Bump examples (stellar#875)

* Update soroban-examples tag

* Undo bump for custom-types because the example was completely rewritten.

* Update upgradeable contract for v21.4.0

* Update token examples for v21.4.0

* Update account contract for v21.4.0

* Update liquidity pool examples for v21.4.0

docs/build/guides/conventions/deploy-contract.mdx

@@ -29,7 +29,7 @@ This guide walks through the process of deploying a smart contract from installe
 
 ### Setup environment
 
-The [deployer example](https://github.com/stellar/soroban-examples/tree/v20.2.0/deployer) demonstrates how to deploy contracts using a contract.
+The [deployer example](https://github.com/stellar/soroban-examples/tree/v21.4.0/deployer) demonstrates how to deploy contracts using a contract.
 
 1. Clone the Soroban Examples Repository:
 

docs/build/guides/conventions/upgrading-contracts.mdx

@@ -31,8 +31,8 @@ The [upgradeable contract example] demonstrates how to upgrade a Wasm contract.
 
 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)][oigp]
 
-[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v20.2.0
-[upgradeable contract example]: https://github.com/stellar/soroban-examples/tree/v20.2.0/upgradeable_contract
+[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v21.4.0
+[upgradeable contract example]: https://github.com/stellar/soroban-examples/tree/v21.4.0/upgradeable_contract
 [Rust programming language]: https://www.rust-lang.org/
 
 ### Code
@@ -42,21 +42,32 @@ The example contains both an "old" and "new" contract, where we upgrade from "ol
 ```rust title="upgradeable_contract/old_contract/src/lib.rs"
 #![no_std]
 
-use soroban_sdk::{contractimpl, contracttype, Address, BytesN, Env};
+use soroban_sdk::{contractimpl, contracterror, contracttype, Address, BytesN, Env};
 
 #[contracttype]
 #[derive(Clone)]
 enum DataKey {
     Admin,
 }
 
+#[contracterror]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+#[repr(u32)]
+pub enum Error {
+    AlreadyInitialized = 1,
+}
+
 #[contract]
 pub struct UpgradeableContract;
 
 #[contractimpl]
 impl UpgradeableContract {
     pub fn init(e: Env, admin: Address) {
+        if e.storage().instance().has(&DataKey::Admin) {
+            return Err(Error::AlreadyInitialized);
+        }
         e.storage().instance().set(&DataKey::Admin, &admin);
+        Ok(())
     }
 
     pub fn version() -> u32 {
@@ -108,6 +119,7 @@ Open the `upgradeable_contract/old_contract/src/test.rs` file to follow along.
 ```rust title="upgradeable_contract/old_contract/srctest.rs"
 #![cfg(test)]
 
+use crate::Error;
 use soroban_sdk::{testutils::Address as _, Address, BytesN, Env};
 
 mod old_contract {
@@ -153,6 +165,28 @@ fn test() {
     assert_eq!(1010101, client.new_v2_fn());
 }
 
+
+#[test]
+fn test_cannot_re_init() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    // Note that we use register_contract_wasm instead of register_contract
+    // because the old contracts WASM is expected to exist in storage.
+    let contract_id = env.register_contract_wasm(None, old_contract::WASM);
+    let client = old_contract::Client::new(&env, &contract_id);
+    let admin = Address::generate(&env);
+    client.init(&admin);
+
+    // `try_init` is expected to return an error. Since client is generated from Wasm,
+    // this is a generic SDK error.
+    let err: soroban_sdk::Error = client.try_init(&admin).err().unwrap().unwrap();
+    // Convert the SDK error to the contract error.
+    let contract_err: Error = err.try_into().unwrap();
+    // Make sure contract error has the expected value.
+    assert_eq!(contract_err, Error::AlreadyInitialized);
+}
+
 ```
 
 We first import Wasm files for both contracts:

docs/build/guides/conventions/wasm-metadata.mdx

@@ -29,4 +29,4 @@ pub trait LiquidityPoolTrait {...
 ```
 
 [`contractmeta!`]: https://docs.rs/soroban-sdk/20.0.2/soroban_sdk/macro.contractmeta.html
-[liquidity pool example]: https://github.com/stellar/soroban-examples/blob/v20.0.0/liquidity_pool/src/lib.rs#L152-L155
+[liquidity pool example]: https://github.com/stellar/soroban-examples/blob/v21.4.0/liquidity_pool/src/lib.rs#L152-L155

docs/build/smart-contracts/example-contracts/TEMPLATE.mdx

@@ -19,16 +19,16 @@ Place each link definition at the bottom of the section it first is used in.
 
 :::
 
-[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v20.0.0
-[example demonstrates]: https://github.com/stellar/soroban-examples/tree/v20.0.0/hello_world
+[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v21.4.0
+[example demonstrates]: https://github.com/stellar/soroban-examples/tree/v21.4.0/hello_world
 [other example]: ../getting-started/setup.mdx
 
 ## Run the Example
 
-First go through the [Setup] process to get your development environment configured, then clone the `v20.0.0` tag of `soroban-examples` repository:
+First go through the [Setup] process to get your development environment configured, then clone the `v21.4.0` tag of `soroban-examples` repository:
 
 ```sh
-git clone -b v20.0.0 https://github.com/stellar/soroban-examples
+git clone -b v21.4.0 https://github.com/stellar/soroban-examples
 ```
 
 Or, skip the development environment setup and open this example in [Gitpod][oigp].
@@ -67,7 +67,7 @@ impl HelloContract {
 mod test;
 ```
 
-Ref: https://github.com/stellar/soroban-examples/tree/v20.0.0/hello_world
+Ref: https://github.com/stellar/soroban-examples/tree/v21.4.0/hello_world
 
 ## How it Works
 

docs/build/smart-contracts/example-contracts/alloc.mdx

@@ -23,19 +23,19 @@ The [allocator example] demonstrates how to utilize the allocator feature when w
 
 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)][oigp]
 
-[allocator example]: https://github.com/stellar/soroban-examples/tree/v20.0.0/alloc
-[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v20.0.0
+[allocator example]: https://github.com/stellar/soroban-examples/tree/v21.4.0/alloc
+[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v21.4.0
 
 The `soroban-sdk` crate provides a lightweight bump-pointer allocator which can be used to emulate heap memory allocation in a Wasm smart contract.
 
 ## Run the Example
 
-First go through the [Setup] process to get your development environment configured, then clone the `v20.0.0` tag of `soroban-examples` repository:
+First go through the [Setup] process to get your development environment configured, then clone the `v21.4.0` tag of `soroban-examples` repository:
 
 [setup]: ../getting-started/setup.mdx
 
 ```
-git clone -b v20.0.0 https://github.com/stellar/soroban-examples
+git clone -b v21.4.0 https://github.com/stellar/soroban-examples
 ```
 
 Or, skip the development environment setup and open this example in [Gitpod][oigp].
@@ -94,7 +94,7 @@ impl AllocContract {
 }
 ```
 
-Ref: https://github.com/stellar/soroban-examples/tree/v20.0.0/alloc
+Ref: https://github.com/stellar/soroban-examples/tree/v21.4.0/alloc
 
 ## How it Works
 

docs/build/smart-contracts/example-contracts/atomic-multi-swap.mdx

@@ -25,6 +25,6 @@ Follow the comments in the code for more information.
 
 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)][oigp]
 
-[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v20.0.0
+[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v21.4.0
 [atomic swap]: atomic-swap.mdx
-[atomic swap batching example]: https://github.com/stellar/soroban-examples/tree/v20.0.0/atomic_multiswap
+[atomic swap batching example]: https://github.com/stellar/soroban-examples/tree/v21.4.0/atomic_multiswap

docs/build/smart-contracts/example-contracts/atomic-swap.mdx

@@ -23,17 +23,17 @@ This is example demonstrates advanced usage of Soroban auth framework and assume
 
 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)][oigp]
 
-[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v20.0.0
-[atomic swap example]: https://github.com/stellar/soroban-examples/tree/v20.0.0/atomic_swap
+[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v21.4.0
+[atomic swap example]: https://github.com/stellar/soroban-examples/tree/v21.4.0/atomic_swap
 
 ## Run the Example
 
-First go through the [Setup] process to get your development environment configured, then clone the `v20.0.0` tag of `soroban-examples` repository:
+First go through the [Setup] process to get your development environment configured, then clone the `v21.4.0` tag of `soroban-examples` repository:
 
 [setup]: ../getting-started/setup.mdx
 
 ```
-git clone -b v20.0.0 https://github.com/stellar/soroban-examples
+git clone -b v21.4.0 https://github.com/stellar/soroban-examples
 ```
 
 Or, skip the development environment setup and open this example in [Gitpod][oigp].
@@ -123,7 +123,7 @@ fn move_token(
 }
 ```
 
-Ref: https://github.com/stellar/soroban-examples/tree/v20.0.0/atomic_swap
+Ref: https://github.com/stellar/soroban-examples/tree/v21.4.0/atomic_swap
 
 ## How it Works
 
@@ -186,7 +186,7 @@ The swap itself is implemented via two token moves: from `a` to `b` and from `b`
 
 Open the [`atomic_swap/src/test.rs`] file to follow along.
 
-[`atomic_swap/src/test.rs`]: https://github.com/stellar/soroban-examples/tree/v20.0.0/atomic_swap/src/test.rs
+[`atomic_swap/src/test.rs`]: https://github.com/stellar/soroban-examples/tree/v21.4.0/atomic_swap/src/test.rs
 
 Refer to another examples for the general information on the test setup.
 

docs/build/smart-contracts/example-contracts/auth.mdx

@@ -27,18 +27,18 @@ This example is an extension of the [storing data example].
 
 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)][oigp]
 
-[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v20.0.0
+[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v21.4.0
 [storing data example]: ../getting-started/storing-data.mdx
-[auth example]: https://github.com/stellar/soroban-examples/tree/v20.0.0/auth
+[auth example]: https://github.com/stellar/soroban-examples/tree/v21.4.0/auth
 
 ## Run the Example
 
-First go through the [Setup] process to get your development environment configured, then clone the `v20.0.0` tag of `soroban-examples` repository:
+First go through the [Setup] process to get your development environment configured, then clone the `v21.4.0` tag of `soroban-examples` repository:
 
 [setup]: ../getting-started/setup.mdx
 
 ```
-git clone -b v20.0.0 https://github.com/stellar/soroban-examples
+git clone -b v21.4.0 https://github.com/stellar/soroban-examples
 ```
 
 Or, skip the development environment setup and open this example in [Gitpod][oigp].
@@ -110,7 +110,7 @@ impl IncrementContract {
 }
 ```
 
-Ref: https://github.com/stellar/soroban-examples/tree/v20.0.0/auth
+Ref: https://github.com/stellar/soroban-examples/tree/v21.4.0/auth
 
 ## How it Works
 
@@ -166,7 +166,7 @@ user.require_auth_for_args((value,).into_val(&env));
 
 Open the [`auth/src/test.rs`] file to follow along.
 
-[`auth/src/test.rs`]: https://github.com/stellar/soroban-examples/tree/v20.0.0/auth/src/test.rs
+[`auth/src/test.rs`]: https://github.com/stellar/soroban-examples/tree/v21.4.0/auth/src/test.rs
 
 ```rust title="auth/src/test.rs"
 fn test() {

docs/build/smart-contracts/example-contracts/cross-contract-call.mdx

@@ -31,17 +31,17 @@ In this example there are two contracts that are compiled separately, deployed s
 
 :::
 
-[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v20.0.0
-[cross contract call example]: https://github.com/stellar/soroban-examples/tree/v20.0.0/cross_contract
+[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v21.4.0
+[cross contract call example]: https://github.com/stellar/soroban-examples/tree/v21.4.0/cross_contract
 
 ## Run the Example
 
-First go through the [Setup] process to get your development environment configured, then clone the `v20.0.0` tag of `soroban-examples` repository:
+First go through the [Setup] process to get your development environment configured, then clone the `v21.4.0` tag of `soroban-examples` repository:
 
 [setup]: ../getting-started/setup.mdx
 
 ```
-git clone -b v20.0.0 https://github.com/stellar/soroban-examples
+git clone -b v21.4.0 https://github.com/stellar/soroban-examples
 ```
 
 Or, skip the development environment setup and open this example in [Gitpod][oigp].
@@ -93,7 +93,7 @@ impl ContractB {
 }
 ```
 
-Ref: https://github.com/stellar/soroban-examples/tree/v20.0.0/cross_contract
+Ref: https://github.com/stellar/soroban-examples/tree/v21.4.0/cross_contract
 
 ## How it Works
 

docs/build/smart-contracts/example-contracts/custom-account.mdx

@@ -38,17 +38,17 @@ While custom accounts are supported by the Stellar protocol and Soroban SDK, the
 
 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)][oigp]
 
-[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v20.0.0
-[custom account example]: https://github.com/stellar/soroban-examples/tree/v20.0.0/account
+[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v21.4.0
+[custom account example]: https://github.com/stellar/soroban-examples/tree/v21.4.0/account
 
 ## Run the Example
 
-First go through the [Setup] process to get your development environment configured, then clone the `v20.0.0` tag of `soroban-examples` repository:
+First go through the [Setup] process to get your development environment configured, then clone the `v21.4.0` tag of `soroban-examples` repository:
 
 [setup]: ../getting-started/setup.mdx
 
 ```
-git clone -b v20.0.0 https://github.com/stellar/soroban-examples
+git clone -b v21.4.0 https://github.com/stellar/soroban-examples
 ```
 
 Or, skip the development environment setup and open this example in [Gitpod][oigp].
@@ -128,7 +128,7 @@ This function allows users to set and modify the per-token spend limit described
 pub fn __check_auth(
     env: Env,
     signature_payload: BytesN<32>,
-    signatures: Vec<Signature>,
+    signatures: Vec<AccSignature>,
     auth_context: Vec<Context>,
 ) -> Result<(), AccError> {
     // Perform authentication.
@@ -174,7 +174,7 @@ Here it is implemented in two steps. First, authentication is performed using th
 fn authenticate(
     env: &Env,
     signature_payload: &BytesN<32>,
-    signatures: &Vec<Signature>,
+    signatures: &Vec<AccSignature>,
 ) -> Result<(), AccError> {
     for i in 0..signatures.len() {
         let signature = signatures.get_unchecked(i);
@@ -278,15 +278,15 @@ Then we check for the standard token function names and verify that for these fu
 
 Open the [`account/src/test.rs`] file to follow along.
 
-[`account/src/test.rs`]: https://github.com/stellar/soroban-examples/tree/v20.0.0/account/src/test.rs
+[`account/src/test.rs`]: https://github.com/stellar/soroban-examples/tree/v21.4.0/account/src/test.rs
 
 Refer to another examples for the general information on the test setup.
 
 Here we only look at some points specific to the account contracts.
 
 ```rust
 fn sign(e: &Env, signer: &Keypair, payload: &BytesN<32>) -> RawVal {
-    Signature {
+    AccSignature {
         public_key: signer_public_key(e, signer),
         signature: signer
             .sign(payload.to_array().as_slice())

docs/build/smart-contracts/example-contracts/deployer.mdx

@@ -35,17 +35,17 @@ In this example there are two contracts that are compiled separately, and the te
 
 :::
 
-[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v20.0.0
-[deployer example]: https://github.com/stellar/soroban-examples/tree/v20.0.0/deployer
+[oigp]: https://gitpod.io/#https://github.com/stellar/soroban-examples/tree/v21.4.0
+[deployer example]: https://github.com/stellar/soroban-examples/tree/v21.4.0/deployer
 
 ## Run the Example
 
-First go through the [Setup] process to get your development environment configured, then clone the `v20.0.0` tag of `soroban-examples` repository:
+First go through the [Setup] process to get your development environment configured, then clone the `v21.4.0` tag of `soroban-examples` repository:
 
 [setup]: ../getting-started/setup.mdx
 
 ```
-git clone -b v20.0.0 https://github.com/stellar/soroban-examples
+git clone -b v21.4.0 https://github.com/stellar/soroban-examples
 ```
 
 Or, skip the development environment setup and open this example in [Gitpod][oigp].
@@ -108,7 +108,7 @@ impl Deployer {
 }
 ```
 
-Ref: https://github.com/stellar/soroban-examples/tree/v20.0.0/deployer
+Ref: https://github.com/stellar/soroban-examples/tree/v21.4.0/deployer
 
 ## How it Works