test failures on 32bit architectures

[alexanderkjall]

Hi, it seems that the isize/usize tests fails on i386, as can be seen here: https://ci.debian.net/data/autopkgtest/testing/i386/r/rust-borsh/64940473/log.gz

The failures are:

429s failures:
429s 
429s ---- roundtrip::test_primitives::test_isize_max stdout ----
429s ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Snapshot Summary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
429s Snapshot file: tests/roundtrip/snapshots/tests__roundtrip__test_primitives__isize_max.snap
429s Snapshot: isize_max
429s Source: tests/roundtrip/test_primitives.rs:21
429s ────────────────────────────────────────────────────────────────────────────────
429s Expression: buf
429s ────────────────────────────────────────────────────────────────────────────────
429s -old snapshot
429s +new results
429s ────────────┬───────────────────────────────────────────────────────────────────
429s     1     1 │ [
429s     2     2 │     255,
429s     3     3 │     255,
429s     4     4 │     255,
429s     5       │-    255,
429s     6       │-    255,
429s     7       │-    255,
429s     8       │-    255,
429s     9     5 │     127,
429s           6 │+    0,
429s           7 │+    0,
429s           8 │+    0,
429s           9 │+    0,
429s    10    10 │ ]
429s ────────────┴───────────────────────────────────────────────────────────────────
429s 
429s thread 'roundtrip::test_primitives::test_isize_max' panicked at tests/roundtrip/test_primitives.rs:21:1:
429s called `Result::unwrap()` on an `Err` value: FileIo(Os { code: 13, kind: PermissionDenied, message: "Permission denied" }, "/usr/share/cargo/registry/borsh-1.5.7/tests/roundtrip/snapshots/tests__roundtrip__test_primitives__isize_max.snap.new")
429s stack backtrace:
429s    0: __rustc::rust_begin_unwind
429s              at /usr/src/rustc-1.87.0/library/std/src/panicking.rs:697:5
429s    1: core::panicking::panic_fmt
429s              at /usr/src/rustc-1.87.0/library/core/src/panicking.rs:75:14
429s    2: core::result::unwrap_failed
429s              at /usr/src/rustc-1.87.0/library/core/src/result.rs:1704:5
429s    3: core::result::Result<T,E>::unwrap
429s              at /usr/src/rustc-1.87.0/library/core/src/result.rs:1109:23
429s    4: tests::roundtrip::test_primitives::test_isize_max
429s              at ./tests/roundtrip/test_primitives.rs:11:13
429s    5: tests::roundtrip::test_primitives::test_isize_max::{{closure}}
429s              at ./tests/roundtrip/test_primitives.rs:6:24
429s    6: core::ops::function::FnOnce::call_once
429s              at /usr/src/rustc-1.87.0/library/core/src/ops/function.rs:250:5
429s    7: core::ops::function::FnOnce::call_once
429s              at /usr/src/rustc-1.87.0/library/core/src/ops/function.rs:250:5
429s note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
429s 
429s ---- roundtrip::test_primitives::test_isize_min stdout ----
429s ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Snapshot Summary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
429s Snapshot file: tests/roundtrip/snapshots/tests__roundtrip__test_primitives__isize_min.snap
429s Snapshot: isize_min
429s Source: tests/roundtrip/test_primitives.rs:20
429s ────────────────────────────────────────────────────────────────────────────────
429s Expression: buf
429s ────────────────────────────────────────────────────────────────────────────────
429s -old snapshot
429s +new results
429s ────────────┬───────────────────────────────────────────────────────────────────
429s     1     1 │ [
429s     2     2 │     0,
429s     3     3 │     0,
429s     4     4 │     0,
429s     5       │-    0,
429s     6       │-    0,
429s     7       │-    0,
429s     8       │-    0,
429s     9     5 │     128,
429s           6 │+    255,
429s           7 │+    255,
429s           8 │+    255,
429s           9 │+    255,
429s    10    10 │ ]
429s ────────────┴───────────────────────────────────────────────────────────────────
429s 
429s thread 'roundtrip::test_primitives::test_isize_min' panicked at tests/roundtrip/test_primitives.rs:20:1:
429s called `Result::unwrap()` on an `Err` value: FileIo(Os { code: 13, kind: PermissionDenied, message: "Permission denied" }, "/usr/share/cargo/registry/borsh-1.5.7/tests/roundtrip/snapshots/tests__roundtrip__test_primitives__isize_min.snap.new")
429s stack backtrace:
429s    0: __rustc::rust_begin_unwind
429s              at /usr/src/rustc-1.87.0/library/std/src/panicking.rs:697:5
429s    1: core::panicking::panic_fmt
429s              at /usr/src/rustc-1.87.0/library/core/src/panicking.rs:75:14
429s    2: core::result::unwrap_failed
429s              at /usr/src/rustc-1.87.0/library/core/src/result.rs:1704:5
429s    3: core::result::Result<T,E>::unwrap
429s              at /usr/src/rustc-1.87.0/library/core/src/result.rs:1109:23
429s    4: tests::roundtrip::test_primitives::test_isize_min
429s              at ./tests/roundtrip/test_primitives.rs:11:13
429s    5: tests::roundtrip::test_primitives::test_isize_min::{{closure}}
429s              at ./tests/roundtrip/test_primitives.rs:6:24
429s    6: core::ops::function::FnOnce::call_once
429s              at /usr/src/rustc-1.87.0/library/core/src/ops/function.rs:250:5
429s    7: core::ops::function::FnOnce::call_once
429s              at /usr/src/rustc-1.87.0/library/core/src/ops/function.rs:250:5
429s note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
429s 
429s ---- roundtrip::test_primitives::test_usize_max stdout ----
429s ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Snapshot Summary ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
429s Snapshot file: tests/roundtrip/snapshots/tests__roundtrip__test_primitives__usize_max.snap
429s Snapshot: usize_max
429s Source: tests/roundtrip/test_primitives.rs:25
429s ────────────────────────────────────────────────────────────────────────────────
429s Expression: buf
429s ────────────────────────────────────────────────────────────────────────────────
429s -old snapshot
429s +new results
429s ────────────┬───────────────────────────────────────────────────────────────────
429s     2     2 │     255,
429s     3     3 │     255,
429s     4     4 │     255,
429s     5     5 │     255,
429s     6       │-    255,
429s     7       │-    255,
429s     8       │-    255,
429s     9       │-    255,
429s           6 │+    0,
429s           7 │+    0,
429s           8 │+    0,
429s           9 │+    0,
429s    10    10 │ ]
429s ────────────┴───────────────────────────────────────────────────────────────────
429s 
429s thread 'roundtrip::test_primitives::test_usize_max' panicked at tests/roundtrip/test_primitives.rs:25:1:
429s called `Result::unwrap()` on an `Err` value: FileIo(Os { code: 13, kind: PermissionDenied, message: "Permission denied" }, "/usr/share/cargo/registry/borsh-1.5.7/tests/roundtrip/snapshots/tests__roundtrip__test_primitives__usize_max.snap.new")
429s stack backtrace:
429s    0: __rustc::rust_begin_unwind
429s              at /usr/src/rustc-1.87.0/library/std/src/panicking.rs:697:5
429s    1: core::panicking::panic_fmt
429s              at /usr/src/rustc-1.87.0/library/core/src/panicking.rs:75:14
429s    2: core::result::unwrap_failed
429s              at /usr/src/rustc-1.87.0/library/core/src/result.rs:1704:5
429s    3: core::result::Result<T,E>::unwrap
429s              at /usr/src/rustc-1.87.0/library/core/src/result.rs:1109:23
429s    4: tests::roundtrip::test_primitives::test_usize_max
429s              at ./tests/roundtrip/test_primitives.rs:11:13
429s    5: tests::roundtrip::test_primitives::test_usize_max::{{closure}}
429s              at ./tests/roundtrip/test_primitives.rs:6:24
429s    6: core::ops::function::FnOnce::call_once
429s              at /usr/src/rustc-1.87.0/library/core/src/ops/function.rs:250:5
429s    7: core::ops::function::FnOnce::call_once
429s              at /usr/src/rustc-1.87.0/library/core/src/ops/function.rs:250:5
429s note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
429s 
429s 
429s failures:
429s     roundtrip::test_primitives::test_isize_max
429s     roundtrip::test_primitives::test_isize_min
429s     roundtrip::test_primitives::test_usize_max
429s 
429s test result: FAILED. 92 passed; 3 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.24s

I tried to look at the test code, but didn't see what was wrong. Would you say that this is just a test failure, or do this expose a bug?

[frol]

isize/usize are platform-dependent types, and as such min/max values are different. Even though borsh serializes isize/usize as i64/u64 regardless of the platform, isize::min_value(), isize::max_value(), and usize::max_value() are different on x32, which is why you see the difference. There is no bug in the serialization/deserialization.

It would be nice to improve the tests to test i32::max/min on both x32 & x64, and i64::max/min for x64 only. @alexanderkjall Would you like to contribute the improvements to the test suite?