fix: use compgen -P prefix -W '"${arr[@]}"' against patsub_replacement

To add a prefix to every element in an array, we have used the
following construct:

  arr=("${arr[@]/#/$prefix}")

However, this can be broken when `shopt -s patsub_replacement` (bash
>= 5.2) is turned on.  In bash >= 5.2, patsub_replacement is enabled
by default.  In particular, when the character `&` contained in
$prefix, if any, will be replaced with the matched string.  To avoid
the unexpected patsub_replacement, one may think about quoting the
replacement as

  arr=("${arr[@]/#/"$prefix"}")

However, this has another problem in bash < 4.3 or when `shopt -s
compat42` is turned on.  In such a case, the inner double quotations
are treated literally so that the `PREFIX` instead of ``"PREFIX"` is
prefixed to elements.  To avoid this situation the outer double
quotations might be removed, but this has even another problem of the
pathname expansions and IFS.  We here instead use _comp_compgen:

  _comp_compgen -Rv arr -- -P "$prefix" -W '"${arr[@]}"'

This patch also contains similar cases for a suffix.

bash_completion

@@ -1572,8 +1572,8 @@ _comp_compgen_usage()
 _comp_compgen_signals()
 {
     local -a sigs
-    _comp_compgen -v sigs -c "SIG${cur#"${1-}"}" -- -P "${1-}" -A signal &&
-        _comp_compgen -U sigs set "${sigs[@]/#${1-}SIG/${1-}}"
+    _comp_compgen -v sigs -c "SIG${cur#"${1-}"}" -- -A signal &&
+        _comp_compgen -RU sigs -- -P "${1-}" -W '"${sigs[@]#SIG}"'
 }
 
 # This function completes on known mac addresses
@@ -2047,9 +2047,8 @@ _comp_compgen_usergroups()
         if ((${#tmp[@]})); then
             local _prefix=${cur%%*([^:])}
             _prefix=${_prefix//\\/}
-            local -a _tmp=("${tmp[@]/#/$_prefix}")
-            _comp_unlocal tmp
-            _comp_compgen_set "${_tmp[@]}"
+            _comp_compgen -Rv tmp -- -P "$_prefix" -W '"${tmp[@]}"'
+            _comp_compgen -U tmp set "${tmp[@]}"
         fi
     elif [[ $cur == *:* ]]; then
         # Completing group after 'user:gr<TAB>'.

completions/_mount.linux

@@ -25,7 +25,7 @@ _comp_cmd_mount()
                 ufs umsdos usbfs vfat xfs'
             _comp_compgen -a fstypes
             [[ $split ]] && ((${#COMPREPLY[@]})) &&
-                COMPREPLY=(${COMPREPLY[@]/#/$prev,})
+                _comp_compgen -Rv COMPREPLY -- -P "$prev," -W '"${COMPREPLY[@]}"'
             return
             ;;
         --bind | -B | --rbind | -R)
@@ -204,7 +204,7 @@ _comp_cmd_mount()
             # COMP_WORDBREAKS is a real pain in the ass
             prev="${prev##*["$COMP_WORDBREAKS"]}"
             [[ $split ]] && ((${COMPREPLY[@]})) &&
-                COMPREPLY=(${COMPREPLY[@]/#/"$prev,"})
+                _comp_compgen -Rv COMPREPLY -- -P "$prev," -W '"${COMPREPLY[@]}"'
             [[ ${COMPREPLY-} == *= ]] && compopt -o nospace
             return
             ;;

completions/_umount.linux

@@ -111,7 +111,7 @@ _comp_cmd_umount()
                 usbfs vfat xfs'
             _comp_compgen -a fstypes
             [[ $split ]] && ((${#COMPREPLY[@]})) &&
-                COMPREPLY=(${COMPREPLY[@]/#/$prev,})
+                _comp_compgen -Rv COMPREPLY -- -P "$prev," -W '"${COMPREPLY[@]}"'
             return
             ;;
         -O)

completions/chromium-browser

@@ -18,7 +18,7 @@ _comp_cmd_chromium_browser()
                 *://*)
                     local prefix="${cur%%://*}://"
                     _comp_compgen_known_hosts -- "${cur#*://}" &&
-                        COMPREPLY=("${COMPREPLY[@]/#/$prefix}")
+                        _comp_compgen -Rv COMPREPLY -- -P "$prefix" -W '"${COMPREPLY[@]}"'
                     _comp_ltrim_colon_completions "$cur"
                     ;;
                 *)

completions/cppcheck

@@ -26,7 +26,7 @@ _comp_cmd_cppcheck()
             _comp_compgen -- -W 'all warning style performance portability
                 information unusedFunction missingInclude' &&
                 [[ $split ]] &&
-                COMPREPLY=(${COMPREPLY[@]/#/"$prev,"})
+                _comp_compgen -Rv COMPREPLY -- -P "$prev," -W '"${COMPREPLY[@]}"'
             return
             ;;
         --error-exitcode)

completions/cvs

@@ -6,7 +6,7 @@ _comp_cmd_cvs__entries()
     [[ -e ${prefix-}CVS/Entries ]] || prefix=""
     entries=($(cut -d/ -f2 -s "${prefix-}CVS/Entries" 2>/dev/null))
     if ((${#entries[@]})); then
-        entries=("${entries[@]/#/${prefix-}}")
+        _comp_compgen -Rv entries -- -P "${prefix-}" -W '"${entries[@]}"'
         compopt -o filenames
     fi
 }

completions/info

@@ -51,7 +51,7 @@ _comp_cmd_info()
 
     _comp_split -F : infopath "$infopath"
     if ((${#infopath[@]})); then
-        infopath=("${infopath[@]/%//$cur*}")
+        _comp_compgen -Rv infopath -- -S "/$cur*" -W '"${infopath[@]}"'
         local IFS=
         _comp_expand_glob COMPREPLY '${infopath[@]}'
         _comp_unlocal IFS

completions/kcov

@@ -33,7 +33,7 @@ _comp_cmd_kcov()
                 cur="${cur##*,}"
                 _comp_compgen -- -W "{0..100}"
                 ((${#COMPREPLY[@]} == 1)) &&
-                    COMPREPLY=(${COMPREPLY/#/$prev,})
+                    _comp_compgen -Rv COMPREPLY -- -P "$prev," -W '"$COMPREPLY"'
             else
                 _comp_compgen -- -W "{0..100}"
                 ((${#COMPREPLY[@]} == 1)) && COMPREPLY=("${COMPREPLY/%/,}")

completions/man

@@ -76,9 +76,12 @@ _comp_cmd_man()
 
     _comp_split -F : manpath "$manpath"
     if ((${#manpath[@]})); then
-        manpath=("${manpath[@]/%//*man$sect/$cur*}" "${manpath[@]/%//*cat$sect/$cur*}")
+        local manfiles
+        _comp_compgen -Rv manfiles -- -S "/*man$sect/$cur*" -W '"${manpath[@]}"'
+        _comp_compgen -aRv manfiles -- -S "/*cat$sect/$cur*" -W '"${manpath[@]}"'
+
         local IFS=
-        _comp_expand_glob COMPREPLY '${manpath[@]}'
+        _comp_expand_glob COMPREPLY '${manfiles[@]}'
         _comp_unlocal IFS
 
         if ((${#COMPREPLY[@]} != 0)); then

completions/povray

@@ -16,7 +16,8 @@ _comp_cmd_povray()
             cur="${povcur#[-+]I}" # to confuse _comp_compgen_filedir
             pfx="${povcur%"$cur"}"
             _comp_compgen_filedir pov
-            ((${#COMPREPLY[@]})) && COMPREPLY=("${COMPREPLY[@]/#/$pfx}")
+            ((${#COMPREPLY[@]})) &&
+                _comp_compgen -Rv COMPREPLY -- -P "$pfx" -W '"${COMPREPLY[@]}"'
             return
             ;;
         [-+]O*)
@@ -40,7 +41,8 @@ _comp_cmd_povray()
             cur="${povcur#[-+]O}" # to confuse _comp_compgen_filedir
             pfx="${povcur%"$cur"}"
             _comp_compgen -a filedir $oext
-            ((${#COMPREPLY[@]})) && COMPREPLY=("${COMPREPLY[@]/#/$pfx}")
+            ((${#COMPREPLY[@]})) &&
+                _comp_compgen -Rv COMPREPLY -- -P "$pfx" -W '"${COMPREPLY[@]}"'
             return
             ;;
         *.ini\[ | *.ini\[*[^]]) # sections in .ini files
@@ -50,7 +52,8 @@ _comp_cmd_povray()
             COMPREPLY=($(command sed -ne \
                 's/^[[:space:]]*\[\('"$cur"'[^]]*\]\).*$/\1/p' -- "$pfx"))
             # to prevent [bar] expand to nothing.  can be done more easily?
-            ((${#COMPREPLY[@]})) && COMPREPLY=("${COMPREPLY[@]/#/${pfx}[}")
+            ((${#COMPREPLY[@]})) &&
+                _comp_compgen -Rv COMPREPLY -- -P "${pfx}[" -W '"${COMPREPLY[@]}"'
             return
             ;;
         *)

completions/pylint

@@ -88,7 +88,8 @@ _comp_cmd_pylint()
             [[ $cur == *,* ]] && prefix="${cur%,*},"
             _comp_compgen -c "${cur##*,}" -- -W "HIGH INFERENCE
                 INFERENCE_FAILURE UNDEFINED"
-            ((${#COMPREPLY[@]} == 1)) && COMPREPLY=(${COMPREPLY/#/$prefix})
+            ((${#COMPREPLY[@]} == 1)) &&
+                _comp_compgen -Rv COMPREPLY -- -P "$prefix" -W '"$COMPREPLY"'
             return
             ;;
         --format | -${noargopts}f)

completions/smartctl

@@ -35,8 +35,8 @@ _comp_cmd_smartctl__drivedb()
         prefix=+
         cur="${cur#+}"
     fi
-    _comp_compgen_filedir h &&
-        [[ $prefix ]] && COMPREPLY=("${COMPREPLY[@]/#/$prefix}")
+    _comp_compgen_filedir h && [[ $prefix ]] &&
+        _comp_compgen -Rv COMPREPLY -- -P "$prefix" -W '"${COMPREPLY[@]}"'
 }
 
 _comp_cmd_smartctl()

test/runLint

@@ -52,6 +52,9 @@ gitgrep '(?<!command)'"$cmdstart"'(grep|ls|sed|cd)(\s|$)' \
 gitgrep '(?<!command)'"$cmdstart"'awk(\s|$)' \
     'invoke awk through "_comp_awk"'
 
+#------------------------------------------------------------------------------
+# Bash pitfalls/styles/compatibilities (which are not detected by shellcheck)
+
 gitgrep '<<<' 'herestrings use temp files, use some other way'
 
 filter_out='^(test/|bash_completion\.sh)' gitgrep ' \[ ' \
@@ -61,3 +64,6 @@ gitgrep "$cmdstart"'unset [^-]' 'Explicitly specify "unset -v/-f"'
 
 gitgrep "$cmdstart"'((set|shopt)\s+[+-][a-z]+\s+posix\b|(local\s+)?POSIXLY_CORRECT\b)' \
     'fiddling with posix mode breaks keybindings with some bash versions'
+
+gitgrep '\$\{([^{}\n]|\{.*\})+/([^{}\n]|\{.*\})+/([^{}"\n]|\{.*\})*\$.*\}' \
+    '$rep of ${var/pat/$rep} needs to be double-quoted for shopt -s patsub_replacement (bash >= 5.2)'