Fix group switching with identical colors

lib/-ftb-generate-complist

@@ -82,7 +82,9 @@ fi
 
 (( same_word )) && tcandidates[2,-1]=()
 
-# sort and remove sort group or other index
+# sort and remove the duplicate group index before the displayed description.
+# Keep the leading index so group reloads do not have to use presentation colors
+# as group identity. The first field is hidden by fzf's --nth setting.
 zstyle -T ":completion:$_ftb_curcontext" sort
 if (( $? != 1 )); then
   if (( colorful )); then
@@ -99,7 +101,15 @@ if (( $? != 1 )); then
     tcandidates=("${(@o)tcandidates}")
   fi
 fi
-typeset -gUa _ftb_complist=("${(@)tcandidates//[0-9]#$bs}")
+local candidate group_id
+local -a indexed_candidates
+for candidate in "${(@)tcandidates}"; do
+  group_id=${candidate%%$bs*}
+  candidate=${candidate//[0-9]#$bs}
+  [[ $group_id == <-> ]] && candidate=$group_id$bs$candidate
+  indexed_candidates+=$candidate
+done
+typeset -gUa _ftb_complist=("${(@)indexed_candidates}")
 
 # hide needless group
 if (( $#_ftb_groups )); then

lib/ftb-switch-group

@@ -8,31 +8,30 @@ local pid=$1 header_lines=$2 active_group_style=$3 tmp_dir=$4 offset=$5
 
 # read completion list
 local -a list=(${(f)mapfile[$tmp_dir/completions.$pid]})
+local -a groups=(${(f)mapfile[$tmp_dir/groups.$pid]})
+local bs=$'\b'
 
-# --- group marker detection (fzf-tab groups) ---------------------------------
-# When groups exist, fzf-tab prefixes each entry with a group SGR like $'\e[94m'.
-# When no groups exist (often file lists), entries may start with $'\e[0m'
-# (reset for LS_COLORS). Treat that as "no groups".
-local -Ua group_sgr_prefixes
+# Each grouped entry starts with its numeric group id and a backspace. This
+# field is hidden by fzf, but remains stable when group colors are identical.
+local -Ua group_ids
 if (( $#list > 10000 && $+commands[grep] )); then
-  group_sgr_prefixes=(${(f)"$(print -l -- ${list:$header_lines} | command grep -a -o $'^\x1b\\[[0-9;]*m')"})
+  group_ids=(${(f)"$(print -l -- ${list:$header_lines} | command grep -a -o $'^[0-9][0-9]*\b')"})
+  group_ids=("${(@)group_ids%$bs}")
 else
-  group_sgr_prefixes=(${(M)${list:$header_lines}#$'\x1b['[0-9;]#*m})
-fi
-
-# if the only marker is reset, there are no real groups
-if (( $#group_sgr_prefixes == 1 )) && [[ $group_sgr_prefixes[1] == $'\e[0m' ]]; then
-  group_sgr_prefixes=()
+  local item
+  for item in "${(@)list:$header_lines}"; do
+    [[ $item == (#b)(<->)$bs* ]] && group_ids+=$match[1]
+  done
 fi
 
 # calculate and persist current group index
 # the index starts from 2, because switching from "all" to "group 1" looks weird
 local current=2
-if (( $#group_sgr_prefixes > 0 )) && [[ -f $tmp_dir/current-group.$pid ]]; then
+if (( $#group_ids > 0 )) && [[ -f $tmp_dir/current-group.$pid ]]; then
   current=$(( $(<$tmp_dir/current-group.$pid) + offset ))
 fi
-(( current > $#group_sgr_prefixes )) && current=1
-(( current == 0 )) && current=$#group_sgr_prefixes
+(( current > $#group_ids )) && current=1
+(( current == 0 )) && current=$#group_ids
 echo $current > $tmp_dir/current-group.$pid
 
 # configure style of active header
@@ -45,17 +44,27 @@ case $active_group_style in
   (*)             sgr_on=$'\x1b[1m';    sgr_off=$'\x1b[22m' ;;  # fallback
 esac
 
-# The ANSI SGR code that marks every line in the currently selected group.
-local current_prefix=$group_sgr_prefixes[current]
+# The hidden marker on every line in the selected group, and its label.
+local current_marker='' current_group=''
+if (( $#group_ids )); then
+  current_marker=$group_ids[current]$bs
+  current_group=$groups[$group_ids[current]]
+fi
 
 # print headers
 if (( header_lines != 0 )); then
-  # Apply style only to the group label (excluding trailing spaces), then disable it
-  print -l ${${(S)list[1,header_lines]/(#b)($current_prefix*)($'\x1b[00m')/${match[1]/%(#b)( #)/$sgr_off$match}$match[2]}/$current_prefix/$current_prefix$sgr_on}
+  # Apply style only to the exact group label, excluding its padding.
+  local header
+  for header in "${(@)list[1,header_lines]}"; do
+    if [[ -n $current_group && $current_group != __hide__* ]]; then
+      header=${header/(#b)($'\x1b['[0-9;]#m)(${(b)current_group})( #)($'\x1b[00m')/$match[1]$sgr_on$match[2]$sgr_off$match[3]$match[4]}
+    fi
+    print -r -- $header
+  done
 fi
 
 if (( $#list > 10000 && $+commands[grep] )); then
-  print -l -- ${list:$header_lines} | command grep -a -F -- "${group_sgr_prefixes[current]}"
+  print -l -- ${list:$header_lines} | command grep -a -- "^$current_marker"
 else
-  print -l -- ${(M)${list:$header_lines}:#${group_sgr_prefixes[current]}*}
+  print -l -- ${(M)${list:$header_lines}:#${current_marker}*}
 fi

test/fzftab.ztst

@@ -248,7 +248,69 @@
 >C1:{package }
 >C1:{openpgp-keys-gentoo-release}
 >C1:{-MERGING-pnpm-bin}
+
+  () {
+    emulate -L zsh -o extended_glob
+    local bs=$'\b'
+    local _ftb_curcontext=identical-colors
+    local -Ua _ftb_groups=('group one' 'group two')
+    local -a _ftb_compcap=(
+      $'alpha\2<\x00>\x00group\x001\x00word\x00alpha'
+      $'beta\2<\x00>\x00group\x002\x00word\x00beta'
+    )
+    local -a _ftb_group_colors=($'\e[0m')
+    -ftb-zstyle() {
+      zstyle $1 ":fzf-tab:$_ftb_curcontext" ${@:2}
+    }
+    zstyle ':fzf-tab:identical-colors' group-colors $'\e[0m' $'\e[0m'
+    . $ZTST_srcdir/../lib/-ftb-generate-complist
+    zstyle -d ':fzf-tab:identical-colors' group-colors
+    local -a first_fields=("${(@0)_ftb_complist[1]}")
+    local -a second_fields=("${(@0)_ftb_complist[2]}")
+    [[ $first_fields[1] == 1${bs}* && $first_fields[2] == alpha ]] &&
+      [[ $second_fields[1] == 2${bs}* && $second_fields[2] == beta ]]
+  }
+0:completion list retains hidden group identity with identical colors
+
+  () {
+    emulate -L zsh
+    local tmp_dir=$ZTST_tmp/identical-group-colors
+    local pid=$$
+    local bs=$'\b'
+    mkdir -p $tmp_dir
+    print -rl -- \
+      $'\e[0mgroup one  \e[00m\e[0mgroup two\e[00m' \
+      1${bs}$'\e[0m·alpha\0alpha\0' \
+      2${bs}$'\e[0m·beta\0beta\0' \
+      > $tmp_dir/completions.$pid
+    print -rl -- 'group one' 'group two' > $tmp_dir/groups.$pid
+    local -a switched=("${(@f)$(
+      $commands[zsh] -f $ZTST_srcdir/../lib/ftb-switch-group $pid 1 bold $tmp_dir 0
+    )}")
+    (( $#switched == 2 )) &&
+      [[ $switched[1] == $'\e[0mgroup one  \e[00m\e[0m\e[1mgroup two\e[22m\e[00m' ]] &&
+      [[ $switched[2] == 2${bs}$'\e[0m·beta\0beta\0' ]]
+  }
+0:group switching uses hidden identity when colors are identical
+
+  () {
+    emulate -L zsh
+    local tmp_dir=$ZTST_tmp/ungrouped-reset-colors
+    local pid=$$
+    mkdir -p $tmp_dir
+    print -rl -- \
+      $'\e[0m·alpha\0alpha\0' \
+      $'\e[0m·beta\0beta\0' \
+      > $tmp_dir/completions.$pid
+    : > $tmp_dir/groups.$pid
+    local -a switched=("${(@f)$(
+      $commands[zsh] -f $ZTST_srcdir/../lib/ftb-switch-group $pid 0 none $tmp_dir 0
+    )}")
+    (( $#switched == 2 )) &&
+      [[ $switched[1] == $'\e[0m·alpha\0alpha\0' ]] &&
+      [[ $switched[2] == $'\e[0m·beta\0beta\0' ]]
+  }
+0:group switching preserves an ungrouped reset-colored list
 %clean
 
   zmodload -ui zsh/zpty
-