Made arrays never encode their length

[VictorKoenders]

Closes #613

Turns out serde never encodes a fixed array length with 32 elements or less. If an array is 33 elements or more, it silently falls back to the &[T] implementation (which does encode the length). Our test cases were only tested with large arrays.

Because the config flags write_fixed_array_length and skip_fixed_array_length were based on a wrong assumption on how serde/bincode 1 worked, these flags have been removed. They may be re-added in the future.

[codecov]

Codecov Report

Patch coverage: 84.61% and project coverage change: +0.48 🎉

Comparison is base (ebc3b6b) 53.89% compared to head (c9fd18d) 54.37%.

Additional details and impacted files

@@            Coverage Diff             @@
##            trunk     #625      +/-   ##
==========================================
+ Coverage   53.89%   54.37%   +0.48%     
==========================================
  Files          51       51              
  Lines        4457     4454       -3     
==========================================
+ Hits         2402     2422      +20     
+ Misses       2055     2032      -23     

Impacted Files	Coverage Δ
src/de/impls.rs	59.77% <ø> (+1.53%)	⬆️
src/enc/impls.rs	88.77% <ø> (-0.12%)	⬇️
src/features/serde/de_borrowed.rs	20.61% <ø> (-0.18%)	⬇️
src/features/serde/de_owned.rs	76.61% <ø> (+1.99%)	⬆️
src/features/serde/mod.rs	30.43% <ø> (-17.40%)	⬇️
src/features/serde/ser.rs	76.72% <ø> (+2.53%)	⬆️
compatibility/src/lib.rs	50.00% <40.00%> (-1.79%)	⬇️
tests/utils.rs	47.36% <52.94%> (+2.13%)	⬆️
src/config.rs	78.94% <87.50%> (-3.67%)	⬇️
compatibility/src/misc.rs	100.00% <100.00%> (ø)
... and 3 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[TommyLike]

@VictorKoenders hello, I use bincode in my project as below:

 signed.write_all(&bincode::encode_to_vec(
            &sig_struct,
            config::standard()
                .skip_fixed_array_length()
                .with_fixed_int_encoding()
                .with_big_endian(),
        )?)?;

it works well for the version of bincode = "2.0.0-rc.2" but when upgrade into rc.3 I found the skip_fixed_array_length has been removed, so what should I do for now, How to remove the length when serializing?

[VictorKoenders]

@TommyLike currently there is no such option. Bincode 1 and 2 should work as you'd expect without the configuration. Is there a particular issue you're running into?

[TommyLike]

@TommyLike currently there is no such option. Bincode 1 and 2 should work as you'd expect without the configuration. Is there a particular issue you're running into?

No, I realized it works as I expected, thanks!