Eeschema: fix connection indicator. (fixes lp:1476005).

* When multiple pins are in the same position and one is not connected,
  show connection indicator correctly.
* LIB_PIN::IsVisible should be a const method so it can be called on
  DANGLING_END_ITEM children without having to discard const.
* Test the (!IsVisible() && GetType() == PIN_POWER_IN) condition in a method
  LIB_PIN::IsPowerConnection to avoid duplicating that condition if the test
  needs to be performed in more than one place. (e.g. dunderheads like myself
  might forget about the necessary GetType() == PIN_POWER_IN and just check
  visibility.)
* Coding style fix: break a couple lines that were above the 99-column maximum.
* Add and/or improve Doxygen comments on SCH_COMPONENT::IsPinDanglingStateChanged
  and SCH_COMPONENT::IsDanglingStateChanged.

eeschema/lib_pin.h

@@ -383,7 +383,13 @@ public:
      *
      * @return True if draw object is visible otherwise false.
      */
-    bool IsVisible() { return ( m_attributes & PIN_INVISIBLE ) == 0; }
+    bool IsVisible() const { return ( m_attributes & PIN_INVISIBLE ) == 0; }
+
+    /**
+     * Return whether this pin forms an implicit power connection: i.e., is hidden
+     * and of type POWER_IN.
+     */
+    bool IsPowerConnection() const { return !IsVisible() && GetType() == PIN_POWER_IN; }
 
     int GetPenSize() const;
 

eeschema/sch_component.cpp

@@ -1628,9 +1628,11 @@ void SCH_COMPONENT::GetEndPoints( std::vector <DANGLING_END_ITEM>& aItemList )
 }
 
 
-bool SCH_COMPONENT::IsPinDanglingStateChanged( std::vector<DANGLING_END_ITEM> &aItemList, LIB_PINS& aLibPins, unsigned aPin )
+bool SCH_COMPONENT::IsPinDanglingStateChanged( std::vector<DANGLING_END_ITEM> &aItemList,
+        LIB_PINS& aLibPins, unsigned aPin )
 {
     bool previousState;
+
     if( aPin < m_isDangling.size() )
     {
         previousState = m_isDangling[aPin];
@@ -1646,8 +1648,20 @@ bool SCH_COMPONENT::IsPinDanglingStateChanged( std::vector<DANGLING_END_ITEM> &a
 
     BOOST_FOREACH( DANGLING_END_ITEM& each_item, aItemList )
     {
-        if( each_item.GetItem() == aLibPins[aPin] )
+        // Some people like to stack pins on top of each other in a symbol to indicate
+        // internal connection. While technically connected, it is not particularly useful
+        // to display them that way, so skip any pins that are in the same symbol as this
+        // one.
+        //
+        // Do not make this exception for hidden pins, because those actually make internal
+        // connections to a power net.
+        const LIB_PIN* item_pin = dynamic_cast<const LIB_PIN*>( each_item.GetItem() );
+
+        if( item_pin
+          && !item_pin->IsPowerConnection()
+          && std::find( aLibPins.begin(), aLibPins.end(), item_pin) != aLibPins.end() )
             continue;
+
         switch( each_item.GetType() )
         {
         case PIN_END:
@@ -1869,7 +1883,7 @@ void SCH_COMPONENT::GetNetListItem( NETLIST_OBJECT_LIST& aNetListItems,
 
             aNetListItems.push_back( item );
 
-            if( ( (int) pin->GetType() == (int) PIN_POWER_IN ) && !pin->IsVisible() )
+            if( pin->IsPowerConnection() )
             {
                 // There is an associated PIN_LABEL.
                 item = new NETLIST_OBJECT();

eeschema/sch_component.h

@@ -402,12 +402,30 @@ public:
     void GetEndPoints( std::vector<DANGLING_END_ITEM>& aItemList );
 
     /**
-     * Test if the component's dangling state has changed for one given pin index.
+     * Test if the component's dangling state has changed for one given pin index. As
+     * a side effect, actually update the dangling status for that pin.
+     *
+     * @param aItemList - list of all DANGLING_END_ITEMs to be tested
+     * @param aLibPins - list of all the LIB_PIN items in this component's symbol
+     * @param aPin - index into aLibPins that identifies the pin to test
+     * @return true if the pin's state has changed.
      */
-    bool IsPinDanglingStateChanged( std::vector<DANGLING_END_ITEM>& aItemList, LIB_PINS& aLibPins, unsigned aPin );
+    bool IsPinDanglingStateChanged( std::vector<DANGLING_END_ITEM>& aItemList,
+            LIB_PINS& aLibPins, unsigned aPin );
 
+    /**
+     * Test if the component's dangling state has changed for all pins. As a side
+     * effect, actually update the dangling status for all pins (does not short-circuit).
+     *
+     * @param aItemList - list of all DANGLING_END_ITEMs to be tested
+     * @return true if any pin's state has changed.
+     */
     bool IsDanglingStateChanged( std::vector<DANGLING_END_ITEM>& aItemList );
 
+    /**
+     * Return whether any pin has dangling status. Does NOT update the internal status,
+     * only checks the existing status.
+     */
     bool IsDangling() const;
 
     wxPoint GetPinPhysicalPosition( LIB_PIN* Pin );