Report sought magnitude when balancing errors occur

src/balance.h

@@ -480,6 +480,13 @@ public:
   optional<amount_t>
   commodity_amount(const optional<const commodity_t&>& commodity = none) const;
 
+  balance_t number() const {
+    balance_t temp;
+    foreach (const amounts_map::value_type& pair, amounts)
+      temp += pair.second.number();
+    return temp;
+  }
+
   /**
    * Annotated commodity methods.  The amounts contained by a balance
    * may use annotated commodities.  The `strip_annotations' method

src/py_balance.cc

@@ -209,6 +209,8 @@ void export_balance()
     .def("commodity_amount", py_commodity_amount_0)
     .def("commodity_amount", py_commodity_amount_1)
 
+    .def("number", &balance_t::number)
+
     .def("strip_annotations", &balance_t::strip_annotations)
 
     .def("valid",  &balance_t::valid)

src/py_value.cc

@@ -285,6 +285,8 @@ void export_value()
     .def("simplified", &value_t::simplified)
     .def("in_place_simplify", &value_t::in_place_simplify)
 
+    .def("number", &value_t::number)
+
     .def("annotate", &value_t::annotate)
     .def("is_annotated", &value_t::is_annotated)
 #if 0

src/value.cc

@@ -279,6 +279,35 @@ void value_t::in_place_simplify()
 #endif
 }
 
+value_t value_t::number() const
+{
+  switch (type()) {
+  case VOID:
+    return 0L;
+  case BOOLEAN:
+    return as_boolean() ? 1L : 0L;
+  case INTEGER:
+    return as_long();
+  case AMOUNT:
+    return as_amount().number();
+  case BALANCE:
+    return as_balance().number();
+  case SEQUENCE:
+    if (! as_sequence().empty()) {
+      value_t temp;
+      foreach (const value_t& value, as_sequence())
+	temp += value.number();
+      return temp;
+    }
+    break;
+  default:
+    break;
+  }
+
+  throw_(value_error, _("Cannot determine numeric value of %1") << label());
+  return false;
+}
+
 value_t& value_t::operator+=(const value_t& val)
 {
   if (is_string()) {

src/value.h

@@ -761,6 +761,8 @@ public:
   }
   void    in_place_simplify();
 
+  value_t number() const;
+
   /**
    * Annotated commodity methods.
    */

src/xact.cc

@@ -83,6 +83,20 @@ void xact_base_t::clear_xdata()
       post->clear_xdata();
 }
 
+value_t xact_base_t::magnitude() const
+{
+  value_t halfbal = 0L;
+  foreach (const post_t * post, posts) {
+    if (post->amount.sign() > 0) {
+      if (post->cost)
+	halfbal += *post->cost;
+      else
+	halfbal += post->amount;
+    }
+  }
+  return halfbal;
+}
+
 bool xact_base_t::finalize()
 {
   // Scan through and compute the total balance for the xact.  This is used
@@ -321,6 +335,8 @@ bool xact_base_t::finalize()
     add_error_context(item_context(*this, _("While balancing transaction")));
     add_error_context(_("Unbalanced remainder is:"));
     add_error_context(value_context(balance));
+    add_error_context(_("Amount to balance against:"));
+    add_error_context(value_context(magnitude()));
     throw_(balance_error, _("Transaction does not balance"));
   }
 
@@ -368,26 +384,12 @@ void xact_t::add_post(post_t * post)
   xact_base_t::add_post(post);
 }
 
-value_t xact_t::magnitude() const
-{
-  value_t halfbal = 0L;
-  foreach (const post_t * post, posts) {
-    if (post->amount.sign() > 0) {
-      if (post->cost)
-	halfbal += post->cost->number();
-      else
-	halfbal += post->amount.number();
-    }
-  }
-  return halfbal;
-}
-
 string xact_t::idstring() const
 {
   std::ostringstream buf;
   buf << format_date(*_date, FMT_WRITTEN);
   buf << payee;
-  magnitude().print(buf);
+  magnitude().number().print(buf);
   return buf.str();
 }
 

src/xact.h

@@ -84,6 +84,8 @@ public:
     return posts.end();
   }
 
+  value_t magnitude() const;
+
   virtual bool finalize();
 
   void clear_xdata();
@@ -129,7 +131,6 @@ public:
 
   virtual void add_post(post_t * post);
 
-  value_t magnitude() const;
   string idstring() const;
   string id() const;
 

test/regress/2E3496BD.test

@@ -14,5 +14,7 @@ While balancing transaction from "$FILE", lines 3-5:
 >   Account2   -1000 EUR @ 1.5 USD
 Unbalanced remainder is:
           100.00 USD
+Amount to balance against:
+         1,600.0 USD
 Error: Transaction does not balance
 === 1