From: Jan Engelhardt <ej@inai.de>
Date: 2026-02-06 21:35:38.854957697 +0100

When blender is built with eigen 5.x rather than 3.x, there are some
compile errors. Probably blender relied on implicit cassert inclusion
through eigen (the latter of which has gone away).

intern/libmv/intern/camera_intrinsics.cc:56:14: error: ‘assert’ was not declared in this scope
intern/libmv/libmv/numeric/numeric.h:150:3: error: there are no arguments to ‘assert’ that depend on a template parameter, so a declaration of ‘assert’ must be available [-Wtemplate-body]
intern/libmv/libmv/simple_pipeline/camera_intrinsics_impl.h:162:3: error: there are no arguments to ‘assert’ that depend on a template parameter, so a declaration of ‘assert’ must be available [-Wtemplate-body]
intern/libmv/libmv/simple_pipeline/camera_intrinsics_impl.h:162:9: error: ‘assert’ was not declared in this scope

---
 intern/libmv/libmv/numeric/numeric.h                        |    1 +
 intern/libmv/libmv/simple_pipeline/camera_intrinsics_impl.h |    1 +
 intern/slim/intern/edge_lengths.cpp                         |    1 +
 intern/slim/intern/uv_initializer.cpp                       |    1 +
 4 files changed, 4 insertions(+)

Index: blender-5.0.1/intern/libmv/libmv/numeric/numeric.h
===================================================================
--- blender-5.0.1.orig/intern/libmv/libmv/numeric/numeric.h
+++ blender-5.0.1/intern/libmv/libmv/numeric/numeric.h
@@ -25,6 +25,7 @@
 #ifndef LIBMV_NUMERIC_NUMERIC_H
 #define LIBMV_NUMERIC_NUMERIC_H
 
+#include <cassert>
 #include <Eigen/Cholesky>
 #include <Eigen/Core>
 #include <Eigen/Eigenvalues>
Index: blender-5.0.1/intern/libmv/libmv/simple_pipeline/camera_intrinsics_impl.h
===================================================================
--- blender-5.0.1.orig/intern/libmv/libmv/simple_pipeline/camera_intrinsics_impl.h
+++ blender-5.0.1/intern/libmv/libmv/simple_pipeline/camera_intrinsics_impl.h
@@ -19,6 +19,7 @@
 // IN THE SOFTWARE.
 
 #include "libmv/threading/parallel_for.h"
+#include <cassert>
 
 namespace libmv {
 
Index: blender-5.0.1/intern/slim/intern/edge_lengths.cpp
===================================================================
--- blender-5.0.1.orig/intern/slim/intern/edge_lengths.cpp
+++ blender-5.0.1/intern/slim/intern/edge_lengths.cpp
@@ -7,6 +7,7 @@
  * \ingroup intern_slim
  */
 
+#include <cassert>
 #include "BLI_task.hh"
 
 #include "edge_lengths.h"
Index: blender-5.0.1/intern/slim/intern/uv_initializer.cpp
===================================================================
--- blender-5.0.1.orig/intern/slim/intern/uv_initializer.cpp
+++ blender-5.0.1/intern/slim/intern/uv_initializer.cpp
@@ -6,6 +6,7 @@
  * \ingroup intern_slim
  */
 
+#include <cassert>
 #include "uv_initializer.h"
 
 #include <Eigen/SparseLU>