From 28123c9412de31ee1d6e0a23fe1e1c9e959b3b86 Mon Sep 17 00:00:00 2001
From: ppedziwiatr <ppedziwiatr@gmail.com>
Date: Thu, 9 Nov 2023 12:10:10 +0100
Subject: [PATCH] feat: throw error if trying to write to kv storage in a view
 function

---
 src/core/modules/impl/handler/JsHandlerApi.ts | 12 +++++------
 .../modules/impl/handler/WasmHandlerApi.ts    |  1 +
 src/legacy/smartweave-global.ts               | 20 +++++++++++++++++++
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/core/modules/impl/handler/JsHandlerApi.ts b/src/core/modules/impl/handler/JsHandlerApi.ts
index 1866f22d..a398d564 100644
--- a/src/core/modules/impl/handler/JsHandlerApi.ts
+++ b/src/core/modules/impl/handler/JsHandlerApi.ts
@@ -144,15 +144,16 @@ export class JsHandlerApi<State> extends AbstractContractHandler<State> {
 
     try {
       await this.swGlobal.kv.open();
-      if (interaction.interactionType === 'write') {
-        await this.swGlobal.kv.begin();
-      }
+      await this.swGlobal.kv.begin();
 
       const handlerResult = await Promise.race([timeoutPromise, this.contractFunction(stateClone, interaction)]);
 
       if (handlerResult && (handlerResult.state !== undefined || handlerResult.result !== undefined)) {
         if (interaction.interactionType === 'write') {
           await this.swGlobal.kv.commit();
+        } else {
+          // view state function should not change anything in the kv storage
+          await this.swGlobal.kv.rollback();
         }
 
         let interactionEvent: InteractionCompleteEvent = null;
@@ -181,9 +182,7 @@ export class JsHandlerApi<State> extends AbstractContractHandler<State> {
       // Will be caught below as unexpected exception.
       throw new Error(`Unexpected result from contract: ${JSON.stringify(handlerResult)}`);
     } catch (err) {
-      if (interaction.interactionType === 'write') {
-        await this.swGlobal.kv.rollback();
-      }
+      await this.swGlobal.kv.rollback();
       switch (err.name) {
         case KnownErrors.ContractError:
           return {
@@ -238,6 +237,7 @@ export class JsHandlerApi<State> extends AbstractContractHandler<State> {
 
   private setupSwGlobal<Input>({ interaction, interactionTx }: InteractionData<Input>) {
     this.swGlobal._activeTx = interactionTx;
+    this.swGlobal.interactionType = interaction.interactionType;
     this.swGlobal.caller = interaction.caller; // either contract tx id (for internal writes) or transaction.owner
   }
 
diff --git a/src/core/modules/impl/handler/WasmHandlerApi.ts b/src/core/modules/impl/handler/WasmHandlerApi.ts
index bd7c16d2..c505f004 100644
--- a/src/core/modules/impl/handler/WasmHandlerApi.ts
+++ b/src/core/modules/impl/handler/WasmHandlerApi.ts
@@ -33,6 +33,7 @@ export class WasmHandlerApi<State> extends AbstractContractHandler<State> {
 
       this.swGlobal._activeTx = interactionTx;
       this.swGlobal.caller = interaction.caller; // either contract tx id (for internal writes) or transaction.owner
+      this.swGlobal.interactionType = interaction.interactionType;
       this.swGlobal.gasLimit = executionContext.evaluationOptions.gasLimit;
       this.swGlobal.gasUsed = 0;
 
diff --git a/src/legacy/smartweave-global.ts b/src/legacy/smartweave-global.ts
index 364c89a2..6e8607a6 100644
--- a/src/legacy/smartweave-global.ts
+++ b/src/legacy/smartweave-global.ts
@@ -6,6 +6,7 @@ import { CacheKey, SortKeyCache } from '../cache/SortKeyCache';
 import { SortKeyCacheRangeOptions } from '../cache/SortKeyCacheRangeOptions';
 import { InteractionState } from '../contract/states/InteractionState';
 import { safeGet } from '../utils/utils';
+import { ContractError, InteractionType } from "../core/modules/impl/HandlerExecutorFactory";
 
 /**
  *
@@ -66,6 +67,8 @@ export class SmartWeaveGlobal {
 
   kv: KV;
 
+  interactionType: InteractionType;
+
   constructor(
     arweave: Arweave,
     contract: { id: string; owner: string },
@@ -218,6 +221,13 @@ export class SWTransaction {
     }
     return this.smartWeaveGlobal._activeTx.source === 'redstone-sequencer' ? 'L2' : 'L1';
   }
+
+  get interactionType(): InteractionType {
+    if (!this.smartWeaveGlobal._activeTx) {
+      throw new Error('No current Tx');
+    }
+    return this.smartWeaveGlobal.interactionType;
+  }
 }
 
 // tslint:disable-next-line: max-classes-per-file
@@ -282,7 +292,13 @@ export class KV {
   ) {}
 
   async put(key: string, value: any): Promise<void> {
+    if (this._transaction.interactionType === 'view') {
+      throw new ContractError('Forbidden write operation for "view" function: "KV.put"');
+    }
+
     this.checkStorageAvailable();
+
+
     await this._storage.put(new CacheKey(key, this._transaction.sortKey), value);
   }
 
@@ -304,6 +320,10 @@ export class KV {
   }
 
   async del(key: string): Promise<void> {
+    if (this._transaction.interactionType === 'view') {
+      throw new ContractError('Forbidden write operation for "view" function: "KV.del"');
+    }
+
     this.checkStorageAvailable();
     const sortKey = this._transaction.sortKey;