🐛 Fix copy ctor and dtor nullptr dereference

Previous changes to inplace_function to reduce memory resulted in a case
where the vtable_ptr_ could be set to nullptr and be dereferenced. This
change checks if vtable_ptr_ is a null reference.

- 🎨 update code to the latest template library standard
- ⬆️ Bump version to 2.0.1

Author: Khalil Estell

conanfile.py

@@ -18,7 +18,6 @@
 from conan.tools.cmake import CMake, cmake_layout
 from conan.tools.files import copy
 from conan.tools.build import check_min_cppstd
-from conan.errors import ConanInvalidConfiguration
 import os
 
 
@@ -27,7 +26,7 @@
 
 class libhal_conan(ConanFile):
     name = "libhal"
-    version = "2.0.0"
+    version = "2.0.1"
     license = "Apache-2.0"
     url = "https://github.com/conan-io/conan-center-index"
     homepage = "https://libhal.github.io/libhal"
@@ -59,19 +58,8 @@ def validate(self):
         if self.settings.get_safe("compiler.cppstd"):
             check_min_cppstd(self, self._min_cppstd)
 
-        def lazy_lt_semver(v1, v2):
-            lv1 = [int(v) for v in v1.split(".")]
-            lv2 = [int(v) for v in v2.split(".")]
-            min_length = min(len(lv1), len(lv2))
-            return lv1[:min_length] < lv2[:min_length]
-
-        compiler = str(self.settings.compiler)
-        version = str(self.settings.compiler.version)
-        minimum_version = self._compilers_minimum_version.get(compiler, False)
-
-        if minimum_version and lazy_lt_semver(version, minimum_version):
-            raise ConanInvalidConfiguration(
-                f"{self.name} {self.version} requires C++{self._min_cppstd}, which your compiler ({compiler}-{version}) does not support")
+    def build_requirements(self):
+        self.tool_requires("cmake/3.27.1")
 
     def requirements(self):
         self.requires("tl-function-ref/1.0.0")
@@ -109,6 +97,8 @@ def package_info(self):
         if self._bare_metal:
             self.cpp_info.defines = [
                 "BOOST_LEAF_EMBEDDED",
+                # TODO(#694): Remove this or have it be configurable. Users
+                # should not be forced to operate without thread support
                 "BOOST_LEAF_NO_THREADS"
             ]
 

demos/libhal.tweaks.hpp

@@ -35,6 +35,10 @@
  *       of the called function will NOT be valid.
  *    4. Move SG14_INPLACE_FUNCTION_THROW is no longer needed and thus
  *       this library no longer needs exceptions.
+ *    5. After removing the `nullptr_t` constructors, there is a new edge case
+ *       where the vtable_ptr_ is now nullptr and not an empty_vtable, which
+ *       means that access to that vtable_ptr_ results in a null pointer
+ *       dereference. A check must be put in the copy ctor and dtor.
  */
 
 #pragma once
@@ -320,7 +324,9 @@ class inplace_function<R(Args...), Capacity, Alignment>
 
   inplace_function& operator=(inplace_function other) noexcept
   {
-    vtable_ptr_->destructor_ptr(std::addressof(storage_));
+    if (vtable_ptr_) {
+      vtable_ptr_->destructor_ptr(std::addressof(storage_));
+    }
 
     vtable_ptr_ = std::exchange(
       other.vtable_ptr_,
@@ -332,7 +338,9 @@ class inplace_function<R(Args...), Capacity, Alignment>
 
   ~inplace_function()
   {
-    vtable_ptr_->destructor_ptr(std::addressof(storage_));
+    if (vtable_ptr_) {
+      vtable_ptr_->destructor_ptr(std::addressof(storage_));
+    }
   }
 
   R operator()(Args... args) const

include/libhal/third_party/inplace_function.hpp

@@ -24,6 +24,9 @@ class TestPackageConan(ConanFile):
     settings = "os", "arch", "compiler", "build_type"
     generators = "CMakeToolchain", "CMakeDeps", "VirtualRunEnv"
 
+    def build_requirements(self):
+        self.tool_requires("cmake/3.27.1")
+
     def requirements(self):
         self.requires(self.tested_reference_str)