feat!: prevent compiling blake3 hashes which barretenberg cannot prove

noir_stdlib/src/hash/mod.nr

@@ -30,11 +30,23 @@ pub fn blake2s<let N: u32>(input: [u8; N]) -> [u8; 32]
 // docs:end:blake2s
 {}
 
-#[foreign(blake3)]
 // docs:start:blake3
 pub fn blake3<let N: u32>(input: [u8; N]) -> [u8; 32]
 // docs:end:blake3
-{}
+{
+    if crate::runtime::is_unconstrained() {
+        // Temporary measure while Barretenberg is main proving system.
+        // Please open an issue if you're working on another proving system and running into problems due to this.
+        crate::static_assert(
+            N <= 1024,
+            "Barretenberg cannot prove blake3 hashes with inputs larger than 1024 bytes",
+        );
+    }
+    __blake3(input)
+}
+
+#[foreign(blake3)]
+fn __blake3<let N: u32>(input: [u8; N]) -> [u8; 32] {}
 
 // docs:start:pedersen_commitment
 pub fn pedersen_commitment<let N: u32>(input: [Field; N]) -> EmbeddedCurvePoint {

test_programs/execution_success/brillig_cow_regression/src/main.nr

@@ -172,6 +172,6 @@ unconstrained fn main(kernel_data: DataToHash) -> pub [Field; NUM_FIELDS_PER_SHA
         }
     }
 
-    let blake3_digest = std::hash::blake3(hash_input_flattened);
-    U256::from_bytes32(blake3_digest).to_u128_limbs()
+    let blake2_digest = std::hash::blake2s(hash_input_flattened);
+    U256::from_bytes32(blake2_digest).to_u128_limbs()
 }

test_programs/execution_success/ram_blowup_regression/src/main.nr

@@ -20,9 +20,9 @@ pub fn field_from_bytes_32_trunc(bytes32: [u8; 32]) -> Field {
     low + high * v
 }
 
-pub fn blake3_to_field<let N: u32>(bytes_to_hash: [u8; N]) -> Field {
-    let blake3_hashed = std::hash::blake3(bytes_to_hash);
-    let hash_in_a_field = field_from_bytes_32_trunc(blake3_hashed);
+pub fn blake2s_to_field<let N: u32>(bytes_to_hash: [u8; N]) -> Field {
+    let blake2s_hashed = std::hash::blake2s(bytes_to_hash);
+    let hash_in_a_field = field_from_bytes_32_trunc(blake2s_hashed);
 
     hash_in_a_field
 }
@@ -36,6 +36,6 @@ fn main(tx_effects_hash_input: [Field; TX_EFFECTS_HASH_INPUT_FIELDS]) -> pub Fie
         }
     }
 
-    let blake3_digest = blake3_to_field(hash_input_flattened);
-    blake3_digest
+    let blake2s_digest = blake2s_to_field(hash_input_flattened);
+    blake2s_digest
 }