Various small improvements to check & repair on business accounts

- don't attempt to merge splits that belong to an invoice transaction. These splits are managed by the business code.
- lot link cleanup can leave empty splits, remove these as well

src/engine/Scrub2.c

@@ -43,6 +43,7 @@
 #include "ScrubP.h"
 #include "cap-gains.h"
 #include "gnc-engine.h"
+#include "gncInvoice.h"
 #include "gnc-lot.h"
 #include "policy-p.h"
 
@@ -355,6 +356,11 @@ xaccScrubMergeSubSplits (Split *split, gboolean strict)
     if (strict && (FALSE == is_subsplit (split))) return FALSE;
 
     txn = split->parent;
+
+    // Don't mess with splits from an invoice transaction
+    // Those are the responsibility of the business code
+    if (gncInvoiceGetInvoiceFromTxn (txn)) return FALSE;
+
     lot = xaccSplitGetLot (split);
 
     ENTER ("(Lot=%s)", gnc_lot_get_title(lot));
@@ -366,6 +372,10 @@ restart:
         if (s == split) continue;
         if (qof_instance_get_destroying(s)) continue;
 
+        // Don't mess with splits from an invoice transaction
+        // Those are the responsibility of the business code
+        if (gncInvoiceGetInvoiceFromTxn (s->parent)) return FALSE;
+
         if (strict)
         {
             /* OK, this split is in the same lot (and thus same account)
@@ -386,9 +396,13 @@ restart:
         rc = TRUE;
         goto restart;
     }
-    if (gnc_numeric_zero_p (split->amount))
+    if (rc && gnc_numeric_zero_p (split->amount))
     {
+        time64 pdate = xaccTransGetDate (txn);
+        gchar *pdatestr = gnc_ctime (&pdate);
         PWARN ("Result of merge has zero amt!");
+        PWARN ("Transaction details - posted date %s - description %s", pdatestr, xaccTransGetDescription(txn));
+        g_free (pdatestr);
     }
     LEAVE (" splits merged=%d", rc);
     return rc;

src/engine/ScrubBusiness.c

@@ -462,13 +462,14 @@ gncScrubBusinessLot (GNCLot *lot)
     return splits_deleted;
 }
 
-void
+gboolean
 gncScrubBusinessSplit (Split *split)
 {
     const gchar *memo = _("Please delete this transaction. Explanation at http://wiki.gnucash.org/wiki/Business_Features_Issues#Double_Posting");
     Transaction *txn;
+    gboolean deleted_split = FALSE;
 
-    if (!split) return;
+    if (!split) return FALSE;
     ENTER ("(split=%p)", split);
 
     txn = xaccSplitGetParent (split);
@@ -500,10 +501,23 @@ gncScrubBusinessSplit (Split *split)
                   txn_date);
             g_free (txn_date);
         }
+        /* Next delete any empty splits that aren't part of an invoice transaction
+         * Such splits may be the result of scrubbing the business lots, which can
+         * merge splits together while reducing superfluous lot links
+         */
+        else if (gnc_numeric_zero_p (xaccSplitGetAmount(split)) && !gncInvoiceGetInvoiceFromTxn (txn))
+        {
+            time64 pdate = xaccTransGetDate (txn);
+            gchar *pdatestr = gnc_ctime (&pdate);
+            PINFO ("Destroying empty split %p from transaction %s (%s)", split, pdatestr, xaccTransGetDescription(txn));
+            xaccSplitDestroy (split);
+            deleted_split = TRUE;
+        }
 
     }
 
     LEAVE ("(split=%p)", split);
+    return deleted_split;
 }
 
 /* ============================================================== */
@@ -563,7 +577,7 @@ gncScrubBusinessAccountSplits (Account *acc, QofPercentageFunc percentagefunc)
 {
     SplitList *splits, *node;
     gint split_count = 0;
-    gint curr_split_no = 0;
+    gint curr_split_no;
     const gchar *str;
     const char *message = _( "Checking business splits in account %s: %u of %u");
 
@@ -577,6 +591,8 @@ gncScrubBusinessAccountSplits (Account *acc, QofPercentageFunc percentagefunc)
     PINFO ("Cleaning up superfluous lot links in account %s \n", str);
     xaccAccountBeginEdit(acc);
 
+restart:
+    curr_split_no = 0;
     splits = xaccAccountGetSplitList(acc);
     split_count = g_list_length (splits);
     for (node = splits; node; node = node->next)
@@ -594,7 +610,10 @@ gncScrubBusinessAccountSplits (Account *acc, QofPercentageFunc percentagefunc)
         }
 
         if (split)
-            gncScrubBusinessSplit (split);
+            // If gncScrubBusinessSplit returns true, a split was deleted and hence
+            // The account split list has become invalid, so we need to start over
+            if (gncScrubBusinessSplit (split))
+                goto restart;
 
         PINFO("Finished processing split %d of %d",
               curr_split_no + 1, split_count);

src/engine/ScrubBusiness.h

@@ -57,7 +57,9 @@ gboolean gncScrubBusinessLot (GNCLot *lot);
 /** The gncScrubBusinessSplit() function will fix all issues found with
  *    the given split.
  *
- *    Currently this function only does one thing: check if the split is
+ *    Current checks are:
+ *
+ *    * check if the split is
  *    part of a transaction that was generated as the result of a doubly
  *    posted invoice/bill/credit note. Refer to
  *    https://bugzilla.gnome.org/show_bug.cgi?id=754209 to learn how this
@@ -66,8 +68,11 @@ gboolean gncScrubBusinessLot (GNCLot *lot);
  *    a warning is written to the trace file. Considering the user may
  *    already have added a correcting transaction we leave it up to the user
  *    to decide whether to also delete the transaction or not.
+ *
+ *    * remove empty splits, on condition they aren't part of an invoice transaction.
+ *    In this case the function returns true so the caller knows a split was removed.
  */
-void gncScrubBusinessSplit (Split *split);
+gboolean gncScrubBusinessSplit (Split *split);
 
 /** The gncScrubBusinessAccountLots() function will call
  *    gncScrubBusinessLot() on each lot in the given account.