Merge pull request #2017 from sideeffects/sendupstream_nodiscard

Add [[nodiscard]] to confusing math functions.

Author: Idclip

openvdb/openvdb/math/Mat3.h

@@ -420,7 +420,7 @@ class Mat3: public Mat<3, T>
     }
 
     /// @brief Return the cofactor matrix of this matrix.
-    Mat3 cofactor() const
+    [[nodiscard]] Mat3 cofactor() const
     {
         return Mat3<T>(
           MyBase::mm[4] * MyBase::mm[8] - MyBase::mm[5] * MyBase::mm[7],
@@ -435,7 +435,7 @@ class Mat3: public Mat<3, T>
     }
 
     /// Return the adjoint of this matrix, i.e., the transpose of its cofactor.
-    Mat3 adjoint() const
+    [[nodiscard]] Mat3 adjoint() const
     {
         return Mat3<T>(
           MyBase::mm[4] * MyBase::mm[8] - MyBase::mm[5] * MyBase::mm[7],
@@ -462,7 +462,7 @@ class Mat3: public Mat<3, T>
 
     /// returns inverse of this
     /// @throws ArithmeticError if singular
-    Mat3 inverse(T tolerance = 0) const
+    [[nodiscard]] Mat3 inverse(T tolerance = 0) const
     {
         Mat3<T> inv(this->adjoint());
 
@@ -518,7 +518,7 @@ class Mat3: public Mat<3, T>
 
     /// @brief Treat @a diag as a diagonal matrix and return the product
     /// of this matrix with @a diag (from the right).
-    Mat3 timesDiagonal(const Vec3<T>& diag) const
+    [[nodiscard]] Mat3 timesDiagonal(const Vec3<T>& diag) const
     {
         Mat3 ret(*this);
 

openvdb/openvdb/math/Mat4.h

@@ -469,7 +469,7 @@ class Mat4: public Mat<4, T>
     }
 
     /// @return transpose of this
-    Mat4 transpose() const
+    [[nodiscard]] Mat4 transpose() const
     {
         return Mat4<T>(
                        MyBase::mm[ 0], MyBase::mm[ 4], MyBase::mm[ 8], MyBase::mm[12],
@@ -482,7 +482,7 @@ class Mat4: public Mat<4, T>
 
     /// @return inverse of this
     /// @throw ArithmeticError if singular
-    Mat4 inverse(T tolerance = 0) const
+    [[nodiscard]] Mat4 inverse(T tolerance = 0) const
     {
         //
         // inv [ A  | b ]  =  [ E  | f ]    A: 3x3, b: 3x1, c': 1x3 d: 1x1

pendingchanges/math_nodiscard.txt

@@ -0,0 +1,6 @@
+OpenVDB:
+  API Changes:
+    Mat3 and Mat4 functions have been marked [[nodiscard]] where it
+    may be confusing if they are operating in place or returning a
+    result, in particular tranpose, invert, adjoint, and
+    timesDiagonal.