use ALIGN for Push::alignment in struct types (#8398)

* use ALIGN for Push::alignment in struct types

* regenerate and add a test for struct alignment

rust/flatbuffers/src/lib.rs

@@ -52,7 +52,7 @@ pub use crate::builder::{Allocator, DefaultAllocator, FlatBufferBuilder};
 pub use crate::endian_scalar::{emplace_scalar, read_scalar, read_scalar_at, EndianScalar};
 pub use crate::follow::{Follow, FollowStart};
 pub use crate::primitives::*;
-pub use crate::push::Push;
+pub use crate::push::{Push, PushAlignment};
 pub use crate::table::{buffer_has_identifier, Table};
 pub use crate::vector::{follow_cast_ref, Vector, VectorIter};
 pub use crate::verifier::{

samples/rust_generated/my_game/sample/vec_3_generated.rs

@@ -50,6 +50,10 @@ impl<'b> flatbuffers::Push for Vec3 {
         let src = ::core::slice::from_raw_parts(self as *const Vec3 as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Vec3 {

src/idl_gen_rust.cpp

@@ -2703,6 +2703,10 @@ class RustGenerator : public BaseGenerator {
         "{{STRUCT_TY}} as *const u8, Self::size());";
     code_ += "        dst.copy_from_slice(src);";
     code_ += "    }";
+    code_ += "    #[inline]";
+    code_ += "    fn alignment() -> flatbuffers::PushAlignment {";
+    code_ += "        flatbuffers::PushAlignment::new({{ALIGN}})";
+    code_ += "    }";
     code_ += "}";
     code_ += "";
 

tests/arrays_test/my_game/example/array_struct_generated.rs

@@ -53,6 +53,10 @@ impl<'b> flatbuffers::Push for ArrayStruct {
         let src = ::core::slice::from_raw_parts(self as *const ArrayStruct as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(8)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for ArrayStruct {

tests/arrays_test/my_game/example/nested_struct_generated.rs

@@ -51,6 +51,10 @@ impl<'b> flatbuffers::Push for NestedStruct {
         let src = ::core::slice::from_raw_parts(self as *const NestedStruct as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(8)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for NestedStruct {

tests/include_test1/my_game/other_name_space/unused_generated.rs

@@ -48,6 +48,10 @@ impl<'b> flatbuffers::Push for Unused {
         let src = ::core::slice::from_raw_parts(self as *const Unused as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Unused {

tests/include_test2/my_game/other_name_space/unused_generated.rs

@@ -48,6 +48,10 @@ impl<'b> flatbuffers::Push for Unused {
         let src = ::core::slice::from_raw_parts(self as *const Unused as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Unused {

tests/monster_test/my_game/example/ability_generated.rs

@@ -49,6 +49,10 @@ impl<'b> flatbuffers::Push for Ability {
         let src = ::core::slice::from_raw_parts(self as *const Ability as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Ability {

tests/monster_test/my_game/example/struct_of_structs_generated.rs

@@ -50,6 +50,10 @@ impl<'b> flatbuffers::Push for StructOfStructs {
         let src = ::core::slice::from_raw_parts(self as *const StructOfStructs as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for StructOfStructs {

tests/monster_test/my_game/example/struct_of_structs_of_structs_generated.rs

@@ -48,6 +48,10 @@ impl<'b> flatbuffers::Push for StructOfStructsOfStructs {
         let src = ::core::slice::from_raw_parts(self as *const StructOfStructsOfStructs as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for StructOfStructsOfStructs {

tests/monster_test/my_game/example/test_generated.rs

@@ -49,6 +49,10 @@ impl<'b> flatbuffers::Push for Test {
         let src = ::core::slice::from_raw_parts(self as *const Test as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(2)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Test {

tests/monster_test/my_game/example/vec_3_generated.rs

@@ -53,6 +53,10 @@ impl<'b> flatbuffers::Push for Vec3 {
         let src = ::core::slice::from_raw_parts(self as *const Vec3 as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(8)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Vec3 {

tests/monster_test/my_game/other_name_space/unused_generated.rs

@@ -48,6 +48,10 @@ impl<'b> flatbuffers::Push for Unused {
         let src = ::core::slice::from_raw_parts(self as *const Unused as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Unused {

tests/monster_test_serialize/my_game/example/ability_generated.rs

@@ -51,6 +51,10 @@ impl<'b> flatbuffers::Push for Ability {
         let src = ::core::slice::from_raw_parts(self as *const Ability as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Ability {

tests/monster_test_serialize/my_game/example/struct_of_structs_generated.rs

@@ -52,6 +52,10 @@ impl<'b> flatbuffers::Push for StructOfStructs {
         let src = ::core::slice::from_raw_parts(self as *const StructOfStructs as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for StructOfStructs {

tests/monster_test_serialize/my_game/example/struct_of_structs_of_structs_generated.rs

@@ -50,6 +50,10 @@ impl<'b> flatbuffers::Push for StructOfStructsOfStructs {
         let src = ::core::slice::from_raw_parts(self as *const StructOfStructsOfStructs as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for StructOfStructsOfStructs {

tests/monster_test_serialize/my_game/example/test_generated.rs

@@ -51,6 +51,10 @@ impl<'b> flatbuffers::Push for Test {
         let src = ::core::slice::from_raw_parts(self as *const Test as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(2)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Test {

tests/monster_test_serialize/my_game/example/vec_3_generated.rs

@@ -55,6 +55,10 @@ impl<'b> flatbuffers::Push for Vec3 {
         let src = ::core::slice::from_raw_parts(self as *const Vec3 as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(8)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Vec3 {

tests/monster_test_serialize/my_game/other_name_space/unused_generated.rs

@@ -50,6 +50,10 @@ impl<'b> flatbuffers::Push for Unused {
         let src = ::core::slice::from_raw_parts(self as *const Unused as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Unused {

tests/namespace_test/namespace_a/namespace_b/struct_in_nested_ns_generated.rs

@@ -49,6 +49,10 @@ impl<'b> flatbuffers::Push for StructInNestedNS {
         let src = ::core::slice::from_raw_parts(self as *const StructInNestedNS as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for StructInNestedNS {

tests/private_annotation_test/object_generated.rs

@@ -48,6 +48,10 @@ impl<'b> flatbuffers::Push for Object {
         let src = ::core::slice::from_raw_parts(self as *const Object as *const u8, Self::size());
         dst.copy_from_slice(src);
     }
+    #[inline]
+    fn alignment() -> flatbuffers::PushAlignment {
+        flatbuffers::PushAlignment::new(4)
+    }
 }
 
 impl<'a> flatbuffers::Verifiable for Object {

tests/rust_usage_test/tests/integration_test.rs

@@ -2422,6 +2422,14 @@ mod push_impls {
                     0, 0, 0, 0,
                     0, 0, 0, 1]);
     }
+
+    #[test]
+    fn push_u8_generated_struct_alignment() {
+        let mut b = flatbuffers::FlatBufferBuilder::new();
+        b.push(1u8);
+        b.push(my_game::example::Test::new(10, 20));
+        check(&b, &[10, 0, 20, 0, 0, 1]);
+    }
 }
 
 #[cfg(test)]