From ceee081c850df8353db54530dcc0d76887485ee3 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Sat, 3 Jul 2021 19:59:34 +0200
Subject: [PATCH 01/15] Added independent update mode for symbolic links

---
 flist.c     |  8 +++++-
 generator.c | 59 +++++++++++++++++++++++++++++++++++++++++
 options.c   | 14 +++++++++-
 rsync.1.md  | 75 ++++++++++++++++++++++++++++++++++++++++++++++++-----
 4 files changed, 147 insertions(+), 9 deletions(-)

diff --git a/flist.c b/flist.c
index 17832533e..cc9b44227 100644
--- a/flist.c
+++ b/flist.c
@@ -62,6 +62,7 @@ extern int implied_dirs;
 extern int ignore_perishable;
 extern int non_perishable_cnt;
 extern int prune_empty_dirs;
+extern int update_links;
 extern int copy_links;
 extern int copy_unsafe_links;
 extern int protocol_version;
@@ -234,10 +235,15 @@ static int readlink_stat(const char *path, STRUCT_STAT *stp, char *linkbuf)
 int link_stat(const char *path, STRUCT_STAT *stp, int follow_dirlinks)
 {
 #ifdef SUPPORT_LINKS
-	if (copy_links)
+	if (copy_links && update_links == 0)
 		return x_stat(path, stp, NULL);
 	if (x_lstat(path, stp, NULL) < 0)
 		return -1;
+	if (update_links && S_ISLNK(stp->st_mode)) {
+		STRUCT_STAT st;
+		if (x_stat(path, &st, NULL) == 0 && !S_ISDIR(st.st_mode))
+			return x_lstat(path, stp, NULL);
+	}
 	if (follow_dirlinks && S_ISLNK(stp->st_mode)) {
 		STRUCT_STAT st;
 		if (x_stat(path, &st, NULL) == 0 && S_ISDIR(st.st_mode))
diff --git a/generator.c b/generator.c
index b56fa569a..e56ed3cf3 100644
--- a/generator.c
+++ b/generator.c
@@ -57,6 +57,9 @@ extern int ignore_errors;
 extern int remove_source_files;
 extern int delay_updates;
 extern int update_only;
+extern int update_links;
+extern int copy_links;
+extern int allow_link_update_dir;
 extern int human_readable;
 extern int ignore_existing;
 extern int ignore_non_existing;
@@ -1540,6 +1543,8 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
 	 && hard_link_check(file, ndx, fname, statret, &sx, itemizing, code))
 		goto cleanup;
 #endif
+	if (DEBUG_GTE(GENR, 1))
+		rprintf(FINFO, "%s src mtime=%ld dest mtime=%ld modify_window=%d statret=%d copy_links=%d update_links=%d allow_link_update_dir=%d\n", fname, file->modtime, (long)sx.st.st_mtime, modify_window, statret, copy_links, update_links, allow_link_update_dir);
 
 	if (preserve_links && ftype == FT_SYMLINK) {
 #ifdef SUPPORT_LINKS
@@ -1588,6 +1593,60 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
 				fnamecmp = fnamecmpbuf;
 			}
 		}
+		if (statret == 0) {
+			if (update_links > 0) {
+				if (S_ISDIR(sx.st.st_mode) && allow_link_update_dir == 0) {
+					if (INFO_GTE(SKIP, 1))
+						rprintf(FINFO, "symlink \"%s\" is a directory on destination and allow-link-update-dir isn't enabled, skipping\n", fname);
+					goto cleanup;
+				}
+				else {
+					int mtime_offset = sx.st.st_mtime - file->modtime;
+					char *st_mode = S_ISDIR(sx.st.st_mode)
+						      ? "directory"
+						      : S_ISLNK(sx.st.st_mode)
+						      ? "symlink"
+						      : S_ISCHR(sx.st.st_mode)
+						      ? "character device"
+						      : S_ISBLK(sx.st.st_mode)
+						      ? "block device"
+						      : S_ISFIFO(sx.st.st_mode)
+						      ? "named pipe"
+						      : S_ISSOCK(sx.st.st_mode)
+						      ? "socket"
+						      : "file";
+					if (mtime_offset > modify_window) {
+						if (INFO_GTE(SKIP, 1))
+							rprintf(FINFO, "%s \"%s\" is newer by %d sec, skipping\n", st_mode, fname, mtime_offset - modify_window);
+						goto cleanup;
+					}
+					else if (mtime_offset < modify_window) {
+						if (INFO_GTE(SKIP, 1))
+							rprintf(FINFO, "%s \"%s\" is older by %d sec, updating\n", st_mode, fname, - mtime_offset - modify_window);
+					}
+					else if (S_ISLNK(sx.st.st_mode)) {
+						char lnk[MAXPATHLEN];
+						int llen = do_readlink(fname, lnk, MAXPATHLEN - 1);
+						lnk[llen] = '\0';
+						if (strcmp(lnk, F_SYMLINK(file)) == 0) {
+							if (INFO_GTE(SKIP, 1))
+								rprintf(FINFO, "symlink \"%s\" points to the same referent %s, skipping\n", fname, lnk);
+							goto cleanup;
+						}
+						else if (INFO_GTE(SKIP, 1))
+							rprintf(FINFO, "symlink \"%s\" points to a different referent on source (%s) than destination (%s), updating\n", fname, F_SYMLINK(file), lnk);
+					}
+					else {
+						if (INFO_GTE(SKIP, 1))
+							rprintf(FINFO, "symlink \"%s\" more recent than %s on destination, updating\n", fname, st_mode);
+					}
+				}
+			}
+			else {
+				if (DEBUG_GTE(GENR, 1))
+					rprintf(FINFO, "update-links not enabled for \"%s\"\n, skipping", fname);
+			}
+		}
 		if (atomic_create(file, fname, sl, NULL, MAKEDEV(0, 0), &sx, statret == 0 ? DEL_FOR_SYMLINK : 0)) {
 			set_file_attrs(fname, file, NULL, NULL, 0);
 			if (itemizing) {
diff --git a/options.c b/options.c
index 578507c6e..277a0542a 100644
--- a/options.c
+++ b/options.c
@@ -48,6 +48,8 @@ int whole_file = -1;
 int append_mode = 0;
 int keep_dirlinks = 0;
 int copy_dirlinks = 0;
+int update_links = 0;
+int allow_link_update_dir = 0;
 int copy_links = 0;
 int copy_devices = 0;
 int write_devices = 0;
@@ -693,6 +695,8 @@ static struct poptOption long_options[] = {
   {"no-one-file-system",0, POPT_ARG_VAL,    &one_file_system, 0, 0, 0 },
   {"no-x",             0,  POPT_ARG_VAL,    &one_file_system, 0, 0, 0 },
   {"update",          'u', POPT_ARG_NONE,   &update_only, 0, 0, 0 },
+  {"update-links",     0,  POPT_ARG_NONE,   &update_links, 0, 0, 0 },
+  {"allow-link-update-dir",0,POPT_ARG_NONE, &allow_link_update_dir, 0, 0, 0 },
   {"existing",         0,  POPT_ARG_NONE,   &ignore_non_existing, 0, 0, 0 },
   {"ignore-non-existing",0,POPT_ARG_NONE,   &ignore_non_existing, 0, 0, 0 },
   {"ignore-existing",  0,  POPT_ARG_NONE,   &ignore_existing, 0, 0, 0 },
@@ -2321,6 +2325,9 @@ int parse_arguments(int *argc_p, const char ***argv_p)
 		parse_filter_str(&filter_list, backup_dir_buf, rule_template(0), 0);
 	}
 
+	if (update_links)
+		preserve_links = 1;
+
 	if (make_backups && !backup_dir)
 		omit_dir_times = -1; /* Implied, so avoid -O to sender. */
 
@@ -2615,7 +2622,7 @@ void server_options(char **args, int *argc_p)
 		argstr[x++] = 'u';
 	if (!do_xfers) /* Note: NOT "dry_run"! */
 		argstr[x++] = 'n';
-	if (preserve_links)
+	if (preserve_links || update_links)
 		argstr[x++] = 'l';
 	if ((xfer_dirs >= 2 && xfer_dirs < 4)
 	 || (xfer_dirs && !recurse && (list_only || (delete_mode && am_sender))))
@@ -2634,6 +2641,11 @@ void server_options(char **args, int *argc_p)
 			if (fuzzy_basis > 1)
 				argstr[x++] = 'y';
 		}
+		if (update_links) {
+			args[ac++] = "--update-links";
+			if (allow_link_update_dir)
+			args[ac++] = "--allow-link-update-dir";
+		}
 	} else {
 		if (copy_links)
 			argstr[x++] = 'L';
diff --git a/rsync.1.md b/rsync.1.md
index 7e40e3617..35677ccfe 100644
--- a/rsync.1.md
+++ b/rsync.1.md
@@ -431,6 +431,8 @@ has its own detailed description later in this manpage.
 --backup-dir=DIR         make backups into hierarchy based in DIR
 --suffix=SUFFIX          backup suffix (default ~ w/o --backup-dir)
 --update, -u             skip files that are newer on the receiver
+--update-links           skip symlinks that are newer on the receiver
+--allow-link-update-dir  newer symlinks may replace older directories
 --inplace                update destination files in-place
 --append                 append data onto shorter files
 --append-verify          --append w/old data in file checksum
@@ -1034,11 +1036,12 @@ expand it.
     will be updated if the sizes are different.)
 
     Note that this does not affect the copying of dirs, symlinks, or other
-    special files.  Also, a difference of file format between the sender and
-    receiver is always considered to be important enough for an update, no
-    matter what date is on the objects.  In other words, if the source has a
-    directory where the destination has a file, the transfer would occur
-    regardless of the timestamps.
+    special files unless the `--update-links` option is enabled.  Also,
+    a difference of file format between the sender and receiver is always
+    considered to be important enough for an update, no matter what date is
+    on the objects.  In other words, if the source has a directory where
+    the destination has a file, the transfer would occur regardless of
+    the timestamps.
 
     This option is a [TRANSFER RULE](#TRANSFER_RULES), so don't expect any
     exclude side effects.
@@ -1050,6 +1053,45 @@ expand it.
     is usually best to avoid combining this with[ `--inplace`](#opt) unless you
     have implemented manual steps to handle any interrupted in-progress files.
 
+0.  `--update-links`
+
+    This option controls rsync behaviour when a symbolic link on the source
+    encounters a destination file in the way of the symlink during transfer.
+    The setting forces rsync to skip any files which exist on the destination
+    and have a modified time that is newer than the symbolic link on the
+    source.  A file in the way of the symlink can be a regular file, a symlink,
+    a named pipe, or a device that exists on the destination.  Such a file with
+    an identical or less recent modification time than the source symlink will
+    be deleted and a symlink pointing to the same item (the referent) as the
+    source symlink on the destination created in its place.  A destination
+    symlink with an identical modification time as the source symlink will
+    only be replaced if the referent is different.  By default, any directory
+    in the way of the source symlink is exempted from removal by a symlink,
+    regardless of its modification time.  To extend the behaviour of this
+    option to directories, see the [`--allow-link-update-dir`](#opt) option
+    below.
+
+    This option may be specified independently of the [`--update`](#opt)
+    ([`-u`](#opt)) option mentioned above, which acts on regular source files
+    only.
+
+0.  `--allow-link-update-dir`
+
+    Enabling this option allows rsync to replace a less recent directory on the
+    destination with a more recent symbolic link from the source.  This option
+    extends the [`--update-links`](#opt) option, which by default preserves any
+    existing directory on the destination from being replaced by a more recent
+    symbolic link.  The modification time of the symbolic link on the source
+    needs to be more recent than the modification time of the directory
+    existing on the destination for this option to take effect.  An exisitng
+    directory with a more recent modification time on the destination than the
+    symlink on the source will not be removed and replaced by the symlink.  A
+    destination directory with an identical modification time as the source
+    symbolic link will be removed and a symlink will be recreated with same
+    referent as the source symlink.
+
+    This option requires the [`--update-links`](#opt) option to be enabled.
+
 0.  `--inplace`
 
     This option changes how rsync transfers a file when its data needs to be
@@ -1179,7 +1221,9 @@ expand it.
     alternately silence the warning by specifying [`--info=nonreg0`](#opt).
 
     The default handling of symlinks is to recreate each symlink's unchanged
-    value on the receiving side.
+    value on the receiving side.  To exempt more recent destination
+    files from being replaced by a link, refer to the [`--update-links`](#opt)
+    option.
 
     See the [SYMBOLIC LINKS](#) section for multi-option info.
 
@@ -4568,7 +4612,7 @@ version uses a new implementation.
 
 ## SYMBOLIC LINKS
 
-Three basic behaviors are possible when rsync encounters a symbolic
+Four basic behaviors are possible when rsync encounters a symbolic
 link in the source directory.
 
 By default, symbolic links are not transferred at all.  A message "skipping
@@ -4582,6 +4626,15 @@ implies [`--links`](#opt).
 If [`--copy-links`](#opt) is specified, then symlinks are "collapsed" by
 copying their referent, rather than the symlink.
 
+If [`--update-links`](#opt) is specified, then symlinks are recreated with
+the same target on the destination unless the existing destination file
+in the way of the symlink is newer or is a directory.
+Unlike [`--links`](#opt), this option preserves all more recent files on the
+destination from being replaced by a symlink.  It is possible to extend having
+an existing less recent directory on the destination replaced by a more recent
+symlink by specifying [`--allow-link-update-dir`](#opt) in addition to
+[`--update-links`](#opt).
+
 Rsync can also distinguish "safe" and "unsafe" symbolic links.  An example
 where this might be used is a web site mirror that wishes to ensure that the
 rsync module that is copied does not include symbolic links to `/etc/passwd` in
@@ -4610,6 +4663,14 @@ first line that is a complete subset of your options:
 0.  `--links --safe-links` The receiver skips creating
     unsafe symlinks found in the transfer and creates the safe ones.
 0.  `--links` Create all symlinks.
+0.  `--update-links` Create symlinks, replace less recent files or files
+    with an identical modification time. Skip any more recent destination
+    files. Unconditionally exclude any existing directories on the destination
+    from deletion and replacement by a symlink when one would otherwise
+    be transferred.
+0.  `--update-links --allow-link-update-dir` Create symlinks, skip any more
+    recent files existing on the destination, allow a less recent
+    directory to be replaced by a more recent symlink.
 
 For the effect of [`--munge-links`](#opt), see the discussion in that option's
 section.

From 15785e0d52f2e864a6bf416e07251bd69bb21d2c Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Sat, 3 Jul 2021 20:09:39 +0200
Subject: [PATCH 02/15] Added test for symlink update mode

---
 testsuite/update-links.test | 560 ++++++++++++++++++++++++++++++++++++
 1 file changed, 560 insertions(+)
 create mode 100644 testsuite/update-links.test

diff --git a/testsuite/update-links.test b/testsuite/update-links.test
new file mode 100644
index 000000000..07e3cae74
--- /dev/null
+++ b/testsuite/update-links.test
@@ -0,0 +1,560 @@
+#! /bin/sh
+
+SELF="$(basename "$0")"
+LSRC="$(readlink -e "$(realpath $0)")"
+LSELF="$(basename "$LSRC")"
+DSELF="$(dirname "$LSRC")"
+
+. "${testsuite:-${DSELF}}/rsync.fns"
+
+log(){
+  echo "${SELF}: $@"
+}
+
+debug(){
+  [ -n "$DEBUG" ] && echo "$@" 1>&2 || :
+}
+
+error(){
+  test_fail "$@"
+}
+
+get_ctime(){
+  stat -c "%Y" "$1" || test_fail "Unable to get ctime of $1"
+}
+
+get_mtime(){
+  stat -c "%Y" "$1" || test_fail "Unable to get mtime of $1"
+}
+
+get_size(){
+  stat -c "%s" "$1" || test_fail "Unable to get size of $1"
+}
+
+get_referent(){
+  readlink "$1" || test_fail "Unable to dereference $1"
+}
+
+get_type(){
+  file -b "$1" || test_fail "Unable to get type of $1"
+}
+
+exists(){
+  [ -h "$1" ] || [ -e "$1" ]
+}
+
+is_a_link(){
+  [ -h "$1" ]
+}
+
+is_a_file(){
+  [ -h "$1" ]
+}
+
+is_a_pipe(){
+  [ -p "$1" ]
+}
+
+points_to_pipe(){
+  is_a_link "$1" && is_a_pipe "$1"
+}
+
+is_a_directory(){
+  ! is_a_link "$1" && [ -d "$1" ]
+}
+
+points_to_dir(){
+  is_a_link "$1" && [ -d "$1" ]
+}
+
+is_newer(){
+  [ $(get_ctime "$1") -gt $(get_ctime "$2") ] || error "$1 is not newer than $2"
+  #DO NOT USE, DEREFERENCES LINKS! [ "$1" -nt "$2" ]
+}
+
+is_older(){
+  [ $(get_ctime "$1") -lt $(get_ctime "$2") ] || error "$1 is not older than $2"
+  #DO NOT USE, DEREFERENCES LINKS! [ "$1" -ot "$2" ]
+}
+
+is_defined(){
+  type "$1" >/dev/null 2>&1
+}
+
+compare(){
+  local s
+  local d
+  s=$($1 "$2")
+  debug "compare $1 $2: output = $s; exit status = $?"
+  d=$($1 "$3")
+  debug "compare $1 $3: output = $d; exit status = $?"
+  case "$s" in
+  "$d")
+    :
+  ;;
+  *)
+    return 1
+  ;;
+  esac
+}
+
+# The size of a symlink equals the length of the link target path
+# Links pointing at /dev/zero & /dev/null will thus have the same size
+is_same_size(){
+  compare get_size "$1" "$2" || test_fail "Files $1 & $2 are not same size"
+}
+
+is_diff_size(){
+  compare get_size "$1" "$2" && test_fail "Files $1 & $2 are supposed to be of different size" || :
+}
+
+is_same_mtime(){
+  compare get_mtime "$1" "$2" || test_fail "Files $1 & $2 have different mtimes"
+}
+
+is_diff_mtime(){
+  compare get_mtime "$1" "$2" && test_fail "Files $1 & $2 are supposed to have different mtimes" || :
+}
+
+is_any_mtime(){
+  compare get_mtime "$1" "$2" || :
+}
+
+is_same_ctime(){
+  compare get_ctime "$1" "$2" || test_fail "Files $1 & $2 have different ctimes"
+}
+
+is_diff_ctime(){
+  compare get_ctime "$1" "$2" && test_fail "Files $1 & $2 are supposed to have different ctimes" || :
+}
+
+is_any_ctime(){
+  compare get_ctime "$1" "$2" || :
+}
+
+is_same_referent(){
+  compare get_referent "$1" "$2" || test_fail "Links $1 & $2 point at a different referent each"
+}
+
+is_diff_referent(){
+  compare get_referent "$1" "$2" && test_fail "Links $1 & $2 should point at a different referent each" || :
+}
+
+touch_links(){
+  debug "touch_links: # touch -h $@"
+  touch -h "$@"
+}
+
+shift_mtime(){
+  local offset
+  local f
+  local epoch
+  local rc
+  offset=$1
+  shift
+  for f in $@; do
+    epoch=$(stat -c%Y "$f")
+    rc=$?
+    debug "shift_mtime: $f; offset = $offset; rc = $rc; touch -hd @$((epoch${offset})) $f"
+    [ $rc -eq 0 ] && touch -hd @$((epoch${offset})) "$f" || error "Unable to stat $f"
+  done
+}
+
+add_a_second(){
+  shift_mtime +1 $@
+}
+
+take_a_second(){
+  shift_mtime -1 $@
+}
+
+show_files(){
+  stat -c "%Y %Z %N" $@ 1>&2 || test_fail "Unable to stat $@"
+}
+
+count_words(){
+  echo $@ | wc -w
+}
+
+get_word(){
+  local i
+  local words
+  i=$1
+  shift
+  words=$@
+  while [ $i -gt 0 ]; do
+    words=${words#* }
+    i=$(($i-1))
+  done
+  echo ${words%% *}
+}
+
+# Sets the referent of $1 to something else than the existing one and the referent of $2
+# choice of out of two variables, purposely defined to be of different length
+# size checks should pass
+cycle_referent(){
+  local links
+  local referent
+  local current
+  local n
+  local next
+  links="/dev/urandom /dev/random"
+  referent=$(get_referent "$1")
+  [ -n "$2" ] && compare_referent=$(get_referent "$2")
+  n=0; while [ $n -le $(count_words $links) ]; do
+    current=$(get_word $n $links)
+    n=$((n+1))
+    [ -n "$2" ] || next="$(get_word $n $links)"
+    case "$current" in
+    ${compare_referent}|${referent})
+      :
+    ;;
+    *)
+      ln -nsf "$current" "$1" && return
+    ;;
+    esac
+  done || test_fail "Unable to cycle referent for $1"
+}
+
+build_symlinks(){
+  rm -rf "$fromdir"
+  mkdir "$fromdir"
+  mkdir "$fromdir/emptydir"
+  mkfifo "$fromdir/fifo"
+  date >"$fromdir/referent"
+  ln -s referent "$fromdir/relative"
+  ln -s "$fromdir/referent" "$fromdir/absolute"
+  ln -s nonexistent "$fromdir/dangling"
+  ln -s "$srcdir/rsync.c" "$fromdir/unsafe"
+  ln -s emptydir "$fromdir/dirlink"
+  ln -s /dev/null "$fromdir/devlink"
+}
+
+# Unused yet
+is_set(){
+  read opt opts << _EOT_
+$@
+_EOT_
+  case "${opts}" in
+  "${opt}"|"${opt} "*|*" ${opt}"*)
+    :
+  ;;
+  *)
+    false
+  ;;
+  esac
+}
+
+list_contains(){
+  read opt opts << _EOT_
+$@
+_EOT_
+  debug "list_contains: opt = $opt; opts = $opts"
+  echo "$opts" | grep -qPo -- "${opt}(?=$|\s)" 1>/dev/null
+}
+
+# Various scenarios that modify either side before re-running rsync & performing a check
+default(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  show_files $fromdir/$file
+  exists $todir/$file && show_files $todir/$file || :
+}
+
+newer_dest_link(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  if exists $todir/$file; then
+    if is_a_link $todir/$file; then
+      take_a_second "$fromdir/$file"
+      add_a_second "$todir/$file"
+      show_files "$todir/$file" "$fromdir/$file"
+    fi
+  else
+    show_files "$fromdir/$file"
+    log "$todir/$file did not get transferred in scenario $scenario with rsync opts $opts"
+  fi
+}
+
+newer_source_link(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  is_a_link $fromdir/$file && touch_links $fromdir/$file $todir/$file && add_a_second $fromdir/$file || :
+}
+
+cycle_dest_link(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  if is_a_link $todir/$file; then
+    cycle_referent $todir/$file $fromdir/$file
+    # Simulate a time difference, making dest_link more recent
+    take_a_second $fromdir/$file
+    add_a_second $todir/$file
+    #show_files $fromdir/$file $todir/$file
+  fi
+}
+
+cycle_dest_newer_source_link(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  cycle_dest_link $fromdir $todir $file $scenario $opts && newer_source_link $fromdir $todir $file $scenario $opts
+  if exists $todir/$file; then
+    show_files "$todir/$file" "$fromdir/$file"
+  else
+    show_files "$fromdir/$file"
+    log "$todir/$file did not get transferred in scenario $scenario with rsync opts $opts"
+  fi
+}
+
+link_update_dir(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  debug "link_update_dir: $todir/$f"
+  # Make all target links directories
+  local f
+  for f in $FILES; do
+    rm $todir/$f 2>/dev/null || log "${scenario}: $f didn't exist"
+    mkdir -p $todir/$f
+    # Make source link more recent than dir just created
+    add_a_second $fromdir/$f
+    show_files $todir/$f
+  done
+}
+
+test_failure(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  debug "${scenario}: has predictably failed"
+  false
+}
+
+test_success(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  debug "${scenario}: has predictably completed"
+  true
+}
+
+# Various checks after a scenario has run, these rules should all pass
+run_checks(){
+  read type fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  local times
+  list_contains "--times" "$opts" || times=any
+  for check in ${times:-${type}}_mtime ${times:-${type}}_ctime ${type}_referent ${type}_size; do
+    debug "check_${scenario}: is_${check} $fromdir/$file $todir/$file"
+    is_${check} $fromdir/$file $todir/$file
+  done
+}
+
+check_existing_dest(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  run_checks same $fromdir $todir $file $scenario $opts
+}
+
+check_default(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  exists $todir/$file && check_existing_dest $fromdir $todir $file $scenario $opts || debug "$todir/$file does not exist, no more checks"
+}
+
+check_newer_dest_link(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  if is_a_link $todir/$file; then
+    if list_contains "--update-links" "$opts"; then
+      # Newer dest links are supposed to be preserved
+      is_same_referent $fromdir/$file $todir/$file
+      # Times will get updated if times is in effect
+      if list_contains "--times" "$opts"; then
+        is_same_mtime $fromdir/$file $todir/$file
+        is_same_ctime $fromdir/$file $todir/$file
+      else
+        is_older $fromdir/$file $todir/$file
+      fi
+    fi
+  fi
+}
+
+check_newer_source_link(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  if is_a_link $todir/$file; then
+    if list_contains "--update-links" "$opts"; then
+      # Newer source links are supposed to be transfered
+      run_checks same $fromdir $todir $file $scenario $opts
+    fi
+  fi
+}
+
+check_cycle_dest_link(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  if is_a_link $todir/$file; then
+    if list_contains "--update-links" "$opts"; then
+      # Newer source links are supposed to be transfered
+      run_checks diff $fromdir $todir $file $scenario $opts
+    fi
+  fi
+}
+
+check_cycle_dest_newer_source_link(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  check_newer_source_link $fromdir $todir $file $scenario $opts
+}
+
+check_link_update_dir(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  if list_contains "--update-links" "$opts"; then
+    if list_contains "--allow-link-update-dir" "$opts"; then
+      if is_a_link $todir/$file; then
+        # Newer source links are supposed to be transfered
+        run_checks same $fromdir $todir $file $scenario $opts
+      else
+        is_a_directory $todir/$file && error "$todir/$file has not been updated by a source link in spite of --allow-link-update-dir"
+      fi
+    fi
+  fi
+}
+
+check_test_failure(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  debug "check_${scenario}: $scenario should have failed, this notice should never be displayed"
+  exit 1
+}
+
+check_test_success(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  debug "check_${scenario}: $scenario should have completed, this notice should always be displayed"
+}
+
+run_rsync(){
+  read fromdir todir file opts << _EOT_
+$@
+_EOT_
+  debug "run_rsync: # $RSYNC $RSYNC_COMMON_OPTS $opts $fromdir/$file $todir/"
+  $RSYNC $RSYNC_COMMON_OPTS $opts $fromdir/$file $todir/ 1>&2 || test_fail "$RSYNC $RSYNC_COMMON_OPTS $opts $fromdir/$file $todir/ failed"
+}
+
+run_scenario(){
+  read fromdir todir file scenario opts << _EOT_
+$@
+_EOT_
+  cd $tmpdir && build_symlinks || error "Unable to change directory to $tmpdir"
+  debug "run_scenario: scenario = $scenario; file = $file; type = $(get_type $fromdir/$file); opts = $opts"
+  run_rsync $fromdir $todir $file $opts
+  is_defined $scenario && $scenario $fromdir $todir $file $scenario $opts
+  run_rsync $fromdir $todir $file $opts
+  check_${scenario} $fromdir $todir $file $scenario $opts
+  rm -rf $fromdir $todir
+}
+
+run_scenarios(){
+  read fromdir todir file opts << _EOT_
+$@
+_EOT_
+  local scenario
+  for scenario in $SCENARIOS; do
+    for t in '' check_; do
+      is_defined ${t}${scenario} || error "No ${t}${scenario} scenario defined"
+    done
+    log "Scenario $scenario running on $file with rsync opts $opts"
+    run_scenario $fromdir $todir $file $scenario $opts
+  done
+}
+
+process_files(){
+  read fromdir todir opts << _EOT_
+$@
+_EOT_
+  local file
+  for file in $FILES; do
+    run_scenarios $fromdir $todir $file $opts
+  done
+}
+
+sort_opts(){
+  echo "$@" | tr ' ' '\n' | sort | xargs echo
+}
+
+strip_whitespace(){
+  echo "${@}" | sed -e 's/ //g'
+}
+
+process_opts(){
+  read fromdir todir opts << _EOT_
+$@
+_EOT_
+  local current
+  local opt
+  debug "process_opts: opts = $opts"
+  for opt in $opts; do
+    debug "process_opts: opt = $opt; done = $done"
+    current="$(sort_opts $current $opt)"
+    if list_contains "$(strip_whitespace ${current})" "$done"; then
+      # Skip item if found on the done list
+      debug "process_opts: $current already processed"
+      continue
+    else
+      debug "process_opts: current = $current"
+      process_files $fromdir $todir $current
+      done="${done:+${done} }$(strip_whitespace ${current})"
+    fi
+    debug "process_opts: opt = $opt; opts = $opts; current = $current"
+  done
+}
+
+process_all_opts(){
+  read fromdir todir all_opts << _EOT_
+$@
+_EOT_
+  local remaining
+  local first
+  remaining=${all_opts}
+  debug "process_all_opts: remaining = ${remaining}"
+  first=${remaining%% *}
+  while [ -n "$remaining" ]; do
+    debug "process_all_opts: remaining before run = ${remaining}"
+    process_opts $fromdir $todir ${remaining}
+    # Remove first parameter for next iteration
+    remaining="${remaining##${remaining%% *} } ${remaining%% *}"
+    debug "process_all_opts: remaining after run = ${remaining}"
+    case ${remaining%% *} in ${first}) break;; esac
+  done
+  log "Completed scenarios with status $?"
+  #echo -e $n | wc -c
+}
+
+# All of the following variables may be overriden at command line
+FILES="${FILES:-relative dangling absolute unsafe devlink dirlink}"
+# For sanity testing only
+#SCENARIOS="test_success test_failure"
+SCENARIOS="${SCENARIOS:-default newer_source_link newer_dest_link cycle_dest_link cycle_dest_newer_source_link link_update_dir}"
+RSYNC=${RSYNC:-${DSELF}/../rsync}
+[ -n "$DEBUG" ] && RSYNC_COMMON_OPTS=${RSYNC_COMMON_OPTS:--i}
+RSYNC_OPTS="--update-links --times --allow-link-update-dir"
+
+process_all_opts $fromdir $todir ${RSYNC_OPTS}

From 8498dbd0f35e151b31a728806fa13dbdc7202cc9 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Sat, 3 Jul 2021 21:49:11 +0200
Subject: [PATCH 03/15] Clarify directory replaced by symlink has to be empty

---
 rsync.1.md | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/rsync.1.md b/rsync.1.md
index 35677ccfe..c271db3dc 100644
--- a/rsync.1.md
+++ b/rsync.1.md
@@ -1077,18 +1077,19 @@ expand it.
 
 0.  `--allow-link-update-dir`
 
-    Enabling this option allows rsync to replace a less recent directory on the
-    destination with a more recent symbolic link from the source.  This option
-    extends the [`--update-links`](#opt) option, which by default preserves any
-    existing directory on the destination from being replaced by a more recent
-    symbolic link.  The modification time of the symbolic link on the source
-    needs to be more recent than the modification time of the directory
-    existing on the destination for this option to take effect.  An exisitng
-    directory with a more recent modification time on the destination than the
-    symlink on the source will not be removed and replaced by the symlink.  A
-    destination directory with an identical modification time as the source
-    symbolic link will be removed and a symlink will be recreated with same
-    referent as the source symlink.
+    Enabling this option allows rsync to replace a less recent empty directory 
+    on the destination with a more recent symbolic link from the source.  This
+    option extends the [`--update-links`](#opt) option, which by default
+    preserves any existing directory on the destination from being replaced
+    by a more recent symbolic link.  The modification time of the symbolic link
+    on the source needs to be more recent than the modification time of the
+    directory existing on the destination for this option to take effect.  An
+    exisitng directory with a more recent modification time on the destination
+    than the symlink on the source will not be removed and replaced by
+    the symlink.  A destination directory with an identical modification time
+    as the source symbolic link will be removed and a symlink will be recreated
+    with same referent as the source symlink.  Non-empty directories are not
+    unlinked under any circumstances.
 
     This option requires the [`--update-links`](#opt) option to be enabled.
 

From 3f8bfa695e6f3fab7a130b121e449eb7254b9635 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Sat, 3 Jul 2021 21:50:15 +0200
Subject: [PATCH 04/15] Include non-empty directory scenario check

---
 testsuite/update-links.test | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/testsuite/update-links.test b/testsuite/update-links.test
index 07e3cae74..71b2673cb 100644
--- a/testsuite/update-links.test
+++ b/testsuite/update-links.test
@@ -59,10 +59,14 @@ points_to_pipe(){
   is_a_link "$1" && is_a_pipe "$1"
 }
 
-is_a_directory(){
+is_a_dir(){
   ! is_a_link "$1" && [ -d "$1" ]
 }
 
+is_empty_dir(){
+  is_a_dir && [ $(find "$1" | wc -l) -eq 1 ]
+}
+
 points_to_dir(){
   is_a_link "$1" && [ -d "$1" ]
 }
@@ -220,6 +224,9 @@ build_symlinks(){
   rm -rf "$fromdir"
   mkdir "$fromdir"
   mkdir "$fromdir/emptydir"
+  mkdir "$fromdir/nonemptydir"
+  touch "$fromdir/nonemptydir/file"
+  mkfifo "$fromdir/fifo"
   mkfifo "$fromdir/fifo"
   date >"$fromdir/referent"
   ln -s referent "$fromdir/relative"
@@ -427,10 +434,17 @@ _EOT_
   if list_contains "--update-links" "$opts"; then
     if list_contains "--allow-link-update-dir" "$opts"; then
       if is_a_link $todir/$file; then
-        # Newer source links are supposed to be transfered
-        run_checks same $fromdir $todir $file $scenario $opts
+        case $file in
+        nonemptydir)
+          error "$file should never be replaced by a link"
+        ;;
+        *)
+          # Newer source links are supposed to be transfered
+          run_checks same $fromdir $todir $file $scenario $opts
+        ;;
+        esac
       else
-        is_a_directory $todir/$file && error "$todir/$file has not been updated by a source link in spite of --allow-link-update-dir"
+        is_empty_dir $todir/$file && error "$todir/$file has not been updated by a source link in spite of --allow-link-update-dir"
       fi
     fi
   fi

From 1e117dd21e384a2db66cf939806442060c764a32 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Sat, 3 Jul 2021 22:46:38 +0200
Subject: [PATCH 05/15] Fixed readlink OpenBSD compatibility

---
 testsuite/update-links.test | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/testsuite/update-links.test b/testsuite/update-links.test
index 71b2673cb..c6b89a134 100644
--- a/testsuite/update-links.test
+++ b/testsuite/update-links.test
@@ -1,7 +1,7 @@
 #! /bin/sh
 
 SELF="$(basename "$0")"
-LSRC="$(readlink -e "$(realpath $0)")"
+LSRC="$(readlink -f "$(realpath $0)")"
 LSELF="$(basename "$LSRC")"
 DSELF="$(dirname "$LSRC")"
 

From 791c7cfbe9fddd35d9ea7564afa871d788a9a76f Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Sun, 4 Jul 2021 00:59:41 +0200
Subject: [PATCH 06/15] Fixed stat & grep FreeBSD compatibility

---
 testsuite/update-links.test | 39 ++++++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/testsuite/update-links.test b/testsuite/update-links.test
index c6b89a134..dd7ad14a8 100644
--- a/testsuite/update-links.test
+++ b/testsuite/update-links.test
@@ -7,6 +7,28 @@ DSELF="$(dirname "$LSRC")"
 
 . "${testsuite:-${DSELF}}/rsync.fns"
 
+set_os_opts(){
+  os=$(uname -s) 
+  case ${os} in
+  Linux)
+    stat_opt=-c
+    size=%s
+    mtime=%Y
+    ctime=%Z
+  ;;
+  FreeBSD)
+    stat_opt=-f
+    size=%z
+    ctime=%Sc
+    mtime=%Sm
+    bsd="-t %s"
+  ;;
+  *)
+    test_fail "OS ${os} unsupported"
+  ;;
+  esac
+}
+
 log(){
   echo "${SELF}: $@"
 }
@@ -20,15 +42,15 @@ error(){
 }
 
 get_ctime(){
-  stat -c "%Y" "$1" || test_fail "Unable to get ctime of $1"
+  stat ${stat_opt} ${ctime} ${bsd} "$1" || test_fail "Unable to get ctime of $1"
 }
 
 get_mtime(){
-  stat -c "%Y" "$1" || test_fail "Unable to get mtime of $1"
+  stat ${stat_opt} ${mtime} ${bsd} "$1" || test_fail "Unable to get mtime of $1"
 }
 
 get_size(){
-  stat -c "%s" "$1" || test_fail "Unable to get size of $1"
+  stat ${stat_opt} ${size} "$1" || test_fail "Unable to get size of $1"
 }
 
 get_referent(){
@@ -154,13 +176,15 @@ shift_mtime(){
   local f
   local epoch
   local rc
+  local time
   offset=$1
   shift
   for f in $@; do
-    epoch=$(stat -c%Y "$f")
+    epoch=$(stat ${stat_opt} ${mtime} ${bsd} "$f")
     rc=$?
     debug "shift_mtime: $f; offset = $offset; rc = $rc; touch -hd @$((epoch${offset})) $f"
-    [ $rc -eq 0 ] && touch -hd @$((epoch${offset})) "$f" || error "Unable to stat $f"
+    case ${os} in FreeBSD) time=$(date -r $((epoch${offset})) +%Y-%m-%dT%H:%M:%S) ;; *) time=@$((epoch${offset})) ;; esac
+    [ $rc -eq 0 ] && touch -hd "${time}" "$f" || error "Unable to stat $f"
   done
 }
 
@@ -173,7 +197,7 @@ take_a_second(){
 }
 
 show_files(){
-  stat -c "%Y %Z %N" $@ 1>&2 || test_fail "Unable to stat $@"
+  stat ${stat_opt} "${mtime} ${ctime} %N" ${bsd} $@ 1>&2 || test_fail "Unable to stat $@"
 }
 
 count_words(){
@@ -257,7 +281,7 @@ list_contains(){
 $@
 _EOT_
   debug "list_contains: opt = $opt; opts = $opts"
-  echo "$opts" | grep -qPo -- "${opt}(?=$|\s)" 1>/dev/null
+  echo "$opts" | egrep -q -- " ${opt} |^${opt} | ${opt}$" 1>/dev/null
 }
 
 # Various scenarios that modify either side before re-running rsync & performing a check
@@ -571,4 +595,5 @@ RSYNC=${RSYNC:-${DSELF}/../rsync}
 [ -n "$DEBUG" ] && RSYNC_COMMON_OPTS=${RSYNC_COMMON_OPTS:--i}
 RSYNC_OPTS="--update-links --times --allow-link-update-dir"
 
+set_os_opts
 process_all_opts $fromdir $todir ${RSYNC_OPTS}

From 95048a16b3a21d5ccc8157db5e97414d87644c25 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Sun, 4 Jul 2021 01:22:02 +0200
Subject: [PATCH 07/15] ctime defaults to mtime due to inabilty to set it by
 non-root users

---
 testsuite/update-links.test | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/testsuite/update-links.test b/testsuite/update-links.test
index dd7ad14a8..4b6f74540 100644
--- a/testsuite/update-links.test
+++ b/testsuite/update-links.test
@@ -13,13 +13,15 @@ set_os_opts(){
   Linux)
     stat_opt=-c
     size=%s
+    # ctime is not normally modifiable by user, defaults to mtime
+    ctime=%Y
     mtime=%Y
-    ctime=%Z
   ;;
   FreeBSD)
     stat_opt=-f
     size=%z
-    ctime=%Sc
+    # ctime is not normally modifiable by user, defaults to mtime
+    ctime=%Sm
     mtime=%Sm
     bsd="-t %s"
   ;;

From d4ef4612472bfb74d18492af6fe4899e71d48ea7 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Tue, 6 Jul 2021 18:15:38 +0200
Subject: [PATCH 08/15] Added explicit checks for empty directory

---
 generator.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/generator.c b/generator.c
index e56ed3cf3..beec8df53 100644
--- a/generator.c
+++ b/generator.c
@@ -1196,6 +1196,19 @@ static BOOL is_below(struct file_struct *file, struct file_struct *subtree)
 		&& (!implied_dirs_are_missing || f_name_has_prefix(file, subtree));
 }
 
+static BOOL dir_empty(char *dirname) {
+	int n = 3;
+	DIR *dir = opendir(dirname);
+	if (dir == NULL)
+		return -1;
+	while (readdir(dir)) {
+		if (!--n)
+			break;
+	}
+	closedir(dir);
+	return n;
+}
+
 /* Acts on the indicated item in cur_flist whose name is fname.  If a dir,
  * make sure it exists, and has the right permissions/timestamp info.  For
  * all other non-regular files (symlinks, etc.) we create them here.  For
@@ -1621,6 +1634,12 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
 						goto cleanup;
 					}
 					else if (mtime_offset < modify_window) {
+						if (S_ISDIR(sx.st.st_mode)) {
+							if (!dir_empty(fname)) {
+								rprintf(FINFO, "directory %s not empty, skipping\n", fname);
+								goto cleanup;
+							}
+						}
 						if (INFO_GTE(SKIP, 1))
 							rprintf(FINFO, "%s \"%s\" is older by %d sec, updating\n", st_mode, fname, - mtime_offset - modify_window);
 					}

From 9fc294a51962028ca57e2ff01176f3c66899e3df Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Tue, 6 Jul 2021 18:18:53 +0200
Subject: [PATCH 09/15] Fixed update-links checks

---
 testsuite/update-links.test | 39 +++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/testsuite/update-links.test b/testsuite/update-links.test
index 4b6f74540..c81565f60 100644
--- a/testsuite/update-links.test
+++ b/testsuite/update-links.test
@@ -88,7 +88,7 @@ is_a_dir(){
 }
 
 is_empty_dir(){
-  is_a_dir && [ $(find "$1" | wc -l) -eq 1 ]
+  is_a_dir "$1" && [ $(find "$1" | wc -l) -eq 1 ]
 }
 
 points_to_dir(){
@@ -348,12 +348,17 @@ link_update_dir(){
   read fromdir todir file scenario opts << _EOT_
 $@
 _EOT_
-  debug "link_update_dir: $todir/$f"
-  # Make all target links directories
+  # Make all target files directories
   local f
   for f in $FILES; do
+    debug "link_update_dir: $todir/$f"
     rm $todir/$f 2>/dev/null || log "${scenario}: $f didn't exist"
     mkdir -p $todir/$f
+    case $f in
+    nonemptydir)
+      touch $todir/$f/testfile
+    ;;
+    esac
     # Make source link more recent than dir just created
     add_a_second $fromdir/$f
     show_files $todir/$f
@@ -457,22 +462,26 @@ check_link_update_dir(){
   read fromdir todir file scenario opts << _EOT_
 $@
 _EOT_
-  if list_contains "--update-links" "$opts"; then
-    if list_contains "--allow-link-update-dir" "$opts"; then
-      if is_a_link $todir/$file; then
-        case $file in
+  if is_a_link $todir/$file; then
+    if list_contains "--update-links" "$opts"; then
+      if list_contains "--allow-link-update-dir" "$opts"; then
+	case $file in
         nonemptydir)
-          error "$file should never be replaced by a link"
-        ;;
-        *)
-          # Newer source links are supposed to be transfered
-          run_checks same $fromdir $todir $file $scenario $opts
+          error "$file should not have been replaced by a link"
         ;;
         esac
       else
-        is_empty_dir $todir/$file && error "$todir/$file has not been updated by a source link in spite of --allow-link-update-dir"
+	case $file in
+	*dir)
+	  error "$file should not have been replaced by a link without --allow-link-update-dir enabled"
+	;;
+	esac
       fi
+    else
+      error "$file should not have been replaced by a link without --update-links enabled"
     fi
+    # Newer source links are supposed to be transfered
+    run_checks same $fromdir $todir $file $scenario $opts
   fi
 }
 
@@ -589,12 +598,12 @@ _EOT_
 }
 
 # All of the following variables may be overriden at command line
-FILES="${FILES:-relative dangling absolute unsafe devlink dirlink}"
+FILES="${FILES:-relative dangling absolute unsafe devlink dirlink emptydir nonemptydir}"
 # For sanity testing only
 #SCENARIOS="test_success test_failure"
 SCENARIOS="${SCENARIOS:-default newer_source_link newer_dest_link cycle_dest_link cycle_dest_newer_source_link link_update_dir}"
 RSYNC=${RSYNC:-${DSELF}/../rsync}
-[ -n "$DEBUG" ] && RSYNC_COMMON_OPTS=${RSYNC_COMMON_OPTS:--i}
+[ -n "$DEBUG" ] && RSYNC_COMMON_OPTS=${RSYNC_COMMON_OPTS:--r -i}
 RSYNC_OPTS="--update-links --times --allow-link-update-dir"
 
 set_os_opts

From 3c57a64e223de8450fac4ae35bab661309a50027 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Thu, 15 Jul 2021 17:46:51 +0200
Subject: [PATCH 10/15] Avoid a redundant macro call

---
 flist.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/flist.c b/flist.c
index cc9b44227..670f1b60d 100644
--- a/flist.c
+++ b/flist.c
@@ -239,15 +239,17 @@ int link_stat(const char *path, STRUCT_STAT *stp, int follow_dirlinks)
 		return x_stat(path, stp, NULL);
 	if (x_lstat(path, stp, NULL) < 0)
 		return -1;
-	if (update_links && S_ISLNK(stp->st_mode)) {
-		STRUCT_STAT st;
-		if (x_stat(path, &st, NULL) == 0 && !S_ISDIR(st.st_mode))
-			return x_lstat(path, stp, NULL);
-	}
-	if (follow_dirlinks && S_ISLNK(stp->st_mode)) {
-		STRUCT_STAT st;
-		if (x_stat(path, &st, NULL) == 0 && S_ISDIR(st.st_mode))
-			*stp = st;
+	if (S_ISLNK(stp->st_mode)) {
+		if (update_links) {
+			STRUCT_STAT st;
+			if (x_stat(path, &st, NULL) == 0 && !S_ISDIR(st.st_mode))
+				return x_lstat(path, stp, NULL);
+		}
+		if (follow_dirlinks) {
+			STRUCT_STAT st;
+			if (x_stat(path, &st, NULL) == 0 && S_ISDIR(st.st_mode))
+				*stp = st;
+		}
 	}
 	return 0;
 #else

From 8b5226e90d2faa39c81b4a6eb6ec24f8fffb3402 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Sat, 8 Jan 2022 16:18:56 +0100
Subject: [PATCH 11/15] Revert "Avoid a redundant macro call"

This reverts commit c3437c114dff2dd65e41fd30df62065253ce2530, the
redundant macro call is intended to avoid running the macro if
neither update_links nor follow_dirlinks are enabled.
---
 flist.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/flist.c b/flist.c
index 670f1b60d..cc9b44227 100644
--- a/flist.c
+++ b/flist.c
@@ -239,17 +239,15 @@ int link_stat(const char *path, STRUCT_STAT *stp, int follow_dirlinks)
 		return x_stat(path, stp, NULL);
 	if (x_lstat(path, stp, NULL) < 0)
 		return -1;
-	if (S_ISLNK(stp->st_mode)) {
-		if (update_links) {
-			STRUCT_STAT st;
-			if (x_stat(path, &st, NULL) == 0 && !S_ISDIR(st.st_mode))
-				return x_lstat(path, stp, NULL);
-		}
-		if (follow_dirlinks) {
-			STRUCT_STAT st;
-			if (x_stat(path, &st, NULL) == 0 && S_ISDIR(st.st_mode))
-				*stp = st;
-		}
+	if (update_links && S_ISLNK(stp->st_mode)) {
+		STRUCT_STAT st;
+		if (x_stat(path, &st, NULL) == 0 && !S_ISDIR(st.st_mode))
+			return x_lstat(path, stp, NULL);
+	}
+	if (follow_dirlinks && S_ISLNK(stp->st_mode)) {
+		STRUCT_STAT st;
+		if (x_stat(path, &st, NULL) == 0 && S_ISDIR(st.st_mode))
+			*stp = st;
 	}
 	return 0;
 #else

From ca89b1e6bd6e03e085fcffbc05a96146785299f7 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Tue, 11 Jan 2022 17:26:41 +0100
Subject: [PATCH 12/15] Avoid an unnecessary lstat call

---
 flist.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/flist.c b/flist.c
index cc9b44227..d163798f6 100644
--- a/flist.c
+++ b/flist.c
@@ -242,7 +242,7 @@ int link_stat(const char *path, STRUCT_STAT *stp, int follow_dirlinks)
 	if (update_links && S_ISLNK(stp->st_mode)) {
 		STRUCT_STAT st;
 		if (x_stat(path, &st, NULL) == 0 && !S_ISDIR(st.st_mode))
-			return x_lstat(path, stp, NULL);
+			return 0;
 	}
 	if (follow_dirlinks && S_ISLNK(stp->st_mode)) {
 		STRUCT_STAT st;

From 04026dc3616b7beb9ab59696cdc5691702dd3988 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Wed, 27 Apr 2022 11:06:13 +0200
Subject: [PATCH 13/15] Documented order of precedence for symlink handling
 options

---
 rsync.1.md | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/rsync.1.md b/rsync.1.md
index c271db3dc..a9fe9dcac 100644
--- a/rsync.1.md
+++ b/rsync.1.md
@@ -1075,6 +1075,9 @@ expand it.
     ([`-u`](#opt)) option mentioned above, which acts on regular source files
     only.
 
+    If specified in tandem, `--update-links` prevails over
+    [`--copy-links`](#opt) and [`--links`](#opt).
+
 0.  `--allow-link-update-dir`
 
     Enabling this option allows rsync to replace a less recent empty directory 
@@ -1226,6 +1229,9 @@ expand it.
     files from being replaced by a link, refer to the [`--update-links`](#opt)
     option.
 
+    If specified in tandem, [`--update-links`](#opt) or [`--copy-links`](#opt)
+    prevail over `--links`.
+
     See the [SYMBOLIC LINKS](#) section for multi-option info.
 
 0.  `--copy-links`, `-L`
@@ -1235,8 +1241,8 @@ expand it.
     references.  If a symlink chain is broken, an error is output and the file
     is dropped from the transfer.
 
-    This option supersedes any other options that affect symlinks in the
-    transfer, since there are no symlinks left in the transfer.
+    This option supersedes any other option that affect symlinks in the
+    transfer but [`--update-links`](#opt), which takes precedence.
 
     This option does not change the handling of existing symlinks on the
     receiving side, unlike versions of rsync prior to 2.6.3 which had the
@@ -4673,6 +4679,14 @@ first line that is a complete subset of your options:
     recent files existing on the destination, allow a less recent
     directory to be replaced by a more recent symlink.
 
+Note that some options are mutually exclusive.  The first option listed
+below prevails over the others, when multiple symlink mode options are
+specified.
+
+0.  `--update-links`
+0.  `--copy-links`
+0.  `--links`
+
 For the effect of [`--munge-links`](#opt), see the discussion in that option's
 section.
 

From 7a1227e98a8d2fc2df542f16783dbf5d75a867b6 Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Wed, 27 Apr 2022 14:29:34 +0200
Subject: [PATCH 14/15] Added Debian package build configuration

---
 debian/compat                               |  1 +
 debian/control                              | 16 +++++++++
 debian/patches/disable_reconfigure_req.diff | 38 +++++++++++++++++++++
 debian/patches/series                       |  1 +
 debian/rules                                |  3 ++
 debian/watch                                |  3 ++
 options.c                                   |  2 ++
 7 files changed, 64 insertions(+)
 create mode 100644 debian/compat
 create mode 100644 debian/control
 create mode 100644 debian/patches/disable_reconfigure_req.diff
 create mode 100644 debian/patches/series
 create mode 100644 debian/rules
 create mode 100644 debian/watch

diff --git a/debian/compat b/debian/compat
new file mode 100644
index 000000000..b4de39476
--- /dev/null
+++ b/debian/compat
@@ -0,0 +1 @@
+11
diff --git a/debian/control b/debian/control
new file mode 100644
index 000000000..39d8275bc
--- /dev/null
+++ b/debian/control
@@ -0,0 +1,16 @@
+Source: rsync
+Section: unknown
+Priority: optional
+Maintainer: unknown <pi@>
+Build-Depends: debhelper (>= 11)
+Standards-Version: 4.1.3
+Homepage: https://github.com/twojstaryzdomu/rsync
+Vcs-Git: https://github.com/twojstaryzdomu/rsync.git
+Vcs-Browser: https://github.com/twojstaryzdomu/rsync
+
+
+Package: rsync
+Section: unknown
+Architecture: any
+Depends: ${shlibs:Depends}, ${misc:Depends}
+Description: rsync description
diff --git a/debian/patches/disable_reconfigure_req.diff b/debian/patches/disable_reconfigure_req.diff
new file mode 100644
index 000000000..1dce71069
--- /dev/null
+++ b/debian/patches/disable_reconfigure_req.diff
@@ -0,0 +1,38 @@
+diff --git a/Makefile.in b/Makefile.in
+index 3cde955..ef71d7e 100644
+--- a/Makefile.in
++++ b/Makefile.in
+@@ -210,15 +210,6 @@ configure.sh config.h.in: configure.ac aclocal.m4
+ 	else \
+ 	    echo "config.h.in has CHANGED."; \
+ 	fi
+-	@if test -f configure.sh.old || test -f config.h.in.old; then \
+-	    if test "$(MAKECMDGOALS)" = reconfigure; then \
+-		echo 'Continuing with "make reconfigure".'; \
+-	    else \
+-		echo 'You may need to run:'; \
+-		echo '  make reconfigure'; \
+-		exit 1; \
+-	    fi \
+-	fi
+ 
+ .PHONY: reconfigure
+ reconfigure: configure.sh
+@@ -232,17 +223,6 @@ restatus:
+ Makefile: Makefile.in config.status configure.sh config.h.in
+ 	@if test -f Makefile; then cp -p Makefile Makefile.old; else touch Makefile.old; fi
+ 	@./config.status
+-	@if diff Makefile Makefile.old >/dev/null 2>&1; then \
+-	    echo "Makefile is unchanged."; \
+-	    rm Makefile.old; \
+-	else \
+-	    if test "$(MAKECMDGOALS)" = reconfigure; then \
+-		echo 'Continuing with "make reconfigure".'; \
+-	    else \
+-		echo "Makefile updated -- rerun your make command."; \
+-		exit 1; \
+-	    fi \
+-	fi
+ 
+ stunnel-rsyncd.conf: $(srcdir)/stunnel-rsyncd.conf.in Makefile
+ 	sed 's;\@bindir\@;$(bindir);g' <$(srcdir)/stunnel-rsyncd.conf.in >stunnel-rsyncd.conf
diff --git a/debian/patches/series b/debian/patches/series
new file mode 100644
index 000000000..0a5931483
--- /dev/null
+++ b/debian/patches/series
@@ -0,0 +1 @@
+disable_reconfigure_req.diff
diff --git a/debian/rules b/debian/rules
new file mode 100644
index 000000000..cbe925d75
--- /dev/null
+++ b/debian/rules
@@ -0,0 +1,3 @@
+#!/usr/bin/make -f
+%:
+	dh $@
diff --git a/debian/watch b/debian/watch
new file mode 100644
index 000000000..6c67a454c
--- /dev/null
+++ b/debian/watch
@@ -0,0 +1,3 @@
+version=4
+opts=filenamemangle=s/.+\/v?(\d\S+)\.tar\.gz/rsync-$1\.tar\.gz/ \
+  https://github.com/twojstaryzdomu/rsync/releases .*/v?(\d\S+)\.tar\.gz
diff --git a/options.c b/options.c
index 277a0542a..521be4adc 100644
--- a/options.c
+++ b/options.c
@@ -1384,6 +1384,8 @@ int parse_arguments(int *argc_p, const char ***argv_p)
 		 * only special cases are returned and listed here. */
 
 		switch (opt) {
+		case 'L':
+			break;
 		case 'V':
 			version_opt_cnt++;
 			break;

From aff59bb50b523185b03a3b5a6cb003d9240f12cf Mon Sep 17 00:00:00 2001
From: twojstaryzdomu <twojstaryzdomu@github.com>
Date: Wed, 27 Apr 2022 14:31:09 +0200
Subject: [PATCH 15/15] Added Debian package build & publish workflow using
 github actions

---
 .github/workflows/build-publish.yml | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 .github/workflows/build-publish.yml

diff --git a/.github/workflows/build-publish.yml b/.github/workflows/build-publish.yml
new file mode 100644
index 000000000..f8d6233d3
--- /dev/null
+++ b/.github/workflows/build-publish.yml
@@ -0,0 +1,27 @@
+name: Build & publish
+on: {push: {branches: [master]}, pull_request: {branches: [master]}, workflow_dispatch}
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: '0'
+    - id: debianise
+      uses: twojstaryzdomu/debianise@HEAD
+      with:
+        create_changelog: true
+        install_build_depends: false
+        debug: true
+    - id: action-gh-release
+      uses: softprops/action-gh-release@v1
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      with:
+        files: ${{ steps.debianise.outputs.files }}
+        name: ${{ steps.debianise.outputs.release_name }}
+        tag_name: ${{ steps.debianise.outputs.tag_name }}
+        fail_on_unmatched_files: true
+        draft: true
+        prerelease: true