Merge rust-bitcoin/rust-bitcoin#2248: Implement ArbitaryOrd for absolute::LockTime

518f0970c9 Implement ArbitaryOrd for absolute::LockTime (Tobin C. Harding)

Pull request description:

  At times we would like to provide types that do not implement `PartialOrd` and `Ord` because it does not make sense. I.e we do not want users writing `a < b`. This could range from kind-of-iffy to down-right-buggy (like comparing absolute locktimes).

  However this decision effects downstream users who may not care about what the ordering means they just need to use it for some other reason e.g., to use as part of a key for a `BTreeMap` (as we do in `miniscript` requiring the `AbsLockTime` type).

  A solution to this problem is to provide a wrapper data type that adds `PartialOrd` and `Ord` implementations. I wrote the `ordered` crate is for this very purpose.

ACKs for top commit:
  apoelstra:
    ACK 518f0970c9
  Kixunil:
    ACK 518f0970c9

Tree-SHA512: 05c753e650b6e2f181caf7dc363c4f8ec89237b42883bd695a64da0661436c9a7e715347f8fcf4fb19ce069cbf75a93032052e946f05fd8029f61860cf9c6225

Cargo-minimal.lock

@@ -45,6 +45,7 @@ dependencies = [
  "hex-conservative",
  "hex_lit",
  "mutagen",
+ "ordered",
  "secp256k1",
  "serde",
  "serde_json",
@@ -235,6 +236,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "ordered"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f0642533dea0bb58bd5cae31bafc1872429f0f12ac8c61fe2b4ba44f80b959b"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.8"

Cargo-recent.lock

@@ -44,6 +44,7 @@ dependencies = [
  "hex-conservative",
  "hex_lit",
  "mutagen",
+ "ordered",
  "secp256k1",
  "serde",
  "serde_json",
@@ -234,6 +235,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "ordered"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f0642533dea0bb58bd5cae31bafc1872429f0f12ac8c61fe2b4ba44f80b959b"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.17"

bitcoin/Cargo.toml

@@ -38,6 +38,7 @@ secp256k1 = { version = "0.28.0", default-features = false, features = ["hashes"
 units = { package = "bitcoin-units", version = "0.1.0", default-features = false, features = ["alloc"] }
 
 base64 = { version = "0.21.3", optional = true }
+ordered = { version = "0.2.0", optional = true }
 # Only use this feature for no-std builds, otherwise use bitcoinconsensus-std.
 bitcoinconsensus = { version = "0.20.2-0.5.0", default-features = false, optional = true }
 

bitcoin/src/blockdata/locktime/absolute.rs

@@ -389,6 +389,20 @@ impl<'de> serde::Deserialize<'de> for LockTime {
     }
 }
 
+#[cfg(feature = "ordered")]
+impl ordered::ArbitraryOrd for LockTime {
+    fn arbitrary_cmp(&self, other: &Self) -> Ordering {
+        use LockTime::*;
+
+        match (self, other) {
+            (Blocks(_), Seconds(_)) => Ordering::Less,
+            (Seconds(_), Blocks(_)) => Ordering::Greater,
+            (Blocks(this), Blocks(that)) => this.cmp(that),
+            (Seconds(this), Seconds(that)) => this.cmp(that),
+        }
+    }
+}
+
 /// An absolute block height, guaranteed to always contain a valid height value.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]

bitcoin/src/lib.rs

@@ -71,6 +71,10 @@ pub extern crate hex;
 /// Re-export the `bitcoin-io` crate.
 pub extern crate io;
 
+/// Re-export the `ordered` crate.
+#[cfg(feature = "ordered")]
+pub extern crate ordered;
+
 /// Rust wrapper library for Pieter Wuille's libsecp256k1.  Implements ECDSA and BIP 340 signatures
 /// for the SECG elliptic curve group secp256k1 and related utilities.
 pub extern crate secp256k1;