Add rcdn -D cleanup for dangling managed symlinks

Makefile.am

@@ -49,6 +49,7 @@ TESTS = \
 	test/rcdn-hooks.t \
 	test/rcdn-hooks-run-in-situ.t \
 	test/rcdn-hooks-run-in-order.t \
+	test/rcdn-dangling-symlinks.t \
 	test/rcup-hooks.t \
 	test/rcup-hooks-run-in-situ.t \
 	test/rcup-hooks-run-in-order.t \

bin/rcdn.in

@@ -20,10 +20,116 @@ remove_link() {
   fi
 }
 
+is_selected_file() {
+  local dest="$1"
+  local selected_file
+  local rc_file="$(de_dot "$dest")"
+
+  if [ -z "$FILES" ]; then
+    return 0
+  fi
+
+  for selected_file in $FILES; do
+    if [ "x$selected_file" = "x$rc_file" ]; then
+      return 0
+    fi
+  done
+
+  return 1
+}
+
+is_managed_target() {
+  local target="$1"
+  local dotfiles_dir
+
+  case "$target" in
+    /*) ;;
+    *) return 1 ;;
+  esac
+
+  for dotfiles_dir in $RESOLVED_DOTFILES_DIRS; do
+    if [ "x$target" = "x$dotfiles_dir" ]; then
+      return 0
+    fi
+
+    case "$target" in
+      "$dotfiles_dir"/*) return 0 ;;
+    esac
+  done
+
+  return 1
+}
+
+is_dotfiles_path() {
+  local file="$1"
+  local dotfiles_dir
+
+  for dotfiles_dir in $RESOLVED_DOTFILES_DIRS; do
+    if [ "x$file" = "x$dotfiles_dir" ]; then
+      return 0
+    fi
+
+    case "$file" in
+      "$dotfiles_dir"/*) return 0 ;;
+    esac
+  done
+
+  return 1
+}
+
+resolve_dotfiles_dirs() {
+  local relative_root_dir="$PWD"
+  local dotfiles_dir
+  local selected_dirs="${SELECTED_DOTFILES_DIRS:-$DOTFILES_DIRS}"
+
+  for dotfiles_dir in $selected_dirs; do
+    cd -- "$relative_root_dir"
+    dotfiles_dir="$(eval echo "$dotfiles_dir")"
+
+    if is_relative "$dotfiles_dir"; then
+      dotfiles_dir="$PWD/$dotfiles_dir"
+    fi
+
+    RESOLVED_DOTFILES_DIRS="$(append_variable "$RESOLVED_DOTFILES_DIRS" "$dotfiles_dir")"
+  done
+
+  cd -- "$relative_root_dir"
+}
+
+remove_dangling_links() {
+  local dangling_link
+  local target
+  local saved_ifs="$IFS"
+
+  resolve_dotfiles_dirs
+  $DEBUG "resolved dotfiles dirs: $RESOLVED_DOTFILES_DIRS"
+
+  IFS='
+'
+  for dangling_link in $(find "$DEST_DIR" -type l ! -exec test -e {} \; -print); do
+    target="$(readlink "$dangling_link")"
+
+    if is_dotfiles_path "$dangling_link"; then
+      continue
+    fi
+
+    if ! is_managed_target "$target"; then
+      continue
+    fi
+
+    if ! is_selected_file "$dangling_link"; then
+      continue
+    fi
+
+    remove_link "$dangling_link" "$dangling_link"
+  done
+  IFS="$saved_ifs"
+}
+
 show_help() {
   local exit_code=${1:-0}
 
-  $PRINT "Usage: rcdn [-hqVv] [-B HOSTNAME] [-d DOT_DIR] [-I EXCL_PAT] [-S EXCL_PAT] [-s EXCL_PAT] [-t TAG] [-U EXCL_PAT] [-u EXCL_PAT] [-x EXCL_PAT]"
+  $PRINT "Usage: rcdn [-DhqVv] [-B HOSTNAME] [-d DOT_DIR] [-I EXCL_PAT] [-S EXCL_PAT] [-s EXCL_PAT] [-t TAG] [-U EXCL_PAT] [-u EXCL_PAT] [-x EXCL_PAT]"
   $PRINT "see rcdn(1) and rcm(7) for more details"
 
   exit $exit_code
@@ -43,9 +149,11 @@ handle_command_line() {
   local undotted=
   local never_undotted=
   local hostname=
+  local remove_dangling=0
 
-  while getopts :VqvhIKk:x:S:s:U:u:t:d:B: opt; do
+  while getopts :DVqvhIKk:x:S:s:U:u:t:d:B: opt; do
     case "$opt" in
+      D) remove_dangling=1 ;;
       h) show_help ;;
       B) hostname="$OPTARG" ;;
       I) includes="$(append_variable "$includes" "$OPTARG")" ;;
@@ -73,6 +181,9 @@ handle_command_line() {
   dotfiles_dirs="${dotfiles_dirs:-$DOTFILES_DIRS}"
   files="$@"
   RUN_HOOKS="$run_hooks"
+  FILES="$files"
+  REMOVE_DANGLING=$remove_dangling
+  SELECTED_DOTFILES_DIRS="$dotfiles_dirs"
 
   for tag in "$tags"; do
     LS_ARGS="$LS_ARGS -t \"$tag\""
@@ -105,9 +216,13 @@ handle_command_line() {
 }
 
 LS_ARGS=-F
+RESOLVED_DOTFILES_DIRS=
 
 handle_command_line "$@"
 : ${DOTFILES_DIRS:=$DOTFILES_DIRS $DEFAULT_DOTFILES_DIR}
+if [ -z "$SELECTED_DOTFILES_DIRS" ]; then
+  SELECTED_DOTFILES_DIRS="$DOTFILES_DIRS"
+fi
 
 run_hooks pre down
 
@@ -127,4 +242,7 @@ for dest_and_src in $dests_and_srcs; do
 done
 
 IFS="$saved_ifs"
+if [ $REMOVE_DANGLING -eq 1 ]; then
+  remove_dangling_links
+fi
 run_hooks post down

man/rcdn.1

@@ -6,7 +6,7 @@
 .Nd remove dotfiles as managed by rcm
 .Sh SYNOPSIS
 .Nm rcdn
-.Op Fl hKkqVv
+.Op Fl DhKkqVv
 .Op Fl B Ar hostname
 .Op Fl d Ar dir
 .Op Fl I Ar excl_pat
@@ -65,6 +65,14 @@ as the host-specific directory instead of computing it
 remove rc files from the
 .Ar DIR .
 This can be specified multiple times.
+.It Fl D
+remove dangling symlinks that are managed by
+.Xr rcm 7 .
+Managed dangling symlinks are symlinks in
+the destination directory
+whose targets are inside the selected dotfiles directories. When
+.Ar files
+are provided, only dangling symlinks matching those files are removed.
 .It Fl h
 show usage instructions.
 .It Fl I Ar EXCL_PAT

test/rcdn-dangling-symlinks.t

@@ -0,0 +1,37 @@
+  $ . "$TESTDIR/helper.sh"
+
+Without -D, rcdn should not remove managed dangling symlinks
+
+  $ touch .dotfiles/alpha
+  > rcup >/dev/null
+  > rm .dotfiles/alpha
+  > rcdn >/dev/null
+  $ assert "alpha should still be a dangling symlink" -h "$HOME/.alpha"
+
+With -D, rcdn should remove managed dangling symlinks
+
+  $ rcdn -D >/dev/null
+  $ refute "alpha should be removed when -D is passed" -e "$HOME/.alpha"
+
+With -D, rcdn should keep unmanaged dangling symlinks
+
+  $ ln -s "$HOME/not-managed-target" "$HOME/.outside"
+  $ rcdn -D >/dev/null
+  $ assert "outside should still be a dangling symlink" -h "$HOME/.outside"
+
+With -D and FILE arguments, cleanup should be restricted to those files
+
+  $ touch .dotfiles/one .dotfiles/two
+  > rcup >/dev/null
+  > rm .dotfiles/one .dotfiles/two
+  $ assert "one should be dangling symlink" -h "$HOME/.one"
+  $ assert "two should be dangling symlink" -h "$HOME/.two"
+  $ rcdn -D one >/dev/null
+  $ refute "one should be removed" -e "$HOME/.one"
+  $ assert "two should remain because it was not requested" -h "$HOME/.two"
+
+With -D, rcdn should not remove dangling symlinks inside source dotfiles dirs
+
+  $ ln -s "$HOME/.dotfiles/missing-in-source" "$HOME/.dotfiles/internal-dangling"
+  $ rcdn -D >/dev/null
+  $ assert "internal source-dir dangling link should not be removed" -h "$HOME/.dotfiles/internal-dangling"