fix: restore rejected staged note entries

lib/stage.sh

@@ -1,15 +1,34 @@
 #!/usr/bin/env bash
 # stage.sh — Git index mutations for readable note staging
 
+# Restore one tracked path to the exact index entry present before staging.
+restore_tracked_note_index() {
+  local repo="$1" readable_path="$2" mode="$3" blob="$4"
+  if ! git -C "$repo" update-index --cacheinfo \
+      "$mode" "$blob" "$readable_path"; then
+    echo "Error: failed to restore index entry after staging refusal: $readable_path" >&2
+    return 1
+  fi
+}
+
 # Stage one readable note. Existing tracked plaintext paths are renormalized so
 # a newly-added clean filter replaces their unchanged plaintext index blobs.
+# Restore the prior entry if post-staging ciphertext verification refuses it.
 stage_readable_note() {
   local repo="$1" notes_dir="$2" relpath="$3"
   local readable_path="$notes_dir/$relpath"
   local tracked_readable=false
+  local original_entry original_metadata original_mode original_blob original_stage
 
   if git -C "$repo" ls-files --error-unmatch -- "$readable_path" >/dev/null 2>&1; then
     tracked_readable=true
+    original_entry=$(git -C "$repo" ls-files --stage -- "$readable_path") || return 1
+    original_metadata="${original_entry%%$'\t'*}"
+    read -r original_mode original_blob original_stage <<< "$original_metadata"
+    if [ "$original_stage" != "0" ] || [ -z "$original_blob" ]; then
+      echo "Error: tracked readable note has no ordinary index entry: $relpath" >&2
+      return 1
+    fi
     git -C "$repo" add -f --renormalize -- "$readable_path"
   else
     git -C "$repo" add -f -- "$readable_path"
@@ -18,6 +37,10 @@ stage_readable_note() {
   local index_blob head_blob="" blob_state blob_status=0
   if ! index_blob=$(git -C "$repo" rev-parse ":$readable_path" 2>/dev/null); then
     echo "Error: staging did not create an index entry for: $relpath" >&2
+    if $tracked_readable; then
+      restore_tracked_note_index \
+        "$repo" "$readable_path" "$original_mode" "$original_blob" || return 1
+    fi
     return 1
   fi
   if git -C "$repo" cat-file -e "HEAD:$readable_path" 2>/dev/null; then
@@ -26,6 +49,8 @@ stage_readable_note() {
   if $tracked_readable && [ -n "$head_blob" ] && [ "$index_blob" = "$head_blob" ]; then
     echo "Error: staging produced no index change for tracked readable note: $relpath" >&2
     echo "Ensure setup configured an active encryption filter, then retry." >&2
+    restore_tracked_note_index \
+      "$repo" "$readable_path" "$original_mode" "$original_blob" || return 1
     return 1
   fi
 
@@ -34,11 +59,15 @@ stage_readable_note() {
       || blob_status=$?
     if [ "$blob_status" -ne 0 ]; then
       echo "Error: failed to inspect staged note blob: $relpath" >&2
+      restore_tracked_note_index \
+        "$repo" "$readable_path" "$original_mode" "$original_blob" || return 1
       return "$blob_status"
     fi
     if [ "$blob_state" != "encrypted" ]; then
       echo "Error: staged tracked readable note is not git-crypt encrypted: $relpath" >&2
       echo "Ensure setup configured an active encryption filter, then retry." >&2
+      restore_tracked_note_index \
+        "$repo" "$readable_path" "$original_mode" "$original_blob" || return 1
       return 1
     fi
   fi

test/stage.bats

@@ -41,11 +41,13 @@ setup() {
   [[ "$output" == *"legacy.md"* ]]
 }
 
-@test "notes stage rejects a changed tracked blob that remains plaintext" {
+@test "notes stage restores a changed tracked blob that remains plaintext" {
   echo "# Legacy plaintext" > "$NOTES_CALLER_PWD/notes/legacy.md"
   git -C "$NOTES_CALLER_PWD" add -f notes/legacy.md
   git -C "$NOTES_CALLER_PWD" commit -q --no-verify -m "legacy plaintext note"
 
+  local original_blob
+  original_blob=$(git -C "$NOTES_CALLER_PWD" rev-parse :notes/legacy.md)
   local clean_filter="$BATS_TEST_TMPDIR/plaintext-clean-filter"
   cat > "$clean_filter" <<'SH'
 #!/usr/bin/env bash
@@ -64,9 +66,12 @@ SH
   [ "$status" -ne 0 ]
   [[ "$output" == *"not git-crypt encrypted"* ]]
   [[ "$output" == *"legacy.md"* ]]
+  run git -C "$NOTES_CALLER_PWD" rev-parse :notes/legacy.md
+  [ "$output" = "$original_blob" ]
+  run git -C "$NOTES_CALLER_PWD" diff --cached --name-only -- notes/legacy.md
+  [ -z "$output" ]
   run git -C "$NOTES_CALLER_PWD" show :notes/legacy.md
-  [[ "$output" == FILTERED:* ]]
-  [[ "$output" != *"GITCRYPT"* ]]
+  [ "$output" = "# Legacy plaintext" ]
 }
 
 @test "notes stage: no args requires explicit scope" {