       if (suc->recommend_shallow && sub->recommend_shallow == 1)
+               argv_array_push(&child->args, "--depth=1");
+       argv_array_pushl(&child->args, "--path", sub->path, NULL);
+       argv_array_pushl(&child->args, "--name", sub->name, NULL);
+       argv_array_pushl(&child->args, "--url", sub->url, NULL);
+       if (suc->references.nr) {
+               struct string_list_item *item;
+               for_each_string_list_item(item, &suc->references)
+                       argv_array_pushl(&child->args, "--reference", item->string, NULL);
+       }
+       if (suc->depth)
+               argv_array_push(&child->args, suc->depth);
+
+cleanup:
+       strbuf_reset(&displaypath_sb);
+       strbuf_reset(&sb);
+
+       return needs_cloning;
+}
+
+static int update_clone_get_next_task(struct child_process *child,
+                                     struct strbuf *err,
+                                     void *suc_cb,
+                                     void **idx_task_cb)
+{
+       struct submodule_update_clone *suc = suc_cb;
+       const struct cache_entry *ce;
+       int index;
+
+       for (; suc->current < suc->list.nr; suc->current++) {
+               ce = suc->list.entries[suc->current];
+               if (prepare_to_clone_next_submodule(ce, child, suc, err)) {
+                       int *p = xmalloc(sizeof(*p));
+                       *p = suc->current;
+                       *idx_task_cb = p;
+                       suc->current++;
+                       return 1;
+               }
+       }
+
+       /*
+        * The loop above tried cloning each submodule once, now try the
+        * stragglers again, which we can imagine as an extension of the
+        * entry list.
+        */
+       index = suc->current - suc->list.nr;
+       if (index < suc->failed_clones_nr) {
+               int *p;
+               ce = suc->failed_clones[index];
+               if (!prepare_to_clone_next_submodule(ce, child, suc, err)) {
+                       suc->current ++;
+                       strbuf_addstr(err, "BUG: submodule considered for "
+                                          "cloning, doesn't need cloning "
+                                          "any more?\n");
+                       return 0;
+               }
+               p = xmalloc(sizeof(*p));
+               *p = suc->current;
+               *idx_task_cb = p;
+               suc->current ++;
+               return 1;
+       }
+
+       return 0;
+}
+
+static int update_clone_start_failure(struct strbuf *err,
+                                     void *suc_cb,
+                                     void *idx_task_cb)
+{
+       struct submodule_update_clone *suc = suc_cb;
+       suc->quickstop = 1;
+       return 1;
+}
+
+static int update_clone_task_finished(int result,
+                                     struct strbuf *err,
+                                     void *suc_cb,
+                                     void *idx_task_cb)
+{
+       const struct cache_entry *ce;
+       struct submodule_update_clone *suc = suc_cb;
+
+       int *idxP = idx_task_cb;
+       int idx = *idxP;
+       free(idxP);
+
+       if (!result)
+               return 0;
+
+       if (idx < suc->list.nr) {
+               ce  = suc->list.entries[idx];
+               strbuf_addf(err, _("Failed to clone '%s'. Retry scheduled"),
+                           ce->name);
+               strbuf_addch(err, '\n');
+               ALLOC_GROW(suc->failed_clones,
+                          suc->failed_clones_nr + 1,
+                          suc->failed_clones_alloc);
+               suc->failed_clones[suc->failed_clones_nr++] = ce;
+               return 0;
+       } else {
+               idx -= suc->list.nr;
+               ce  = suc->failed_clones[idx];
+               strbuf_addf(err, _("Failed to clone '%s' a second time, aborting"),
+                           ce->name);
+               strbuf_addch(err, '\n');
+               suc->quickstop = 1;
+               return 1;
+       }
+
+       return 0;
+}
+
+static int gitmodules_update_clone_config(const char *var, const char *value,
+                                         void *cb)
+{
+       int *max_jobs = cb;
+       if (!strcmp(var, "submodule.fetchjobs"))
+               *max_jobs = parse_submodule_fetchjobs(var, value);
+       return 0;
+}
+
+static int update_clone(int argc, const char **argv, const char *prefix)
+{
+       const char *update = NULL;
+       int max_jobs = 1;
+       struct string_list_item *item;
+       struct pathspec pathspec;
+       struct submodule_update_clone suc = SUBMODULE_UPDATE_CLONE_INIT;
+
+       struct option module_update_clone_options[] = {
+               OPT_STRING(0, "prefix", &prefix,
+                          N_("path"),
+                          N_("path into the working tree")),
+               OPT_STRING(0, "recursive-prefix", &suc.recursive_prefix,
+                          N_("path"),
+                          N_("path into the working tree, across nested "
+                             "submodule boundaries")),
+               OPT_STRING(0, "update", &update,
+                          N_("string"),
+                          N_("rebase, merge, checkout or none")),
+               OPT_STRING_LIST(0, "reference", &suc.references, N_("repo"),
+                          N_("reference repository")),
+               OPT_STRING(0, "depth", &suc.depth, "<depth>",
+                          N_("Create a shallow clone truncated to the "
+                             "specified number of revisions")),
+               OPT_INTEGER('j', "jobs", &max_jobs,
+                           N_("parallel jobs")),
+               OPT_BOOL(0, "recommend-shallow", &suc.recommend_shallow,
+                           N_("whether the initial clone should follow the shallow recommendation")),
+               OPT__QUIET(&suc.quiet, N_("don't print cloning progress")),
+               OPT_BOOL(0, "progress", &suc.progress,
+                           N_("force cloning progress")),
+               OPT_END()
+       };
+
+       const char *const git_submodule_helper_usage[] = {
+               N_("git submodule--helper update_clone [--prefix=<path>] [<path>...]"),
+               NULL
+       };
+       suc.prefix = prefix;
+
+       config_from_gitmodules(gitmodules_update_clone_config, &max_jobs);
+       git_config(gitmodules_update_clone_config, &max_jobs);
+
+       argc = parse_options(argc, argv, prefix, module_update_clone_options,
+                            git_submodule_helper_usage, 0);
+
+       if (update)
+               if (parse_submodule_update_strategy(update, &suc.update) < 0)
+                       die(_("bad value for update parameter"));
+
+       if (module_list_compute(argc, argv, prefix, &pathspec, &suc.list) < 0)
+               return 1;
+
+       if (pathspec.nr)
+               suc.warn_if_uninitialized = 1;
+
+       /* Overlay the parsed .gitmodules file with .git/config */
+       gitmodules_config();
+       git_config(submodule_config, NULL);
+
+       run_processes_parallel(max_jobs,
+                              update_clone_get_next_task,
+                              update_clone_start_failure,
+                              update_clone_task_finished,
+                              &suc);
+
+       /*
+        * We saved the output and put it out all at once now.
+        * That means:
+        * - the listener does not have to interleave their (checkout)
+        *   work with our fetching.  The writes involved in a
+        *   checkout involve more straightforward sequential I/O.
+        * - the listener can avoid doing any work if fetching failed.
+        */
+       if (suc.quickstop)
+               return 1;
+
+       for_each_string_list_item(item, &suc.projectlines)
+               fprintf(stdout, "%s", item->string);
+
+       return 0;
+}
+
+static int resolve_relative_path(int argc, const char **argv, const char *prefix)
+{
+       struct strbuf sb = STRBUF_INIT;
+       if (argc != 3)
+               die("submodule--helper relative-path takes exactly 2 arguments, got %d", argc);
+
+       printf("%s", relative_path(argv[1], argv[2], &sb));
+       strbuf_release(&sb);
+       return 0;
+}
+
+static const char *remote_submodule_branch(const char *path)
+{
+       const struct submodule *sub;
+       gitmodules_config();
+       git_config(submodule_config, NULL);
+
+       sub = submodule_from_path(&null_oid, path);
+       if (!sub)
+               return NULL;
+
+       if (!sub->branch)
+               return "master";
+
+       if (!strcmp(sub->branch, ".")) {
+               unsigned char sha1[20];
+               const char *refname = resolve_ref_unsafe("HEAD", 0, sha1, NULL);
+
+               if (!refname)
+                       die(_("No such ref: %s"), "HEAD");
+
+               /* detached HEAD */
+               if (!strcmp(refname, "HEAD"))
+                       die(_("Submodule (%s) branch configured to inherit "
+                             "branch from superproject, but the superproject "
+                             "is not on any branch"), sub->name);
+
+               if (!skip_prefix(refname, "refs/heads/", &refname))
+                       die(_("Expecting a full ref name, got %s"), refname);
+               return refname;
+       }
+
+       return sub->branch;
+}
+
+static int resolve_remote_submodule_branch(int argc, const char **argv,
+               const char *prefix)
+{
+       const char *ret;
+       struct strbuf sb = STRBUF_INIT;
+       if (argc != 2)
+               die("submodule--helper remote-branch takes exactly one arguments, got %d", argc);
+
+       ret = remote_submodule_branch(argv[1]);
+       if (!ret)
+               die("submodule %s doesn't exist", argv[1]);
+
+       printf("%s", ret);
+       strbuf_release(&sb);
+       return 0;
+}
+
+static int push_check(int argc, const char **argv, const char *prefix)
+{
+       struct remote *remote;
+       const char *superproject_head;
+       char *head;
+       int detached_head = 0;
+       struct object_id head_oid;
+
+       if (argc < 3)
+               die("submodule--helper push-check requires at least 2 arguments");
+
+       /*
+        * superproject's resolved head ref.
+        * if HEAD then the superproject is in a detached head state, otherwise
+        * it will be the resolved head ref.
+        */
+       superproject_head = argv[1];
+       argv++;
+       argc--;
+       /* Get the submodule's head ref and determine if it is detached */
+       head = resolve_refdup("HEAD", 0, head_oid.hash, NULL);
+       if (!head)
+               die(_("Failed to resolve HEAD as a valid ref."));
+       if (!strcmp(head, "HEAD"))
+               detached_head = 1;
+
+       /*
+        * The remote must be configured.
+        * This is to avoid pushing to the exact same URL as the parent.
+        */
+       remote = pushremote_get(argv[1]);
+       if (!remote || remote->origin == REMOTE_UNCONFIGURED)
+               die("remote '%s' not configured", argv[1]);
+
+       /* Check the refspec */
+       if (argc > 2) {
+               int i, refspec_nr = argc - 2;
+               struct ref *local_refs = get_local_heads();
+               struct refspec *refspec = parse_push_refspec(refspec_nr,
+                                                            argv + 2);
+
+               for (i = 0; i < refspec_nr; i++) {
+                       struct refspec *rs = refspec + i;
+
+                       if (rs->pattern || rs->matching)
+                               continue;
+
+                       /* LHS must match a single ref */
+                       switch (count_refspec_match(rs->src, local_refs, NULL)) {
+                       case 1:
+                               break;
+                       case 0:
+                               /*
+                                * If LHS matches 'HEAD' then we need to ensure
+                                * that it matches the same named branch
+                                * checked out in the superproject.
+                                */
+                               if (!strcmp(rs->src, "HEAD")) {
+                                       if (!detached_head &&
+                                           !strcmp(head, superproject_head))
+                                               break;
+                                       die("HEAD does not match the named branch in the superproject");
+                               }
+                       default:
+                               die("src refspec '%s' must name a ref",
+                                   rs->src);
+                       }
+               }
+               free_refspec(refspec_nr, refspec);
+       }
+       free(head);
+
+       return 0;
+}
+
+static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
+{
+       int i;
+       struct pathspec pathspec;
+       struct module_list list = MODULE_LIST_INIT;
+       unsigned flags = ABSORB_GITDIR_RECURSE_SUBMODULES;
+
+       struct option embed_gitdir_options[] = {
+               OPT_STRING(0, "prefix", &prefix,
+                          N_("path"),
+                          N_("path into the working tree")),
+               OPT_BIT(0, "--recursive", &flags, N_("recurse into submodules"),
+                       ABSORB_GITDIR_RECURSE_SUBMODULES),
+               OPT_END()
+       };
+
+       const char *const git_submodule_helper_usage[] = {
+               N_("git submodule--helper embed-git-dir [<path>...]"),
+               NULL
+       };
+
+       argc = parse_options(argc, argv, prefix, embed_gitdir_options,
+                            git_submodule_helper_usage, 0);
+
+       gitmodules_config();
+       git_config(submodule_config, NULL);
+
+       if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
+               return 1;
+
+       for (i = 0; i < list.nr; i++)
+               absorb_git_dir_into_superproject(prefix,
+                               list.entries[i]->name, flags);
+
+       return 0;
+}
+
+static int is_active(int argc, const char **argv, const char *prefix)
+{
+       if (argc != 2)
+               die("submodule--helper is-active takes exactly 1 argument");
+
+       gitmodules_config();
+
+       return !is_submodule_active(the_repository, argv[1]);
+}
+
+#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},
-       {"name", module_name},
-       {"clone", module_clone},
+       {"list", module_list, 0},
+       {"name", module_name, 0},
+       {"clone", module_clone, 0},
+       {"update-clone", update_clone, 0},
+       {"relative-path", resolve_relative_path, 0},
+       {"resolve-relative-url", resolve_relative_url, 0},
+       {"resolve-relative-url-test", resolve_relative_url_test, 0},
+       {"init", module_init, SUPPORT_SUPER_PREFIX},
+       {"remote-branch", resolve_remote_submodule_branch, 0},
+       {"push-check", push_check, 0},
+       {"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
+       {"is-active", is_active, 0},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
 {
        int i;
-       if (argc < 2)
-               die(_("fatal: submodule--helper subcommand must be "
-                     "called with a subcommand"));
+       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))
+       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);
                        return commands[i].fn(argc - 1, argv + 1, prefix);
+               }
+       }
 
-       die(_("fatal: '%s' is not a valid submodule--helper "
+       die(_("'%s' is not a valid submodule--helper "
              "subcommand"), argv[1]);
 }