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fetch: Treat non-standard JSON-RPC errors as standard#367
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The [JSON-RPC specification](https://www.jsonrpc.org/specification) says that a JSON-RPC-compliant server must return a response with either a `result` or an `error` field, and if an `error` field is present, then it must be an object with the following fields: `code`, `message`, and `data`. The `isJsonRpcError` from `@metamask/utils` (via the [`JsonRpcError` type][2]) not only checks for the three aforementioned properties, but also allows an additional, optional `stack` property to be present. However, it does not allow any other properties beyond the four declared. This is a problem because the new implementation of the `fetch` middleware makes use of this function to know how to handle errors, and as a result, non-standard error responses are being treated as successful responses (and the errors themselves are being discarded). This is particularly noticeable when using Ganache as a local RPC server, because it produces such non-standard error responses, such as when a transaction fails. To correct this bug, this commit brings the error-handling code in the `fetch` middleware closer to the original implementation, and updates the tests to ensure that Ganache errors are treated correctly. [1]: https://www.jsonrpc.org/specification [2]: https://github.com/MetaMask/utils/blob/55b22a77e75641c4c8b05eec73982084ac9e7332/src/json.ts#L301
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Tested on mobile as a part of getting MetaMask/metamask-mobile#14273 to pass CI and this seems to work. |
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The JSON-RPC specification says that a JSON-RPC-compliant server must return a response with either a
resultor anerrorfield, and if anerrorfield is present, then it must be an object with the following fields:code,message, anddata. TheisJsonRpcErrorfrom@metamask/utils(via theJsonRpcErrortype) not only checks for the three aforementioned properties, but also allows an additional, optionalstackproperty to be present. However, it does not allow any other properties beyond the four declared.This is a problem because the new implementation of the
fetchmiddleware makes use of this function to know how to handle errors, and as a result, non-standard error responses are being treated as successful responses (and the errors themselves are being discarded). This is particularly noticeable when using Ganache as a local RPC server, because it produces such non-standard error responses, such as when a transaction fails.To correct this bug, this commit brings the error-handling code in the
fetchmiddleware closer to the original implementation, and updates the tests to ensure that Ganache errors are treated correctly.