fix(dump): detect sparse absolute persistence loss

Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>

src/foundation/dump_verify.c

@@ -17,12 +17,15 @@ bool cbm_dump_verify_is_degraded(int committed_nodes, int persisted_nodes, doubl
     if (committed_nodes < 0) {
         return false;
     }
-    if (committed_nodes <= min_floor) {
-        return false;
-    }
     if (persisted_nodes < 0) {
         return true;
     }
+    if (committed_nodes > 0 && persisted_nodes == 0) {
+        return true;
+    }
+    if (committed_nodes <= min_floor) {
+        return false;
+    }
     return (double)persisted_nodes < (double)committed_nodes * ratio;
 }
 

src/foundation/dump_verify.h

@@ -20,7 +20,8 @@ enum { CBM_DUMP_VERIFY_MIN_FLOOR = 50 };
  * True when persisted_nodes is implausibly below committed_nodes.
  *
  * Returns false when ratio <= 0 (gate disabled), committed_nodes < 0 (no dump),
- * committed_nodes <= min_floor (sparse repo), or persisted >= committed * ratio.
+ * or persisted >= committed * ratio. Sparse repositories skip the ratio gate,
+ * but complete persistence loss is degraded for every positive committed count.
  * Returns true when persisted_nodes < 0 (count error).
  */
 bool cbm_dump_verify_is_degraded(int committed_nodes, int persisted_nodes, double ratio,

tests/test_dump_verify.c

@@ -22,6 +22,11 @@ TEST(dump_verify_sparse_at_floor) {
     PASS();
 }
 
+TEST(dump_verify_sparse_zero_persisted) {
+    ASSERT_TRUE(cbm_dump_verify_is_degraded(12, 0, 0.5, CBM_DUMP_VERIFY_MIN_FLOOR));
+    PASS();
+}
+
 TEST(dump_verify_shortfall_below_ratio) {
     ASSERT_TRUE(cbm_dump_verify_is_degraded(1000, 400, 0.5, CBM_DUMP_VERIFY_MIN_FLOOR));
     PASS();
@@ -54,6 +59,7 @@ TEST(dump_verify_count_error) {
 
 TEST(dump_verify_ratio_zero_disables) {
     ASSERT_FALSE(cbm_dump_verify_is_degraded(1000, 10, 0.0, CBM_DUMP_VERIFY_MIN_FLOOR));
+    ASSERT_FALSE(cbm_dump_verify_is_degraded(12, 0, 0.0, CBM_DUMP_VERIFY_MIN_FLOOR));
     PASS();
 }
 
@@ -76,6 +82,7 @@ TEST(dump_verify_edges_shrank_nodes_ok) {
 SUITE(dump_verify) {
     RUN_TEST(dump_verify_no_baseline);
     RUN_TEST(dump_verify_sparse_at_floor);
+    RUN_TEST(dump_verify_sparse_zero_persisted);
     RUN_TEST(dump_verify_shortfall_below_ratio);
     RUN_TEST(dump_verify_just_above_ratio);
     RUN_TEST(dump_verify_just_below_ratio);