.ssp: doc structure related fixes (& to epub toc_nav)

for document abstraction and its .ssp output, removed the
requirement of including --abstraction & --serial flags to produce
correct output (for: .dom_status, .dom_status_collapsed &
.last_descendant)

- meta_processing_xml_dom() includes show_abstraction, so --pod2
  and --show-abstraction run the dom pass; last_descendant is
  derived from that pass via after_doc_get_descendants()

The accumulators are now verified as eight wide locals of
docAbstraction(), so each document starts clean and no two threads
share one.
- bug: the four dom accumulators were template scope (shared) and
  nine wide, while their end of document reset was eight wide, so
  the first document of a run differed from the rest and parallel
  runs raced on one buffer, (which also mis-nested epub toc_nav)

test/ reference .ssp regenerated: accelerando only, trailing zero
dropped.
test-abstraction-ssp.sh now runs parallel and diffs output against
a serial run.

(assisted by Claude-Code)

4 files changed, 42 insertions, 12 deletions

diff --git a/org/ocda.org b/org/ocda.org
index 1e9d79e..3a287e8 100644
--- a/org/ocda.org
+++ b/org/ocda.org
@@ -221,6 +221,11 @@ string[string] object_number_poem = [
   "end"   : ""
 ];
 string[] lv_ancestors_txt = [ "", "", "", "", "", "", "", "", ];
+/+ ↓ dom structure state, per document (not shared, parallel safe) +/
+int[] dom_structure_markedup_tags_status         = [ 0, 0, 0, 0, 0, 0, 0, 0,];
+int[] dom_structure_markedup_tags_status_buffer  = [ 0, 0, 0, 0, 0, 0, 0, 0,];
+int[] dom_structure_collapsed_tags_status        = [ 0, 0, 0, 0, 0, 0, 0, 0,];
+int[] dom_structure_collapsed_tags_status_buffer = [ 0, 0, 0, 0, 0, 0, 0, 0,];
 int[string] lv = [
   "lv" : eN.bi.off,
   "h0" : eN.bi.off,
@@ -1619,10 +1624,6 @@ obj_cite_digit_                             = 0;
 html_segnames_ptr                           = 0;
 html_segnames_ptr_cntr                      = 0;
 content_non_header                          = "8";
-dom_structure_markedup_tags_status          = [ 0, 0, 0, 0, 0, 0, 0, 0,];
-dom_structure_markedup_tags_status_buffer   = [ 0, 0, 0, 0, 0, 0, 0, 0,];
-dom_structure_collapsed_tags_status         = [ 0, 0, 0, 0, 0, 0, 0, 0,];
-dom_structure_collapsed_tags_status_buffer  = [ 0, 0, 0, 0, 0, 0, 0, 0,];
 lev_anchor_tag = "";
 anchor_tag = "";
 // identify parts
diff --git a/org/ocda_functions.org b/org/ocda_functions.org
index fc174fd..bda15b7 100644
--- a/org/ocda_functions.org
+++ b/org/ocda_functions.org
@@ -83,10 +83,6 @@ string content_non_header = "8";
 // ocn
 OCNset obj_cite_digits;
 int obj_cite_digit_, obj_cite_digit_off, obj_cite_digit_bkidx, obj_cite_digit_type;
-int[] dom_structure_markedup_tags_status         = [ 0, 0, 0, 0, 0, 0, 0, 0, 0,];
-int[] dom_structure_markedup_tags_status_buffer  = [ 0, 0, 0, 0, 0, 0, 0, 0, 0,];
-int[] dom_structure_collapsed_tags_status        = [ 0, 0, 0, 0, 0, 0, 0, 0, 0,];
-int[] dom_structure_collapsed_tags_status_buffer = [ 0, 0, 0, 0, 0, 0, 0, 0, 0,];
 static auto obj_im = ObjInlineMarkup();
 static auto obj_att = ObjAttributes();
 auto object_citation_number = OCNemitter();
diff --git a/org/spine.org b/org/spine.org
index 6d67e3b..4f2d551 100644
--- a/org/spine.org
+++ b/org/spine.org
@@ -1015,6 +1015,8 @@ struct OptActions {
   @trusted bool meta_processing_xml_dom() {
     return (
       opts["abstraction"]
+      || show_abstraction
+      || show_abstraction_db
       || html
       || epub
       || odt
diff --git a/org/test_shell_script_ssp_document_abstraction.org b/org/test_shell_script_ssp_document_abstraction.org
index eb7ca77..ccbe6dd 100644
--- a/org/test_shell_script_ssp_document_abstraction.org
+++ b/org/test_shell_script_ssp_document_abstraction.org
@@ -26,6 +26,9 @@
 # Regression test for spine's document abstraction.
 # Generates .ssp files for all sample documents and diffs
 # against committed reference files.
+# Also checks that a parallel run and a serial run of the same documents
+# produce identical .ssp (guards against per-document state leaking
+# between documents or between worker threads).
 #
 # Usage:
 #   ./test/test-abstraction-ssp.sh                # uses result/bin/spine
@@ -102,7 +105,7 @@ if [ "$GENERATE" = true ]; then
   echo "Generating reference .ssp files..."
   rm -rf "$REF_DIR"
   mkdir -p "$REF_DIR"
-  $SPINE_BIN --abstraction --serial --show-abstraction --skip-output --output="$SCRIPT_DIR/reference" "$SAMPLES_DIR"/* 2>&1 | tail -1
+  $SPINE_BIN --show-abstraction --skip-output --output="$SCRIPT_DIR/reference" "$SAMPLES_DIR"/* 2>&1 | tail -1
   # flatten language subdirs into reference dir
   find "$SCRIPT_DIR/reference" -name "*.ssp" ! -path "$REF_DIR/*" -exec mv {} "$REF_DIR/" \;
   # clean up empty language dirs
@@ -123,11 +126,22 @@ fi
 echo "Generating current .ssp files..."
 rm -rf "$TMP_DIR"
 mkdir -p "$TMP_DIR"
-$SPINE_BIN --abstraction --serial --show-abstraction --skip-output --output="$SCRIPT_DIR/current" "$SAMPLES_DIR"/* 2>&1 | tail -1
+$SPINE_BIN --abstraction --show-abstraction --skip-output --output="$SCRIPT_DIR/current" "$SAMPLES_DIR"/* 2>&1 | tail -1
 # flatten
 find "$SCRIPT_DIR/current" -name "*.ssp" ! -path "$TMP_DIR/*" -exec mv {} "$TMP_DIR/" \;
 find "$SCRIPT_DIR/current" -mindepth 1 -type d -empty -delete 2>/dev/null || true
 
+# generate the same .ssp serially, to check that parallel and serial
+# processing agree (per-document state leaking between documents, or
+# between worker threads, shows up here)
+SER_DIR="$SCRIPT_DIR/current-serial/abstraction"
+echo "Generating current .ssp files (serial)..."
+rm -rf "$SCRIPT_DIR/current-serial"
+mkdir -p "$SER_DIR"
+$SPINE_BIN --show-abstraction --serial --skip-output --output="$SCRIPT_DIR/current-serial" "$SAMPLES_DIR"/* 2>&1 | tail -1
+find "$SCRIPT_DIR/current-serial" -name "*.ssp" ! -path "$SER_DIR/*" -exec mv {} "$SER_DIR/" \;
+find "$SCRIPT_DIR/current-serial" -mindepth 1 -type d -empty -delete 2>/dev/null || true
+
 # diff
 echo "Comparing against reference..."
 FAILURES=0
@@ -157,12 +171,29 @@ for cur_file in "$TMP_DIR"/*.ssp; do
   fi
 done
 
+# parallel vs serial determinism
+for cur_file in "$TMP_DIR"/*.ssp; do
+  basename=$(basename "$cur_file")
+  ser_file="$SER_DIR/$basename"
+  if [ ! -f "$ser_file" ]; then
+    echo "MISSING (serial run): $basename"
+    FAILURES=$((FAILURES + 1))
+    continue
+  fi
+  if ! diff -q "$cur_file" "$ser_file" > /dev/null 2>&1; then
+    echo "NON-DETERMINISTIC: $basename (parallel and serial runs differ)"
+    diff --unified=3 "$cur_file" "$ser_file" | head -30
+    echo "  ..."
+    FAILURES=$((FAILURES + 1))
+  fi
+done
+
 # clean up
-rm -rf "$SCRIPT_DIR/current"
+rm -rf "$SCRIPT_DIR/current" "$SCRIPT_DIR/current-serial"
 
 if [ "$FAILURES" -eq 0 ]; then
   REF_COUNT=$(ls "$REF_DIR"/*.ssp | wc -l)
-  echo "PASS: all $REF_COUNT .ssp files match reference"
+  echo "PASS: all $REF_COUNT .ssp files match reference (parallel and serial agree)"
   exit 0
 else
   echo "FAIL: $FAILURES difference(s) found"