Release v4.0.0 alpha.2

[ascjones]

Version 4.0.0-alpha.2

Breaking Changes

New ink crate

The ink_lang crate has been replaced in #1223 by a new top level ink
crate. All existing sub-crates are reexported and should be used via the new ink crate, so e.g. ink::env instead of
ink_env. Contract authors should now import the top level ink crate instead of the individual crates.

Migration

• In Cargo.toml Replace all individual ink_* crate dependencies with the ink crate.
• In the contract source:
  • Remove the commonly used use ink_lang as ink idiom.
  • Replace all usages of individual crates with reexports, e.g. ink_env ➜ ink::env.

Storage Rework

#1331 changes the way ink! works with contract storage. Storage keys
are generated at compile-time, and user facing abstractions which determine how contract data is laid out in storage
have changed.

Migration

• Initialize Mapping fields with Mapping::default() instead of ink_lang::utils::initialize_contract in
  constructors. See erc20 and other examples which use a Mapping.
• Remove SpreadAllocate, SpreadLayout and PackedLayout implementations.

Removal of wee-alloc support

ink! uses a bump allocator by default, additionally we supported another allocator (wee-alloc)
through a feature flag. wee-alloc is no longer maintained and we removed support for it.

Changed

• Introduce ink entrance crate ‒ #1223
• Use XXH32 instead of sha256 for calculating storage keys ‒ #1393

Fixed

• Trim single whitespace prefix in the metadata docs field ‒ #1385
• Allow pay_with_call to take multiple arguments ‒ #1401

Added

• Add ink_env::pay_with_call! helper macro for off-chain emulation of sending payments with contract message calls ‒ #1379

Removed

• Remove wee-alloc ‒ #1403

[cmichi]

Please include the suggestions I made, other than that 👍 .

[HCastano]

Small thing, can we make sure #1401 gets in to the release?

[ascjones]

Small thing, can we make sure #1401 gets in to the release?

Sure, I will pick this up again tomorrow and include that

[codecov-commenter]

Codecov Report

Merging #1408 (8841505) into master (b04f097) will decrease coverage by 5.82%.
The diff coverage is n/a.

❗ Current head 8841505 differs from pull request most recent head 1da9af9. Consider uploading reports for the commit 1da9af9 to get more accurate results

@@            Coverage Diff             @@
##           master    #1408      +/-   ##
==========================================
- Coverage   71.98%   66.15%   -5.83%     
==========================================
  Files         187      186       -1     
  Lines        5953     5927      -26     
==========================================
- Hits         4285     3921     -364     
- Misses       1668     2006     +338     

Impacted Files	Coverage Δ
crates/ink/ir/src/ir/contract.rs	0.00% <0.00%> (-100.00%)	⬇️
crates/ink/ir/src/ir/ink_test.rs	0.00% <0.00%> (-87.50%)	⬇️
crates/ink/ir/src/ir/trait_def/mod.rs	0.00% <0.00%> (-83.34%)	⬇️
crates/ink/ir/src/ir/storage_item/config.rs	0.00% <0.00%> (-73.34%)	⬇️
crates/ink/ir/src/ir/storage_item/mod.rs	0.00% <0.00%> (-72.35%)	⬇️
crates/ink/ir/src/ir/blake2.rs	20.00% <0.00%> (-60.00%)	⬇️
crates/ink/ir/src/ir/trait_def/config.rs	7.14% <0.00%> (-57.15%)	⬇️
crates/ink/ir/src/ir/trait_def/item/trait_item.rs	45.90% <0.00%> (-45.91%)	⬇️
crates/ink/ir/src/ir/config.rs	64.00% <0.00%> (-36.00%)	⬇️
crates/ink/ir/src/ir/utils.rs	57.40% <0.00%> (-35.19%)	⬇️
... and 17 more

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[HCastano]