kiss: bail out if package removal would break alternatives (#89)

Co-authored-by: git-bruh <e817509a-8ee9-4332-b0ad-3a6bdf9ab63f@aleeas.com>
Reviewed-on: https://codeberg.org/kiss-community/kiss/pulls/89

contrib/kiss-preferred

@@ -1,12 +0,0 @@
-#!/bin/sh -e
-# Lists the owners of all files with conflicts
-
-kiss a | while read -r _ path; do
-    if owner=$(kiss owns "$path" 2>/dev/null) && [ "$owner" ]; then
-        printf '%s %s\n' "$owner" "$path"
-
-    else
-        printf 'warning: %s has no owner\n' "$path" >&2
-    fi
-done
-

kiss

@@ -1319,6 +1319,33 @@ pkg_alternatives() {
     fi
 }
 
+pkg_preferred() {
+    set +f
+
+    ok "$1" || set -- "$sys_db/"*
+
+    # shellcheck disable=2046
+    set -- $(
+        for pkg; do
+            pkg="${pkg##*/}"
+            printf '%s\n' "$pkg/manifest"
+        done
+    )
+
+    cd "$sys_db"
+
+    for manifest; do
+        [ -f "$manifest" ] || die "'${manifest%%/*}' not found"
+    done
+
+    pkg_alternatives |
+        cut -d' ' -f2- |
+        grep -Fxf - "$@" /dev/null |
+        sed 's/\/manifest:/ /'
+
+    cd "$OLDPWD"
+}
+
 pkg_swap() {
     # Swap between package alternatives.
     [ -d "$sys_db/$1" ] || die "'$1' not found"
@@ -1515,7 +1542,21 @@ pkg_removable() {
     ! grep -lFx -- "$1" */depends ||
         die "$1" "Not removable, has dependents"
 
+    preferred="$(pkg_preferred "$1")"
+    cnt=0
+
+    IFS=$newline
+
+    for line in $preferred; do
+        printf '%s\n' "$line"
+        : $((cnt+=1))
+    done
+
+    [ ! "$cnt" -gt 0 ] ||
+        die "$1" "Not removable, package leaves behind $cnt orphaned alternative(s)"
+
     set -f
+
     cd "$OLDPWD"
 }
 
@@ -1911,7 +1952,7 @@ args() {
             esac
         ;;
 
-        b|build|c|checksum|d|download|i|install|l|list|r|remove)
+        b|build|c|checksum|d|download|i|install|l|list|p|preferred|r|remove)
             for _arg do case ${action%%"${action#?}"}-$_arg in
                 i-*\!*|i-*\**|i-*\[*|i-*\ *|i-*\]*|i-*"$newline"*)
                     die "Invalid argument: '!*[ ]\\n' ('$_arg')"
@@ -1991,6 +2032,7 @@ args() {
         H|help-ext)     pkg_help_ext "$@" ;;
         i|install)      for pkg do pkg_install "$pkg"; done ;;
         l|list)         pkg_list_version "$@" ;;
+        p|preferred)    pkg_preferred "$@" ;;
         r|remove)       for pkg in $redro; do pkg_remove "$pkg"; done ;;
         s|search)       for pkg do pkg_find "$pkg" all; done ;;
         u|update)       pkg_update ;;