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

Author: gitster

.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. <[email protected]>,
     <CAKvOHKAFXQwt4D8yUCCkf_TQL79mYaJ=KAKhtpDNTvHJFuX1NA@mail.gmail.com>,
     <[email protected]>,
 
+* 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+  and "$GIT_COMMON_DIR/remotes/" has been long superseded by storing remotes in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+short-hand notation for remote repositories., 2005-07-16) and was superseded by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")