Fix bug in caching of surface deformations.

This bug has an effect if the DetUnits of a large tracker structure
are not listed at all. The net effect of this fix is that omitting
them leaves them and the associated surface deformations unchanged.

Alignment/CommonAlignment/interface/Alignable.h

@@ -195,7 +195,7 @@ class Alignable
   /// and pointers to surface deformations
   virtual int surfaceDeformationIdPairs(std::vector<std::pair<int,SurfaceDeformation*> > &) const = 0;
 
-  /// cache the current position, rotation and other parameters (e.g. surface deformations)
+  /// cache the current position, rotation and other parameters (e.g. surface deformations), also for possible components
   virtual void cacheTransformation();
 
   /// restore the previously cached transformation, also for possible components

Alignment/CommonAlignment/src/Alignable.cc

@@ -243,9 +243,18 @@ AlignmentSurfaceDeformations* Alignable::surfaceDeformations( void ) const
 
 void Alignable::cacheTransformation()
 {
+  // first treat itself
   theCachedSurface = theSurface;
   theCachedDisplacement = theDisplacement;
   theCachedRotation = theRotation;
+
+  // now treat components (a clean design would move that to AlignableComposite...)
+  const Alignables comps(this->components());
+
+  for (auto it = comps.begin(); it != comps.end(); ++it) {
+    (*it)->cacheTransformation();
+  }
+
 }
 
 void Alignable::restoreCachedTransformation()