[576722] Fix z-order regression

Since the z-order (bugzilla 574273), there is a potential regression
that occurs in a context of "unsynchronized diagrams".
It seems possible that the method
AbstractDDiagramEditPart.refreshChildren() is called with some edges
that are visible at the GMF level but without a corresponding edit part.
I think that it is a temporary state but this method must handle it.

A corresponding test will be added later, when the causes will be better
understood.

Bug: 576722
Change-Id: I01dedc16aec1eb353b481020a3d35fe0bed2081c
Signed-off-by: Laurent Redor <laurent.redor@obeo.fr>

1 files changed, 3 insertions, 1 deletions

diff --git a/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/edit/api/part/AbstractDDiagramEditPart.java b/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/edit/api/part/AbstractDDiagramEditPart.java
index 012ee87d3c..18afe645ac 100644
--- a/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/edit/api/part/AbstractDDiagramEditPart.java
+++ b/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/edit/api/part/AbstractDDiagramEditPart.java
@@ -365,8 +365,10 @@ public abstract class AbstractDDiagramEditPart extends DiagramEditPart implement
                             ((SiriusPolylineConnectionEx) figureToMove).refreshLine();
                         }
                     }
+                    // Increase the GMF index only when a corresponding figure is found (to avoid a potential
+                    // IndexOutOfBoundsException).
+                    visibleGmfIndex++;
                 }
-                visibleGmfIndex++;
             }
         }
     }