chore: introduce execution oracle (#7521)

Discussing this and related topics with @Thunkar we realized that the
`getContractAddress` and similar oracles were duplicated: they existed
both in `UnconstrainedContext` and in `cheatcodes`. In my mind,
`cheatcodes` are oracles that only exist on TXE and that should not be
relied on for regular applications (i.e. they are not part of the PXE
API), whereas `UnconstrainedContext` _does_ use the regular PXE API.

These are clearly sort of standard, as can be seen in the fact that
we're using them outside of `UnconstrainedContext`, so I removed them
from both the context and cheatcodes, and created a new
`oracle::execution` mod with these four oracles.

noir-projects/aztec-nr/authwit/src/cheatcodes.nr

@@ -1,7 +1,7 @@
 use dep::aztec::{
     protocol_types::address::AztecAddress,
     context::{public_context::PublicContext, call_interfaces::CallInterface}, test::helpers::cheatcodes,
-    hash::hash_args
+    oracle::execution::{get_block_number, get_contract_address}, hash::hash_args
 };
 
 use crate::auth::{compute_inner_authwit_hash, compute_authwit_message_hash, set_authorized};
@@ -12,7 +12,7 @@ pub fn add_private_authwit_from_call_interface<C, M, T, P, Env>(
     call_interface: C
 ) where C: CallInterface<M, T, P, Env> {
     let target = call_interface.get_contract_address();
-    let inputs = cheatcodes::get_private_context_inputs(cheatcodes::get_block_number());
+    let inputs = cheatcodes::get_private_context_inputs(get_block_number());
     let chain_id = inputs.tx_context.chain_id;
     let version = inputs.tx_context.version;
     let args_hash = hash_args(call_interface.get_args());
@@ -27,10 +27,10 @@ pub fn add_public_authwit_from_call_interface<C, M, T, P, Env>(
     caller: AztecAddress,
     call_interface: C
 ) where C: CallInterface<M, T, P, Env> {
-    let current_contract = cheatcodes::get_contract_address();
+    let current_contract = get_contract_address();
     cheatcodes::set_contract_address(on_behalf_of);
     let target = call_interface.get_contract_address();
-    let inputs = cheatcodes::get_private_context_inputs(cheatcodes::get_block_number());
+    let inputs = cheatcodes::get_private_context_inputs(get_block_number());
     let chain_id = inputs.tx_context.chain_id;
     let version = inputs.tx_context.version;
     let args_hash = hash_args(call_interface.get_args());

noir-projects/aztec-nr/aztec/src/context/unconstrained_context.nr

@@ -1,5 +1,8 @@
 use dep::protocol_types::{address::AztecAddress, traits::Deserialize};
-use crate::oracle::storage::{raw_storage_read, storage_read};
+use crate::oracle::{
+    execution::{get_chain_id, get_version, get_contract_address, get_block_number},
+    storage::{raw_storage_read, storage_read}
+};
 
 struct UnconstrainedContext {
     block_number: u32,
@@ -14,10 +17,17 @@ impl UnconstrainedContext {
         // not even be accessed. However any performance gains are minimal, and we'd rather fail early if a user
         // incorrectly attempts to create an UnconstrainedContext in an environment in which these oracles are not
         // available.
-        let block_number = block_number_oracle();
-        let contract_address = contract_address_oracle();
-        let chain_id = chain_id_oracle();
-        let version = version_oracle();
+        let block_number = get_block_number();
+        let contract_address = get_contract_address();
+        let chain_id = get_chain_id();
+        let version = get_version();
+        Self { block_number, contract_address, version, chain_id }
+    }
+
+    unconstrained fn at(contract_address: AztecAddress) -> Self {
+        let block_number = get_block_number();
+        let chain_id = get_chain_id();
+        let version = get_version();
         Self { block_number, contract_address, version, chain_id }
     }
 
@@ -48,15 +58,3 @@ impl UnconstrainedContext {
         T::deserialize(self.raw_storage_read(storage_slot))
     }
 }
-
-#[oracle(getContractAddress)]
-unconstrained fn contract_address_oracle() -> AztecAddress {}
-
-#[oracle(getBlockNumber)]
-unconstrained fn block_number_oracle() -> u32 {}
-
-#[oracle(getChainId)]
-unconstrained fn chain_id_oracle() -> Field {}
-
-#[oracle(getVersion)]
-unconstrained fn version_oracle() -> Field {}

noir-projects/aztec-nr/aztec/src/note/note_getter/test.nr

@@ -5,11 +5,12 @@ use crate::{
     note_header::NoteHeader,
     note_getter_options::{NoteGetterOptions, Sort, SortOrder, Comparator, PropertySelector},
     note_getter::constrain_get_notes_internal
-}
+},
+    oracle::execution::get_contract_address
 };
 use dep::protocol_types::address::AztecAddress;
 
-use crate::test::{helpers::{test_environment::TestEnvironment, cheatcodes}, mocks::mock_note::MockNote};
+use crate::test::{helpers::test_environment::TestEnvironment, mocks::mock_note::MockNote};
 
 global storage_slot: Field = 42;
 
@@ -18,7 +19,7 @@ fn setup() -> TestEnvironment {
 }
 
 fn build_valid_note(value: Field) -> MockNote {
-    MockNote::new(value).contract_address(cheatcodes::get_contract_address()).storage_slot(storage_slot).build()
+    MockNote::new(value).contract_address(get_contract_address()).storage_slot(storage_slot).build()
 }
 
 fn assert_equivalent_vec_and_array<T, let N: u32>(
@@ -174,7 +175,7 @@ fn rejects_mismatched_storage_slot() {
     let mut env = setup();
     let mut context = env.private();
 
-    let note = MockNote::new(1).contract_address(cheatcodes::get_contract_address()).build(); // We're not setting the right storage slot
+    let note = MockNote::new(1).contract_address(get_contract_address()).build(); // We're not setting the right storage slot
 
     let mut opt_notes = [Option::none(); MAX_NOTE_HASH_READ_REQUESTS_PER_CALL];
     opt_notes[0] = Option::some(note);

noir-projects/aztec-nr/aztec/src/oracle/execution.nr

@@ -0,0 +1,29 @@
+use dep::protocol_types::address::AztecAddress;
+
+#[oracle(getContractAddress)]
+unconstrained fn get_contract_address_oracle() -> AztecAddress {}
+
+#[oracle(getBlockNumber)]
+unconstrained fn get_block_number_oracle() -> u32 {}
+
+#[oracle(getChainId)]
+unconstrained fn get_chain_id_oracle() -> Field {}
+
+#[oracle(getVersion)]
+unconstrained fn get_version_oracle() -> Field {}
+
+unconstrained pub fn get_contract_address() -> AztecAddress {
+    get_contract_address_oracle()
+}
+
+unconstrained pub fn get_block_number() -> u32 {
+    get_block_number_oracle()
+}
+
+unconstrained pub fn get_chain_id() -> Field {
+    get_chain_id_oracle()
+}
+
+unconstrained pub fn get_version() -> Field {
+    get_version_oracle()
+}

noir-projects/aztec-nr/aztec/src/oracle/mod.nr

@@ -5,6 +5,7 @@
 mod arguments;
 mod call_private_function;
 mod encryption;
+mod execution;
 mod get_contract_instance;
 mod get_l1_to_l2_membership_witness;
 mod get_nullifier_membership_witness;

noir-projects/aztec-nr/aztec/src/state_vars/private_mutable/test.nr

@@ -1,5 +1,8 @@
 use dep::protocol_types::{address::AztecAddress, point::Point};
-use crate::{context::PrivateContext, state_vars::private_mutable::PrivateMutable};
+use crate::{
+    context::PrivateContext, state_vars::private_mutable::PrivateMutable,
+    oracle::execution::get_contract_address
+};
 use crate::test::{mocks::mock_note::MockNote, helpers::{cheatcodes, test_environment::TestEnvironment}};
 use std::test::OracleMock;
 
@@ -24,7 +27,7 @@ fn test_initialize_or_replace_without_nullifier() {
     let state_var = in_private(&mut env);
 
     let value = 42;
-    let mut note = MockNote::new(value).contract_address(cheatcodes::get_contract_address()).storage_slot(storage_slot).build();
+    let mut note = MockNote::new(value).contract_address(get_contract_address()).storage_slot(storage_slot).build();
 
     let _ = OracleMock::mock("checkNullifierExists").returns(0);
     state_var.initialize_or_replace(&mut note).discard();

noir-projects/aztec-nr/aztec/src/test/helpers/cheatcodes.nr

@@ -10,26 +10,10 @@ unconstrained pub fn reset() {
     oracle_reset();
 }
 
-unconstrained pub fn get_chain_id() -> Field {
-    oracle_get_chain_id()
-}
-
-unconstrained pub fn get_version() -> Field {
-    oracle_get_version()
-}
-
-unconstrained pub fn get_contract_address() -> AztecAddress {
-    oracle_get_contract_address()
-}
-
 unconstrained pub fn set_contract_address(address: AztecAddress) {
     oracle_set_contract_address(address);
 }
 
-unconstrained pub fn get_block_number() -> u32 {
-    oracle_get_block_number()
-}
-
 unconstrained pub fn advance_blocks_by(blocks: u32) {
     oracle_advance_blocks_by(blocks);
 }
@@ -125,21 +109,9 @@ unconstrained pub fn set_fn_selector(selector: FunctionSelector) {
 #[oracle(reset)]
 unconstrained fn oracle_reset() {}
 
-#[oracle(getChainId)]
-unconstrained fn oracle_get_chain_id() -> Field {}
-
-#[oracle(getVersion)]
-unconstrained fn oracle_get_version() -> Field {}
-
-#[oracle(getContractAddress)] 
-unconstrained fn oracle_get_contract_address() -> AztecAddress {}
-
 #[oracle(setContractAddress)]
 unconstrained fn oracle_set_contract_address(address: AztecAddress) {}
 
-#[oracle(getBlockNumber)]
-unconstrained fn oracle_get_block_number() -> u32 {}
-
 #[oracle(advanceBlocksBy)]
 unconstrained fn oracle_advance_blocks_by(blocks: u32) {}
 

noir-projects/aztec-nr/aztec/src/test/helpers/test_environment.nr

@@ -16,7 +16,7 @@ use crate::note::{
     note_header::NoteHeader, note_interface::NoteInterface,
     utils::{compute_inner_note_hash, compute_note_hash_for_consumption}
 };
-use crate::oracle::notes::notify_created_note;
+use crate::oracle::{execution::{get_block_number, get_contract_address}, notes::notify_created_note};
 
 struct TestEnvironment {}
 
@@ -27,19 +27,19 @@ impl TestEnvironment {
     }
 
     fn block_number(_self: Self) -> u32 {
-        cheatcodes::get_block_number()
+        get_block_number()
     }
 
     fn contract_address(_self: Self) -> AztecAddress {
-        cheatcodes::get_contract_address()
+        get_contract_address()
     }
 
     fn impersonate(_self: Self, address: AztecAddress) {
         cheatcodes::set_contract_address(address)
     }
 
     fn advance_block_to(&mut self, block_number: u32) {
-        let difference = block_number - cheatcodes::get_block_number();
+        let difference = block_number - get_block_number();
         self.advance_block_by(difference);
     }
 
@@ -53,7 +53,7 @@ impl TestEnvironment {
     }
 
     fn private(&mut self) -> PrivateContext {
-        self.private_at(cheatcodes::get_block_number())
+        self.private_at(get_block_number())
     }
 
     // unconstrained is a key word, so we mis-spell purposefully here, like we do with contrakt
@@ -62,7 +62,7 @@ impl TestEnvironment {
     }
 
     fn private_at(&mut self, historical_block_number: u32) -> PrivateContext {
-        if historical_block_number >= cheatcodes::get_block_number() {
+        if historical_block_number >= get_block_number() {
             self.advance_block_to(historical_block_number + 1);
         }
 
@@ -114,7 +114,7 @@ impl TestEnvironment {
 
         let selector = FunctionSelector::from_signature("constructor(Field,Field)");
 
-        let mut context = self.private_at(cheatcodes::get_block_number());
+        let mut context = self.private_at(get_block_number());
 
         let _ = context.call_private_function(address, selector, args);
 
@@ -131,12 +131,12 @@ impl TestEnvironment {
     ) -> T where C: CallInterface<M, PrivateContextInputs, PrivateCircuitPublicInputs, Env>, T: Deserialize<N> {
         let original_fn = call_interface.get_original();
         let original_msg_sender = cheatcodes::get_msg_sender();
-        let original_contract_address = cheatcodes::get_contract_address();
+        let original_contract_address = get_contract_address();
         let target_address = call_interface.get_contract_address();
 
         cheatcodes::set_contract_address(target_address);
         cheatcodes::set_msg_sender(original_contract_address);
-        let mut inputs = cheatcodes::get_private_context_inputs(cheatcodes::get_block_number() - 1);
+        let mut inputs = cheatcodes::get_private_context_inputs(get_block_number() - 1);
         inputs.call_context.function_selector = call_interface.get_selector();
         inputs.call_context.is_static_call = call_interface.get_is_static();
         let public_inputs = original_fn(inputs);
@@ -153,12 +153,12 @@ impl TestEnvironment {
     ) where C: CallInterface<M, PrivateContextInputs, PrivateCircuitPublicInputs, Env> {
         let original_fn = call_interface.get_original();
         let original_msg_sender = cheatcodes::get_msg_sender();
-        let original_contract_address = cheatcodes::get_contract_address();
+        let original_contract_address = get_contract_address();
         let target_address = call_interface.get_contract_address();
 
         cheatcodes::set_contract_address(target_address);
         cheatcodes::set_msg_sender(original_contract_address);
-        let mut inputs = cheatcodes::get_private_context_inputs(cheatcodes::get_block_number() - 1);
+        let mut inputs = cheatcodes::get_private_context_inputs(get_block_number() - 1);
         inputs.call_context.function_selector = call_interface.get_selector();
         inputs.call_context.is_static_call = call_interface.get_is_static();
         let public_inputs = original_fn(inputs);
@@ -175,7 +175,7 @@ impl TestEnvironment {
     ) -> T where C: CallInterface<M, PublicContextInputs, T, Env> {
         let original_fn = call_interface.get_original();
         let original_msg_sender = cheatcodes::get_msg_sender();
-        let original_contract_address = cheatcodes::get_contract_address();
+        let original_contract_address = get_contract_address();
         let original_fn_selector = cheatcodes::get_function_selector();
         let target_address = call_interface.get_contract_address();
         let fn_selector = call_interface.get_selector();
@@ -225,7 +225,7 @@ impl TestEnvironment {
         storage_slot: Field,
         contract_address: AztecAddress
     ) where Note: NoteInterface<N, M> {
-        let original_contract_address = cheatcodes::get_contract_address();
+        let original_contract_address = get_contract_address();
         cheatcodes::set_contract_address(contract_address);
         let note_hash_counter = cheatcodes::get_side_effects_counter();
 

noir-projects/aztec-nr/aztec/src/test/helpers/utils.nr

@@ -10,7 +10,7 @@ use crate::test::helpers::cheatcodes;
 use crate::keys::public_keys::{PUBLIC_KEYS_LENGTH, PublicKeys};
 use crate::hash::hash_args;
 
-use crate::oracle::notes::notify_nullified_note;
+use crate::oracle::{execution::{get_block_number, get_contract_address}, notes::notify_nullified_note};
 
 pub fn apply_side_effects_private(contract_address: AztecAddress, public_inputs: PrivateCircuitPublicInputs) {
     let mut nullifiers = &[];
@@ -47,10 +47,10 @@ impl<let N: u32> Deployer<N> {
         );
         let address = instance.to_address();
         cheatcodes::advance_blocks_by(1);
-        let block_number = cheatcodes::get_block_number();
+        let block_number = get_block_number();
         let original_fn = call_interface.get_original();
         let original_msg_sender = cheatcodes::get_msg_sender();
-        let original_contract_address = cheatcodes::get_contract_address();
+        let original_contract_address = get_contract_address();
 
         cheatcodes::set_contract_address(address);
         cheatcodes::set_msg_sender(original_contract_address);
@@ -77,7 +77,7 @@ impl<let N: u32> Deployer<N> {
         cheatcodes::advance_blocks_by(1);
         let original_fn = call_interface.get_original();
         let original_msg_sender = cheatcodes::get_msg_sender();
-        let original_contract_address = cheatcodes::get_contract_address();
+        let original_contract_address = get_contract_address();
         let original_fn_selector = cheatcodes::get_function_selector();
 
         cheatcodes::set_fn_selector(call_interface.get_selector());

noir-projects/noir-contracts/contracts/private_token_contract/src/test/utils.nr

@@ -3,7 +3,8 @@ use dep::aztec::{
     test::helpers::{cheatcodes, test_environment::TestEnvironment},
     protocol_types::storage::map::derive_storage_slot_in_map,
     note::{note_getter::{MAX_NOTES_PER_PAGE, view_notes}, note_viewer_options::NoteViewerOptions},
-    oracle::{unsafe_rand::unsafe_rand, storage::storage_read}, context::PrivateContext
+    oracle::{execution::get_contract_address, unsafe_rand::unsafe_rand, storage::storage_read},
+    context::PrivateContext
 };
 
 use crate::{types::{token_note::TokenNote}, PrivateToken};
@@ -58,7 +59,7 @@ pub fn check_private_balance(
     address: AztecAddress,
     address_amount: Field
 ) {
-    let current_contract_address = cheatcodes::get_contract_address();
+    let current_contract_address = get_contract_address();
     cheatcodes::set_contract_address(token_contract_address);
 
     let header = context.get_header();