Update bazel_deps and bazel-toolchain

This switches to boost 1.91.0 and allows building on Ubuntu 26.04

A few local changes are necessary to build in those environments

Author: jpieper

.bazelrc

@@ -13,6 +13,12 @@ test --test_output=errors
 
 build:host --platforms=@local_config_platform//:host
 build:host --linkopt=-lrt
+# bazel_deps select()s on this to pick compiler-specific copts (e.g.
+# libxcb's -Wno-* warnings). The host build uses the bundled
+# llvm_toolchain, so declare CLANG. Target builds use a different
+# toolchain and don't go through these select()s.
+build:host --define CLANG=true
+test:host --define CLANG=true
 build:host --copt=-Werror
 build:host --copt=-Wno-parentheses-equality
 # Catch the `return X(); if (...) ...` family at compile time. clang

WORKSPACE

@@ -28,7 +28,7 @@ bazel_toolchain_dependencies()
 load("@com_github_mjbots_bazel_toolchain//toolchain:rules.bzl", "llvm_toolchain")
 llvm_toolchain(
     name = "llvm_toolchain",
-    llvm_version = "10.0.0",
+    llvm_version = "20.1.8",
     urls = {
         "windows" : ["https://github.com/mjbots/bazel-toolchain/releases/download/0.5.6-mj20201011/LLVM-10.0.0-win64.tar.xz"],
     },

mjlib/base/BUILD

@@ -83,6 +83,15 @@ cc_library(
     name = "error_code",
     hdrs = ["error_code.h"],
     srcs = ["error_code.cc"],
+    # Boost.System (>= 1.84) uses std::mutex internally to guard error
+    # category init. Embedded toolchains (no OS) don't ship <mutex>; tell
+    # Boost to use a no-op mutex instead. This is propagated to all
+    # consumers via cc_library.defines so any downstream firmware build
+    # picks it up automatically.
+    defines = select({
+        "@platforms//os:none": ["BOOST_SYSTEM_DISABLE_THREADS"],
+        "//conditions:default": [],
+    }),
     deps = [
         ":stringify",
         "@boost//:system",

mjlib/base/error_code.h

@@ -99,3 +99,38 @@ inline std::ostream& operator<<(std::ostream& ostr, const error_code& ec) {
 
 }
 }
+
+// Boost.Asio (>= 1.81) introduced a "disposition" concept used by awaitable
+// completion machinery to convert error-style completion arguments into
+// exceptions. Asio ships a specialisation for boost::system::error_code; for
+// mjlib::base::error_code (a wrapper that adds context messages) we need our
+// own. The trait inherently throws, so it's only available when exceptions
+// are enabled -- e.g. host builds, not embedded firmware.
+#ifdef __cpp_exceptions
+#include <boost/asio/disposition.hpp>
+
+namespace boost {
+namespace asio {
+
+template <>
+struct disposition_traits<mjlib::base::error_code> {
+  static bool not_an_error(const mjlib::base::error_code& ec) noexcept {
+    return !ec;
+  }
+
+  static void throw_exception(const mjlib::base::error_code& ec) {
+    throw boost::system::system_error(ec.boost_error_code(), ec.message());
+  }
+
+  static std::exception_ptr to_exception_ptr(
+      const mjlib::base::error_code& ec) noexcept {
+    return ec
+        ? std::make_exception_ptr(
+              boost::system::system_error(ec.boost_error_code(), ec.message()))
+        : nullptr;
+  }
+};
+
+}
+}
+#endif  // __cpp_exceptions

mjlib/base/json5_write_archive.h

@@ -184,7 +184,7 @@ class Json5WriteArchive : public VisitArchive<Json5WriteArchive> {
     } else if (!std::isfinite(value)) {
       stream_ << (options_.standard ? "null" : "NaN");
     } else {
-      stream_ << fmt::format(format_string, value);
+      stream_ << fmt::format(fmt::runtime(format_string), value);
     }
   }
 

mjlib/io/realtime_executor.h

@@ -17,7 +17,6 @@
 #include <boost/asio/any_io_executor.hpp>
 #include <boost/asio/defer.hpp>
 #include <boost/asio/dispatch.hpp>
-#include <boost/asio/execution/execute.hpp>
 #include <boost/asio/execution_context.hpp>
 #include <boost/asio/post.hpp>
 
@@ -79,8 +78,8 @@ class RealtimeExecutor {
   void execute(Callback&& callback) const {
     Service& s = const_cast<Service&>(service());
     s.StartWork();
-    boost::asio::execution::execute(
-        base_, Wrap<typename std::decay<Callback>::type>(&s, std::move(callback)));
+    base_.execute(
+        Wrap<typename std::decay<Callback>::type>(&s, std::move(callback)));
   }
 
   template <typename Callback, typename Allocator>

tools/workspace/bazel_deps/repository.bzl

@@ -20,6 +20,6 @@ def bazel_deps_repository(name):
     github_archive(
         name = name,
         repo = "mjbots/bazel_deps",
-        commit = "18eeb7e59ab3535ef93c45716313b9a037c972a1",
-        sha256 = "7b5891127d884743d23779f42a2d80dfcea93fe97efb16372495497e19ff8468",
+        commit = "3d32bc0ff10c15bd4b435be8851a3042b6c8911b",
+        sha256 = "e8dadbedebe026834c1a7fd23e1ad5267011e6041813b45d1d63911d58e27438",
     )

tools/workspace/bazel_toolchain/repository.bzl

@@ -20,6 +20,6 @@ def bazel_toolchain_repository():
     github_archive(
         name = "com_github_mjbots_bazel_toolchain",
         repo = "mjbots/bazel-toolchain",
-        commit = "47efd434976067fec4689a3e5cca9859b82b08ec",
-        sha256 = "86428e992ad64e74bca6e388e4dc2846dee8fd8060b1b5cd8dfdc33631ef9103",
+        commit = "9cc9535ef65a9361ba144be54d3f72c19346abf2",
+        sha256 = "54ce65745967b8447c095385d23aca8e56c2ae889d51b61bd2239e450ccb43fd",
     )

tools/workspace/imgui/package.BUILD

@@ -41,6 +41,14 @@ cc_library(
         ],
     }),
     includes = ["."],
+    copts = select({
+        "@com_github_mjbots_bazel_deps//conditions:clang" : [
+            # imgui zero-initializes its own structs with memset/memcpy;
+            # newer clang flags this on non-trivially-copyable types.
+            "-Wno-nontrivial-memcall",
+        ],
+        "//conditions:default" : [],
+    }),
     deps = select({
         "@bazel_tools//src/conditions:windows" : [
         ],