cmake dependency: avoid setting property to None as a workaround

It's an improper object model, but was used to signal to a subclass that
self.traceparser did not exist. However, since it is always initialized
from self.cmakebin, we can just check that instead.

mesonbuild/dependencies/cmake.py

@@ -94,10 +94,6 @@ class CMakeDependency(ExternalDependency):
         super().__init__(DependencyTypeName('cmake'), environment, kwargs, language=language)
         self.name = name
         self.is_libtool = False
-        # Store a copy of the CMake path on the object itself so it is
-        # stored in the pickled coredata and recovered.
-        self.cmakebin:  T.Optional[CMakeExecutor] = None
-        self.cmakeinfo: T.Optional[CMakeInfo] = None
 
         # Where all CMake "build dirs" are located
         self.cmake_root_dir = environment.scratch_dir
@@ -105,14 +101,12 @@ class CMakeDependency(ExternalDependency):
         # T.List of successfully found modules
         self.found_modules: T.List[str] = []
 
-        # Initialize with None before the first return to avoid
-        # AttributeError exceptions in derived classes
-        self.traceparser: T.Optional[CMakeTraceParser] = None
-
+        # Store a copy of the CMake path on the object itself so it is
+        # stored in the pickled coredata and recovered.
+        #
         # TODO further evaluate always using MachineChoice.BUILD
         self.cmakebin = CMakeExecutor(environment, CMakeDependency.class_cmake_version, self.for_machine, silent=self.silent)
         if not self.cmakebin.found():
-            self.cmakebin = None
             msg = f'CMake binary for machine {self.for_machine} not found. Giving up.'
             if self.required:
                 raise DependencyException(msg)

mesonbuild/dependencies/dev.py

@@ -407,7 +407,7 @@ class LLVMDependencyCMake(CMakeDependency):
 
         super().__init__(name, env, kwargs, language='cpp', force_use_global_compilers=True)
 
-        if self.traceparser is None:
+        if not self.cmakebin.found():
             return
 
         if not self.is_found: