Rename util::hash module

The `util::hash` module provides two functions for computing a merkle
root from a list/iterator of hashes.

Rename the module to `merkle_root` and move it to the crate root,
deprecate the original functions.

Done as part of flattening the `util` module.

bitcoin/src/blockdata/block.rs

@@ -15,7 +15,7 @@ use core::fmt;
 
 use crate::util;
 use crate::util::Error::{BlockBadTarget, BlockBadProofOfWork};
-use crate::util::hash::bitcoin_merkle_root;
+use crate::merkle_tree::bitcoin_merkle_root;
 use crate::hashes::{Hash, HashEngine};
 use crate::hash_types::{Wtxid, BlockHash, TxMerkleNode, WitnessMerkleNode, WitnessCommitment};
 use crate::consensus::{encode, Encodable, Decodable};

bitcoin/src/lib.rs

@@ -92,6 +92,7 @@ pub mod blockdata;
 pub mod consensus;
 pub mod error;
 pub mod hash_types;
+pub mod merkle_tree;
 pub mod policy;
 pub mod pow;
 pub mod sighash;

bitcoin/src/merkle_tree.rs

@@ -1,10 +1,7 @@
 // Written in 2014 by Andrew Poelstra <apoelstra@wpsoftware.net>
 // SPDX-License-Identifier: CC0-1.0
 
-//! Bitcoin hash functions.
+//! Bitcoin merkle tree functions.
-//!
-//! This module provides utility functions related to hashing data, including
-//! merkleization.
 //!
 
 use core::iter;
@@ -108,7 +105,7 @@ mod tests {
     #[test]
     fn both_merkle_root_functions_return_the_same_result() {
         // testnet block 000000000000045e0b1660b6445b5e5c5ab63c9a4f956be7e1e69be04fa4497b
-        let segwit_block = include_bytes!("../../tests/data/testnet_block_000000000000045e0b1660b6445b5e5c5ab63c9a4f956be7e1e69be04fa4497b.raw");
+        let segwit_block = include_bytes!("../tests/data/testnet_block_000000000000045e0b1660b6445b5e5c5ab63c9a4f956be7e1e69be04fa4497b.raw");
         let block: Block = deserialize(&segwit_block[..]).expect("Failed to deserialize block");
         assert!(block.check_merkle_root()); // Sanity check.
 

bitcoin/src/util/merkleblock.rs

@@ -528,7 +528,7 @@ mod tests {
     use secp256k1::rand::prelude::*;
 
     use crate::consensus::encode::{deserialize, serialize};
-    use crate::util::hash::bitcoin_merkle_root;
+    use crate::merkle_tree::bitcoin_merkle_root;
     use crate::util::merkleblock::{MerkleBlock, PartialMerkleTree};
     use crate::Block;
 

bitcoin/src/util/mod.rs

@@ -11,7 +11,6 @@ pub mod ecdsa;
 pub mod schnorr;
 pub mod amount;
 pub mod base58;
-pub mod hash;
 pub mod merkleblock;
 pub mod psbt;
 pub mod taproot;
@@ -95,6 +94,34 @@ pub use crate::bip32;
 #[deprecated(since = "0.30.0", note = "Please use crate::bip158")]
 pub use crate::bip158;
 
+/// Functions from the `hash` module were renamed and moved to `../merkle_tree`.
+pub mod hash {
+    use crate::consensus::encode::Encodable;
+    use crate::hashes::Hash;
+    use crate::io;
+
+    /// Calculates the merkle root of a list of *hashes*, inline (in place) in `hashes`.
+    #[deprecated(since = "0.30.0", note = "Please use crate::merkle_tree::bitcoin_merkle_root_inline")]
+    pub fn bitcoin_merkle_root_inline<T>(hashes: &mut [T]) -> Option<T>
+    where
+        T: Hash + Encodable,
+    <T as Hash>::Engine: io::Write,
+    {
+        crate::merkle_tree::bitcoin_merkle_root_inline(hashes)
+    }
+
+    /// Calculates the merkle root of an iterator of *hashes*.
+    #[deprecated(since = "0.30.0", note = "Please use crate::merkle_tree::bitcoin_merkle_root")]
+    pub fn bitcoin_merkle_root<T, I>(hashes: I) -> Option<T>
+    where
+        T: Hash + Encodable,
+    <T as Hash>::Engine: io::Write,
+        I: Iterator<Item=T>,
+    {
+        crate::merkle_tree::bitcoin_merkle_root(hashes)
+    }
+}
+
 /// The `misc` module was moved and re-named to `sign_message`.
 pub mod misc {
     use crate::prelude::*;