diff --git a/Documentation/config.txt b/Documentation/config.txt
index 0bcb679..e09d32c 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2847,6 +2847,18 @@ submodule.fetchJobs::
in parallel. A value of 0 will give some reasonable default.
If unset, it defaults to 1.
+submodule.alternateLocation::
+ Specifies how the submodules obtain alternates when submodules are
+ cloned. Possible values are `no`, `superproject`.
+ By default `no` is assumed, which doesn't add references. When the
+ value is set to `superproject` the submodule to be cloned computes
+ its alternates location relative to the superprojects alternate.
+
+submodule.alternateErrorStrategy
+ Specifies how to treat errors with the alternates for a submodule
+ as computed via `submodule.alternateLocation`. Possible values are
+ `ignore`, `info`, `die`.
+
tag.forceSignAnnotated::
A boolean to specify whether annotated tags created should be GPG signed.
If `--annotate` is specified on the command line, it takes
diff --git a/builtin/clone.c b/builtin/clone.c
index fdb2ca9..0593aee 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -944,6 +944,25 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
else
fprintf(stderr, _("Cloning into '%s'...\n"), dir);
}
+
+ if (option_recursive) {
+ if (option_required_reference.nr &&
+ option_optional_reference.nr)
+ die(_("clone --recursive is not compatible with "
+ "both --reference and --reference-if-able"));
+ else if (option_required_reference.nr) {
+ string_list_append(&option_config,
+ "submodule.alternateLocation=superproject");
+ string_list_append(&option_config,
+ "submodule.alternateErrorStrategy=die");
+ } else if (option_optional_reference.nr) {
+ string_list_append(&option_config,
+ "submodule.alternateLocation=superproject");
+ string_list_append(&option_config,
+ "submodule.alternateErrorStrategy=info");
+ }
+ }
+
init_db(option_template, INIT_DB_QUIET);
write_config(&option_config);
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index a10a777..a71c903 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -472,6 +472,90 @@ static int clone_submodule(const char *path, const char *gitdir, const char *url
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 }
+
+int add_possible_reference_from_superproject(
+ struct alternate_object_database *alt, void *sas_cb)
+{
+ struct submodule_alternate_setup *sas = sas_cb;
+
+ /* directory name, minus trailing slash */
+ size_t namelen = alt->name - alt->base - 1;
+ struct strbuf name = STRBUF_INIT;
+ strbuf_add(&name, alt->base, namelen);
+
+ /*
+ * If the alternate object store is another repository, try the
+ * standard layout with .git/modules/<name>/objects
+ */
+ if (ends_with(name.buf, ".git/objects")) {
+ char *sm_alternate;
+ struct strbuf sb = STRBUF_INIT;
+ struct strbuf err = STRBUF_INIT;
+ strbuf_add(&sb, name.buf, name.len - 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);
+ }
+
+ strbuf_release(&name);
+ 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);
+
+ sas.submodule_name = sm_name;
+ sas.reference = reference;
+ if (!strcmp(error_strategy, "die"))
+ sas.error_mode = SUBMODULE_ALTERNATE_ERROR_DIE;
+ if (!strcmp(error_strategy, "info"))
+ sas.error_mode = SUBMODULE_ALTERNATE_ERROR_INFO;
+ if (!strcmp(sm_alternate, "superproject"))
+ foreach_alt_odb(add_possible_reference_from_superproject, &sas);
+}
+
static int module_clone(int argc, const char **argv, const char *prefix)
{
const char *name = NULL, *url = NULL, *depth = NULL;@@ -532,6 +616,9 @@ 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);
+
+ prepare_possible_alternates(name, &reference);
+
if (clone_submodule(path, sm_gitdir, url, depth, &reference, quiet))
die(_("clone of '%s' into submodule path '%s' failed"),
url, path);diff --git a/t/t7408-submodule-reference.sh b/t/t7408-submodule-reference.sh
index dff47af..1c1e289 100755
--- a/t/t7408-submodule-reference.sh
+++ b/t/t7408-submodule-reference.sh
@@ -82,4 +82,47 @@ test_expect_success 'updating superproject keeps alternates' '
test_alternate_is_used super-clone/.git/modules/sub/objects/info/alternates super-clone/sub
'
+test_expect_success 'submodules use alternates when cloning a superproject' '
+ test_when_finished "rm -rf super-clone" &&
+ git clone --reference super --recursive super super-clone &&
+ (
+ cd super-clone &&
+ # test superproject has alternates setup correctly
+ test_alternate_is_used .git/objects/info/alternates . &&
+ # test submodule has correct setup
+ test_alternate_is_used .git/modules/sub/objects/info/alternates sub
+ )
+'
+
+test_expect_success 'missing submodule alternate fails clone and submodule update' '
+ test_when_finished "rm -rf super-clone" &&
+ git clone super super2 &&
+ test_must_fail git clone --recursive --reference super2 super2 super-clone &&
+ (
+ cd super-clone &&
+ # test superproject has alternates setup correctly
+ test_alternate_is_used .git/objects/info/alternates . &&
+ # update of the submodule succeeds
+ test_must_fail git submodule update --init &&
+ # and we have no alternates:
+ test_must_fail test_alternate_is_used .git/modules/sub/objects/info/alternates sub &&
+ test_must_fail test_path_is_file sub/file1
+ )
+'
+
+test_expect_success 'ignoring missing submodule alternates passes clone and submodule update' '
+ test_when_finished "rm -rf super-clone" &&
+ git clone --reference-if-able super2 --recursive super2 super-clone &&
+ (
+ cd super-clone &&
+ # test superproject has alternates setup correctly
+ test_alternate_is_used .git/objects/info/alternates . &&
+ # update of the submodule succeeds
+ git submodule update --init &&
+ # and we have no alternates:
+ test_must_fail test_alternate_is_used .git/modules/sub/objects/info/alternates sub &&
+ test_path_is_file sub/file1
+ )
+'
+
test_done
--
2.9.2.737.g4a14654