Update sdk version to 0.4.2, add the alloc example (#193)

Cargo.toml

@@ -22,6 +22,7 @@ members = [
     "logging",
     "errors",
     "wallet",
+    "alloc",
 ]
 
 [profile.release-with-logs]
@@ -39,11 +40,11 @@ codegen-units = 1
 lto = true
 
 [workspace.dependencies.soroban-sdk]
-version = "0.4.1"
+version = "0.4.2"
 git = "https://github.com/stellar/rs-soroban-sdk"
-rev = "980778e"
+rev = "135c3c8"
 
 [workspace.dependencies.soroban-auth]
-version = "0.4.1"
+version = "0.4.2"
 git = "https://github.com/stellar/rs-soroban-sdk"
-rev = "980778e"
+rev = "135c3c8"

alloc/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "soroban-alloc-contract"
+version = "0.0.0"
+authors = ["Stellar Development Foundation <[email protected]>"]
+license = "Apache-2.0"
+edition = "2021"
+publish = false
+
+[lib]
+crate-type = ["cdylib"]
+doctest = false
+
+[dependencies]
+soroban-sdk = { workspace = true, features = ["alloc"] }
+
+[dev_dependencies]
+soroban-sdk = { workspace = true, features = ["testutils", "alloc"] }

alloc/src/lib.rs

@@ -0,0 +1,24 @@
+#![no_std]
+use soroban_sdk::{contractimpl, Env};
+
+extern crate alloc;
+
+pub struct AllocContract;
+
+#[contractimpl]
+impl AllocContract {
+    /// Allocates a temporary vector holding values (0..count), then computes and returns their sum.
+    pub fn sum(_env: Env, count: u32) -> u32 {
+        let mut v1 = alloc::vec![];
+        (0..count).for_each(|i| v1.push(i));
+
+        let mut sum = 0;
+        for i in v1 {
+            sum += i;
+        }
+
+        sum
+    }
+}
+
+mod test;

alloc/src/test.rs

@@ -0,0 +1,18 @@
+#![cfg(test)]
+
+use super::{AllocContract, AllocContractClient};
+use soroban_sdk::{testutils::Logger, Env};
+
+extern crate std;
+
+#[test]
+fn test() {
+    let env = Env::default();
+    let contract_id = env.register_contract(None, AllocContract);
+    let client = AllocContractClient::new(&env, &contract_id);
+    assert_eq!(client.sum(&1), 0);
+    assert_eq!(client.sum(&2), 1);
+    assert_eq!(client.sum(&5), 10);
+
+    std::println!("{}", env.logger().all().join("\n"));
+}