Replace unstable-nu6 and zfuture feature flags with cfg flags

Neither of these should have been feature flags, as they gate breaking
changes to the Zcash consensus rules (and in some ways are incompatible
with each other), while feature flags should be additive.

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
             extra_flags: orchard
             rustflags: '--cfg zcash_unstable="orchard"'
           - state: NU6
-            extra_flags: unstable-nu6
+            rustflags: '--cfg zcash_unstable="nu6"'
 
         exclude:
           - target: macOS
@@ -103,7 +103,7 @@ jobs:
             os: windows-latest
 
           - state: ZFuture
-            extra_flags: zfuture
+            rustflags: '--cfg zcash_unstable="zfuture"'
 
     env:
       RUSTFLAGS: ${{ matrix.rustflags }}

Cargo.toml

@@ -7,8 +7,7 @@ members = [
     "components/zcash_protocol",
     "zcash_client_backend",
     "zcash_client_sqlite",
-    # Disabled until we replace the `zfutures` feature flag with a compiler flag.
-    # "zcash_extensions",
+    "zcash_extensions",
     "zcash_history",
     "zcash_keys",
     "zcash_primitives",

components/zcash_protocol/CHANGELOG.md

@@ -11,6 +11,11 @@ and this library adheres to Rust's notion of
 - `zcash_protocol::memo`:
   - `impl TryFrom<&MemoBytes> for Memo`
 
+### Removed
+- `unstable-nu6` and `zfuture` feature flags (use `--cfg zcash_unstable=\"nu6\"`
+  or `--cfg zcash_unstable=\"zfuture\"` in `RUSTFLAGS` and `RUSTDOCFLAGS`
+  instead).
+
 ## [0.1.0] - 2024-03-06
 The entries below are relative to the `zcash_primitives` crate as of the tag
 `zcash_primitives-0.14.0`.

components/zcash_protocol/Cargo.toml

@@ -45,14 +45,3 @@ test-dependencies = [
 
 ## Exposes support for working with a local consensus (e.g. regtest).
 local-consensus = []
-
-#! ### Experimental features
-#!
-#! ⚠️ Enabling these features will likely make your code incompatible with current Zcash
-#! consensus rules!
-
-## Exposes the in-development NU6 features.
-unstable-nu6 = []
-
-## Exposes early in-development features that are not yet planned for any network upgrade.
-zfuture = []

components/zcash_protocol/src/consensus.rs

@@ -354,9 +354,9 @@ impl Parameters for MainNetwork {
             NetworkUpgrade::Heartwood => Some(BlockHeight(903_000)),
             NetworkUpgrade::Canopy => Some(BlockHeight(1_046_400)),
             NetworkUpgrade::Nu5 => Some(BlockHeight(1_687_104)),
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             NetworkUpgrade::Nu6 => None,
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             NetworkUpgrade::ZFuture => None,
         }
     }
@@ -384,9 +384,9 @@ impl Parameters for TestNetwork {
             NetworkUpgrade::Heartwood => Some(BlockHeight(903_800)),
             NetworkUpgrade::Canopy => Some(BlockHeight(1_028_500)),
             NetworkUpgrade::Nu5 => Some(BlockHeight(1_842_420)),
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             NetworkUpgrade::Nu6 => None,
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             NetworkUpgrade::ZFuture => None,
         }
     }
@@ -452,14 +452,14 @@ pub enum NetworkUpgrade {
     /// The [Nu6] network upgrade.
     ///
     /// [Nu6]: https://z.cash/upgrade/nu6/
-    #[cfg(feature = "unstable-nu6")]
+    #[cfg(zcash_unstable = "nu6")]
     Nu6,
     /// The ZFUTURE network upgrade.
     ///
     /// This upgrade is expected never to activate on mainnet;
     /// it is intended for use in integration testing of functionality
     /// that is a candidate for integration in a future network upgrade.
-    #[cfg(feature = "zfuture")]
+    #[cfg(zcash_unstable = "zfuture")]
     ZFuture,
 }
 
@@ -474,9 +474,9 @@ impl fmt::Display for NetworkUpgrade {
             NetworkUpgrade::Heartwood => write!(f, "Heartwood"),
             NetworkUpgrade::Canopy => write!(f, "Canopy"),
             NetworkUpgrade::Nu5 => write!(f, "Nu5"),
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             NetworkUpgrade::Nu6 => write!(f, "Nu6"),
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             NetworkUpgrade::ZFuture => write!(f, "ZFUTURE"),
         }
     }
@@ -491,9 +491,9 @@ impl NetworkUpgrade {
             NetworkUpgrade::Heartwood => BranchId::Heartwood,
             NetworkUpgrade::Canopy => BranchId::Canopy,
             NetworkUpgrade::Nu5 => BranchId::Nu5,
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             NetworkUpgrade::Nu6 => BranchId::Nu6,
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             NetworkUpgrade::ZFuture => BranchId::ZFuture,
         }
     }
@@ -510,7 +510,7 @@ const UPGRADES_IN_ORDER: &[NetworkUpgrade] = &[
     NetworkUpgrade::Heartwood,
     NetworkUpgrade::Canopy,
     NetworkUpgrade::Nu5,
-    #[cfg(feature = "unstable-nu6")]
+    #[cfg(zcash_unstable = "nu6")]
     NetworkUpgrade::Nu6,
 ];
 
@@ -549,11 +549,11 @@ pub enum BranchId {
     /// The consensus rules deployed by [`NetworkUpgrade::Nu5`].
     Nu5,
     /// The consensus rules deployed by [`NetworkUpgrade::Nu6`].
-    #[cfg(feature = "unstable-nu6")]
+    #[cfg(zcash_unstable = "nu6")]
     Nu6,
     /// Candidates for future consensus rules; this branch will never
     /// activate on mainnet.
-    #[cfg(feature = "zfuture")]
+    #[cfg(zcash_unstable = "zfuture")]
     ZFuture,
 }
 
@@ -571,9 +571,9 @@ impl TryFrom<u32> for BranchId {
             0xf5b9_230b => Ok(BranchId::Heartwood),
             0xe9ff_75a6 => Ok(BranchId::Canopy),
             0xc2d6_d0b4 => Ok(BranchId::Nu5),
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             0xc8e7_1055 => Ok(BranchId::Nu6),
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             0xffff_ffff => Ok(BranchId::ZFuture),
             _ => Err("Unknown consensus branch ID"),
         }
@@ -590,9 +590,9 @@ impl From<BranchId> for u32 {
             BranchId::Heartwood => 0xf5b9_230b,
             BranchId::Canopy => 0xe9ff_75a6,
             BranchId::Nu5 => 0xc2d6_d0b4,
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             BranchId::Nu6 => 0xc8e7_1055,
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             BranchId::ZFuture => 0xffff_ffff,
         }
     }
@@ -658,15 +658,15 @@ impl BranchId {
                 .activation_height(NetworkUpgrade::Canopy)
                 .map(|lower| (lower, params.activation_height(NetworkUpgrade::Nu5))),
             BranchId::Nu5 => params.activation_height(NetworkUpgrade::Nu5).map(|lower| {
-                #[cfg(feature = "zfuture")]
+                #[cfg(zcash_unstable = "zfuture")]
                 let upper = params.activation_height(NetworkUpgrade::ZFuture);
-                #[cfg(not(feature = "zfuture"))]
+                #[cfg(not(zcash_unstable = "zfuture"))]
                 let upper = None;
                 (lower, upper)
             }),
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             BranchId::Nu6 => None,
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             BranchId::ZFuture => params
                 .activation_height(NetworkUpgrade::ZFuture)
                 .map(|lower| (lower, None)),
@@ -694,9 +694,9 @@ pub mod testing {
             BranchId::Heartwood,
             BranchId::Canopy,
             BranchId::Nu5,
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             BranchId::Nu6,
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             BranchId::ZFuture,
         ])
     }

components/zcash_protocol/src/local_consensus.rs

@@ -26,10 +26,6 @@ use crate::consensus::{BlockHeight, NetworkType, NetworkUpgrade, Parameters};
 ///         heartwood: Some(BlockHeight::from_u32(1)),
 ///         canopy: Some(BlockHeight::from_u32(1)),
 ///         nu5: Some(BlockHeight::from_u32(1)),
-///         #[cfg(feature = "unstable-nu6")]
-///         nu6: Some(BlockHeight::from_u32(1)),
-///         #[cfg(feature = "zfuture")]
-///         z_future: Some(BlockHeight::from_u32(1)),
 ///         };
 ///     ```
 ///     
@@ -41,9 +37,9 @@ pub struct LocalNetwork {
     pub heartwood: Option<BlockHeight>,
     pub canopy: Option<BlockHeight>,
     pub nu5: Option<BlockHeight>,
-    #[cfg(feature = "unstable-nu6")]
+    #[cfg(zcash_unstable = "nu6")]
     pub nu6: Option<BlockHeight>,
-    #[cfg(feature = "zfuture")]
+    #[cfg(zcash_unstable = "zfuture")]
     pub z_future: Option<BlockHeight>,
 }
 
@@ -61,9 +57,9 @@ impl Parameters for LocalNetwork {
             NetworkUpgrade::Heartwood => self.heartwood,
             NetworkUpgrade::Canopy => self.canopy,
             NetworkUpgrade::Nu5 => self.nu5,
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             NetworkUpgrade::Nu6 => self.nu6,
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             NetworkUpgrade::ZFuture => self.z_future,
         }
     }
@@ -85,9 +81,9 @@ mod tests {
         let expected_heartwood = BlockHeight::from_u32(4);
         let expected_canopy = BlockHeight::from_u32(5);
         let expected_nu5 = BlockHeight::from_u32(6);
-        #[cfg(feature = "unstable-nu6")]
+        #[cfg(zcash_unstable = "nu6")]
         let expected_nu6 = BlockHeight::from_u32(7);
-        #[cfg(feature = "zfuture")]
+        #[cfg(zcash_unstable = "zfuture")]
         let expected_z_future = BlockHeight::from_u32(7);
 
         let regtest = LocalNetwork {
@@ -97,9 +93,9 @@ mod tests {
             heartwood: Some(expected_heartwood),
             canopy: Some(expected_canopy),
             nu5: Some(expected_nu5),
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             nu6: Some(expected_nu6),
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             z_future: Some(expected_z_future),
         };
 
@@ -109,9 +105,9 @@ mod tests {
         assert!(regtest.is_nu_active(NetworkUpgrade::Heartwood, expected_heartwood));
         assert!(regtest.is_nu_active(NetworkUpgrade::Canopy, expected_canopy));
         assert!(regtest.is_nu_active(NetworkUpgrade::Nu5, expected_nu5));
-        #[cfg(feature = "unstable-nu6")]
+        #[cfg(zcash_unstable = "nu6")]
         assert!(regtest.is_nu_active(NetworkUpgrade::Nu6, expected_nu6));
-        #[cfg(feature = "zfuture")]
+        #[cfg(zcash_unstable = "zfuture")]
         assert!(!regtest.is_nu_active(NetworkUpgrade::ZFuture, expected_nu5));
     }
 
@@ -123,9 +119,9 @@ mod tests {
         let expected_heartwood = BlockHeight::from_u32(4);
         let expected_canopy = BlockHeight::from_u32(5);
         let expected_nu5 = BlockHeight::from_u32(6);
-        #[cfg(feature = "unstable-nu6")]
+        #[cfg(zcash_unstable = "nu6")]
         let expected_nu6 = BlockHeight::from_u32(7);
-        #[cfg(feature = "zfuture")]
+        #[cfg(zcash_unstable = "zfuture")]
         let expected_z_future = BlockHeight::from_u32(7);
 
         let regtest = LocalNetwork {
@@ -135,9 +131,9 @@ mod tests {
             heartwood: Some(expected_heartwood),
             canopy: Some(expected_canopy),
             nu5: Some(expected_nu5),
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             nu6: Some(expected_nu6),
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             z_future: Some(expected_z_future),
         };
 
@@ -165,7 +161,7 @@ mod tests {
             regtest.activation_height(NetworkUpgrade::Nu5),
             Some(expected_nu5)
         );
-        #[cfg(feature = "zfuture")]
+        #[cfg(zcash_unstable = "zfuture")]
         assert_eq!(
             regtest.activation_height(NetworkUpgrade::ZFuture),
             Some(expected_z_future)
@@ -180,9 +176,9 @@ mod tests {
         let expected_heartwood = BlockHeight::from_u32(4);
         let expected_canopy = BlockHeight::from_u32(5);
         let expected_nu5 = BlockHeight::from_u32(6);
-        #[cfg(feature = "unstable-nu6")]
+        #[cfg(zcash_unstable = "nu6")]
         let expected_nu6 = BlockHeight::from_u32(7);
-        #[cfg(feature = "zfuture")]
+        #[cfg(zcash_unstable = "zfuture")]
         let expected_z_future = BlockHeight::from_u32(7);
 
         let regtest = LocalNetwork {
@@ -192,9 +188,9 @@ mod tests {
             heartwood: Some(expected_heartwood),
             canopy: Some(expected_canopy),
             nu5: Some(expected_nu5),
-            #[cfg(feature = "unstable-nu6")]
+            #[cfg(zcash_unstable = "nu6")]
             nu6: Some(expected_nu6),
-            #[cfg(feature = "zfuture")]
+            #[cfg(zcash_unstable = "zfuture")]
             z_future: Some(expected_z_future),
         };
 

zcash_client_sqlite/Cargo.toml

@@ -97,8 +97,6 @@ zcash_address = { workspace = true, features = ["test-dependencies"] }
 
 [features]
 default = ["multicore"]
-unstable-nu6 = ["zcash_primitives/unstable-nu6"]
-zfuture = ["zcash_primitives/zfuture"]
 
 ## Enables multithreading support for creating proofs and building subtrees.
 multicore = ["maybe-rayon/threads", "zcash_primitives/multicore"]

zcash_client_sqlite/src/testing.rs

@@ -119,9 +119,9 @@ impl TestBuilder<()> {
                 heartwood: Some(BlockHeight::from_u32(100_000)),
                 canopy: Some(BlockHeight::from_u32(100_000)),
                 nu5: Some(BlockHeight::from_u32(100_000)),
-                #[cfg(feature = "unstable-nu6")]
+                #[cfg(zcash_unstable = "nu6")]
                 nu6: None,
-                #[cfg(feature = "zfuture")]
+                #[cfg(zcash_unstable = "zfuture")]
                 z_future: None,
             },
             cache: (),

zcash_extensions/Cargo.toml

@@ -16,7 +16,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 
 [dependencies]
 blake2b_simd.workspace = true
-zcash_primitives = { workspace = true, features = ["zfuture" ] }
+zcash_primitives.workspace = true
 
 [dev-dependencies]
 ff.workspace = true
@@ -29,7 +29,6 @@ zcash_proofs.workspace = true
 
 [features]
 transparent-inputs = []
-unstable-nu6 = ["zcash_primitives/unstable-nu6"]
 
 [lib]
 bench = false

zcash_extensions/src/lib.rs

@@ -3,5 +3,10 @@
 // Catch documentation errors caused by code changes.
 #![deny(rustdoc::broken_intra_doc_links)]
 
+// For workspace compilation reasons, we have this crate in the workspace and just leave
+// it empty if `zfuture` is not enabled.
+
+#[cfg(zcash_unstable = "zfuture")]
 pub mod consensus;
+#[cfg(zcash_unstable = "zfuture")]
 pub mod transparent;