[Core] Optionally delete `Ref` `nullptr` comparisons

Adds an optional (default false) compile option to enable comparing
`Ref` to `nullptr` to ensure correct use, as well as future expandsion
for more general dev checks (enabled with `dev_mode`)

.github/workflows/android_builds.yml

@@ -6,7 +6,7 @@ on:
 env:
   # Used for the cache key. Add version suffix to force clean build.
   GODOT_BASE_BRANCH: master
-  SCONSFLAGS: verbose=yes warnings=extra werror=yes debug_symbols=no module_text_server_fb_enabled=yes
+  SCONSFLAGS: verbose=yes warnings=extra werror=yes debug_symbols=no module_text_server_fb_enabled=yes strict_checks=yes
 
 concurrency:
   group: ci-${{github.actor}}-${{github.head_ref || github.run_number}}-${{github.ref}}-android

.github/workflows/ios_builds.yml

@@ -6,7 +6,7 @@ on:
 env:
   # Used for the cache key. Add version suffix to force clean build.
   GODOT_BASE_BRANCH: master
-  SCONSFLAGS: verbose=yes warnings=extra werror=yes debug_symbols=no module_text_server_fb_enabled=yes
+  SCONSFLAGS: verbose=yes warnings=extra werror=yes debug_symbols=no module_text_server_fb_enabled=yes strict_checks=yes
 
 concurrency:
   group: ci-${{github.actor}}-${{github.head_ref || github.run_number}}-${{github.ref}}-ios

.github/workflows/linux_builds.yml

@@ -6,7 +6,7 @@ on:
 env:
   # Used for the cache key. Add version suffix to force clean build.
   GODOT_BASE_BRANCH: master
-  SCONSFLAGS: verbose=yes warnings=extra werror=yes module_text_server_fb_enabled=yes
+  SCONSFLAGS: verbose=yes warnings=extra werror=yes module_text_server_fb_enabled=yes strict_checks=yes
   DOTNET_NOLOGO: true
   DOTNET_CLI_TELEMETRY_OPTOUT: true
   TSAN_OPTIONS: suppressions=misc/error_suppressions/tsan.txt

.github/workflows/macos_builds.yml

@@ -6,7 +6,7 @@ on:
 env:
   # Used for the cache key. Add version suffix to force clean build.
   GODOT_BASE_BRANCH: master
-  SCONSFLAGS: verbose=yes warnings=extra werror=yes module_text_server_fb_enabled=yes
+  SCONSFLAGS: verbose=yes warnings=extra werror=yes module_text_server_fb_enabled=yes strict_checks=yes
 
 concurrency:
   group: ci-${{github.actor}}-${{github.head_ref || github.run_number}}-${{github.ref}}-macos

.github/workflows/web_builds.yml

@@ -6,7 +6,7 @@ on:
 env:
   # Used for the cache key. Add version suffix to force clean build.
   GODOT_BASE_BRANCH: master
-  SCONSFLAGS: verbose=yes warnings=extra werror=yes debug_symbols=no use_closure_compiler=yes
+  SCONSFLAGS: verbose=yes warnings=extra werror=yes debug_symbols=no use_closure_compiler=yes strict_checks=yes
   EM_VERSION: 3.1.64
   EM_CACHE_FOLDER: "emsdk-cache"
 

.github/workflows/windows_builds.yml

@@ -7,7 +7,7 @@ on:
 env:
   # Used for the cache key. Add version suffix to force clean build.
   GODOT_BASE_BRANCH: master
-  SCONSFLAGS: verbose=yes warnings=extra werror=yes module_text_server_fb_enabled=yes d3d12=yes "angle_libs=${{github.workspace}}/"
+  SCONSFLAGS: verbose=yes warnings=extra werror=yes module_text_server_fb_enabled=yes d3d12=yes strict_checks=yes "angle_libs=${{github.workspace}}/"
   SCONS_CACHE_MSVC_CONFIG: true
 
 concurrency:

SConstruct

@@ -230,7 +230,11 @@ opts.Add("custom_modules", "A list of comma-separated directory paths containing
 opts.Add(BoolVariable("custom_modules_recursive", "Detect custom modules recursively for each specified path.", True))
 
 # Advanced options
-opts.Add(BoolVariable("dev_mode", "Alias for dev options: verbose=yes warnings=extra werror=yes tests=yes", False))
+opts.Add(
+    BoolVariable(
+        "dev_mode", "Alias for dev options: verbose=yes warnings=extra werror=yes tests=yes strict_checks=yes", False
+    )
+)
 opts.Add(BoolVariable("tests", "Build the unit tests", False))
 opts.Add(BoolVariable("fast_unsafe", "Enable unsafe options for faster rebuilds", False))
 opts.Add(BoolVariable("ninja", "Use the ninja backend for faster rebuilds", False))
@@ -262,6 +266,7 @@ opts.Add(
     "",
 )
 opts.Add(BoolVariable("use_precise_math_checks", "Math checks use very precise epsilon (debug option)", False))
+opts.Add(BoolVariable("strict_checks", "Enforce stricter checks (debug option)", False))
 opts.Add(BoolVariable("scu_build", "Use single compilation unit build", False))
 opts.Add("scu_limit", "Max includes per SCU file when using scu_build (determines RAM use)", "0")
 opts.Add(BoolVariable("engine_update_check", "Enable engine update checks in the Project Manager", True))
@@ -602,12 +607,16 @@ if env["dev_mode"]:
     env["warnings"] = ARGUMENTS.get("warnings", "extra")
     env["werror"] = methods.get_cmdline_bool("werror", True)
     env["tests"] = methods.get_cmdline_bool("tests", True)
+    env["strict_checks"] = methods.get_cmdline_bool("strict_checks", True)
 if env["production"]:
     env["use_static_cpp"] = methods.get_cmdline_bool("use_static_cpp", True)
     env["debug_symbols"] = methods.get_cmdline_bool("debug_symbols", False)
     # LTO "auto" means we handle the preferred option in each platform detect.py.
     env["lto"] = ARGUMENTS.get("lto", "auto")
 
+if env["strict_checks"]:
+    env.Append(CPPDEFINES=["STRICT_CHECKS"])
+
 # Run SCU file generation script if in a SCU build.
 if env["scu_build"]:
     max_includes_per_scu = 8

core/object/ref_counted.h

@@ -86,6 +86,11 @@ public:
 	_FORCE_INLINE_ bool operator!=(const T *p_ptr) const {
 		return reference != p_ptr;
 	}
+#ifdef STRICT_CHECKS
+	// Delete these to prevent raw comparisons with `nullptr`.
+	bool operator==(std::nullptr_t) const = delete;
+	bool operator!=(std::nullptr_t) const = delete;
+#endif // STRICT_CHECKS
 
 	_FORCE_INLINE_ bool operator<(const Ref<T> &p_r) const {
 		return reference < p_r.reference;