fix(avm-simulator): nested calls should preserve static context

yarn-project/simulator/src/avm/avm_simulator.test.ts

@@ -880,7 +880,9 @@ describe('AVM simulator: transpiled Noir contracts', () => {
       const results = await new AvmSimulator(context).executeBytecode(callBytecode);
 
       expect(results.reverted).toBe(true); // The outer call should revert.
-      expect(results.revertReason?.message).toEqual('Static calls cannot alter storage');
+      expect(results.revertReason?.message).toEqual(
+        'Static call cannot update the state, emit L2->L1 messages or generate logs',
+      );
     });
 
     it(`Nested calls rethrow exceptions`, async () => {

yarn-project/simulator/src/avm/errors.ts

@@ -68,6 +68,16 @@ export class OutOfGasError extends AvmExecutionError {
   }
 }
 
+/**
+ * Error is thrown when a static call attempts to alter some state
+ */
+export class StaticCallAlterationError extends InstructionExecutionError {
+  constructor() {
+    super('Static call cannot update the state, emit L2->L1 messages or generate logs');
+    this.name = 'StaticCallAlterationError';
+  }
+}
+
 /**
  * Error thrown to propagate a nested call's revert.
  * @param message - the error's message

yarn-project/simulator/src/avm/opcodes/accrued_substate.test.ts

@@ -7,7 +7,7 @@ import { mock } from 'jest-mock-extended';
 import { type CommitmentsDB } from '../../index.js';
 import { type AvmContext } from '../avm_context.js';
 import { Field, Uint8 } from '../avm_memory_types.js';
-import { InstructionExecutionError } from '../errors.js';
+import { InstructionExecutionError, StaticCallAlterationError } from '../errors.js';
 import { initContext, initExecutionEnvironment, initHostStorage } from '../fixtures/index.js';
 import { AvmPersistableStateManager } from '../journal/journal.js';
 import {
@@ -19,7 +19,6 @@ import {
   NullifierExists,
   SendL2ToL1Message,
 } from './accrued_substate.js';
-import { StaticCallStorageAlterError } from './storage.js';
 
 describe('Accrued Substate', () => {
   let context: AvmContext;
@@ -482,7 +481,7 @@ describe('Accrued Substate', () => {
     ];
 
     for (const instruction of instructions) {
-      await expect(instruction.execute(context)).rejects.toThrow(StaticCallStorageAlterError);
+      await expect(instruction.execute(context)).rejects.toThrow(StaticCallAlterationError);
     }
   });
 });

yarn-project/simulator/src/avm/opcodes/accrued_substate.ts

@@ -1,11 +1,10 @@
 import type { AvmContext } from '../avm_context.js';
 import { Uint8 } from '../avm_memory_types.js';
-import { InstructionExecutionError } from '../errors.js';
+import { InstructionExecutionError, StaticCallAlterationError } from '../errors.js';
 import { NullifierCollisionError } from '../journal/nullifiers.js';
 import { Opcode, OperandType } from '../serialization/instruction_serialization.js';
 import { Addressing } from './addressing_mode.js';
 import { Instruction } from './instruction.js';
-import { StaticCallStorageAlterError } from './storage.js';
 
 export class NoteHashExists extends Instruction {
   static type: string = 'NOTEHASHEXISTS';
@@ -65,7 +64,7 @@ export class EmitNoteHash extends Instruction {
     context.machineState.consumeGas(this.gasCost(memoryOperations));
 
     if (context.environment.isStaticCall) {
-      throw new StaticCallStorageAlterError();
+      throw new StaticCallAlterationError();
     }
 
     const noteHash = memory.get(this.noteHashOffset).toFr();
@@ -125,7 +124,7 @@ export class EmitNullifier extends Instruction {
 
   public async execute(context: AvmContext): Promise<void> {
     if (context.environment.isStaticCall) {
-      throw new StaticCallStorageAlterError();
+      throw new StaticCallAlterationError();
     }
 
     const memoryOperations = { reads: 1, indirect: this.indirect };
@@ -210,7 +209,7 @@ export class EmitUnencryptedLog extends Instruction {
 
   public async execute(context: AvmContext): Promise<void> {
     if (context.environment.isStaticCall) {
-      throw new StaticCallStorageAlterError();
+      throw new StaticCallAlterationError();
     }
 
     const memoryOperations = { reads: 1 + this.logSize, indirect: this.indirect };
@@ -244,7 +243,7 @@ export class SendL2ToL1Message extends Instruction {
 
   public async execute(context: AvmContext): Promise<void> {
     if (context.environment.isStaticCall) {
-      throw new StaticCallStorageAlterError();
+      throw new StaticCallAlterationError();
     }
 
     const memoryOperations = { reads: 2, indirect: this.indirect };

yarn-project/simulator/src/avm/opcodes/external_calls.test.ts

@@ -243,7 +243,9 @@ describe('External Calls', () => {
         successOffset,
         /*temporaryFunctionSelectorOffset=*/ 0,
       );
-      await expect(() => instruction.execute(context)).rejects.toThrow(/Static calls cannot alter storage/);
+      await expect(() => instruction.execute(context)).rejects.toThrow(
+        'Static call cannot update the state, emit L2->L1 messages or generate logs',
+      );
     });
   });
 

yarn-project/simulator/src/avm/opcodes/external_calls.ts

@@ -40,7 +40,7 @@ abstract class ExternalCall extends Instruction {
     // Function selector is temporary since eventually public contract bytecode will be one blob
     // containing all functions, and function selector will become an application-level mechanism
     // (e.g. first few bytes of calldata + compiler-generated jump table)
-    private temporaryFunctionSelectorOffset: number,
+    private functionSelectorOffset: number,
   ) {
     super();
   }
@@ -59,7 +59,9 @@ abstract class ExternalCall extends Instruction {
     const calldata = memory.getSlice(argsOffset, calldataSize).map(f => f.toFr());
     const l2Gas = memory.get(gasOffset).toNumber();
     const daGas = memory.getAs<Field>(gasOffset + 1).toNumber();
-    const functionSelector = memory.getAs<Field>(this.temporaryFunctionSelectorOffset).toFr();
+    const functionSelector = memory.getAs<Field>(this.functionSelectorOffset).toFr();
+    // If we are already in a static call, we propagate the environment.
+    const callType = context.environment.isStaticCall ? 'STATICCALL' : this.type;
 
     const allocatedGas = { l2Gas, daGas };
     const memoryOperations = { reads: calldataSize + 5, writes: 1 + this.retSize, indirect: this.indirect };
@@ -71,7 +73,7 @@ abstract class ExternalCall extends Instruction {
       callAddress.toFr(),
       calldata,
       allocatedGas,
-      this.type,
+      callType,
       FunctionSelector.fromField(functionSelector),
     );
     const startSideEffectCounter = nestedContext.persistableState.trace.accessCounter;

yarn-project/simulator/src/avm/opcodes/storage.test.ts

@@ -5,9 +5,10 @@ import { type MockProxy, mock } from 'jest-mock-extended';
 
 import { type AvmContext } from '../avm_context.js';
 import { Field } from '../avm_memory_types.js';
+import { StaticCallAlterationError } from '../errors.js';
 import { initContext, initExecutionEnvironment } from '../fixtures/index.js';
 import { type AvmPersistableStateManager } from '../journal/journal.js';
-import { SLoad, SStore, StaticCallStorageAlterError } from './storage.js';
+import { SLoad, SStore } from './storage.js';
 
 describe('Storage Instructions', () => {
   let context: AvmContext;
@@ -68,7 +69,7 @@ describe('Storage Instructions', () => {
 
       const instruction = () =>
         new SStore(/*indirect=*/ 0, /*srcOffset=*/ 0, /*size=*/ 1, /*slotOffset=*/ 1).execute(context);
-      await expect(instruction()).rejects.toThrow(StaticCallStorageAlterError);
+      await expect(instruction()).rejects.toThrow(StaticCallAlterationError);
     });
   });
 

yarn-project/simulator/src/avm/opcodes/storage.ts

@@ -3,7 +3,7 @@ import { Fr } from '@aztec/foundation/fields';
 import type { AvmContext } from '../avm_context.js';
 import { type Gas, getBaseGasCost, getMemoryGasCost, mulGas, sumGas } from '../avm_gas.js';
 import { Field, type MemoryOperations } from '../avm_memory_types.js';
-import { InstructionExecutionError } from '../errors.js';
+import { StaticCallAlterationError } from '../errors.js';
 import { Opcode, OperandType } from '../serialization/instruction_serialization.js';
 import { Addressing } from './addressing_mode.js';
 import { Instruction } from './instruction.js';
@@ -44,7 +44,7 @@ export class SStore extends BaseStorageInstruction {
 
   public async execute(context: AvmContext): Promise<void> {
     if (context.environment.isStaticCall) {
-      throw new StaticCallStorageAlterError();
+      throw new StaticCallAlterationError();
     }
 
     const memoryOperations = { reads: this.size + 1, indirect: this.indirect };
@@ -100,13 +100,3 @@ export class SLoad extends BaseStorageInstruction {
     memory.assert(memoryOperations);
   }
 }
-
-/**
- * Error is thrown when a static call attempts to alter storage
- */
-export class StaticCallStorageAlterError extends InstructionExecutionError {
-  constructor() {
-    super('Static calls cannot alter storage');
-    this.name = 'StaticCallStorageAlterError';
-  }
-}