Fix several compiler warnings

* -Wmaybe-uninitialized
* -Wunused-parameter
* -Wunused-variable
* -Wnonnull
* -Wstringop-truncation
* -Wstringop-overflow

src/Gui/OverlayManager.cpp

@@ -1178,7 +1178,7 @@ class OverlayManager::Private {
         OverlayTabWidget *dst = nullptr;
         int dstIndex = -1;
         QDockWidget *dstDock = nullptr;
-        Qt::DockWidgetArea dstDockArea;
+        Qt::DockWidgetArea dstDockArea {};
 
         if (!tabWidget) {
             rect = QRect(pos - dragOffset, dragSize);

src/Gui/Tree.cpp

@@ -4727,11 +4727,12 @@ void DocumentItem::updateItemSelection(DocumentObjectItem* item)
     const char* docname = obj->getDocument()->getName();
     const auto& subname = str.str();
 
+#ifdef FC_DEBUG
     if (!subname.empty()) {
         auto parentItem = item->getParentItem();
         assert(parentItem);
     }
-
+#endif
 
     if (!selected) {
         Gui::Selection().rmvSelection(docname, objname, subname.c_str());

src/Mod/Import/App/PreCompiled.h

@@ -51,6 +51,7 @@
 
 // boost
 #include <boost/algorithm/string/predicate.hpp>
+#include <boost/core/ignore_unused.hpp>
 #include <boost/range/adaptor/indexed.hpp>
 
 // OpenCasCade =====================================================================================

src/Mod/Import/App/ReaderGltf.cpp

@@ -24,6 +24,7 @@
 
 #include "PreCompiled.h"
 #ifndef _PreComp_
+#include <boost/core/ignore_unused.hpp>
 #include <Standard_Version.hxx>
 #if OCC_VERSION_HEX >= 0x070500
 #include <BRep_Builder.hxx>
@@ -73,7 +74,7 @@ void ReaderGltf::read(Handle(TDocStd_Document) hDoc)
     processDocument(hDoc);
 
 #else
-    (void)hDoc;
+    boost::ignore_unused(hDoc);
     throw Base::RuntimeError("gITF support requires OCCT 7.5.0 or later");
 #endif
 }
@@ -100,6 +101,8 @@ void ReaderGltf::processDocument(Handle(TDocStd_Document) hDoc)
             }
         }
     }
+#else
+    boost::ignore_unused(hDoc);
 #endif
 }
 
@@ -138,6 +141,9 @@ TopoDS_Shape ReaderGltf::processSubShapes(Handle(TDocStd_Document) hDoc,
             aColorTool->SetColor(faceLabel, rgba, XCAFDoc_ColorSurf);
         }
     }
+#else
+    boost::ignore_unused(hDoc);
+    boost::ignore_unused(subShapeLabels);
 #endif
 
     return {std::move(compound)};

src/Mod/Import/App/WriterGltf.cpp

@@ -24,6 +24,7 @@
 
 #include "PreCompiled.h"
 #ifndef _PreComp_
+#include <boost/core/ignore_unused.hpp>
 #include <Standard_Version.hxx>
 #include <TColStd_IndexedDataMapOfStringString.hxx>
 #if OCC_VERSION_HEX >= 0x070500
@@ -62,6 +63,7 @@ void WriterGltf::write(Handle(TDocStd_Document) hDoc) const  // NOLINT
         throw Base::FileException("Cannot save to file: ", file);
     }
 #else
+    boost::ignore_unused(hDoc);
     throw Base::RuntimeError("gITF support requires OCCT 7.5.0 or later");
 #endif
 }

src/Mod/Import/App/dxf/ImpExpDxf.cpp

@@ -1073,12 +1073,11 @@ void ImpExpDxfWrite::exportBSpline(BRepAdaptor_Curve& c)
             s = c.Value(f);
             ePt = c.Value(l);
             Base::Console().Message(
-                "DxfWrite::exportBSpline - no result- from:(%.3f,%.3f) to:(%.3f,%.3f) poles: %d\n",
+                "DxfWrite::exportBSpline - no result- from:(%.3f,%.3f) to:(%.3f,%.3f)\n",
                 s.X(),
                 s.Y(),
                 ePt.X(),
-                ePt.Y(),
-                spline->NbPoles());
+                ePt.Y());
             TColgp_Array1OfPnt controlPoints(0, 1);
             controlPoints.SetValue(0, s);
             controlPoints.SetValue(1, ePt);

src/Mod/Mesh/App/WildMagic4/Wm4System.cpp

@@ -927,7 +927,7 @@ char* System::Strcpy (char* acDst, size_t uiDstSize, const char* acSrc)
         // copy failed.
         return nullptr;
     }
-    strncpy(acDst,acSrc,uiSrcLen);
+    strncpy(acDst,acSrc,uiSrcLen + 1);
     acDst[uiSrcLen] = 0;
     return acDst;
 #endif
@@ -962,7 +962,7 @@ char* System::Strcat (char* acDst, size_t uiDstSize, const char* acSrc)
         // the concatenation failed.
         return nullptr;
     }
-    strncat(acDst,acSrc,uiSrcLen);
+    strncat(acDst,acSrc,uiSrcLen + 1);
     acDst[uiSumLen] = 0;
     return acDst;
 #endif

src/Mod/Part/App/WireJoiner.cpp

@@ -21,6 +21,7 @@
  ****************************************************************************/
 
 #include "PreCompiled.h"
+#include <boost/core/ignore_unused.hpp>
 #include <boost/geometry/geometries/register/point.hpp>
 #include <boost/graph/graph_concepts.hpp>
 
@@ -1730,6 +1731,7 @@ class WireJoiner::WireJoinerP {
         }
         for (auto &info : edges) {
             if (auto wire = info.wireInfo.get()) {
+                boost::ignore_unused(wire);
 
                 // Originally here there was a call to the precompiler macro assertCheck(), which
                 // has been replaced with the precompiler macro assert()

src/Mod/Sketcher/App/SketchObject.cpp

@@ -9478,6 +9478,7 @@ std::pair<std::string,std::string> SketchObject::getElementName(
     index.appendToStringBuffer(ret.second);
     if (auto realName = convertInternalName(ret.second.c_str())) {
         Data::MappedElement mappedElement;
+        (void)realName;
 // Todo: Do we need to add the InternalShape?
 //        if (mapped)
 //            mappedElement = InternalShape.getShape().getElementName(name);

src/Mod/Sketcher/App/planegcs/GCS.cpp

@@ -2084,7 +2084,7 @@ int System::solve_BFGS(SubSystem* subsys, bool /*isFine*/, bool isRedundantsolvi
     }
 
     double divergingLim = 1e6 * err + 1e12;
-    double h_norm;
+    double h_norm {};
 
     for (int iter = 1; iter < maxIterNumber; iter++) {
         h_norm = h.norm();
@@ -2241,7 +2241,7 @@ int System::solve_LM(SubSystem* subsys, bool isRedundantsolving)
             mu = tau * diag_A.lpNorm<Eigen::Infinity>();
         }
 
-        double h_norm;
+        double h_norm {};
         // determine increment using adaptive damping
         int k = 0;
         while (k < 50) {

src/Mod/Sketcher/Gui/CommandConstraints.cpp

@@ -2214,11 +2214,11 @@ class DrawSketchHandlerDimension : public DrawSketchHandler
                 GeoId1, static_cast<int>(PosId1), GeoId2, ActDist);
         }
         // Circle/arc - line, circle/arc - circle/arc cases
-        else if (PosId1 == Sketcher::PointPos::none
-                 && PosId2 == Sketcher::PointPos::none) {
+        else if (PosId1 == Sketcher::PointPos::none && PosId2 == Sketcher::PointPos::none) {
             const Part::Geometry* geo1 = Obj->getGeometry(GeoId1);
             const Part::Geometry* geo2 = Obj->getGeometry(GeoId2);
-            double radius1, radius2;
+            double radius1 {};
+            double radius2 {};
             Base::Vector3d center1, center2;
             if (isCircle(*geo1)) {
                 auto conic = static_cast<const Part::GeomCircle*>(geo1);

src/Mod/Sketcher/Gui/DrawSketchHandlerOffset.h

@@ -527,7 +527,8 @@ class DrawSketchHandlerOffset: public DrawSketchHandlerOffsetBase
 
         vCCO = generatevCC(listOfOffsetGeoIds);
 
-        int geoIdCandidate1, geoIdCandidate2;
+        int geoIdCandidate1 {};
+        int geoIdCandidate2 {};
 
         int newCurveCounter = 0;
         int prevCurveCounter = 0;

src/Mod/Sketcher/Gui/EditModeGeometryCoinConverter.cpp

@@ -315,7 +315,7 @@ template<typename GeoType,
          EditModeGeometryCoinConverter::AnalyseMode analysemode>
 void EditModeGeometryCoinConverter::convert(const Sketcher::GeometryFacade* geometryfacade,
                                             [[maybe_unused]] int geoid,
-                                            int subLayer)
+                                            [[maybe_unused]] int subLayer)
 {
     auto geo = static_cast<const GeoType*>(geometryfacade->getGeometry());
     auto layerId = getSafeGeomLayerId(geometryfacade);

src/Mod/Sketcher/Gui/EditModeGeometryCoinConverter.h

@@ -154,7 +154,7 @@ class EditModeGeometryCoinConverter
     template<typename GeoType, PointsMode pointmode, CurveMode curvemode, AnalyseMode analysemode>
     void convert(const Sketcher::GeometryFacade* geometryfacade,
                  [[maybe_unused]] int geoId,
-                 int subLayerId = 0);
+                 [[maybe_unused]] int subLayerId = 0);
 
 private:
     /// Reference to ViewProviderSketch in order to access the public and the Attorney Interface

src/Mod/Spreadsheet/Gui/SheetModel.cpp

@@ -389,8 +389,8 @@ QVariant SheetModel::data(const QModelIndex& index, int role) const
     else if (prop->isDerivedFrom(App::PropertyFloat::getClassTypeId())
              || prop->isDerivedFrom(App::PropertyInteger::getClassTypeId())) {
         /* Number */
-        double d;
-        long l;
+        double d {};
+        long l {};
         bool isInteger = false;
         if (prop->isDerivedFrom(App::PropertyFloat::getClassTypeId())) {
             d = static_cast<const App::PropertyFloat*>(prop)->getValue();

src/Mod/TechDraw/Gui/QGIViewDimension.cpp

@@ -2550,7 +2550,7 @@ void QGIViewDimension::drawAngle(TechDraw::DrawViewDimension* dimension,
 
     double endAngle = (endPoint - angleVertex).Angle();
     double startAngle = (startPoint - angleVertex).Angle();
-    double arcRadius;
+    double arcRadius {};
 
     int standardStyle = viewProvider->StandardAndStyle.getValue();
     int renderExtent = viewProvider->RenderingExtent.getValue();