feat: add ERC20FlashMint extension (#407)

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**NOTE: It is impossible to write any unit tests until it is possible to
mock `contract::address()` in tests (see
OpenZeppelin/stylus-test-helpers#5

<!-- Fill in with issue number -->
Resolves #355

#### PR Checklist

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- [x] Tests
- [x] Documentation
- [x] Changelog

---------

Co-authored-by: Nenad <[email protected]>
Co-authored-by: Nenad <[email protected]>
Co-authored-by: Daniel Bigos <[email protected]>
Co-authored-by: Alisander Qoshqosh <[email protected]>

.github/workflows/test.yml

@@ -57,7 +57,7 @@ jobs:
 
         # https://twitter.com/jonhoo/status/1571290371124260865
       - name: Run unit tests
-        run: cargo nextest run --locked --features std --all-targets
+        run: cargo nextest run --locked --features std --all-targets -p openzeppelin-stylus -p openzeppelin-stylus-proc -p openzeppelin-crypto
 
         # https://github.com/rust-lang/cargo/issues/6669
       - name: Run doc tests
@@ -93,7 +93,7 @@ jobs:
         run: cargo generate-lockfile
 
       - name: Run unit tests
-        run: cargo nextest run --locked --features std --all-targets
+        run: cargo nextest run --locked --features std --all-targets -p openzeppelin-stylus -p openzeppelin-stylus-proc -p openzeppelin-crypto
   coverage:
     # Use llvm-cov to build and collect coverage and outputs in a format that
     # is compatible with codecov.io.
@@ -141,7 +141,7 @@ jobs:
         run: cargo generate-lockfile
 
       - name: Cargo llvm-cov
-        run: cargo llvm-cov --locked --features std --lcov --output-path lcov.info
+        run: cargo llvm-cov --locked --features std --lcov --output-path lcov.info -p openzeppelin-stylus -p openzeppelin-stylus-proc -p openzeppelin-crypto
 
       - name: Record Rust version
         run: echo "RUST=$(rustc --version)" >> "$GITHUB_ENV"

.gitignore

@@ -9,3 +9,7 @@ docs/build/
 **/.DS_Store
 
 **/nitro-testnode
+
+lcov.info
+
+lcov.infos

CHANGELOG.md

@@ -9,15 +9,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- 
+- `Erc20FlashMint` extension. #407
 
 ### Changed
 
-- Use `AddAssignUnchecked` and `SubAssignUnchecked` in `erc20::_update` calculations. #467
+- Use `AddAssignUnchecked` and `SubAssignUnchecked` in `erc20::_update`. #467
 
 ### Changed (Breaking)
 
-- `Nonce::use_nonce` now panics on exceeding `U256::MAX`. #467
+- Add full support for reentrancy (changed `VestingWallet` signature for some functions). #407
+- `Nonce::use_nonce` panics on exceeding `U256::MAX`. #467
 
 ### Fixed
 

Cargo.toml

@@ -7,6 +7,7 @@ members = [
   "lib/e2e-proc",
   "examples/erc20",
   "examples/erc20-permit",
+  "examples/erc20-flash-mint",
   "examples/erc721",
   "examples/erc721-consecutive",
   "examples/erc721-metadata",
@@ -31,6 +32,7 @@ default-members = [
   "lib/e2e-proc",
   "examples/erc20",
   "examples/erc20-permit",
+  "examples/erc20-flash-mint",
   "examples/erc721",
   "examples/erc721-consecutive",
   "examples/erc721-metadata",

contracts/Cargo.toml

@@ -28,6 +28,7 @@ rand.workspace = true
 # features, because this crate is meant to be used in a `no_std` environment.
 # Currently, the std feature is only used for testing purposes.
 std = []
+reentrant = ["stylus-sdk/reentrant"]
 
 [lib]
 crate-type = ["lib"]

contracts/src/finance/vesting_wallet.rs

@@ -253,7 +253,7 @@ pub trait IVestingWallet {
     ///
     /// # Arguments
     ///
-    /// * `&self` - Read access to the contract's state.
+    /// * `&mut self` - Write access to the contract's state.
     /// * `token` - Address of the releasable token.
     ///
     /// # Errors
@@ -266,7 +266,8 @@ pub trait IVestingWallet {
     /// If total allocation exceeds `U256::MAX`.
     /// If scaled, total allocation (mid calculation) exceeds `U256::MAX`.
     #[selector(name = "releasable")]
-    fn releasable_erc20(&self, token: Address) -> Result<U256, Self::Error>;
+    fn releasable_erc20(&mut self, token: Address)
+        -> Result<U256, Self::Error>;
 
     /// Release the native tokens (Ether) that have already vested.
     ///
@@ -335,7 +336,7 @@ pub trait IVestingWallet {
     ///
     /// # Arguments
     ///
-    /// * `&self` - Read access to the contract's state.
+    /// * `&mut self` - Write access to the contract's state.
     /// * `token` - Address of the token being released.
     /// * `timestamp` - Point in time for which to check the vested amount.
     ///
@@ -350,7 +351,7 @@ pub trait IVestingWallet {
     /// If scaled, total allocation (mid calculation) exceeds `U256::MAX`.
     #[selector(name = "vestedAmount")]
     fn vested_amount_erc20(
-        &self,
+        &mut self,
         token: Address,
         timestamp: u64,
     ) -> Result<U256, Self::Error>;
@@ -410,7 +411,10 @@ impl IVestingWallet for VestingWallet {
     }
 
     #[selector(name = "releasable")]
-    fn releasable_erc20(&self, token: Address) -> Result<U256, Self::Error> {
+    fn releasable_erc20(
+        &mut self,
+        token: Address,
+    ) -> Result<U256, Self::Error> {
         let vested = self.vested_amount_erc20(token, block::timestamp())?;
         // SAFETY: total vested amount is by definition greater than or equal to
         // the released amount.
@@ -467,13 +471,13 @@ impl IVestingWallet for VestingWallet {
 
     #[selector(name = "vestedAmount")]
     fn vested_amount_erc20(
-        &self,
+        &mut self,
         token: Address,
         timestamp: u64,
     ) -> Result<U256, Self::Error> {
         let erc20 = IErc20::new(token);
         let balance = erc20
-            .balance_of(Call::new(), contract::address())
+            .balance_of(Call::new_in(self), contract::address())
             .map_err(|_| InvalidToken { token })?;
 
         let total_allocation = balance

contracts/src/token/erc1155/extensions/uri_storage.rs

@@ -96,7 +96,7 @@ mod tests {
     use stylus_sdk::prelude::storage;
 
     use super::Erc1155UriStorage;
-    use crate::token::erc1155::{extensions::Erc1155MetadataUri, Erc1155};
+    use crate::token::erc1155::extensions::Erc1155MetadataUri;
 
     fn random_token_id() -> U256 {
         let num: u32 = rand::random();