feat(rpc): Implement getblockchaininfo RPC method (#3891)

* Implement `getblockchaininfo` RPC method

* add a test for `get_blockchain_info`

* fix tohex/fromhex

* move comment

* Update lightwalletd acceptance test for getblockchaininfo RPC (#3914)

* change(rpc): Return getblockchaininfo network upgrades in height order (#3915)

* Update lightwalletd acceptance test for getblockchaininfo RPC

* Update some doc comments for network upgrades

* List network upgrades in order in the getblockchaininfo RPC

Also:
- Use a constant for the "missing consensus branch ID" RPC value
- Simplify fetching consensus branch IDs
- Make RPC type derives consistent
- Update RPC type documentation

* Make RPC type derives consistent

* Fix a confusing test comment

* get hashand height at the same time

* fix estimated_height

* fix lint

* add extra check

Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>

* fix typo

Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>

* split test

Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>

* fix(rpc): ignore an expected error in the RPC acceptance tests (#3961)

* Add ignored regexes to test command failure regex methods

* Ignore empty chain error in getblockchaininfo

We expect this error when zebrad starts up with an empty state.

Co-authored-by: teor <teor@riseup.net>
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

zebra-chain/src/chain_tip.rs

@@ -25,6 +25,9 @@ pub trait ChainTip {
     /// Return the block hash of the best chain tip.
     fn best_tip_hash(&self) -> Option<block::Hash>;
 
+    /// Return the height and the hash of the best chain tip.
+    fn best_tip_height_and_hash(&self) -> Option<(block::Height, block::Hash)>;
+
     /// Return the block time of the best chain tip.
     fn best_tip_block_time(&self) -> Option<DateTime<Utc>>;
 
@@ -70,6 +73,10 @@ impl ChainTip for NoChainTip {
         None
     }
 
+    fn best_tip_height_and_hash(&self) -> Option<(block::Height, block::Hash)> {
+        None
+    }
+
     fn best_tip_block_time(&self) -> Option<DateTime<Utc>> {
         None
     }

zebra-chain/src/chain_tip/mock.rs

@@ -12,6 +12,9 @@ pub struct MockChainTipSender {
     /// A sender that sets the `best_tip_height` of a [`MockChainTip`].
     best_tip_height: watch::Sender<Option<block::Height>>,
 
+    /// A sender that sets the `best_tip_hash` of a [`MockChainTip`].
+    best_tip_hash: watch::Sender<Option<block::Hash>>,
+
     /// A sender that sets the `best_tip_block_time` of a [`MockChainTip`].
     best_tip_block_time: watch::Sender<Option<DateTime<Utc>>>,
 }
@@ -22,6 +25,9 @@ pub struct MockChainTip {
     /// A mocked `best_tip_height` value set by the [`MockChainTipSender`].
     best_tip_height: watch::Receiver<Option<block::Height>>,
 
+    /// A mocked `best_tip_hash` value set by the [`MockChainTipSender`].
+    best_tip_hash: watch::Receiver<Option<block::Hash>>,
+
     /// A mocked `best_tip_height` value set by the [`MockChainTipSender`].
     best_tip_block_time: watch::Receiver<Option<DateTime<Utc>>>,
 }
@@ -35,15 +41,18 @@ impl MockChainTip {
     /// Initially, the best tip height is [`None`].
     pub fn new() -> (Self, MockChainTipSender) {
         let (height_sender, height_receiver) = watch::channel(None);
+        let (hash_sender, hash_receiver) = watch::channel(None);
         let (time_sender, time_receiver) = watch::channel(None);
 
         let mock_chain_tip = MockChainTip {
             best_tip_height: height_receiver,
+            best_tip_hash: hash_receiver,
             best_tip_block_time: time_receiver,
         };
 
         let mock_chain_tip_sender = MockChainTipSender {
             best_tip_height: height_sender,
+            best_tip_hash: hash_sender,
             best_tip_block_time: time_sender,
         };
 
@@ -57,7 +66,14 @@ impl ChainTip for MockChainTip {
     }
 
     fn best_tip_hash(&self) -> Option<block::Hash> {
-        unreachable!("Method not used in tests");
+        *self.best_tip_hash.borrow()
+    }
+
+    fn best_tip_height_and_hash(&self) -> Option<(block::Height, block::Hash)> {
+        let height = (*self.best_tip_height.borrow())?;
+        let hash = (*self.best_tip_hash.borrow())?;
+
+        Some((height, hash))
     }
 
     fn best_tip_block_time(&self) -> Option<DateTime<Utc>> {
@@ -84,6 +100,13 @@ impl MockChainTipSender {
             .expect("attempt to send a best tip height to a dropped `MockChainTip`");
     }
 
+    /// Send a new best tip hash to the [`MockChainTip`].
+    pub fn send_best_tip_hash(&self, hash: impl Into<Option<block::Hash>>) {
+        self.best_tip_hash
+            .send(hash.into())
+            .expect("attempt to send a best tip hash to a dropped `MockChainTip`");
+    }
+
     /// Send a new best tip block time to the [`MockChainTip`].
     pub fn send_best_tip_block_time(&self, block_time: impl Into<Option<DateTime<Utc>>>) {
         self.best_tip_block_time

zebra-chain/src/parameters/network.rs

@@ -101,6 +101,15 @@ impl Network {
         (canopy_activation + ZIP_212_GRACE_PERIOD_DURATION)
             .expect("ZIP-212 grace period ends at a valid block height")
     }
+
+    /// Return the network name as defined in
+    /// [BIP70](https://github.com/bitcoin/bips/blob/master/bip-0070.mediawiki#paymentdetailspaymentrequest)
+    pub fn bip70_network_name(&self) -> String {
+        match self {
+            Network::Mainnet => "main".to_string(),
+            Network::Testnet => "test".to_string(),
+        }
+    }
 }
 
 impl Default for Network {

zebra-chain/src/parameters/network_upgrade.rs

@@ -6,9 +6,11 @@ use crate::block;
 use crate::parameters::{Network, Network::*};
 
 use std::collections::{BTreeMap, HashMap};
+use std::fmt;
 use std::ops::Bound::*;
 
 use chrono::{DateTime, Duration, Utc};
+use hex::{FromHex, ToHex};
 
 #[cfg(any(test, feature = "proptest-impl"))]
 use proptest_derive::Arbitrary;
@@ -118,15 +120,60 @@ const FAKE_TESTNET_ACTIVATION_HEIGHTS: &[(block::Height, NetworkUpgrade)] = &[
 
 /// The Consensus Branch Id, used to bind transactions and blocks to a
 /// particular network upgrade.
-#[derive(Copy, Clone, Debug, Eq, Hash, PartialEq)]
+#[derive(Copy, Clone, Debug, Eq, Hash, PartialEq, Serialize, Deserialize)]
 pub struct ConsensusBranchId(u32);
 
+impl ConsensusBranchId {
+    /// Return the hash bytes in big-endian byte-order suitable for printing out byte by byte.
+    ///
+    /// Zebra displays consensus branch IDs in big-endian byte-order,
+    /// following the convention set by zcashd.
+    fn bytes_in_display_order(&self) -> [u8; 4] {
+        self.0.to_be_bytes()
+    }
+}
+
 impl From<ConsensusBranchId> for u32 {
     fn from(branch: ConsensusBranchId) -> u32 {
         branch.0
     }
 }
 
+impl ToHex for &ConsensusBranchId {
+    fn encode_hex<T: FromIterator<char>>(&self) -> T {
+        self.bytes_in_display_order().encode_hex()
+    }
+
+    fn encode_hex_upper<T: FromIterator<char>>(&self) -> T {
+        self.bytes_in_display_order().encode_hex_upper()
+    }
+}
+
+impl ToHex for ConsensusBranchId {
+    fn encode_hex<T: FromIterator<char>>(&self) -> T {
+        self.bytes_in_display_order().encode_hex()
+    }
+
+    fn encode_hex_upper<T: FromIterator<char>>(&self) -> T {
+        self.bytes_in_display_order().encode_hex_upper()
+    }
+}
+
+impl FromHex for ConsensusBranchId {
+    type Error = <[u8; 4] as FromHex>::Error;
+
+    fn from_hex<T: AsRef<[u8]>>(hex: T) -> Result<Self, Self::Error> {
+        let branch = <[u8; 4]>::from_hex(hex)?;
+        Ok(ConsensusBranchId(u32::from_be_bytes(branch)))
+    }
+}
+
+impl fmt::Display for ConsensusBranchId {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str(&self.encode_hex::<String>())
+    }
+}
+
 /// Network Upgrade Consensus Branch Ids.
 ///
 /// Branch ids are the same for mainnet and testnet. If there is a testnet
@@ -175,8 +222,8 @@ const TESTNET_MINIMUM_DIFFICULTY_START_HEIGHT: block::Height = block::Height(299
 pub const TESTNET_MAX_TIME_START_HEIGHT: block::Height = block::Height(653_606);
 
 impl NetworkUpgrade {
-    /// Returns a BTreeMap of activation heights and network upgrades for
-    /// `network`.
+    /// Returns a map between activation heights and network upgrades for `network`,
+    /// in ascending height order.
     ///
     /// If the activation height of a future upgrade is not known, that
     /// network upgrade does not appear in the list.
@@ -186,7 +233,7 @@ impl NetworkUpgrade {
     /// When the environment variable TEST_FAKE_ACTIVATION_HEIGHTS is set
     /// and it's a test build, this returns a list of fake activation heights
     /// used by some tests.
-    pub(crate) fn activation_list(network: Network) -> BTreeMap<block::Height, NetworkUpgrade> {
+    pub fn activation_list(network: Network) -> BTreeMap<block::Height, NetworkUpgrade> {
         let (mainnet_heights, testnet_heights) = {
             #[cfg(not(feature = "zebra-test"))]
             {
@@ -263,7 +310,7 @@ impl NetworkUpgrade {
         NetworkUpgrade::activation_list(network).contains_key(&height)
     }
 
-    /// Returns a BTreeMap of NetworkUpgrades and their ConsensusBranchIds.
+    /// Returns an unordered mapping between NetworkUpgrades and their ConsensusBranchIds.
     ///
     /// Branch ids are the same for mainnet and testnet.
     ///
@@ -410,6 +457,16 @@ impl NetworkUpgrade {
 }
 
 impl ConsensusBranchId {
+    /// The value used by `zcashd` RPCs for missing consensus branch IDs.
+    ///
+    /// # Consensus
+    ///
+    /// This value must only be used in RPCs.
+    ///
+    /// The consensus rules handle missing branch IDs by rejecting blocks and transactions,
+    /// so this substitute value must not be used in consensus-critical code.
+    pub const RPC_MISSING_ID: ConsensusBranchId = ConsensusBranchId(0);
+
     /// Returns the current consensus branch id for `network` and `height`.
     ///
     /// Returns None if the network has no branch id at this height.

zebra-chain/src/parameters/tests.rs

@@ -233,3 +233,21 @@ fn branch_id_consistent(network: Network) {
         }
     }
 }
+
+// TODO: split this file in unit.rs and prop.rs
+use hex::{FromHex, ToHex};
+use proptest::prelude::*;
+
+proptest! {
+    #[test]
+    fn branch_id_hex_roundtrip(nu in any::<NetworkUpgrade>()) {
+        zebra_test::init();
+
+        if let Some(branch) = nu.branch_id() {
+            let hex_branch: String = branch.encode_hex();
+            let new_branch = ConsensusBranchId::from_hex(hex_branch.clone()).expect("hex branch_id should parse");
+            prop_assert_eq!(branch, new_branch);
+            prop_assert_eq!(hex_branch, new_branch.to_string());
+        }
+    }
+}

zebra-rpc/Cargo.toml

@@ -13,6 +13,7 @@ zebra-network = { path = "../zebra-network" }
 zebra-node-services = { path = "../zebra-node-services" }
 zebra-state = { path = "../zebra-state" }
 
+chrono = "0.4.19"
 futures = "0.3.21"
 
 # lightwalletd sends JSON-RPC requests over HTTP 1.1
@@ -21,6 +22,9 @@ hyper = { version = "0.14.17", features = ["http1", "server"] }
 jsonrpc-core = "18.0.0"
 jsonrpc-derive = "18.0.0"
 jsonrpc-http-server = "18.0.0"
+# zebra-rpc needs the preserve_order feature in serde_json, which is a dependency of jsonrpc-core
+serde_json = { version = "1.0.79", features = ["preserve_order"] }
+indexmap = { version = "1.8.0", features = ["serde"] }
 
 tokio = { version = "1.17.0", features = ["time", "rt-multi-thread", "macros", "tracing"] }
 tower = "0.4.12"