sbshadow: add --yes/--no, sbpull: pass flag, return sbshadow status

sbshadow --yes applies the plan without asking, --no shows it and
leaves the tree unchanged, so non-interactive callers (sb-builder runs
it as a detached job with no stdin) never hit the prompt. No flag keeps
the interactive prompt. SBO_REPO overrides the repo path for testing.

sbpull passes the flag on, and now returns sbshadow's exit status
instead of popd's, which made a failed sbshadow look successful.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 20 insertions, 2 deletions

diff --git a/sbshadow b/sbshadow
index b928df1..25cf923 100755
--- a/sbshadow
+++ b/sbshadow
@@ -13,10 +13,24 @@
 # phantom-dep hintfiles with mkhint -F.
 #
 # Called by slackrepo_setup_SBo-danix.sh and by sbpull after a subtree pull.
+#
+# Usage: sbshadow [--yes|--no]
+#   no flag  show the plan and ask before changing anything
+#   --yes    apply the plan without asking
+#   --no     show the plan only, tree unchanged (preview)
+# SBO_REPO overrides the repo path (used to test against a throwaway repo).
 
 set -euo pipefail
 
-REPO="/var/lib/sbopkg/SBo-danix"
+answer=""
+case "${1:-}" in
+  --yes) answer=y ;;
+  --no)  answer=n ;;
+  "")    ;;
+  *)     echo "usage: sbshadow [--yes|--no]" >&2; exit 2 ;;
+esac
+
+REPO="${SBO_REPO:-/var/lib/sbopkg/SBo-danix}"
 UPSTREAM="current"
 
 cd "$REPO"
@@ -47,7 +61,11 @@ else
   (( ${#to_restore[@]} )) && printf 'unshadow: %s\n' "${to_restore[@]}"
   echo
 
-  read -rp "Proceed? [y/N] " confirm
+  if [[ -n $answer ]]; then
+    confirm=$answer
+  else
+    read -rp "Proceed? [y/N] " confirm
+  fi
   if [[ ! "$confirm" =~ ^[Yy]$ ]]; then
     echo "sbshadow: aborted, tree unchanged."
   else