Add #[non_exhaustive] to most public enums

Additionally, utilizes the `clippy::exhaustive_enums` lint to prevent
new exhaustive ones from appearing in the public interface.

This makes it non-breaking to add new variants to enums that aren't
intended to be exhaustively matched on.

Author: chitoyuu

gdnative-async/src/lib.rs

@@ -6,6 +6,8 @@
 //!
 //! This crate assumes that all user non-Rust code follow the official threading guidelines.
 
+#![warn(clippy::exhaustive_enums)]
+
 // Workaround for macros that expect the `gdnative` crate.
 extern crate gdnative_core as gdnative;
 

gdnative-core/src/core_types/error.rs

@@ -5,6 +5,7 @@ use crate::sys;
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[repr(u32)]
+#[non_exhaustive]
 pub enum GodotError {
     Failed = sys::godot_error_GODOT_FAILED as u32,
     Unavailable = sys::godot_error_GODOT_ERR_UNAVAILABLE as u32,

gdnative-core/src/core_types/geom/rect2.rs

@@ -267,6 +267,7 @@ pub struct MarginError(i64);
 ///
 /// [margin]: https://docs.godotengine.org/en/stable/classes/class_%40globalscope.html#enum-globalscope-margin
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[non_exhaustive]
 pub enum Margin {
     Left,
     Top,

gdnative-core/src/core_types/string.rs

@@ -390,6 +390,7 @@ pub struct GodotChar(libc::wchar_t);
 
 /// Error indicating that a `GodotChar` cannot be converted to a `char`.
 #[derive(Debug)]
+#[non_exhaustive]
 pub enum GodotCharError {
     /// The character cannot be represented as a Unicode code point.
     InvalidCodePoint,

gdnative-core/src/core_types/variant.rs

@@ -81,6 +81,7 @@ macro_rules! decl_variant_type {
     ) => {
         #[repr(u32)]
         #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+        #[non_exhaustive]
         pub enum VariantType {
             $(
                 $variant = $c_const as u32,
@@ -99,6 +100,7 @@ macro_rules! decl_variant_type {
         /// For `Variant`s containing objects, the original `Variant` is returned unchanged, due to
         /// the limitations of statically-determined memory management.
         #[repr(u32)]
+        #[non_exhaustive]
         pub enum VariantDispatch {
             $(
                 $variant $( ($inner) )?,
@@ -186,6 +188,7 @@ impl VariantType {
 #[allow(clippy::unnecessary_cast)] // False positives: casts necessary for cross-platform
 #[repr(u32)]
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[non_exhaustive]
 pub enum CallError {
     InvalidMethod =
         sys::godot_variant_call_error_error_GODOT_CALL_ERROR_CALL_ERROR_INVALID_METHOD as u32,
@@ -236,6 +239,7 @@ impl std::error::Error for CallError {}
 #[allow(clippy::unnecessary_cast)] // False positives: casts necessary for cross-platform
 #[repr(u32)]
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[non_exhaustive]
 pub enum VariantOperator {
     // Comparison
     Equal = sys::godot_variant_operator_GODOT_VARIANT_OP_EQUAL as u32,
@@ -856,6 +860,7 @@ pub trait CoerceFromVariant: Sized + private::Sealed {
 }
 
 #[derive(Clone, PartialEq, Eq, Debug)]
+#[non_exhaustive]
 /// Error type returned by `FromVariant::from_variant`.
 pub enum FromVariantError {
     /// An unspecified error.
@@ -924,11 +929,13 @@ pub enum FromVariantError {
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[non_exhaustive]
 pub enum VariantEnumRepr {
     ExternallyTagged,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[non_exhaustive]
 pub enum VariantStructRepr {
     Unit,
     Tuple,

gdnative-core/src/core_types/vector3.rs

@@ -15,7 +15,10 @@ pub struct Vector3 {
     pub z: f32,
 }
 
-#[allow(clippy::unnecessary_cast)] // False positives: casts necessary for cross-platform
+#[allow(
+    clippy::unnecessary_cast, // False positives: casts necessary for cross-platform
+    clippy::exhaustive_enums, // explicitly exhaustive since there can't be more axes for Vector3
+)]
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 #[repr(u32)]
 pub enum Axis {

gdnative-core/src/export/method.rs

@@ -97,6 +97,7 @@ type ScriptMethodFn = unsafe extern "C" fn(
 ) -> sys::godot_variant;
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+#[non_exhaustive]
 pub enum RpcMode {
     Disabled,
     Remote,
@@ -483,6 +484,7 @@ varargs_into_tuple!(A, B, C, D, E, F, G, H, I, J, K, L);
 /// For methods that return this error, see [`Varargs::check_length()`], [`Varargs::get()`] or [`Varargs::get_opt()`].
 /// Another context where this type is used is when destructuring `Varargs` into tuples.
 #[derive(Debug)]
+#[non_exhaustive]
 pub enum VarargsError {
     /// At least one argument type mismatches.
     InvalidArgumentType {

gdnative-core/src/export/property/hint.rs

@@ -145,6 +145,7 @@ impl EnumHint {
 
 /// Possible hints for integers.
 #[derive(Clone, Debug)]
+#[non_exhaustive]
 pub enum IntHint<T> {
     /// Hints that an integer or float property should be within a range.
     Range(RangeHint<T>),
@@ -260,6 +261,7 @@ impl ExpEasingHint {
 
 /// Possible hints for floats.
 #[derive(Clone, Debug)]
+#[non_exhaustive]
 pub enum FloatHint<T> {
     /// Hints that an integer or float property should be within a range.
     Range(RangeHint<T>),
@@ -325,6 +327,7 @@ impl<T> From<ExpEasingHint> for FloatHint<T> {
 
 /// Possible hints for strings.
 #[derive(Clone, Debug)]
+#[non_exhaustive]
 pub enum StringHint {
     /// Hints that an integer, float or string property is an enumerated value to pick in a list.
     Enum(EnumHint),
@@ -373,6 +376,7 @@ impl StringHint {
 
 /// Possible hints for `Color`.
 #[derive(Clone, Debug)]
+#[non_exhaustive]
 pub enum ColorHint {
     /// Hints that a color property should be edited without changing its alpha component.
     NoAlpha,

gdnative-core/src/export/user_data.rs

@@ -165,6 +165,7 @@ pub type DefaultUserData<T> = LocalCellData<T>;
 
 /// Error type indicating that an operation can't fail.
 #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
+#[allow(clippy::exhaustive_enums)] // explicitly uninhabited
 pub enum Infallible {}
 
 impl std::fmt::Display for Infallible {
@@ -186,6 +187,7 @@ impl std::fmt::Display for Infallible {
 /// As there is no universal way to deal with such situations, behavior of locking wrappers can
 /// be customized using this enum.
 #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
+#[non_exhaustive]
 pub enum DeadlockPolicy {
     /// Block on all locks. Deadlocks are possible.
     Allow,
@@ -223,6 +225,7 @@ impl LockOptions for DefaultLockPolicy {
 
 /// Error indicating that a lock wasn't obtained.
 #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
+#[non_exhaustive]
 pub enum LockFailed {
     Pessimistic,
     Timeout(Duration),
@@ -562,6 +565,7 @@ mod local_cell {
 
     /// Error indicating that a borrow has failed.
     #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
+    #[non_exhaustive]
     pub enum LocalCellError {
         DifferentThread {
             original: ThreadId,

gdnative-core/src/lib.rs

@@ -19,7 +19,7 @@
 //!
 //! [thread-safety]: https://docs.godotengine.org/en/stable/tutorials/threads/thread_safe_apis.html
 
-#![deny(clippy::missing_inline_in_public_items)]
+#![warn(clippy::missing_inline_in_public_items, clippy::exhaustive_enums)]
 #![allow(
     clippy::transmute_ptr_to_ptr,
     clippy::missing_safety_doc,