Add support for arbitrary

.github/workflows/rust.yml

@@ -49,7 +49,7 @@ jobs:
       run: cargo install cargo-hack
 
     - name: Powerset
-      run: cargo hack test --feature-powerset --lib --optional-deps "std serde" --depth 3 --skip rustc-dep-of-std
+      run: cargo hack test --feature-powerset --lib --optional-deps --depth 3 --skip "compiler_builtins core rustc-dep-of-std"
 
     - name: Docs
       run: cargo doc --features example_generated

Cargo.toml

@@ -21,6 +21,7 @@ exclude = ["tests", ".github"]
 
 [dependencies]
 serde = { version = "1.0", optional = true, default-features = false }
+arbitrary = { version = "1.0", optional = true }
 core = { version = "1.0.0", optional = true, package = "rustc-std-workspace-core" }
 compiler_builtins = { version = "0.1.2", optional = true }
 
@@ -30,6 +31,7 @@ rustversion = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
 serde_test = "1.0"
+arbitrary = { version = "1.0", features = ["derive"] }
 
 [features]
 std = []

src/external.rs

@@ -3,6 +3,9 @@
 #[cfg(feature = "serde")]
 pub mod serde_support;
 
+#[cfg(feature = "arbitrary")]
+pub mod arbitrary_support;
+
 /// Implements traits from external libraries for the internal bitflags type.
 #[macro_export(local_inner_macros)]
 #[doc(hidden)]
@@ -27,6 +30,15 @@ macro_rules! __impl_external_bitflags {
                 )*
             }
         }
+
+        __impl_external_bitflags_arbitrary! {
+            $InternalBitFlags: $T {
+                $(
+                    $(#[$attr $($args)*])*
+                    $Flag;
+                )*
+            }
+        }
     };
 }
 
@@ -80,3 +92,40 @@ macro_rules! __impl_external_bitflags_serde {
         }
     ) => {};
 }
+
+/// Implement `Arbitrary` for the internal bitflags type.
+#[macro_export(local_inner_macros)]
+#[doc(hidden)]
+#[cfg(feature = "arbitrary")]
+macro_rules! __impl_external_bitflags_arbitrary {
+    (
+            $InternalBitFlags:ident: $T:ty {
+                $(
+                    $(#[$attr:ident $($args:tt)*])*
+                    $Flag:ident;
+                )*
+            }
+    ) => {
+        impl<'a> $crate::__private::arbitrary::Arbitrary<'a> for $InternalBitFlags {
+            fn arbitrary(
+                u: &mut $crate::__private::arbitrary::Unstructured<'a>,
+            ) -> $crate::__private::arbitrary::Result<Self> {
+                Self::from_bits(u.arbitrary()?).ok_or_else(|| $crate::__private::arbitrary::Error::IncorrectFormat)
+            }
+        }
+    };
+}
+
+#[macro_export(local_inner_macros)]
+#[doc(hidden)]
+#[cfg(not(feature = "arbitrary"))]
+macro_rules! __impl_external_bitflags_arbitrary {
+    (
+            $InternalBitFlags:ident: $T:ty {
+                $(
+                    $(#[$attr:ident $($args:tt)*])*
+                    $Flag:ident;
+                )*
+            }
+    ) => {};
+}

src/external/arbitrary_support.rs

@@ -0,0 +1,19 @@
+#[cfg(test)]
+mod tests {
+    use arbitrary::Arbitrary;
+
+    bitflags! {
+        #[derive(Arbitrary)]
+        struct Color: u32 {
+            const RED = 0x1;
+            const GREEN = 0x2;
+            const BLUE = 0x4;
+        }
+    }
+
+    #[test]
+    fn test_arbitrary() {
+        let mut unstructured = arbitrary::Unstructured::new(&[0_u8; 256]);
+        let _color = Color::arbitrary(&mut unstructured);
+    }
+}

src/lib.rs

@@ -361,6 +361,9 @@ pub mod __private {
 
     #[cfg(feature = "serde")]
     pub use serde;
+
+    #[cfg(feature = "arbitrary")]
+    pub use arbitrary;
 }
 
 /*