[Bf-blender-cvs] [30845b5c8e0] master: Doc: expand on comment for why bound-box access could cause issues

[Campbell Barton]

Commit: 30845b5c8e042f42331b0c2a8a57ad05837b114e
Author: Campbell Barton
Date:   Tue Sep 14 13:27:15 2021 +1000
Branches: master
https://developer.blender.org/rB30845b5c8e042f42331b0c2a8a57ad05837b114e

Doc: expand on comment for why bound-box access could cause issues

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M	source/blender/blenkernel/intern/constraint.c

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diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index 72f14d94833..b9b15eba6a4 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -3900,7 +3900,11 @@ static void clampto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *tar
 
     unit_m4(targetMatrix);
     INIT_MINMAX(curveMin, curveMax);
-    /* XXX(campbell): don't think this is good calling this here. */
+    /* XXX(@campbellbarton): don't think this is good calling this here because
+     * the other object's data is lazily initializing bounding-box information.
+     * This could cause issues when evaluating from a thread.
+     * If the depsgraph ensures the bound-box is always available, a code-path could
+     * be used that doesn't lazy initialize to avoid thread safety issues in the future. */
     BKE_object_minmax(ct->tar, curveMin, curveMax, true);
 
     /* get targetmatrix */