rpc: match Core header, address, and mempool JSON

changelog.d/rpc-core-header-shape.md

@@ -0,0 +1,12 @@
+Fixed
+
+- **Block header and block RPC match Bitcoin Core's JSON for inactive
+  headers, genesis, and difficulty text.** `getblockheader` and `getblock`
+  return a stored header that is no longer on the active chain
+  (`confirmations: -1`, its own `previousblockhash`, and a Class A body when
+  one exists). Genesis omits `previousblockhash`. `getblockheader` includes
+  `nextblockhash` and `target`. `getblockchaininfo` includes `bits` and
+  `target`. Difficulty uses 16 significant digits. `validateaddress` reports
+  `isscript` for P2TR and P2A and omits witness fields on pay-to-anchor.
+  `getmempoolinfo` includes `fullrbf`, `maxdatacarriersize` (null), and the
+  cluster limits. BTC amounts print as 8-decimal numbers.

crates/rbitcoin-mempool/src/lib.rs

@@ -57,7 +57,7 @@ pub use fee_est::{
 pub use fee_flow::FeeFlowMeter;
 pub use graph::{
     frontier_feerate_from_chunks, weight_above_from_chunks, Chunk, Cluster, MempoolGraphStats,
-    SelectBudget, Selected, TxEntry, TxGraph,
+    SelectBudget, Selected, TxEntry, TxGraph, MAX_CLUSTER_COUNT, MAX_CLUSTER_VSIZE,
 };
 pub use orphanage::{OrphanSnapshot, Orphanage};
 pub use packed::VinAux;

crates/rbitcoin-net/src/tx_relay.rs

@@ -3071,6 +3071,23 @@ impl MempoolHub {
         Some((stats, a_mod, d_mod, chunk_fee, chunk_w))
     }
 
+    /// Core `-limitclustercount` and `-limitclustersize` (count, vbytes).
+    pub fn cluster_limits(&self) -> (u32, u64) {
+        let g = self.lock_read();
+        (
+            g.graph.cluster_count_limit() as u32,
+            g.graph.cluster_vsize_limit(),
+        )
+    }
+
+    /// Defaults when no hub is attached (`MAX_CLUSTER_COUNT`, `MAX_CLUSTER_VSIZE`).
+    pub fn default_cluster_limits() -> (u32, u64) {
+        (
+            rbitcoin_mempool::MAX_CLUSTER_COUNT as u32,
+            rbitcoin_mempool::MAX_CLUSTER_VSIZE,
+        )
+    }
+
     /// Cluster count/size overlay (`None` = keep default).
     pub fn set_cluster_limits(&self, count: Option<u32>, size_kvb: Option<u32>) {
         self.lock_write().set_cluster_limits(count, size_kvb);

crates/rbitcoin-node/src/health/metrics.rs

@@ -233,9 +233,7 @@ fn chain_gauges(out: &mut Exposition, chain: &ChainHub, sh_index: bool) {
         "Seconds since the tip block time.",
         age,
     );
-    let difficulty = rec.map_or(0.0, |(_, rec)| {
-        rbitcoin_consensus::difficulty_from_bits(rec.bits)
-    });
+    let difficulty = rec.map_or(0.0, |(_, rec)| rbitcoin_rpc::difficulty_rpc_f64(rec.bits));
     out.gauge(
         "rbitcoin_difficulty",
         "Tip difficulty (getblockchaininfo.difficulty).",

crates/rbitcoin-query/src/chain_view.rs

@@ -193,6 +193,22 @@ impl Query {
         Ok(g.map.get(hash).copied().map(Height))
     }
 
+    /// Active-chain height of a hash already loaded from the header archive.
+    ///
+    /// Skips the extra header read in [`Self::height_of_hash`]. An ancestry
+    /// walk then costs one `prev_fk` read per step plus this index.
+    pub fn confirmed_height_of_hash(&self, hash: &[u8; 32]) -> Result<Option<Height>, QueryError> {
+        let Some(tip) = self.tip_height() else {
+            return Ok(None);
+        };
+        self.ensure_height_by_hash_index(tip)?;
+        let g = self
+            .height_by_hash
+            .lock()
+            .unwrap_or_else(|e| e.into_inner());
+        Ok(g.map.get(hash).copied().map(Height))
+    }
+
     /// Ensure height index matches `tip`.
     ///
     /// Incremental for any `new_tip ≠ prev_tip`. Full walk only when the map

crates/rbitcoin-rpc/Cargo.toml

@@ -21,7 +21,7 @@ tower = { workspace = true }
 tower-http = { workspace = true }
 tokio = { workspace = true }
 serde = { workspace = true }
-serde_json = { workspace = true }
+serde_json = { workspace = true, features = ["arbitrary_precision"] }
 getrandom = "0.4"
 base64 = "0.23"
 

crates/rbitcoin-rpc/src/lib.rs

@@ -9,7 +9,8 @@ mod server;
 
 pub use auth::{default_socket_path, default_token_path, read_cookie_file, RpcAuth};
 pub use methods::{
-    gbt_template, submit_received_block, RpcActive, RpcContext, RpcRegtest, SubmitBlockOutcome,
+    difficulty_rpc_f64, gbt_template, submit_received_block, RpcActive, RpcContext, RpcRegtest,
+    SubmitBlockOutcome,
 };
 pub use server::{run_rpc, RpcConfig, RpcHandle, DEFAULT_RPC_WORK_QUEUE, RPC_MAX_HTTP_BODY};