Fix a wxRecursionGuard crash when library symbol is missing.

The various wxCHECKs in the SCH_PIN object where being raised inside
the SCH_SYMBOL object which would also raise it's own wxCHECK that
would cause a recursion guard failure and segfault.  The offending
wxCHECKs were replaced with null pointer checks.  Missing library
symbol links will be shown with the missing library symbol.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/17146

eeschema/sch_pin.cpp

@@ -126,7 +126,8 @@ wxString SCH_PIN::GetShownNumber() const
 
 ELECTRICAL_PINTYPE SCH_PIN::GetType() const
 {
-    wxCHECK( m_libPin, ELECTRICAL_PINTYPE::PT_NC );
+    if( !m_libPin )
+        return ELECTRICAL_PINTYPE::PT_NC;
 
     if( !m_alt.IsEmpty() )
         return m_libPin->GetAlt( m_alt ).m_Type;
@@ -137,7 +138,8 @@ ELECTRICAL_PINTYPE SCH_PIN::GetType() const
 
 GRAPHIC_PINSHAPE SCH_PIN::GetShape() const
 {
-    wxCHECK( m_libPin, GRAPHIC_PINSHAPE::LINE );
+    if( !m_libPin )
+        return GRAPHIC_PINSHAPE::LINE;
 
     if( !m_alt.IsEmpty() )
         return m_libPin->GetAlt( m_alt ).m_Shape;
@@ -148,7 +150,8 @@ GRAPHIC_PINSHAPE SCH_PIN::GetShape() const
 
 PIN_ORIENTATION SCH_PIN::GetOrientation() const
 {
-    wxCHECK( m_libPin, PIN_ORIENTATION::PIN_RIGHT );
+    if( !m_libPin )
+        return PIN_ORIENTATION::PIN_RIGHT;
 
     return m_libPin->GetOrientation();
 }
@@ -156,7 +159,8 @@ PIN_ORIENTATION SCH_PIN::GetOrientation() const
 
 int SCH_PIN::GetLength() const
 {
-    wxCHECK( m_libPin, 0 );
+    if( !m_libPin )
+        return 0;
 
     return m_libPin->GetLength();
 }
@@ -301,7 +305,8 @@ bool SCH_PIN::IsStacked( const SCH_PIN* aPin ) const
 
 bool SCH_PIN::IsGlobalPower() const
 {
-    wxCHECK( m_libPin, false );
+    if( !m_libPin )
+        return false;
 
     return m_libPin->IsGlobalPower();
 }
@@ -425,8 +430,6 @@ const BOX2I SCH_PIN::GetBoundingBox( bool aIncludeInvisiblePins, bool aIncludeNa
     if( m_libPin )
         r = m_libPin->GetBoundingBox( aIncludeInvisiblePins, aIncludeNameAndNumber,
                                       aIncludeElectricalType );
-    else
-        wxFAIL;
 
     r.RevertYAxis();
 
@@ -491,7 +494,8 @@ bool SCH_PIN::HasConnectivityChanges( const SCH_ITEM* aItem,
 
 bool SCH_PIN::ConnectionPropagatesTo( const EDA_ITEM* aItem ) const
 {
-    wxCHECK( m_libPin, false );
+    if( !m_libPin )
+        return false;
 
     // Reciprocal checking is done in CONNECTION_GRAPH anyway
     return !( m_libPin->GetType() == ELECTRICAL_PINTYPE::PT_NC );
@@ -511,6 +515,9 @@ bool SCH_PIN::operator==( const SCH_ITEM& aOther ) const
     if( m_position != other.m_position )
         return false;
 
+    if( !m_libPin )
+        return false;
+
     return m_libPin == other.m_libPin;
 }
 

eeschema/sch_symbol.cpp

@@ -2177,12 +2177,12 @@ bool SCH_SYMBOL::UpdateDanglingState( std::vector<DANGLING_END_ITEM>& aItemListB
 }
 
 
-VECTOR2I SCH_SYMBOL::GetPinPhysicalPosition( const LIB_PIN* Pin ) const
+VECTOR2I SCH_SYMBOL::GetPinPhysicalPosition( const LIB_PIN* aPin ) const
 {
-    wxCHECK_MSG( Pin != nullptr && Pin->Type() == LIB_PIN_T, VECTOR2I( 0, 0 ),
-                 wxT( "Cannot get physical position of pin." ) );
+    if( ( aPin == nullptr ) || ( aPin->Type() != LIB_PIN_T ) )
+        return VECTOR2I( 0, 0 );
 
-    return m_transform.TransformCoordinate( Pin->GetPosition() ) + m_pos;
+    return m_transform.TransformCoordinate( aPin->GetPosition() ) + m_pos;
 }
 
 
@@ -2699,7 +2699,8 @@ bool SCH_SYMBOL::IsSymbolLikePowerGlobalLabel() const
 
 bool SCH_SYMBOL::IsPower() const
 {
-    wxCHECK( m_part, false );
+    if( !m_part )
+        return false;
 
     return m_part->IsPower();
 }