pybind11: Remove any usages of Ref<> with dtype=object

Author: EricCousineau-TRI

bindings/pydrake/solvers/mathematicalprogram_py.cc

@@ -258,7 +258,7 @@ PYBIND11_MODULE(_mathematicalprogram_py, m) {
                &MathematicalProgram::AddBoundingBoxConstraint))
       .def("AddBoundingBoxConstraint",
            [](MathematicalProgram* self, double lb, double ub,
-              const Eigen::Ref<MatrixX<symbolic::Variable>>& vars) {
+              const Eigen::Ref<const MatrixX<symbolic::Variable>>& vars) {
              return self->AddBoundingBoxConstraint(lb, ub, vars);
            })
       .def("AddConstraint",

bindings/pydrake/systems/trajectory_optimization_py.cc

@@ -15,6 +15,8 @@ PYBIND11_MODULE(trajectory_optimization, m) {
   // NOLINTNEXTLINE(build/namespaces): Emulate placement in namespace.
   using namespace drake::systems::trajectory_optimization;
 
+  using solvers::VectorXDecisionVariable;
+
   py::module::import("pydrake.symbolic");
   py::module::import("pydrake.systems.framework");
   py::module::import("pydrake.systems.primitives");
@@ -25,22 +27,35 @@ PYBIND11_MODULE(trajectory_optimization, m) {
       .def("time", &MultipleShooting::time)
       .def("timestep", &MultipleShooting::timestep)
       .def("fixed_timestep", &MultipleShooting::fixed_timestep)
+      // TODO(eric.cousineau): The original bindings returned references
+      // instead of copies using VectorXBlock. Restore this once dtype=custom
+      // is resolved.
       .def("state",
-           overload_cast_explicit<const solvers::VectorXDecisionVariable&>(
-               &MultipleShooting::state))
+           [](const MultipleShooting& self) -> VectorXDecisionVariable {
+             return self.state();
+           })
       .def("state",
-           overload_cast_explicit<
-               Eigen::VectorBlock<const solvers::VectorXDecisionVariable>, int>(
-               &MultipleShooting::state))
-      .def("initial_state", &MultipleShooting::initial_state)
-      .def("final_state", &MultipleShooting::final_state)
+           [](const MultipleShooting& self, int index) ->
+               VectorXDecisionVariable {
+             return self.state(index);
+           })
+      .def("initial_state",
+           [](const MultipleShooting& self) -> VectorXDecisionVariable {
+             return self.initial_state();
+           })
+      .def("final_state",
+           [](const MultipleShooting& self) -> VectorXDecisionVariable {
+             return self.final_state();
+           })
       .def("input",
-           overload_cast_explicit<const solvers::VectorXDecisionVariable&>(
-               &MultipleShooting::input))
+           [](const MultipleShooting& self) -> VectorXDecisionVariable {
+             return self.input();
+           })
       .def("input",
-           overload_cast_explicit<
-               Eigen::VectorBlock<const solvers::VectorXDecisionVariable>, int>(
-               &MultipleShooting::input))
+           [](const MultipleShooting& self, int index) ->
+                VectorXDecisionVariable {
+             return self.input(index);
+           })
       .def("AddRunningCost",
            [](MultipleShooting& prog, const symbolic::Expression& g) {
              prog.AddRunningCost(g);

tools/workspace/pybind11/repository.bzl

@@ -5,9 +5,10 @@ load("@drake//tools/workspace:github.bzl", "github_archive")
 
 _REPOSITORY = "RobotLocomotion/pybind11"
 
-_COMMIT = "77211dfa6933858bdad00a77867ee4ca4b80cfd0"
+# PR DRAFT(eric.cousineau): Change this once RobotLocomotion/pybind11#17 lands.
+_COMMIT = "f8d6b820a30936d21f261e2162464f1cabe4ceda"
 
-_SHA256 = "bbc405fbe4225f8a6e86bc6a21372957f11db2953b601d98eb7ef12c9f6473b6"
+_SHA256 = "86a155960e9fc585e31c750c315c2ea0ae8b5b2bcbff21dea1898c0331fd4e0b"
 
 def pybind11_repository(
         name,