Spreadsheet: improve cyclic dependency exception handling

src/Mod/Spreadsheet/App/Cell.cpp

@@ -585,9 +585,9 @@ bool Cell::getSpans(int &rows, int &columns) const
     return isUsed(SPANS_SET);
 }
 
-void Cell::setException(const std::string &e)
+void Cell::setException(const std::string &e, bool silent)
 {
-    if(e.size() && owner && owner->sheet()) {
+    if(!silent && e.size() && owner && owner->sheet()) {
         FC_ERR(owner->sheet()->getFullName() << '.' 
                 << address.toString() << ": " << e);
     }

src/Mod/Spreadsheet/App/Cell.h

@@ -85,7 +85,7 @@ public:
     void setSpans(int rows, int columns);
     bool getSpans(int & rows, int & columns) const;
 
-    void setException(const std::string & e);
+    void setException(const std::string & e, bool silent=false);
 
     void clearException();
 

src/Mod/Spreadsheet/App/Sheet.cpp

@@ -858,15 +858,15 @@ DocumentObjectExecReturn *Sheet::execute(void)
             FC_LOG(addr.toString());
             recomputeCell(addr);
         }
-    } catch (std::exception&) {
+    } catch (std::exception &) {
         for(auto &v : VertexList) {
             Cell * cell = cells.getValue(v.first);
             // Mark as erroneous
-            cellErrors.insert(v.first);
-            if (cell)
-                cell->setException("Pending computation due to cyclic dependency");
-            updateProperty(v.first);
-            updateAlias(v.first);
+            if(cell)  {
+                cellErrors.insert(v.first);
+                cell->setException("Pending computation due to cyclic dependency",true);
+                cellUpdated(v.first);
+            }
         }
 
         // Try to be more user friendly by finding individual loops
@@ -912,10 +912,10 @@ DocumentObjectExecReturn *Sheet::execute(void)
             } catch (std::exception&) {
                 // Cycle detected; flag all with errors
                 std::ostringstream ss;
-                ss << "Cyclic dependency" << std::endl;
+                ss << "Cyclic dependency";
                 int count = 0;
                 for(auto &v : VertexList) {
-                    if(count==20)
+                    if(count++%20 == 0)
                         ss << std::endl;
                     else
                         ss << ", ";
@@ -924,8 +924,10 @@ DocumentObjectExecReturn *Sheet::execute(void)
                 std::string msg = ss.str();
                 for(auto &v : VertexList) {
                     Cell * cell = cells.getValue(v.first);
-                    if (cell)
-                        cell->setException(msg.c_str());
+                    if (cell) {
+                        cell->setException(msg.c_str(),true);
+                        cellUpdated(v.first);
+                    }
                 }
             }
         }