clone: create promisor remotes from advertised hints

Documentation/config/promisor.adoc

@@ -89,3 +89,13 @@ variable. The fields are checked only if the
 `promisor.acceptFromServer` config variable is not set to "None". If
 set to "None", this config variable has no effect. See
 linkgit:gitprotocol-v2[5].
+
+promisor.createRemotes::
+        If set to "true", linkgit:git-clone[1] will create entries for
+        any promisor remotes advertised by the server via the
+        "promisor-remote" capability. Each remote is added to the new
+        repository's configuration with its advertised URL, marked as a
+        promisor remote, and given a default fetch refspec
+        (`+refs/heads/*:refs/remotes/<name>/*`). Optional fields such as
+        `partialCloneFilter` and `token` are recorded when present. The
+        remote is only created if it is not already configured locally.

builtin/clone.c

@@ -47,6 +47,8 @@
 #include "hook.h"
 #include "bundle.h"
 #include "bundle-uri.h"
+#include "promisor-remote.h"
+#include "connect.h"
 
 /*
  * Overall FIXMEs:
@@ -1585,15 +1587,23 @@ int cmd_clone(int argc,
 		free(to_free);
 	}
 
-	if (!option_rev)
-		write_refspec_config(src_ref_prefix, our_head_points_at,
-				     remote_head_points_at, &branch_top);
+        if (!option_rev)
+                write_refspec_config(src_ref_prefix, our_head_points_at,
+                                     remote_head_points_at, &branch_top);
+
+        {
+                const char *promisor_remote_info;
+
+                if (server_feature_v2("promisor-remote", &promisor_remote_info))
+                        promisor_remote_configure_from_info(the_repository,
+                                                            promisor_remote_info);
+        }
 
-	if (filter_options.choice)
-		partial_clone_register(remote_name, &filter_options);
+        if (filter_options.choice)
+                partial_clone_register(remote_name, &filter_options);
 
-	if (is_local)
-		clone_local(path, git_dir);
+        if (is_local)
+                clone_local(path, git_dir);
 	else if (mapped_refs && complete_refs_before_fetch) {
 		if (transport_fetch_refs(transport, mapped_refs))
 			die(_("remote transport reported error"));

promisor-remote.c

@@ -9,6 +9,7 @@
 #include "trace2.h"
 #include "transport.h"
 #include "strvec.h"
+#include "strbuf.h"
 #include "packfile.h"
 #include "environment.h"
 #include "url.h"
@@ -769,23 +770,110 @@ char *promisor_remote_reply(const char *info)
 
 void mark_promisor_remotes_as_accepted(struct repository *r, const char *remotes)
 {
-	struct string_list accepted_remotes = STRING_LIST_INIT_DUP;
-	struct string_list_item *item;
+        struct string_list accepted_remotes = STRING_LIST_INIT_DUP;
+        struct string_list_item *item;
 
-	string_list_split(&accepted_remotes, remotes, ";", -1);
+        string_list_split(&accepted_remotes, remotes, ";", -1);
 
-	for_each_string_list_item(item, &accepted_remotes) {
-		char *decoded_remote = url_percent_decode(item->string);
-		struct promisor_remote *p = repo_promisor_remote_find(r, decoded_remote);
+        for_each_string_list_item(item, &accepted_remotes) {
+                char *decoded_remote = url_percent_decode(item->string);
+                struct promisor_remote *p = repo_promisor_remote_find(r, decoded_remote);
 
-		if (p)
-			p->accepted = 1;
-		else
-			warning(_("accepted promisor remote '%s' not found"),
-				decoded_remote);
+                if (p)
+                        p->accepted = 1;
+                else
+                        warning(_("accepted promisor remote '%s' not found"),
+                                decoded_remote);
 
-		free(decoded_remote);
-	}
+                free(decoded_remote);
+        }
+
+        string_list_clear(&accepted_remotes, 0);
+}
+
+static int remote_is_already_configured(struct repository *repo, const char *remote_name)
+{
+        const char *value;
+        char *key = xstrfmt("remote.%s.url", remote_name);
+        int configured = 0;
+
+        if (!repo_config_get_string_tmp(repo, key, &value) && value && *value)
+                configured = 1;
+
+        free(key);
+        return configured;
+}
+
+static void set_remote_config_value(struct repository *repo, const char *remote_name,
+                                   const char *suffix, const char *value)
+{
+        char *key = xstrfmt("remote.%s.%s", remote_name, suffix);
+
+        repo_config_set(repo, key, value);
+        free(key);
+}
+
+static void set_remote_fetch_default(struct repository *repo, const char *remote_name)
+{
+        char *key = xstrfmt("remote.%s.fetch", remote_name);
+        struct strbuf value = STRBUF_INIT;
+
+        strbuf_addf(&value, "+refs/heads/*:refs/remotes/%s/*", remote_name);
+        repo_config_set_multivar(repo, key, value.buf, "^$", 0);
+
+        free(key);
+        strbuf_release(&value);
+}
+
+static void configure_remote_from_advertisement(struct repository *repo,
+                                               struct promisor_info *info)
+{
+        set_remote_config_value(repo, info->name, "url", info->url);
+        set_remote_config_value(repo, info->name, "promisor", "true");
+        set_remote_fetch_default(repo, info->name);
+
+        if (info->filter)
+                set_remote_config_value(repo, info->name,
+                                        promisor_field_filter, info->filter);
+
+        if (info->token)
+                set_remote_config_value(repo, info->name,
+                                        promisor_field_token, info->token);
+}
+
+void promisor_remote_configure_from_info(struct repository *repo, const char *info)
+{
+        struct string_list remote_info = STRING_LIST_INIT_DUP;
+        struct string_list_item *item;
+        int create_remotes;
+        int created = 0;
+
+        if (!info || !*info)
+                return;
+
+        if (repo_config_get_bool(repo, "promisor.createremotes", &create_remotes) ||
+            !create_remotes)
+                return;
+
+        string_list_split(&remote_info, info, ";", -1);
+
+        for_each_string_list_item(item, &remote_info) {
+                struct promisor_info *advertised =
+                        parse_one_advertised_remote(item->string);
+
+                if (!advertised)
+                        continue;
+
+                if (!remote_is_already_configured(repo, advertised->name)) {
+                        configure_remote_from_advertisement(repo, advertised);
+                        created = 1;
+                }
+
+                promisor_info_free(advertised);
+        }
+
+        string_list_clear(&remote_info, 0);
 
-	string_list_clear(&accepted_remotes, 0);
+        if (created)
+                repo_promisor_remote_reinit(repo);
 }

promisor-remote.h

@@ -67,4 +67,10 @@ void mark_promisor_remotes_as_accepted(struct repository *repo, const char *remo
  */
 int repo_has_accepted_promisor_remote(struct repository *r);
 
+/*
+ * Create promisor remotes in the configuration based on the
+ * "promisor-remote" capability advertisement received from a server.
+ */
+void promisor_remote_configure_from_info(struct repository *repo, const char *info);
+
 #endif /* PROMISOR_REMOTE_H */

t/t5710-promisor-remote-capability.sh

@@ -327,10 +327,10 @@ test_expect_success "clone with promisor.sendFields" '
 '
 
 test_expect_success "clone with promisor.checkFields" '
-	git -C server config promisor.advertise true &&
-	test_when_finished "rm -rf client" &&
+        git -C server config promisor.advertise true &&
+        test_when_finished "rm -rf client" &&
 
-	git -C server remote add otherLop "https://invalid.invalid"  &&
+        git -C server remote add otherLop "https://invalid.invalid"  &&
 	git -C server config remote.otherLop.token "fooBar" &&
 	git -C server config remote.otherLop.stuff "baz" &&
 	git -C server config remote.otherLop.partialCloneFilter "blob:limit=10k" &&
@@ -357,14 +357,38 @@ test_expect_success "clone with promisor.checkFields" '
 	test_grep ! "clone> promisor-remote=lop;otherLop" trace &&
 
 	# Check that the largest object is still missing on the server
-	check_missing_objects server 1 "$oid"
+        check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "clone creates promisor remotes from hints" '
+        git -C server config promisor.advertise true &&
+        test_when_finished "rm -rf client" &&
+
+        test_when_finished "git -C server config --unset-all promisor.sendFields" &&
+        test_config -C server promisor.sendFields "partialCloneFilter, token" &&
+        git -C server config remote.lop.partialCloneFilter "blob:none" &&
+        git -C server config remote.lop.token "lop-token" &&
+        test_when_finished "git -C server config --unset remote.lop.token" &&
+
+        GIT_NO_LAZY_FETCH=0 git clone \
+                -c promisor.acceptfromserver=All \
+                -c promisor.createRemotes=true \
+                --no-local --filter="blob:limit=5k" server client &&
+
+        test_cmp_config -C client "file://$(pwd)/lop" remote.lop.url &&
+        test_cmp_config -C client true remote.lop.promisor &&
+        test_cmp_config -C client "+refs/heads/*:refs/remotes/lop/*" remote.lop.fetch &&
+        test_cmp_config -C client blob:none remote.lop.partialCloneFilter &&
+        test_cmp_config -C client lop-token remote.lop.token &&
+
+        check_missing_objects server 1 "$oid"
 '
 
 test_expect_success "clone with promisor.advertise set to 'true' but don't delete the client" '
-	git -C server config promisor.advertise true &&
+        git -C server config promisor.advertise true &&
 
-	# Clone from server to create a client
-	GIT_NO_LAZY_FETCH=0 git clone -c remote.lop.promisor=true \
+        # Clone from server to create a client
+        GIT_NO_LAZY_FETCH=0 git clone -c remote.lop.promisor=true \
 		-c remote.lop.fetch="+refs/heads/*:refs/remotes/lop/*" \
 		-c remote.lop.url="file://$(pwd)/lop" \
 		-c promisor.acceptfromserver=All \