Add docs.rs feature flag labels to `incrementalmerkletree` and `shardtree`

incrementalmerkletree/Cargo.toml

@@ -13,6 +13,10 @@ repository = "https://github.com/zcash/incrementalmerkletree"
 categories = ["algorithms", "data-structures"]
 rust-version = "1.60"
 
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
 [dependencies]
 either = "1.8"
 proptest = { version = "1.0.0", optional = true }
@@ -21,10 +25,10 @@ proptest = { version = "1.0.0", optional = true }
 proptest = "1.0.0"
 
 [features]
-# The legacy-api feature guards types and functions that were previously 
+# The legacy-api feature guards types and functions that were previously
 # part of the `zcash_primitives` crate. Those types were removed in the
 # `zcash_primitives` 0.12 release and are now maintained here.
 legacy-api = []
-# The test-dependencies feature guards types and functions that are 
+# The test-dependencies feature guards types and functions that are
 # useful for testing incremental Merkle trees and Merkle tree frontiers.
 test-dependencies = ["proptest"]

incrementalmerkletree/src/frontier.rs

@@ -281,6 +281,7 @@ impl<H: Hashable + Clone, const DEPTH: u8> Frontier<H, DEPTH> {
 }
 
 #[cfg(feature = "legacy-api")]
+#[cfg_attr(docsrs, doc(cfg(feature = "legacy-api")))]
 pub struct PathFiller<H> {
     queue: VecDeque<H>,
 }
@@ -307,6 +308,7 @@ impl<H: Hashable> PathFiller<H> {
 /// A Merkle tree of note commitments.
 #[derive(Clone, Debug, PartialEq, Eq)]
 #[cfg(feature = "legacy-api")]
+#[cfg_attr(docsrs, doc(cfg(feature = "legacy-api")))]
 pub struct CommitmentTree<H, const DEPTH: u8> {
     pub(crate) left: Option<H>,
     pub(crate) right: Option<H>,
@@ -600,6 +602,7 @@ pub mod testing {
     use crate::frontier::CommitmentTree;
 
     #[cfg(feature = "legacy-api")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "legacy-api")))]
     pub fn arb_commitment_tree<
         H: Hashable + Clone + Debug,
         T: Strategy<Value = H>,

incrementalmerkletree/src/lib.rs

@@ -43,6 +43,8 @@
 //! Note: we often refer to `ommers` (plural) when describing leaf-to-root paths, so in that
 //! context `ommers` refers to the node's ommer, plus each ancestor's ommer.
 
+#![cfg_attr(docsrs, feature(doc_cfg))]
+
 use either::Either;
 use std::cmp::Ordering;
 use std::convert::{TryFrom, TryInto};
@@ -53,9 +55,11 @@ use std::ops::{Add, AddAssign, Range, Sub};
 pub mod frontier;
 
 #[cfg(feature = "legacy-api")]
+#[cfg_attr(docsrs, doc(cfg(feature = "legacy-api")))]
 pub mod witness;
 
 #[cfg(feature = "test-dependencies")]
+#[cfg_attr(docsrs, doc(cfg(feature = "test-dependencies")))]
 pub mod testing;
 
 /// A type for metadata that is used to determine when and how a leaf can be pruned from a tree.

shardtree/Cargo.toml

@@ -12,6 +12,10 @@ homepage = "https://github.com/zcash/incrementalmerkletree"
 repository = "https://github.com/zcash/incrementalmerkletree"
 categories = ["algorithms", "data-structures"]
 
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
 [dependencies]
 assert_matches = { version = "1.5", optional = true }
 bitflags = "1.3"

shardtree/src/lib.rs

@@ -20,6 +20,8 @@
 //! to be inserted, along with the necessary nodes to build a path from the marked leaf to
 //! the root of the shard containing it.
 
+#![cfg_attr(docsrs, feature(doc_cfg))]
+
 use core::fmt::Debug;
 use either::Either;
 use std::collections::{BTreeMap, BTreeSet};
@@ -51,6 +53,7 @@ pub mod store;
 pub mod testing;
 
 #[cfg(feature = "legacy-api")]
+#[cfg_attr(docsrs, doc(cfg(feature = "legacy-api")))]
 mod legacy;
 
 /// A sparse binary Merkle tree of the specified depth, represented as an ordered collection of