Wasm binary size budget

.github/workflows/ci.yml

@@ -62,6 +62,31 @@ jobs:
       - run: cargo fmt --all --check
       - run: cargo test --workspace
 
+  stellar-size-check:
+    needs: changes
+    if: needs.changes.outputs.stellar == 'true'
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: stellar
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: rustup target add wasm32-unknown-unknown
+      - run: cargo build --target wasm32-unknown-unknown --release
+      - name: Check Wasm sizes
+        run: |
+          BUDGET=112640 # 110 KB in bytes
+          for wasm in target/wasm32-unknown-unknown/release/*.wasm; do
+            size=$(stat -c%s "$wasm")
+            name=$(basename "$wasm" .wasm)
+            echo "Contract $name size: $size bytes (Budget: $BUDGET bytes)"
+            if [ "$size" -gt "$BUDGET" ]; then
+              echo "Error: Contract $name exceeds Wasm size budget!"
+              exit 1
+            fi
+          done
+
   solana:
     needs: changes
     if: needs.changes.outputs.solana == 'true'

stellar/Cargo.toml

@@ -9,3 +9,10 @@ resolver = "2"
 
 [workspace.dependencies]
 soroban-sdk = "22.0.0"
+
+[profile.release]
+opt-level = "z"     # Optimize for size
+lto = "fat"         # Enable Link Time Optimization (LTO)
+codegen-units = 1   # Reduce parallel code generation units to increase optimization
+panic = "abort"     # Remove panic landing pads
+strip = "symbols"   # Strip symbols from the binary

stellar/SIZE.md

@@ -0,0 +1,30 @@
+# Stellar Contract Wasm Size Budget
+
+This document tracks the Wasm binary sizes of the Stellar contracts and sets budgets to ensure they remain within Soroban limits.
+
+## Current Measurements (Initial)
+
+| Contract | Debug | Release | Optimized | Budget | Headroom |
+|---|---|---|---|---|---|
+| `stealth-announcer` | 2.6 MB | 2.9 KB | 1.3 KB | 110 KB | 108.7 KB |
+| `stealth-registry` | 2.6 MB | 5.5 KB | 2.1 KB | 110 KB | 107.9 KB |
+| `stealth-sender` | 2.7 MB | 13 KB | 4.1 KB | 110 KB | 105.9 KB |
+| `wraith-names` | 2.7 MB | 18 KB | 6.0 KB | 110 KB | 104 KB |
+
+*\* `stellar contract optimize` is currently unavailable in the environment due to missing `wasm-opt`. Initial optimizations will focus on build profile settings.*
+
+## Wasm Size Budget
+
+Soroban has a hard limit on contract Wasm size (currently ~140 KB for some operations, but upload limits can be higher). We aim for a budget of **110 KB** per contract to allow for ~20% headroom.
+
+## What to do if you exceed the budget
+
+If a contract exceeds its budget, follow these steps:
+
+1. **Audit Dependencies**: Check `Cargo.toml` for unused features or heavy dependencies. Use `cargo tree`.
+2. **Profile Build**: Ensure `lto = "fat"`, `codegen-units = 1`, and `opt-level = "z"` are set in `Cargo.toml`.
+3. **Refactor Code**:
+    *   Replace `panic!`, `assert!`, and `unwrap()` with `Result` or `panic_with_error!`.
+    *   Avoid `std::string::String` and `std::vec::Vec` where possible; use `soroban_sdk` equivalents.
+    *   Minimize use of `format!` and complex formatting.
+4. **Use `wasm-opt`**: If not already done, run `stellar contract optimize`.