Fix 32bit tests (#331)

* Fix CheckedBitPattern derive tests on i686.

* Fix try_box_from_bytes test on i686.

* Fix CI

* Add MSRV note to derive feature

Author: zachs18

.github/workflows/rust.yml

@@ -19,7 +19,7 @@ jobs:
         include:
         # versions (all on linux-x86_64)
         - { rust: 1.34.0, os: ubuntu-latest }
-        - { rust: 1.61.0, os: ubuntu-latest }
+        - { rust: 1.68.0, os: ubuntu-latest }
         - { rust: stable, os: ubuntu-latest }
         - { rust: beta, os: ubuntu-latest }
         - { rust: nightly, os: ubuntu-latest }
@@ -38,7 +38,7 @@ jobs:
     - run: cargo test --verbose --no-default-features
     - run: cargo test --verbose
     - run: cargo test --verbose --features derive
-      if: matrix.rust == '1.61.0'
+      if: matrix.rust == '1.68.0'
     - run: cargo test --verbose --all-features
       if: matrix.rust == 'nightly'
     - run: cargo test --verbose --manifest-path=derive/Cargo.toml --all-features

Cargo.toml

@@ -14,7 +14,10 @@ exclude = ["/pedantic.bat", "derive/", "contiguous_bitset/"]
 [features]
 # In v2 we'll fix these names to be more "normal".
 
-# Enable deriving the various `bytemuck` traits.
+# All MSRV notes below are GUIDELINES and future versions may require even more
+# MSRV on any feature.
+
+# MSRV 1.68.0: Enable deriving the various `bytemuck` traits.
 derive = ["bytemuck_derive"]
 # Enable features requiring items from `extern crate alloc`.
 extern_crate_alloc = []
@@ -25,9 +28,6 @@ zeroable_maybe_uninit = []
 # Implement `Zeroable` for `std::sync::atomic` types.
 zeroable_atomics = []
 
-# All MSRV notes below are GUIDELINES and future versions may require even more
-# MSRV on any feature.
-
 # MSRV 1.36: Use `align_offset` method instead of casting to `usize` to check
 # alignment of pointers, this *may* improve codegen in some cases (but it has
 # never been formally benchmarked!)

derive/Cargo.toml

@@ -9,7 +9,7 @@ keywords = ["transmute", "bytes", "casting"]
 categories = ["encoding", "no-std"]
 edition = "2018"
 license = "Zlib OR Apache-2.0 OR MIT"
-rust-version = "1.61"
+rust-version = "1.68"
 #note(lokathor): do not publish with this set
 #resolver = "3"
 

derive/tests/basic.rs

@@ -431,10 +431,16 @@ fn checkedbitpattern_aligned_struct() {
 
 #[test]
 fn checkedbitpattern_c_default_discriminant_enum_with_fields() {
+  // these cfg's *actually* care about align_of::<u64>(), but that is highly
+  // correlated with target pointer width.
+  #[cfg(target_pointer_width = "64")]
   let pod = [
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xcc, 0x55, 0x55, 0x55,
     0x55, 0x55, 0x55, 0xcc,
   ];
+  #[cfg(target_pointer_width = "32")]
+  let pod =
+    [0x00, 0x00, 0x00, 0x00, 0xcc, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0xcc];
   let value = bytemuck::checked::pod_read_unaligned::<
     CheckedBitPatternCDefaultDiscriminantEnumWithFields,
   >(&pod);
@@ -443,10 +449,14 @@ fn checkedbitpattern_c_default_discriminant_enum_with_fields() {
     CheckedBitPatternCDefaultDiscriminantEnumWithFields::A(0xcc555555555555cc)
   );
 
+  #[cfg(target_pointer_width = "64")]
   let pod = [
     0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xcc, 0x55, 0x55, 0x55,
     0x55, 0x55, 0x55, 0xcc,
   ];
+  #[cfg(target_pointer_width = "32")]
+  let pod =
+    [0x01, 0x00, 0x00, 0x00, 0xcc, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0xcc];
   let value = bytemuck::checked::pod_read_unaligned::<
     CheckedBitPatternCDefaultDiscriminantEnumWithFields,
   >(&pod);
@@ -490,19 +500,36 @@ fn checkedbitpattern_int_enum_with_fields() {
 
 #[test]
 fn checkedbitpattern_nested_enum_with_fields() {
-  // total size 24 bytes. first byte always the u8 discriminant.
+  // these cfg's *actually* care about align_of::<u64>(), but that is highly
+  // correlated with target pointer width.
 
+  // total size 24 bytes on 64-bit. first byte always the u8 discriminant.
+  #[cfg(target_pointer_width = "64")]
   #[repr(C, align(8))]
   struct Align8Bytes([u8; 24]);
 
+  // total size 16 bytes on 64-bit. first byte always the u8 discriminant.
+  #[cfg(target_pointer_width = "32")]
+  #[repr(C, align(8))]
+  struct Align8Bytes([u8; 16]);
+
   // first we'll check variantA, nested variant A
-  let pod = Align8Bytes([
+  #[cfg(target_pointer_width = "64")]
+  let mut pod = Align8Bytes([
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x00, // byte 0 discriminant = 0 = variant A, bytes 1-7 irrelevant padding.
     0x00, 0x00, 0x00, 0x00, 0xcc, 0x55, 0x55,
     0xcc, // bytes 8-15 are the nested CheckedBitPatternCEnumWithFields,
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // bytes 16-23 padding
   ]);
+  #[cfg(target_pointer_width = "32")]
+  let mut pod = Align8Bytes([
+    0x00, 0x00, 0x00,
+    0x00, // byte 0 discriminant = 0 = variant A, bytes 1-3 irrelevant padding.
+    0x00, 0x00, 0x00, 0x00, 0xcc, 0x55, 0x55,
+    0xcc, // bytes 4-11 are the nested CheckedBitPatternCEnumWithFields,
+    0x00, 0x00, 0x00, 0x00, // bytes 12-15 padding
+  ]);
   let value =
     bytemuck::checked::from_bytes::<CheckedBitPatternEnumNested>(&pod.0);
   assert_eq!(
@@ -513,18 +540,13 @@ fn checkedbitpattern_nested_enum_with_fields() {
   );
 
   // next we'll check invalid first discriminant fails
-  let pod = Align8Bytes([
-    0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-    0x00, // byte 0 discriminant = 2 = invalid, bytes 1-7 padding
-    0x00, 0x00, 0x00, 0x00, 0xcc, 0x55, 0x55,
-    0xcc, // bytes 8-15 are the nested CheckedBitPatternCEnumWithFields = A,
-    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // bytes 16-23 padding
-  ]);
+  pod.0[0] = 0x02; // set the discriminant
   let result =
     bytemuck::checked::try_from_bytes::<CheckedBitPatternEnumNested>(&pod.0);
   assert_eq!(result, Err(CheckedCastError::InvalidBitPattern));
 
   // next we'll check variant B, nested variant B
+  #[cfg(target_pointer_width = "64")]
   let pod = Align8Bytes([
     0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x00, // byte 0 discriminant = 1 = variant B, bytes 1-7 padding
@@ -533,7 +555,18 @@ fn checkedbitpattern_nested_enum_with_fields() {
            * CheckedBitPatternCDefaultDiscrimimantEnumWithFields, 1 (LE byte
            * order) = variant B */
     0xcc, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-    0xcc, // bytes 16-13 is the data contained in nested variant B
+    0xcc, // bytes 16-23 is the data contained in nested variant B
+  ]);
+  #[cfg(target_pointer_width = "32")]
+  let pod = Align8Bytes([
+    0x01, 0x00, 0x00,
+    0x00, // byte 0 discriminant = 1 = variant B, bytes 1-3 padding
+    0x01, 0x00, 0x00,
+    0x00, /* bytes 4-11 is C int size discriminant of
+           * CheckedBitPatternCDefaultDiscrimimantEnumWithFields, 1 (LE byte
+           * order) = variant B */
+    0xcc, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
+    0xcc, // bytes 12-15 is the data contained in nested variant B
   ]);
   let value =
     bytemuck::checked::from_bytes::<CheckedBitPatternEnumNested>(&pod.0);
@@ -547,6 +580,7 @@ fn checkedbitpattern_nested_enum_with_fields() {
   );
 
   // finally we'll check variant B, nested invalid discriminant
+  #[cfg(target_pointer_width = "64")]
   let pod = Align8Bytes([
     0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x00, // 1 discriminant = variant B, bytes 1-7 padding
@@ -555,7 +589,18 @@ fn checkedbitpattern_nested_enum_with_fields() {
            * CheckedBitPatternCDefaultDiscrimimantEnumWithFields, 0x08 is
            * invalid */
     0xcc, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-    0xcc, // bytes 16-13 is the data contained in nested variant B
+    0xcc, // bytes 16-23 is the data contained in nested variant B
+  ]);
+  #[cfg(target_pointer_width = "32")]
+  let pod = Align8Bytes([
+    0x01, 0x00, 0x00,
+    0x00, // 1 discriminant = variant B, bytes 1-7 padding
+    0x08, 0x00, 0x00,
+    0x00, /* bytes 4-11 is C int size discriminant of
+           * CheckedBitPatternCDefaultDiscrimimantEnumWithFields, 0x08 is
+           * invalid */
+    0xcc, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
+    0xcc, // bytes 12-15 is the data contained in nested variant B
   ]);
   let result =
     bytemuck::checked::try_from_bytes::<CheckedBitPatternEnumNested>(&pod.0);

tests/std_tests.rs

@@ -58,7 +58,7 @@ fn test_try_from_box_bytes() {
 
   // Different layout: target alignment is less than source alignment.
   assert_eq!(
-    try_from_box_bytes::<u32>(Box::new(0u64).into()).map_err(|(x, _)| x),
+    try_from_box_bytes::<u16>(Box::new(0u64).into()).map_err(|(x, _)| x),
     Err(PodCastError::AlignmentMismatch)
   );