Merge branch 'ps/3.0-remote-deprecation'

Following the procedure we established to introduce breaking
changes for Git 3.0, allow an early opt-in for removing support of
$GIT_DIR/branches/ and $GIT_DIR/remotes/ directories to configure
remotes.

* ps/3.0-remote-deprecation:
  remote: announce removal of "branches/" and "remotes/"
  builtin/pack-redundant: remove subcommand with breaking changes
  ci: repurpose "linux-gcc" job for deprecations
  ci: merge linux-gcc-default into linux-gcc
  Makefile: wire up build option for deprecated features

.github/workflows/main.yml

@@ -265,9 +265,8 @@ jobs:
           - jobname: linux-reftable
             cc: clang
             pool: ubuntu-latest
-          - jobname: linux-gcc
+          - jobname: linux-breaking-changes
             cc: gcc
-            cc_package: gcc-8
             pool: ubuntu-20.04
           - jobname: linux-TEST-vars
             cc: gcc
@@ -285,9 +284,6 @@ jobs:
           - jobname: osx-meson
             cc: clang
             pool: macos-13
-          - jobname: linux-gcc-default
-            cc: gcc
-            pool: ubuntu-latest
           - jobname: linux-leaks
             cc: gcc
             pool: ubuntu-latest

.gitlab-ci.yml

@@ -45,17 +45,13 @@ test:linux:
       - jobname: linux-reftable
         image: ubuntu:latest
         CC: clang
-      - jobname: linux-gcc
+      - jobname: linux-breaking-changes
         image: ubuntu:20.04
         CC: gcc
-        CC_PACKAGE: gcc-8
       - jobname: linux-TEST-vars
         image: ubuntu:20.04
         CC: gcc
         CC_PACKAGE: gcc-8
-      - jobname: linux-gcc-default
-        image: ubuntu:latest
-        CC: gcc
       - jobname: linux-leaks
         image: ubuntu:latest
         CC: gcc

Documentation/BreakingChanges.txt

@@ -154,6 +154,31 @@ Cf. <xmqq1rjuz6n3.fsf_-_@gitster.c.googlers.com>,
     <CAKvOHKAFXQwt4D8yUCCkf_TQL79mYaJ=KAKhtpDNTvHJFuX1NA@mail.gmail.com>,
     <20230323204047.GA9290@coredump.intra.peff.net>,
 
+* Support for storing shorthands for remote URLs in "$GIT_COMMON_DIR/branches/"
+  and "$GIT_COMMON_DIR/remotes/" has been long superseded by storing remotes in
+  the repository configuration.
++
+The mechanism has originally been introduced in f170e4b39d ([PATCH] fetch/pull:
+short-hand notation for remote repositories., 2005-07-16) and was superseded by
+6687f8fea2 ([PATCH] Use .git/remote/origin, not .git/branches/origin.,
+2005-08-20), where we switched from ".git/branches/" to ".git/remotes/". That
+commit already mentions an upcoming deprecation of the ".git/branches/"
+directory, and starting with a1d4aa7424 (Add repository-layout document.,
+2005-09-01) we have also marked this layout as deprecated. Eventually we also
+started to migrate away from ".git/remotes/" in favor of config-based remotes,
+and we have marked the directory as legacy in 3d3d282146 (Documentation:
+Grammar correction, wording fixes and cleanup, 2011-08-23)
++
+As our documentation mentions, these directories are not to be found in modern
+repositories at all and most users aren't even aware of these mechanisms. They
+have been deprecated for almost 20 years and 14 years respectively, and we are
+not aware of any active users that have complained about this deprecation.
+Furthermore, the ".git/branches/" directory is nowadays misleadingly named and
+may cause confusion as "branches" are almost exclusively used in the context of
+references.
++
+These features will be removed.
+
 == Superseded features that will not be deprecated
 
 Some features have gained newer replacements that aim to improve the design in

Documentation/gitrepository-layout.txt

@@ -153,7 +153,7 @@ config.worktree::
 	linkgit:git-worktree[1]).
 
 branches::
-	A slightly deprecated way to store shorthands to be used
+	A deprecated way to store shorthands to be used
 	to specify a URL to 'git fetch', 'git pull' and 'git push'.
 	A file can be stored as `branches/<name>` and then
 	'name' can be given to these commands in place of
@@ -162,7 +162,8 @@ branches::
 	and not likely to be found in modern repositories. This
 	directory is ignored if $GIT_COMMON_DIR is set and
 	"$GIT_COMMON_DIR/branches" will be used instead.
-
++
+Git will stop reading remotes from this directory in Git 3.0.
 
 hooks::
 	Hooks are customization scripts used by various Git
@@ -238,6 +239,8 @@ remotes::
 	and not likely to be found in modern repositories. This
 	directory is ignored if $GIT_COMMON_DIR is set and
 	"$GIT_COMMON_DIR/remotes" will be used instead.
++
+Git will stop reading remotes from this directory in Git 3.0.
 
 logs::
 	Records of changes made to refs are stored in this directory.

GIT-BUILD-OPTIONS.in

@@ -45,4 +45,5 @@ TEST_OUTPUT_DIRECTORY=@TEST_OUTPUT_DIRECTORY@
 TEST_SHELL_PATH=@TEST_SHELL_PATH@
 USE_GETTEXT_SCHEME=@USE_GETTEXT_SCHEME@
 USE_LIBPCRE2=@USE_LIBPCRE2@
+WITH_BREAKING_CHANGES=@WITH_BREAKING_CHANGES@
 X=@X@

Makefile

@@ -1273,7 +1273,9 @@ BUILTIN_OBJS += builtin/mv.o
 BUILTIN_OBJS += builtin/name-rev.o
 BUILTIN_OBJS += builtin/notes.o
 BUILTIN_OBJS += builtin/pack-objects.o
+ifndef WITH_BREAKING_CHANGES
 BUILTIN_OBJS += builtin/pack-redundant.o
+endif
 BUILTIN_OBJS += builtin/pack-refs.o
 BUILTIN_OBJS += builtin/patch-id.o
 BUILTIN_OBJS += builtin/prune-packed.o
@@ -2236,6 +2238,10 @@ ifdef FSMONITOR_OS_SETTINGS
 	COMPAT_OBJS += compat/fsmonitor/fsm-path-utils-$(FSMONITOR_OS_SETTINGS).o
 endif
 
+ifdef WITH_BREAKING_CHANGES
+	BASIC_CFLAGS += -DWITH_BREAKING_CHANGES
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK = NoThanks
 endif
@@ -3194,6 +3200,7 @@ GIT-BUILD-OPTIONS: FORCE
 		-e "s|@TEST_SHELL_PATH@|\'$(TEST_SHELL_PATH_SQ)\'|" \
 		-e "s|@USE_GETTEXT_SCHEME@|\'$(USE_GETTEXT_SCHEME)\'|" \
 		-e "s|@USE_LIBPCRE2@|\'$(USE_LIBPCRE2)\'|" \
+		-e "s|@WITH_BREAKING_CHANGES@|\'$(WITH_BREAKING_CHANGES)\'|" \
 		-e "s|@X@|\'$(X)\'|" \
 		GIT-BUILD-OPTIONS.in >$@+
 	@if grep -q '^[A-Z][A-Z_]*=@.*@$$' $@+; then echo "Unsubstituted build options in $@" >&2 && exit 1; fi

builtin/remote.c

@@ -642,10 +642,12 @@ static int migrate_file(struct remote *remote)
 	strbuf_addf(&buf, "remote.%s.fetch", remote->name);
 	for (i = 0; i < remote->fetch.nr; i++)
 		git_config_set_multivar(buf.buf, remote->fetch.items[i].raw, "^$", 0);
+#ifndef WITH_BREAKING_CHANGES
 	if (remote->origin == REMOTE_REMOTES)
 		unlink_or_warn(git_path("remotes/%s", remote->name));
 	else if (remote->origin == REMOTE_BRANCHES)
 		unlink_or_warn(git_path("branches/%s", remote->name));
+#endif /* WITH_BREAKING_CHANGES */
 	strbuf_release(&buf);
 
 	return 0;

ci/lib.sh

@@ -329,11 +329,6 @@ export SKIP_DASHED_BUILT_INS=YesPlease
 
 case "$distro" in
 ubuntu-*)
-	if test "$jobname" = "linux-gcc-default"
-	then
-		break
-	fi
-
 	# Python 2 is end of life, and Ubuntu 23.04 and newer don't actually
 	# have it anymore. We thus only test with Python 2 on older LTS
 	# releases.

ci/run-build-and-tests.sh

@@ -13,8 +13,9 @@ esac
 run_tests=t
 
 case "$jobname" in
-linux-gcc)
+linux-breaking-changes)
 	export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+	export WITH_BREAKING_CHANGES=YesPlease
 	;;
 linux-TEST-vars)
 	export OPENSSL_SHA1_UNSAFE=YesPlease

contrib/buildsystems/CMakeLists.txt

@@ -1205,6 +1205,7 @@ string(REPLACE "@TEST_OUTPUT_DIRECTORY@" "" git_build_options "${git_build_optio
 string(REPLACE "@TEST_SHELL_PATH@" "'${TEST_SHELL_PATH}'" git_build_options "${git_build_options}")
 string(REPLACE "@USE_GETTEXT_SCHEME@" "" git_build_options "${git_build_options}")
 string(REPLACE "@USE_LIBPCRE2@" "" git_build_options "${git_build_options}")
+string(REPLACE "@WITH_BREAKING_CHANGES@" "" git_build_options "${git_build_options}")
 string(REPLACE "@X@" "${EXE_EXTENSION}" git_build_options "${git_build_options}")
 if(USE_VCPKG)
 	string(APPEND git_build_options "PATH=\"$PATH:$TEST_DIRECTORY/../compat/vcbuild/vcpkg/installed/x64-windows/bin\"\n")

git.c

@@ -587,7 +587,9 @@ static struct cmd_struct commands[] = {
 	{ "name-rev", cmd_name_rev, RUN_SETUP },
 	{ "notes", cmd_notes, RUN_SETUP },
 	{ "pack-objects", cmd_pack_objects, RUN_SETUP },
+#ifndef WITH_BREAKING_CHANGES
 	{ "pack-redundant", cmd_pack_redundant, RUN_SETUP | NO_PARSEOPT },
+#endif
 	{ "pack-refs", cmd_pack_refs, RUN_SETUP },
 	{ "patch-id", cmd_patch_id, RUN_SETUP_GENTLY | NO_PARSEOPT },
 	{ "pickaxe", cmd_blame, RUN_SETUP },

meson.build

@@ -655,6 +655,12 @@ build_options_config.set('GIT_TEST_UTF8_LOCALE', '')
 build_options_config.set_quoted('LOCALEDIR', fs.as_posix(get_option('prefix') / get_option('localedir')))
 build_options_config.set('GITWEBDIR', fs.as_posix(get_option('prefix') / get_option('datadir') / 'gitweb'))
 
+if get_option('breaking_changes')
+  build_options_config.set('WITH_BREAKING_CHANGES', 'YesPlease')
+else
+  build_options_config.set('WITH_BREAKING_CHANGES', '')
+endif
+
 if get_option('sane_tool_path') != ''
   build_options_config.set_quoted('BROKEN_PATH_FIX', 's|^\# @BROKEN_PATH_FIX@$|git_broken_path_fix "' + get_option('sane_tool_path') + '"|')
 else

meson_options.txt

@@ -59,6 +59,8 @@ option('sha256_backend', type: 'combo', choices: ['openssl', 'nettle', 'gcrypt',
   description: 'The backend used for hashing objects with the SHA256 object format.')
 
 # Build tweaks.
+option('breaking_changes', type: 'boolean', value: false,
+  description: 'Enable upcoming breaking changes.')
 option('macos_use_homebrew_gettext', type: 'boolean', value: true,
   description: 'Use gettext from Homebrew instead of the slightly-broken system-provided one.')
 

remote.c

@@ -294,6 +294,7 @@ static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 	rewrite->instead_of_nr++;
 }
 
+#ifndef WITH_BREAKING_CHANGES
 static const char *skip_spaces(const char *s)
 {
 	while (isspace(*s))
@@ -301,6 +302,21 @@ static const char *skip_spaces(const char *s)
 	return s;
 }
 
+static void warn_about_deprecated_remote_type(const char *type,
+					      const struct remote *remote)
+{
+	warning(_("reading remote from \"%s/%s\", which is nominated for removal.\n"
+		  "\n"
+		  "If you still use the \"remotes/\" directory it is recommended to\n"
+		  "migrate to config-based remotes:\n"
+		  "\n"
+		  "\tgit remote rename %s %s\n"
+		  "\n"
+		  "If you cannot, please let us know why you still need to use it by\n"
+		  "sending an e-mail to <git@vger.kernel.org>."),
+		type, remote->name, remote->name, remote->name);
+}
+
 static void read_remotes_file(struct remote_state *remote_state,
 			      struct remote *remote)
 {
@@ -309,6 +325,9 @@ static void read_remotes_file(struct remote_state *remote_state,
 
 	if (!f)
 		return;
+
+	warn_about_deprecated_remote_type("remotes", remote);
+
 	remote->configured_in_repo = 1;
 	remote->origin = REMOTE_REMOTES;
 	while (strbuf_getline(&buf, f) != EOF) {
@@ -338,6 +357,8 @@ static void read_branches_file(struct remote_state *remote_state,
 	if (!f)
 		return;
 
+	warn_about_deprecated_remote_type("branches", remote);
+
 	strbuf_getline_lf(&buf, f);
 	fclose(f);
 	strbuf_trim(&buf);
@@ -375,6 +396,7 @@ static void read_branches_file(struct remote_state *remote_state,
 	strbuf_release(&buf);
 	free(to_free);
 }
+#endif /* WITH_BREAKING_CHANGES */
 
 static int handle_config(const char *key, const char *value,
 			 const struct config_context *ctx, void *cb)
@@ -591,6 +613,7 @@ static void read_config(struct repository *repo, int early)
 	alias_all_urls(repo->remote_state);
 }
 
+#ifndef WITH_BREAKING_CHANGES
 static int valid_remote_nick(const char *name)
 {
 	if (!name[0] || is_dot_or_dotdot(name))
@@ -602,6 +625,7 @@ static int valid_remote_nick(const char *name)
 			return 0;
 	return 1;
 }
+#endif /* WITH_BREAKING_CHANGES */
 
 static const char *remotes_remote_for_branch(struct remote_state *remote_state,
 					     struct branch *branch,
@@ -744,12 +768,14 @@ remotes_remote_get_1(struct remote_state *remote_state, const char *name,
 				   &name_given);
 
 	ret = make_remote(remote_state, name, 0);
+#ifndef WITH_BREAKING_CHANGES
 	if (valid_remote_nick(name) && have_git_dir()) {
 		if (!valid_remote(ret))
 			read_remotes_file(remote_state, ret);
 		if (!valid_remote(ret))
 			read_branches_file(remote_state, ret);
 	}
+#endif /* WITH_BREAKING_CHANGES */
 	if (name_given && !valid_remote(ret))
 		add_url_alias(remote_state, ret, name);
 	if (!valid_remote(ret))

remote.h

@@ -21,8 +21,10 @@ struct transport_ls_refs_options;
 enum {
 	REMOTE_UNCONFIGURED = 0,
 	REMOTE_CONFIG,
+#ifndef WITH_BREAKING_CHANGES
 	REMOTE_REMOTES,
 	REMOTE_BRANCHES
+#endif /* WITH_BREAKING_CHANGES */
 };
 
 struct rewrite {

t/t5323-pack-redundant.sh

@@ -36,6 +36,12 @@ relationship between packs and objects is as follows:
 
 . ./test-lib.sh
 
+if ! test_have_prereq WITHOUT_BREAKING_CHANGES
+then
+	skip_all='skipping git-pack-redundant tests; built with breaking changes'
+	test_done
+fi
+
 main_repo=main.git
 shared_repo=shared.git
 

t/t5505-remote.sh

@@ -1113,7 +1113,7 @@ Pull: refs/heads/main:refs/heads/origin
 Pull: refs/heads/next:refs/heads/origin2
 EOF
 
-test_expect_success 'migrate a remote from named file in $GIT_DIR/remotes' '
+test_expect_success WITHOUT_BREAKING_CHANGES 'migrate a remote from named file in $GIT_DIR/remotes' '
 	git clone one five &&
 	origin_url=$(pwd)/one &&
 	(
@@ -1139,7 +1139,7 @@ test_expect_success 'migrate a remote from named file in $GIT_DIR/remotes' '
 	)
 '
 
-test_expect_success 'migrate a remote from named file in $GIT_DIR/branches' '
+test_expect_success WITHOUT_BREAKING_CHANGES 'migrate a remote from named file in $GIT_DIR/branches' '
 	git clone --template= one six &&
 	origin_url=$(pwd)/one &&
 	(
@@ -1155,7 +1155,7 @@ test_expect_success 'migrate a remote from named file in $GIT_DIR/branches' '
 	)
 '
 
-test_expect_success 'migrate a remote from named file in $GIT_DIR/branches (2)' '
+test_expect_success WITHOUT_BREAKING_CHANGES 'migrate a remote from named file in $GIT_DIR/branches (2)' '
 	git clone --template= one seven &&
 	(
 		cd seven &&

t/t5510-fetch.sh

@@ -34,14 +34,11 @@ test_expect_success "clone and setup child repos" '
 	git clone . three &&
 	(
 		cd three &&
-		git config branch.main.remote two &&
-		git config branch.main.merge refs/heads/one &&
-		mkdir -p .git/remotes &&
-		cat >.git/remotes/two <<-\EOF
-		URL: ../two/.git/
-		Pull: refs/heads/main:refs/heads/two
-		Pull: refs/heads/one:refs/heads/one
-		EOF
+		git config set remote.two.url ../two/.git/ &&
+		git config set remote.two.fetch refs/heads/main:refs/heads/two &&
+		git config set --append remote.two.fetch refs/heads/one:refs/heads/one &&
+		git config set branch.main.remote two &&
+		git config set branch.main.merge refs/heads/one
 	) &&
 	git clone . bundle &&
 	git clone . seven

t/t5515-fetch-merge-logic.sh

@@ -104,28 +104,31 @@ test_expect_success setup '
 	git config remote.config-glob.fetch refs/heads/*:refs/remotes/rem/* &&
 	remotes="$remotes config-glob" &&
 
-	mkdir -p .git/remotes &&
-	cat >.git/remotes/remote-explicit <<-\EOF &&
-	URL: ../.git/
-	Pull: refs/heads/main:remotes/rem/main
-	Pull: refs/heads/one:remotes/rem/one
-	Pull: two:remotes/rem/two
-	Pull: refs/heads/three:remotes/rem/three
-	EOF
-	remotes="$remotes remote-explicit" &&
+	if test_have_prereq WITHOUT_BREAKING_CHANGES
+	then
+		mkdir -p .git/remotes &&
+		cat >.git/remotes/remote-explicit <<-\EOF &&
+		URL: ../.git/
+		Pull: refs/heads/main:remotes/rem/main
+		Pull: refs/heads/one:remotes/rem/one
+		Pull: two:remotes/rem/two
+		Pull: refs/heads/three:remotes/rem/three
+		EOF
+		remotes="$remotes remote-explicit" &&
 
-	cat >.git/remotes/remote-glob <<-\EOF &&
-	URL: ../.git/
-	Pull: refs/heads/*:refs/remotes/rem/*
-	EOF
-	remotes="$remotes remote-glob" &&
+		cat >.git/remotes/remote-glob <<-\EOF &&
+		URL: ../.git/
+		Pull: refs/heads/*:refs/remotes/rem/*
+		EOF
+		remotes="$remotes remote-glob" &&
 
-	mkdir -p .git/branches &&
-	echo "../.git" > .git/branches/branches-default &&
-	remotes="$remotes branches-default" &&
+		mkdir -p .git/branches &&
+		echo "../.git" > .git/branches/branches-default &&
+		remotes="$remotes branches-default" &&
 
-	echo "../.git#one" > .git/branches/branches-one &&
-	remotes="$remotes branches-one" &&
+		echo "../.git#one" > .git/branches/branches-one &&
+		remotes="$remotes branches-one"
+	fi &&
 
 	for remote in $remotes ; do
 		git config branch.br-$remote.remote $remote &&

t/t5516-fetch-push.sh

@@ -975,7 +975,7 @@ test_expect_success 'allow push to HEAD of non-bare repository (config)' '
 	! grep "warning: updating the current branch" stderr
 '
 
-test_expect_success 'fetch with branches' '
+test_expect_success WITHOUT_BREAKING_CHANGES 'fetch with branches' '
 	mk_empty testrepo &&
 	git branch second $the_first_commit &&
 	git checkout second &&
@@ -991,7 +991,7 @@ test_expect_success 'fetch with branches' '
 	git checkout main
 '
 
-test_expect_success 'fetch with branches containing #' '
+test_expect_success WITHOUT_BREAKING_CHANGES 'fetch with branches containing #' '
 	mk_empty testrepo &&
 	mkdir testrepo/.git/branches &&
 	echo "..#second" > testrepo/.git/branches/branch2 &&
@@ -1005,7 +1005,7 @@ test_expect_success 'fetch with branches containing #' '
 	git checkout main
 '
 
-test_expect_success 'push with branches' '
+test_expect_success WITHOUT_BREAKING_CHANGES 'push with branches' '
 	mk_empty testrepo &&
 	git checkout second &&
 
@@ -1022,7 +1022,7 @@ test_expect_success 'push with branches' '
 	)
 '
 
-test_expect_success 'push with branches containing #' '
+test_expect_success WITHOUT_BREAKING_CHANGES 'push with branches containing #' '
 	mk_empty testrepo &&
 
 	test_when_finished "rm -rf .git/branches" &&
@@ -1211,18 +1211,16 @@ test_expect_success 'push --porcelain --dry-run rejected' '
 '
 
 test_expect_success 'push --prune' '
-	mk_test testrepo heads/main heads/second heads/foo heads/bar &&
+	mk_test testrepo heads/main heads/foo heads/bar &&
 	git push --prune testrepo : &&
 	check_push_result testrepo $the_commit heads/main &&
-	check_push_result testrepo $the_first_commit heads/second &&
 	! check_push_result testrepo $the_first_commit heads/foo heads/bar
 '
 
 test_expect_success 'push --prune refspec' '
-	mk_test testrepo tmp/main tmp/second tmp/foo tmp/bar &&
+	mk_test testrepo tmp/main tmp/foo tmp/bar &&
 	git push --prune testrepo "refs/heads/*:refs/tmp/*" &&
 	check_push_result testrepo $the_commit tmp/main &&
-	check_push_result testrepo $the_first_commit tmp/second &&
 	! check_push_result testrepo $the_first_commit tmp/foo tmp/bar
 '
 

t/test-lib.sh

@@ -1862,6 +1862,10 @@ test_lazy_prereq CURL '
 	curl --version
 '
 
+test_lazy_prereq WITHOUT_BREAKING_CHANGES '
+	test -z "$WITH_BREAKING_CHANGES"
+'
+
 # SHA1 is a test if the hash algorithm in use is SHA-1.  This is both for tests
 # which will not work with other hash algorithms and tests that work but don't
 # test anything meaningful (e.g. special values which cause short collisions).