Pin Bitcoin Core to v31.0rc1 tag in CI

.github/workflows/ci.yml

@@ -6,30 +6,28 @@ on:
       - master
   pull_request:
 
+env:
+  BITCOIN_CORE_VERSION: '31.0rc1'
+
 jobs:
   test:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: actions-rust-lang/setup-rust-toolchain@v1
-      - name: Install Bitcoin Dependencies
+      - name: Install dependencies
         run: |
           sudo apt-get update
-          sudo apt-get install -y build-essential cmake pkgconf python3 libevent-dev libboost-dev ccache capnproto libcapnp-dev libxml2-utils
-      - name: ccache
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/ccache
-          key: ccache-${{ runner.os }}-${{ github.sha }}
-          restore-keys: ccache-${{ runner.os }}-
-      - name: Checkout Bitcoin Core
-        run: git clone --depth 1 --branch master https://github.com/bitcoin/bitcoin.git bitcoin-core
-      - name: Build Bitcoin Core
+          sudo apt-get install -y capnproto libcapnp-dev libxml2-utils
+      - name: Download Bitcoin Core
         run: |
-          cd bitcoin-core
-          git apply ../bitcoin-core-ipc-extranonce.patch
-          cmake -B build -DENABLE_WALLET=ON -DENABLE_IPC=ON -DBUILD_TESTS=OFF -DBUILD_BENCH=OFF -DBUILD_TX=OFF -DBUILD_UTIL=OFF -DCMAKE_C_COMPILER_LAUNCHER=ccache -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
-          cmake --build build -j $(nproc) --target bitcoin bitcoin-node
+          VERSION="${BITCOIN_CORE_VERSION}"
+          SERIES="${VERSION%%rc*}"
+          RC="${VERSION##*rc}"
+          URL="https://bitcoincore.org/bin/bitcoin-core-${SERIES}/test.rc${RC}/bitcoin-${VERSION}-x86_64-linux-gnu.tar.gz"
+          curl -fsSLO "${URL}"
+          tar xzf "bitcoin-${VERSION}-x86_64-linux-gnu.tar.gz"
+          mv "bitcoin-${VERSION}" bitcoin-core
       - name: Run Test Suite
         run: cargo test
       - name: Validate CAMT.053 Fixture

DEVELOP.md

@@ -6,36 +6,52 @@
 - [Cap'n Proto](https://capnproto.org/install.html) compiler (`capnp`)
   - macOS: `brew install capnp`
   - Debian/Ubuntu: `apt install capnproto`
-- Bitcoin Core source tree (for the integration test)
+- Bitcoin Core binary (for the integration test)
 
-## Building Bitcoin Core
+## Getting Bitcoin Core
 
 The integration test uses Bitcoin Core's IPC interface (multiprocess mode). You
-need to build the `bitcoin` and `bitcoin-node` targets from source, with wallet
-support enabled.
+need the `bitcoin` and `bitcoin-node` binaries.
+
+### Option A: Download pre-built binaries (recommended)
+
+Download the release tarball and extract it into the project directory:
+
+```bash
+VERSION="31.0rc1"
+curl -fsSLO "https://bitcoincore.org/bin/bitcoin-core-${VERSION%%rc*}/test.rc${VERSION##*rc}/bitcoin-${VERSION}-x86_64-linux-gnu.tar.gz"
+tar xzf "bitcoin-${VERSION}-x86_64-linux-gnu.tar.gz"
+mv "bitcoin-${VERSION}" bitcoin-core
+```
+
+On macOS (Apple Silicon):
+```bash
+VERSION="31.0rc1"
+curl -fsSLO "https://bitcoincore.org/bin/bitcoin-core-${VERSION%%rc*}/test.rc${VERSION##*rc}/bitcoin-${VERSION}-aarch64-apple-darwin.tar.gz"
+tar xzf "bitcoin-${VERSION}-aarch64-apple-darwin.tar.gz"
+mv "bitcoin-${VERSION}" bitcoin-core
+```
+
+The test looks for the binary at `bitcoin-core/bin/bitcoin`.
+
+### Option B: Build from source
 
 1. Clone Bitcoin Core into the project directory:
    ```bash
    git clone https://github.com/bitcoin/bitcoin.git bitcoin-core
    ```
 
-2. Apply the required patch (pads the coinbase scriptSig for low block heights
-   so that `createNewBlock` via IPC succeeds at height ≤ 16):
+2. Configure and build:
    ```bash
    cd bitcoin-core
-   git apply ../bitcoin-core-ipc-extranonce.patch
-   ```
-
-3. Configure and build:
-   ```bash
    cmake -B build -DENABLE_WALLET=ON -DENABLE_IPC=ON -DBUILD_TESTS=OFF -DBUILD_BENCH=OFF
    cmake --build build -j$(nproc) --target bitcoin bitcoin-node
    cd ..
    ```
 
    On macOS, replace `$(nproc)` with `$(sysctl -n hw.logicalcpu)`.
 
-The test expects the binary at `bitcoin-core/build/bin/bitcoin`.
+The test also looks for the binary at `bitcoin-core/build/bin/bitcoin`.
 
 ## Running tests
 
@@ -54,8 +70,9 @@ The integration test (`cargo test --test regtest`) does the following:
 1. Starts a Bitcoin Core node in regtest mode with IPC (`-ipcbind=unix`).
 2. Creates two deterministic wallets (`mining` and `accounting`) using fixed
    `tprv` keys with `wpkh()` (BIP 84) descriptors.
-3. Mines 101 blocks via IPC (`createNewBlock` + `submitSolution`) for coinbase
-   maturity.
+3. Mines 17 blocks via RPC `generatetoaddress` (avoids the IPC extranonce issue
+   at low heights), then 84 blocks via IPC (`createNewBlock` + `submitSolution`)
+   for a total of 101 blocks (coinbase maturity).
 4. Simulates a 12-month salary scenario: monthly EUR salary → BTC at mock
    exchange rates, with random spending.
 5. Exports a CAMT.053 XML statement and verifies it via roundtrip reconstruction.
@@ -76,11 +93,12 @@ xmllint --schema tests/fixtures/camt.053.001.02.xsd \
 
 ### Deterministic blocks
 
-All blocks are mined via Bitcoin Core's Cap'n Proto IPC interface. The test
-brute-forces a valid nonce for each block and caches the coinbase solution
-(coinbase hex, version, timestamp, nonce) in
+IPC-mined blocks (heights 17+) are produced via Bitcoin Core's Cap'n Proto IPC
+interface. The test brute-forces a valid nonce for each block and caches the
+coinbase solution (coinbase hex, version, timestamp, nonce) in
 `tests/fixtures/coinbase_cache.json`. On subsequent runs, cached solutions are
-replayed, producing identical block hashes and transaction IDs.
+replayed, producing identical block hashes and transaction IDs. The first 17
+blocks are mined via RPC and are not cached.
 
 If the cache is missing or stale (e.g. after changing wallet keys or transaction
 amounts), the test regenerates it automatically and emits warnings:
@@ -101,12 +119,14 @@ because Schnorr signatures include randomness by default. This would make
 transaction IDs non-deterministic even with identical inputs, defeating the
 purpose of the coinbase cache.
 
-### Bitcoin Core patch
+### Bitcoin Core extranonce patch
 
 The file `bitcoin-core-ipc-extranonce.patch` patches `src/node/interfaces.cpp`
 to set `include_dummy_extranonce = true` when the chain height is below 17.
 Without this, `createNewBlock` fails with `bad-cb-length` at early heights
 because the BIP 34 height push is only 1 byte, but consensus requires coinbase
 scriptSig to be at least 2 bytes.
 
-This patch will be upstreamed to Bitcoin Core.
+The integration test avoids this issue by mining the first 17 blocks via RPC
+`generatetoaddress` instead of IPC. The patch is only needed if you want to use
+IPC mining at heights ≤ 16.