Fix: Prevent use of uninitialized memory when creating Bezier spline

When Constructing bezier splines from dna, the positions of the
left/right handles were set directly in the internal vectors, by
requesting a reference to them. The problem is that
BezierSpline::handle_positions_left() calls ensure_auto_handles()
before returning the reference. That function does some calculations on
uninitialized memory if the positions array is not yet filled.

Differential Revision: https://developer.blender.org/D13107

1 files changed, 9 insertions, 4 deletions

diff --git a/source/blender/blenkernel/intern/spline_bezier.cc b/source/blender/blenkernel/intern/spline_bezier.cc
index e760bf3495e..166fe0f5464 100644
--- a/source/blender/blenkernel/intern/spline_bezier.cc
+++ b/source/blender/blenkernel/intern/spline_bezier.cc
@@ -142,11 +142,14 @@ Span<float3> BezierSpline::handle_positions_left() const
   this->ensure_auto_handles();
   return handle_positions_left_;
 }
-MutableSpan<float3> BezierSpline::handle_positions_left()
+MutableSpan<float3> BezierSpline::handle_positions_left(const bool write_only)
 {
-  this->ensure_auto_handles();
+  if (!write_only) {
+    this->ensure_auto_handles();
+  }
   return handle_positions_left_;
 }
+
 Span<BezierSpline::HandleType> BezierSpline::handle_types_right() const
 {
   return handle_types_right_;
@@ -160,9 +163,11 @@ Span<float3> BezierSpline::handle_positions_right() const
   this->ensure_auto_handles();
   return handle_positions_right_;
 }
-MutableSpan<float3> BezierSpline::handle_positions_right()
+MutableSpan<float3> BezierSpline::handle_positions_right(const bool write_only)
 {
-  this->ensure_auto_handles();
+  if (!write_only) {
+    this->ensure_auto_handles();
+  }
   return handle_positions_right_;
 }