add mint constraints and test

[Henry-E]

Added new mint constraints so that it's possible to initialize a PDA mint account in the same way as token accounts.

New Constraint Tokens / Keywords

mint_decimals: a u8 corresponding to the decimals argument of the InitializeMint function in the SPL token program
mint_authority: a program account, account info or cpi account that will be assigned as the mint's authority. Corresponds to mint_authority argument of the InitializeMint function in the SPL token program

Example usage

pub struct TestTokenSeedsInit<'info> {
    #[account(
        init,
        mint_decimals = 6 as u8,
        mint_authority = authority,
        seeds = [b"my-mint-seed".as_ref(), &[mint_bump]],
        payer = authority,
        space = Mint::LEN,
    )]
    pub mint: CpiAccount<'info, Mint>,
    #[account(
        init,
        token = mint,
        authority = authority,
        seeds = [b"my-token-seed".as_ref(), &[token_bump]],
        payer = authority,
        space = TokenAccount::LEN,
    )]
    pub my_pda: CpiAccount<'info, TokenAccount>,
    pub authority: AccountInfo<'info>,
    pub system_program: AccountInfo<'info>,
    pub rent: Sysvar<'info, Rent>,
    pub token_program: AccountInfo<'info>,
}

[secretshardul]

EDIT: Resolved, solution in comments below

Getting an error when I import your repo to use this feature.

Finished release [optimized] target(s) in 8.27s
Running: /Users/hp/.local/share/solana/install/releases/1.7.3/solana-release/bin/sdk/bpf/dependencies/bpf-tools/llvm/bin/llvm-readelf --dyn-symbols /Users/hp/Documents/solana-season-hack/cyclos/target/deploy/cyclos.so

To deploy this program:
  $ solana program deploy /Users/hp/Documents/solana-season-hack/cyclos/target/deploy/cyclos.so
thread 'main' panicked at 'Code not parseable: Error("Invalid attribute")', lang/syn/src/idl/file.rs:351:62
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::result::unwrap_failed
   3: anchor_syn::idl::file::parse_account_derives
   4: anchor_syn::idl::file::parse
   5: anchor::extract_idl
   6: anchor::build_cwd
   7: anchor::build
   8: anchor::main

Here's my code

    #[account(
        init,
        mint_decimals = 6 as u8,
        mint_authority = open_orders_authority,
        seeds = [b"Mint".as_ref(), &[_mint_bump]],
        payer = authority,
        space = size_of::<Mint>()
    )]
    pub mint: CpiAccount<'info, Mint>,

Imported your repo in Cargo.toml in this way:

[dependencies]
anchor-lang = { git = "https://github.com/Henry-E/anchor", branch = "add_mint_constraints" }
anchor-spl = { git = "https://github.com/Henry-E/anchor", branch = "add_mint_constraints" }

Travis build points to an error, is this the reason why I'm getting this issue?

error: this expression borrows a reference (`&anchor_lang::prelude::Pubkey`) that is immediately dereferenced by the compiler
   --> spl/src/token.rs:139:9
    |
139 |         &authority,
    |         ^^^^^^^^^^ help: change this to: `authority`

[armaniferrante]

Getting an error when I import your repo to use this feature.

Finished release [optimized] target(s) in 8.27s
Running: /Users/hp/.local/share/solana/install/releases/1.7.3/solana-release/bin/sdk/bpf/dependencies/bpf-tools/llvm/bin/llvm-readelf --dyn-symbols /Users/hp/Documents/solana-season-hack/cyclos/target/deploy/cyclos.so

To deploy this program:
  $ solana program deploy /Users/hp/Documents/solana-season-hack/cyclos/target/deploy/cyclos.so
thread 'main' panicked at 'Code not parseable: Error("Invalid attribute")', lang/syn/src/idl/file.rs:351:62
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::result::unwrap_failed
   3: anchor_syn::idl::file::parse_account_derives
   4: anchor_syn::idl::file::parse
   5: anchor::extract_idl
   6: anchor::build_cwd
   7: anchor::build
   8: anchor::main

Here's my code

    #[account(
        init,
        mint_decimals = 6 as u8,
        mint_authority = open_orders_authority,
        seeds = [b"Mint".as_ref(), &[_mint_bump]],
        payer = authority,
        space = size_of::<Mint>()
    )]
    pub mint: CpiAccount<'info, Mint>,

Imported your repo in Cargo.toml in this way:

[dependencies]
anchor-lang = { git = "https://github.com/Henry-E/anchor", branch = "add_mint_constraints" }
anchor-spl = { git = "https://github.com/Henry-E/anchor", branch = "add_mint_constraints" }

Travis build points to an error, is this the reason why I'm getting this issue?

error: this expression borrows a reference (`&anchor_lang::prelude::Pubkey`) that is immediately dereferenced by the compiler
   --> spl/src/token.rs:139:9
    |
139 |         &authority,
    |         ^^^^^^^^^^ help: change this to: `authority`

You'll need to use the CLI compiled with these changes as well.

[Henry-E]

Yeh, you need to use cargo run --manifest-path ../anchor/Cargo.toml test or something similar when running a local version of the CLI

[secretshardul]

Yeh, you need to use cargo run --manifest-path ../anchor/Cargo.toml test or something similar when running a local version of the CLI

Resolved, thanks a lot

[Henry-E]

Updated the pull request using cargo fmt so that it will pass the build requirement.

Also reduced the number of system program calls from 3 to 1. The original code from the associated token program splits call into three because it can't be sure if the account has already been initialized with some lamports. We don't have that same requirement.

@armaniferrante With regards to open orders initializing, I don't actually feel comfortable enough with all of the different syntax being used to access account variables to add it. Apologies!

[Henry-E]

It says the builds are still failing after running cargo fmt is there anything else it might be?

[secretshardul]

The second macro could be extended to create associated token accounts? This will be more convenient than spl_associated_token_account::create_associated_token_account. Or there's already a way?

[Henry-E]

omg, all the builds finally passed

[armaniferrante]

Debatable whether this should be enforced. 🤷

[armaniferrante]

It made more sense with the old token = <mint>, authority = <auth> syntax, since having the token first made things more clear. But with the new syntax, it's not really necessary.

[Henry-E]

I agree, there's no reason to enforce this.

[Henry-E]

We will have to add in the fallback option eventually for the case where a PDA account already has some lamports in it.

Maybe the fallback could just transfer any lamports inside the account to the authority? Then there should be 0 lamports inside the account when it is passed to createAccount.