fix: guard RpcDataSource against invalid decimals to prevent NaN bala…#8781
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…nces
Two fixes that together stop entries like
`eip155:4326/erc20:0x000…000: { amount: "NaN" }` from leaking into
`assetsBalance`.
- `#collectMetadataForBalances`: only reuse existing native metadata when
it has finite `decimals` (via new `#hasValidDecimals` helper). Empty
`name`/`symbol` are still accepted, and `decimals: 0` is valid. Bad
state metadata (e.g. `{ decimals: null, name: '', symbol: '', type:
'native' }`) is replaced by the chain-status stub so the pipeline
resolves a usable `decimals`.
- `#convertToHumanReadable`: defensively return `'0'` when `decimals`
isn't a finite non-negative number or when `rawBalance` can't be
parsed. Defaulting decimals to a fixed value (e.g. 18) would silently
produce wrong amounts; `'0'` matches the existing safe fallback used
in the error path.
Adds 7 tests covering the bug payload (`decimals: null`), `NaN`
decimals, negative decimals, non-numeric raw balance, and the
`decimals: 0` / missing `name`/`symbol` valid cases.
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This update introduces a new helper method, `#pickValidDecimals`, to ensure that the first valid `decimals` value is selected from metadata sources, preventing stale `decimals: NaN` entries from shadowing valid values. The `#handleBalanceUpdate` method has been updated to utilize this helper, ensuring accurate balance calculations. Additionally, the changelog has been updated to reflect these changes and their implications for balance handling.
…lances This update enhances the `#hasValidDecimals` guard to ensure that only finite and non-negative `decimals` values are accepted for balance calculations. It prevents stale metadata with negative decimals from affecting balance resolution, ensuring that the chain-status stub is used correctly. Additionally, tests have been added to verify this behavior, and the changelog has been updated accordingly.
This update refines the `#hasValidDecimals` method by consolidating the validation logic for asset metadata decimals into a single line. This change enhances code readability while maintaining the existing functionality that ensures only valid, non-negative decimals are accepted.
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May 13, 2026
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<!-- Please submit this PR as a draft initially. Do not mark it as "Ready for review" until the template has been completely filled out, and PR status checks have passed at least once. --> ## **Description** patch assets controller 7.0.0 core PRs: - MetaMask/core#8789 - MetaMask/core#8781 - MetaMask/core#8786 <!-- Write a short description of the changes included in this pull request, also include relevant motivation and context. Have in mind the following questions: 1. What is the reason for the change? 2. What is the improvement/solution? --> ## **Changelog** <!-- If this PR is not End-User-Facing and should not show up in the CHANGELOG, you can choose to either: 1. Write `CHANGELOG entry: null` 2. Label with `no-changelog` If this PR is End-User-Facing, please write a short User-Facing description in the past tense like: `CHANGELOG entry: Added a new tab for users to see their NFTs` `CHANGELOG entry: Fixed a bug that was causing some NFTs to flicker` (This helps the Release Engineer do their job more quickly and accurately) --> CHANGELOG entry: patch assets controller 7.0.0 ## **Related issues** Fixes: ## **Manual testing steps** 1. Go to this page... 2. 3. ## **Screenshots/Recordings** <!-- If applicable, add screenshots and/or recordings to visualize the before and after of your change. --> ### **Before** <!-- [screenshots/recordings] --> ### **After** <!-- [screenshots/recordings] --> ## **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/main/.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/main/.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. <!-- CURSOR_SUMMARY --> --- > [!NOTE] > **Medium Risk** > Touches token/native balance normalization and default asset metadata keying; mistakes could lead to incorrect balances or duplicate/missing asset entries in state. > > **Overview** > Applies a Yarn patch override for `@metamask/assets-controller@7.0.0` and updates the lockfile to use the patched package. > > The patch tightens `RpcDataSource` balance conversion by validating `decimals` and raw balances (defaulting invalid values to `"0"`), and only reuses existing asset metadata when it has valid `decimals` (with a helper to pick the first valid decimals source). > > It also standardizes default/native asset identifiers: `mUSD` defaults now use an EIP-55 checksummed address and `DEFAULT_ASSET_METADATA` keys are stored/queried as checksummed CAIP-19 IDs (no `.toLowerCase()`), and `buildNativeAssetsFromConstant` now runs IDs through `normalizeAssetId`. > > <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit 58b729d. Bugbot is set up for automated code reviews on this repo. Configure [here](https://www.cursor.com/dashboard/bugbot).</sup> <!-- /CURSOR_SUMMARY -->
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…nces
Two fixes that together stop entries like
eip155:4326/erc20:0x000…000: { amount: "NaN" }from leaking intoassetsBalance.#collectMetadataForBalances: only reuse existing native metadata when it has finitedecimals(via new#hasValidDecimalshelper). Emptyname/symbolare still accepted, anddecimals: 0is valid. Bad state metadata (e.g.{ decimals: null, name: '', symbol: '', type: 'native' }) is replaced by the chain-status stub so the pipeline resolves a usabledecimals.#convertToHumanReadable: defensively return'0'whendecimalsisn't a finite non-negative number or whenrawBalancecan't be parsed. Defaulting decimals to a fixed value (e.g. 18) would silently produce wrong amounts;'0'matches the existing safe fallback used in the error path.Adds 7 tests covering the bug payload (
decimals: null),NaNdecimals, negative decimals, non-numeric raw balance, and thedecimals: 0/ missingname/symbolvalid cases.Explanation
References
Checklist
Note
Medium Risk
Touches balance formatting and native metadata selection in
RpcDataSource, which can affect emittedassetsBalance/assetsInfovalues across chains and accounts. Changes are defensive and well-tested but could alter behavior for edge-case metadata payloads.Overview
Prevents
RpcDataSourcefrom emitting{ amount: "NaN" }(or silently wrong'0') balances when native asset metadata in state contains invaliddecimals.Native metadata reuse is now gated by a new
#hasValidDecimals(finite, non-negative;0allowed), otherwise falling back to the chain-status stub, and decimals selection no longer uses??—a new#pickValidDecimalsskipsNaN/negative values so stale state can’t shadow valid pipeline metadata.#convertToHumanReadablenow returns'0'whendecimalsis invalid or the raw balance is unparsable, and the PR adds focused unit tests covering null/NaN/negative decimals and invalid raw balances (plus validdecimals: 0cases).Reviewed by Cursor Bugbot for commit 37b8e8c. Bugbot is set up for automated code reviews on this repo. Configure here.