create_symref: drop support for writing symbolic links

The parent commit deprecated the writing of symbolic links
for symrefs.  Now that some time has passed, we can follow
through by dropping the code.

Signed-off-by: Jeff King <[email protected]>

Author: peff

Makefile

@@ -81,9 +81,6 @@ include shared.mak
 #
 # Define NO_SYS_SELECT_H if you don't have sys/select.h.
 #
-# Define NO_SYMLINK_HEAD if you never want .git/HEAD to be a symbolic link.
-# Enable it on Windows.  By default, symrefs are still used.
-#
 # Define NO_SVN_TESTS if you want to skip time-consuming SVN interoperability
 # tests.  These tests take up a significant amount of the total test time
 # but are not needed unless you plan to talk to SVN repos.
@@ -1928,9 +1925,6 @@ endif
 ifdef OPEN_RETURNS_EINTR
 	COMPAT_CFLAGS += -DOPEN_RETURNS_EINTR
 endif
-ifdef NO_SYMLINK_HEAD
-	BASIC_CFLAGS += -DNO_SYMLINK_HEAD
-endif
 ifdef NO_GETTEXT
 	BASIC_CFLAGS += -DNO_GETTEXT
 	USE_GETTEXT_SCHEME ?= fallthrough

config.mak.uname

@@ -247,7 +247,6 @@ ifeq ($(uname_O),Cygwin)
 		NO_D_TYPE_IN_DIRENT = YesPlease
 		NO_STRCASESTR = YesPlease
 		NO_MEMMEM = YesPlease
-		NO_SYMLINK_HEAD = YesPlease
 		NO_IPV6 = YesPlease
 		OLD_ICONV = UnfortunatelyYes
 		# There are conflicting reports about this.
@@ -460,7 +459,6 @@ ifeq ($(uname_S),Windows)
 	NEEDS_CRYPTO_WITH_SSL = YesPlease
 	NO_LIBGEN_H = YesPlease
 	NO_POLL = YesPlease
-	NO_SYMLINK_HEAD = YesPlease
 	NO_IPV6 = YesPlease
 	NO_SETENV = YesPlease
 	NO_STRCASESTR = YesPlease
@@ -675,7 +673,6 @@ ifeq ($(uname_S),MINGW)
 	NEEDS_CRYPTO_WITH_SSL = YesPlease
 	NO_LIBGEN_H = YesPlease
 	NO_POLL = YesPlease
-	NO_SYMLINK_HEAD = YesPlease
 	NO_SETENV = YesPlease
 	NO_STRCASESTR = YesPlease
 	NO_STRLCPY = YesPlease

configure.ac

@@ -1223,9 +1223,6 @@ if test -z "$HAVE_BSD_SYSCTL"; then
 fi
 
 ## Other checks.
-# Define NO_SYMLINK_HEAD if you never want .git/HEAD to be a symbolic link.
-# Enable it on Windows.  By default, symrefs are still used.
-#
 # Define NO_PTHREADS if we do not have pthreads.
 #
 # Define PTHREAD_LIBS to the linker flag used for Pthread support.

refs/files-backend.c

@@ -2094,39 +2094,6 @@ static int commit_ref_update(struct files_ref_store *refs,
 	return 0;
 }
 
-#if defined(NO_SYMLINK_HEAD) || defined(WITH_BREAKING_CHANGES)
-#define create_ref_symlink(a, b) (-1)
-#else
-static int create_ref_symlink(struct ref_lock *lock, const char *target)
-{
-	static int warn_once = 1;
-	char *ref_path;
-	int ret = -1;
-
-	ref_path = get_locked_file_path(&lock->lk);
-	unlink(ref_path);
-	ret = symlink(target, ref_path);
-	free(ref_path);
-
-	if (ret)
-		fprintf(stderr, "no symlink - falling back to symbolic ref\n");
-
-	if (warn_once)
-		warning(_("'core.preferSymlinkRefs=true' is nominated for removal.\n"
-			  "hint: The use of symbolic links for symbolic refs is deprecated\n"
-			  "hint: and will be removed in Git 3.0. The configuration that\n"
-			  "hint: tells Git to use them is thus going away. You can unset\n"
-			  "hint: it with:\n"
-			  "hint:\n"
-			  "hint:\tgit config unset core.preferSymlinkRefs\n"
-			  "hint:\n"
-			  "hint: Git will then use the textual symref format instead."));
-	warn_once = 0;
-
-	return ret;
-}
-#endif
-
 static int create_symref_lock(struct ref_lock *lock, const char *target,
 			      struct strbuf *err)
 {
@@ -3308,20 +3275,6 @@ static int files_transaction_finish(struct ref_store *ref_store,
 			}
 		}
 
-		/*
-		 * We try creating a symlink, if that succeeds we continue to the
-		 * next update. If not, we try and create a regular symref.
-		 */
-		if (update->new_target && refs->prefer_symlink_refs)
-			/*
-			 * By using the `NOT_CONSTANT()` trick, we can avoid
-			 * errors by `clang`'s `-Wunreachable` logic that would
-			 * report that the `continue` statement is not reachable
-			 * when `NO_SYMLINK_HEAD` is `#define`d.
-			 */
-			if (NOT_CONSTANT(!create_ref_symlink(lock, update->new_target)))
-				continue;
-
 		if (update->flags & REF_NEEDS_COMMIT) {
 			clear_loose_ref_cache(refs);
 			if (commit_ref(lock)) {

t/t0600-reffiles-backend.sh

@@ -467,41 +467,6 @@ test_expect_success POSIXPERM 'git reflog expire honors core.sharedRepository' '
 	esac
 '
 
-test_expect_success SYMLINKS,!MINGW 'symref transaction supports symlinks' '
-	test_when_finished "git symbolic-ref -d TEST_SYMREF_HEAD" &&
-	git update-ref refs/heads/new @ &&
-	test_config core.prefersymlinkrefs true &&
-	cat >stdin <<-EOF &&
-	start
-	symref-create TEST_SYMREF_HEAD refs/heads/new
-	prepare
-	commit
-	EOF
-	git update-ref --no-deref --stdin <stdin 2>err &&
-	if test_have_prereq WITH_BREAKING_CHANGES
-	then
-		test_path_is_file .git/TEST_SYMREF_HEAD &&
-		echo "ref: refs/heads/new" >expect &&
-		test_cmp expect .git/TEST_SYMREF_HEAD &&
-		test_must_be_empty err
-	else
-		test_path_is_symlink .git/TEST_SYMREF_HEAD &&
-		test "$(test_readlink .git/TEST_SYMREF_HEAD)" = refs/heads/new &&
-		cat >expect <<-EOF &&
-		warning: ${SQ}core.preferSymlinkRefs=true${SQ} is nominated for removal.
-		hint: The use of symbolic links for symbolic refs is deprecated
-		hint: and will be removed in Git 3.0. The configuration that
-		hint: tells Git to use them is thus going away. You can unset
-		hint: it with:
-		hint:
-		hint:	git config unset core.preferSymlinkRefs
-		hint:
-		hint: Git will then use the textual symref format instead.
-		EOF
-		test_cmp expect err
-	fi
-'
-
 test_expect_success 'symref transaction supports false symlink config' '
 	test_when_finished "git symbolic-ref -d TEST_SYMREF_HEAD" &&
 	git update-ref refs/heads/new @ &&

t/t7201-co.sh

@@ -406,18 +406,6 @@ test_expect_success 'checkout w/--track from tag fails' '
 	test "z$(git rev-parse main^0)" = "z$(git rev-parse HEAD)"
 '
 
-test_expect_success 'detach a symbolic link HEAD' '
-	git checkout main &&
-	git config --bool core.prefersymlinkrefs yes &&
-	git checkout side &&
-	git checkout main &&
-	it=$(git symbolic-ref HEAD) &&
-	test "z$it" = zrefs/heads/main &&
-	here=$(git rev-parse --verify refs/heads/main) &&
-	git checkout side^ &&
-	test "z$(git rev-parse --verify refs/heads/main)" = "z$here"
-'
-
 test_expect_success 'checkout with --track fakes a sensible -b <name>' '
 	git config remote.origin.fetch "+refs/heads/*:refs/remotes/origin/*" &&
 	git update-ref refs/remotes/origin/koala/bear renamer &&

t/t9903-bash-prompt.sh

@@ -49,15 +49,6 @@ test_expect_success 'prompt - branch name' '
 	test_cmp expected "$actual"
 '
 
-test_expect_success SYMLINKS 'prompt - branch name - symlink symref' '
-	printf " (main)" >expected &&
-	test_when_finished "git checkout main" &&
-	test_config core.preferSymlinkRefs true &&
-	git checkout main &&
-	__git_ps1 >"$actual" &&
-	test_cmp expected "$actual"
-'
-
 test_expect_success 'prompt - unborn branch' '
 	printf " (unborn)" >expected &&
 	git checkout --orphan unborn &&