From 537b3fe32b8af594359e6c9180b9889288173e99 Mon Sep 17 00:00:00 2001
From: Pedro Figueiredo <pedro.figueiredo@consensys.net>
Date: Thu, 3 Oct 2024 15:04:59 +0100
Subject: [PATCH] fix: Max approval and array value spending cap bugs (#27573)
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## **Description**

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Write a short description of the changes included in this pull request,
also include relevant motivation and context. Have in mind the following
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1. What is the reason for the change?
2. What is the improvement/solution?
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This PR fixes two bugs.

The first happens when the user approves a token for the max amount.
This value is decoded by sourcify and is tipically expressed in
scientific notation. However, this number has more than 15 significant
digits. The fix is to coerce the number to a string (also accepted by
bignumber js), forcing it to be expressed with 15 significant digits
only.

<img width="320" alt="Screenshot 2024-10-02 at 17 26 55"
src="https://github.com/user-attachments/assets/50ad83e0-a497-4b0b-92f5-aa9b30fb765f">

The second bug happens because sometimes the decoded data from sourcify
expresses a value of a param as an array of elements. An exception was
added to the param lookup, so that we don't try to use an array value as
the spending cap to be displayed.

<img width="320" alt="Screenshot 2024-10-02 at 17 13 34"
src="https://github.com/user-attachments/assets/fc31bdc3-3db3-48a6-be35-54a9abfc0409">


[![Open in GitHub
Codespaces](https://github.com/codespaces/badge.svg)](https://codespaces.new/MetaMask/metamask-extension/pull/27573?quickstart=1)

## **Related issues**

Fixes: https://github.com/MetaMask/metamask-extension/issues/27535

## **Manual testing steps**

### First bug
1. Go to Uniswap
2. Select a token that hasn't been approved yet, and click to approve
3. The app shouldn't crash

### Second bug
1. Go to https://ethereumfilm.xyz/ethereum-stories
2. Click mint on one of the posters or mini-movies
3. The app shouldn't crash

## **Screenshots/Recordings**

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before and after of your change. -->

### **Before**

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### **After**

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## **Pre-merge author checklist**

- [ ] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask
Extension Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I’ve included tests if applicable
- [ ] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.
---
 .../confirm/info/approve/hooks/use-approve-token-simulation.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ui/pages/confirmations/components/confirm/info/approve/hooks/use-approve-token-simulation.ts b/ui/pages/confirmations/components/confirm/info/approve/hooks/use-approve-token-simulation.ts
index e05823738b5c..19f26c9c9300 100644
--- a/ui/pages/confirmations/components/confirm/info/approve/hooks/use-approve-token-simulation.ts
+++ b/ui/pages/confirmations/components/confirm/info/approve/hooks/use-approve-token-simulation.ts
@@ -33,13 +33,14 @@ export const useApproveTokenSimulation = (
       (param) =>
         param.value !== undefined &&
         !isHexString(param.value) &&
+        param.value.length === undefined &&
         !isBoolean(param.value),
     );
     if (paramIndex === -1) {
       return 0;
     }
 
-    return new BigNumber(value.data[0].params[paramIndex].value)
+    return new BigNumber(value.data[0].params[paramIndex].value.toString())
       .dividedBy(new BigNumber(10).pow(Number(decimals)))
       .toNumber();
   }, [value, decimals]);