Make it possible to build with the "circuit" feature for no_std targets

.github/workflows/ci.yml

@@ -63,7 +63,7 @@ jobs:
           echo "#![no_std]" > ./ci-build/src/lib.rs
       - name: Add dependencies of the synthetic crate (e.g. sapling-crypto)
         working-directory: ./ci-build
-        run: cargo add --no-default-features --path ../crate_root
+        run: cargo add --no-default-features --features "circuit" --path ../crate_root
       - name: Add lazy_static with the spin_no_std feature
         working-directory: ./ci-build
         run: cargo add lazy_static --no-default-features --features "spin_no_std"
@@ -73,6 +73,12 @@ jobs:
       - name: Show Cargo.toml for the synthetic crate
         working-directory: ./ci-build
         run: cat Cargo.toml
+      - name: DEBUG cargo tree -i -p getrandom -e features
+        working-directory: ./ci-build
+        run: cargo tree -i -p getrandom -e features
+      - name: DEBUG cargo tree -i -p rand_core -e features
+        working-directory: ./ci-build
+        run: cargo tree -i -p rand_core -e features
       - name: Add target
         working-directory: ./ci-build
         run: rustup target add ${{ matrix.target }}

.github/workflows/lints-stable.yml

@@ -43,7 +43,7 @@ jobs:
           echo "#![no_std]" > ./ci-build/src/lib.rs
       - name: Add dependencies of the synthetic crate (e.g. sapling-crypto)
         working-directory: ./ci-build
-        run: cargo add --no-default-features --path ../crate_root
+        run: cargo add --no-default-features --features "circuit" --path ../crate_root
       - name: Add lazy_static with the spin_no_std feature
         working-directory: ./ci-build
         run: cargo add lazy_static --no-default-features --features "spin_no_std"
@@ -53,6 +53,12 @@ jobs:
       - name: Show Cargo.toml for the synthetic crate
         working-directory: ./ci-build
         run: cat Cargo.toml
+      - name: DEBUG cargo tree -i -p getrandom -e features
+        working-directory: ./ci-build
+        run: cargo tree -i -p getrandom -e features
+      - name: DEBUG cargo tree -i -p rand_core -e features
+        working-directory: ./ci-build
+        run: cargo tree -i -p rand_core -e features
       - name: Add target
         working-directory: ./ci-build
         run: rustup target add ${{ matrix.target }}

CHANGELOG.md

@@ -6,6 +6,11 @@ and this project adheres to Rust's notion of
 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- The "circuit" feature no longer implies the "std" feature. "circuit" can now
+  potentially be used in `no_std` environments.
+- `orchard::bundle::batch` is now only available when the "std" feature is enabled
+  together with the "circuit" feature.
 
 ## [0.11.0] - 2025-02-20
 

Cargo.toml

@@ -83,7 +83,7 @@ bench = false
 [features]
 default = ["circuit", "multicore", "std"]
 std = ["core2/std", "group/wnaf-memuse", "reddsa/std"]
-circuit = ["dep:halo2_gadgets", "dep:halo2_proofs", "std"]
+circuit = ["dep:halo2_gadgets", "dep:halo2_proofs"]
 unstable-frost = []
 multicore = ["halo2_proofs?/multicore"]
 dev-graph = ["halo2_proofs?/dev-graph", "image", "plotters"]
@@ -106,3 +106,7 @@ debug = true
 
 [profile.bench]
 debug = true
+
+[patch.crates-io]
+halo2_gadgets = { git = "https://github.com/zcash/halo2.git", rev = "7e173f8e2e6e8717052e472384bdf28e58eaff19" }
+halo2_proofs = { git = "https://github.com/zcash/halo2.git", rev = "7e173f8e2e6e8717052e472384bdf28e58eaff19" }

src/bundle.rs

@@ -4,9 +4,9 @@ use alloc::vec::Vec;
 
 pub mod commitments;
 
-#[cfg(feature = "circuit")]
+#[cfg(all(feature = "circuit", feature = "std"))]
 mod batch;
-#[cfg(feature = "circuit")]
+#[cfg(all(feature = "circuit", feature = "std"))]
 pub use batch::BatchValidator;
 
 use core::fmt;