v2.4.0-rc0

This is the Cairo version associated with Starknet 0.13.0. Contracts written with 2.4.0 are not declarable on Starknet until the upgrade.

Major Updates

• Added basic byte array formatting:
  • Added core::fmt::Formatter for creating a ByteArray constructively.
  • Added core::fmt::Display and core::fmt::Debug as traits describing how to write a value based on a format string.
  • Added derive for Debug for easy implementation of core::fmt::Debug.
  • Inline macros write! and writeln! - adds to a formatter: write!(f, "format_string({})", value).
  • Inline macro format! - creates a byte array: format!("format_string({})", value).
  • Inline macros print! and println! - prints a format string to stdout for debug: print!("format_string({})", value).
  • Inline macro panic! - panics with a formatted byte array: panic!("format_string({})", value).
  • Inline macro assert! - asserts condition:
    • Panic with the format string if the condition is false: assert!(cond, "format_string({})", value).
    • Panic with the condition as a bytearray if the condition is false: assert!(cond).
  • In test plugin only Inline macro assert_eq! - asserts equality condition: assert_eq!(a, b, "Extra description {}, param");
• Contracts with sierra versions 1.4.0 and up calculate gas usage in a more efficient way.
• Removed need for available_gas in tests not testing specific gas usage - Now using a default large value. (#4172)
  • If testing not using dynamic gas - add #[available_gas(static)] instead.
• Added Cairo Editions, allowing introducing opt-in for features that make break existing code.
  • Currently 2 editions exist: 2023_01 (default) and 2023_10.
• Added prelude (control for which code is in the context for all cairo code).
  • Previously - all the corelib base module was in the context of all cairo code.
  • Now - it is according to edition configured per crate:
    • 2023_01 - The prelude includes all the top level of the corelib as of the state of the corelib at release 2.3.1.
    • 2023_10 - A much smaller subset.
  • Users are encouraged to update their packages to the newest edition.
• Updated ExecutionInfo to be an extended version.

Bug Fixes

• Added support for bool and non copy nullable. #4340
• Raise diagnostic on impl inference cycle. #4367

Optimizations

• Removing extra store temps happening before store locals. #4173
• Added cast for signed integers. #3623
• Changed bytes31 casts to use libfunc upcast. #4098
• Accessing a member of a struct does not cause all the struct to be stored. #4263
• Avoid storing zero sized objects on the stack. #4290
• Adding Zero-Sized handling in the Sierra-to-casm compiler for better stack merging capabilities, and more efficient casm.

New Features

• Added libfunc for efficient u256 inv_mod_n. #3603
• Added Nullable deref_or method by @enitrat in #4037
• Added Option unwrap_or and unwrap_default by @Eikix in #4203
• Added append_array to Array. #4260
• Added match_nullable_snapshot. #4253
• Testing #[should_panic(expected: 'error')] supported - no need for wrapping ( ) in the case of a single var.
• Testing #[should_panic(expected: "error")] supported - for testing panicking with byte array.
• Add verify_signature function for secp curves. #4120
• Zero and One traits by @enitrat in #4254
• Support match on felt252 continuous from 0 and on values. #4284
• Skip attributes with no related item, getting better diagnostics for later code. #4296
• Added plugin suites. #4349
• Better compiler performance by avoiding data copies. #4244
• Caching compiler parser actions. #4247
• Allocate arguments before return values, generating more easily read Sierra code. #4258
• Move literal values validation to parser. #4295
• Made inline macro plugins point to the inner syntax, Improving diagnostics. #4345

Others

• docs: fix typo by @shuoer86 in #4235
• fix typos by @vuittont60 in #4264
• Remove redundent diagnostics for inline macros. #4346

New Contributors

• @shuoer86 made their first contribution in #4235
• @Eikix made their first contribution in #4203
• @vuittont60 made their first contribution in #4264

Full Changelog: v2.3.1...v2.4.0-rc0