zvariant v3.14.0: test failures on 32-bit x86 (i686-unknown-linux-gnu)

[decathorpe]

With the most recent release, the dev-dependency on a git snapshot of the glib crate was replaced with a normal dependency, which allowed me to run test suite of zvariant during package builds for Fedora Linux - which in turn has surfaced a few test failures on 32-bit x86 (i.e. i686).

This is the output (truncated to only --lib results, doc-tests all passed) from cargo test --release (with a few more distro-specific flags which should not affect results):

running 37 tests
(...)
failures:
---- tests::dict_value stdout ----
[src/lib.rs:1027] encoded.len() = 40
thread 'tests::dict_value' panicked at 'no entry found for key', src/lib.rs:1047:24
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
---- tests::f64_value stdout ----
thread 'tests::f64_value' panicked at 'assertion failed: (decode_with_gvariant::<_, f64>(encoded) - -5.759340900185448e-128).abs() <\n    f64::EPSILON', src/lib.rs:391:13
---- tests::i32_value stdout ----
thread 'tests::i32_value' panicked at 'assertion failed: `(left == right)`
  left: `-180071088`,
 right: `1347765493`', src/lib.rs:364:13
---- tests::i16_value stdout ----
thread 'tests::i16_value' panicked at 'assertion failed: `(left == right)`
  left: `-2736`,
 right: `20725`', src/lib.rs:342:13
---- tests::i64_value stdout ----
thread 'tests::i64_value' panicked at 'assertion failed: `(left == right)`
  left: `-773399484024203952`,
 right: `5788608029063988469`', src/lib.rs:377:13
---- tests::option_value stdout ----
thread 'tests::option_value' panicked at 'assertion failed: `(left == right)`
  left: `Some(4096)`,
 right: `Some(16)`', src/lib.rs:1580:9
---- tests::u32_value stdout ----
thread 'tests::u32_value' panicked at 'assertion failed: `(left == right)`
  left: `2881137594`,
 right: `3131816619`', src/lib.rs:353:13
---- tests::u16_value stdout ----
thread 'tests::u16_value' panicked at 'assertion failed: `(left == right)`
  left: `43962`,
 right: `47787`', src/lib.rs:331:13
failures:
    tests::dict_value
    tests::f64_value
    tests::i16_value
    tests::i32_value
    tests::i64_value
    tests::option_value
    tests::u16_value
    tests::u32_value
test result: FAILED. 29 passed; 8 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

It's not easy to reproduce this on a x86_64 host system because you need a cross-compiler setup for 32-bit GLib, but I can try to provide reproducing steps that use containers / VMs of some sort if that helps.

[zeenix]

@decathorpe Ooh interesting. Thanks so much for filing these. Obviously I never tested on 32-bit machines. 😆 I'll check it out..

[zeenix]

This is very strange. It seems the bytes are being read as big endian by glib, which uses the host endian. If this was just i686 machine, the native encoding should be little endian. 🤔

[zeenix]

Ah, I know what happened. You mixed up the error message of this issue with #358. 😆

[zeenix]

Ah, I know what happened. You mixed up the error message of this issue with #358. laughing

Assuming this is the case, #362 should fix both the issues you filed. Please test and let me know. 🙏

[decathorpe]

Oh, this is embarassing. You're indeed right. I had both logs open in browser tabs and pasted the wrong one into the issues. :( I'll test the PR, and report back.

[decathorpe]

I can confirm that this PR fixes the failure I saw on i686.

[zeenix]

It's ok. It happens. 😊

Thanks for testing! I wish there was an i686 runner available from GH.