51 lines
2.2 KiB
Markdown
51 lines
2.2 KiB
Markdown
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# Errors
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This document outlines the recommended usage and APIs for error handling in Cosmos SDK modules. {synopsis}
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Modules are encouraged to define and register their own errors to provide better
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context on failed message or handler execution. Typically, these errors should be
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common or general errors which can be further wrapped to provide additional specific
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execution context.
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## Registration
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Modules should define and register their custom errors in `x/{module}/errors.go`.
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Registration of errors is handled via the [`errors` package](https://github.com/cosmos/cosmos-sdk/blob/main/errors/errors.go).
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Example:
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+++ https://github.com/cosmos/cosmos-sdk/blob/v0.46.0/x/distribution/types/errors.go#L1-L21
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Each custom module error must provide the codespace, which is typically the module name
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(e.g. "distribution") and is unique per module, and a uint32 code. Together, the codespace and code
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provide a globally unique Cosmos SDK error. Typically, the code is monotonically increasing but does not
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necessarily have to be. The only restrictions on error codes are the following:
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* Must be greater than one, as a code value of one is reserved for internal errors.
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* Must be unique within the module.
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Note, the Cosmos SDK provides a core set of *common* errors. These errors are defined in [`types/errors/errors.go`](https://github.com/cosmos/cosmos-sdk/blob/main/types/errors/errors.go).
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## Wrapping
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The custom module errors can be returned as their concrete type as they already fulfill the `error`
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interface. However, module errors can be wrapped to provide further context and meaning to failed
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execution.
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Example:
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+++ https://github.com/cosmos/cosmos-sdk/blob/v0.46.0/x/bank/keeper/keeper.go#L143-L184
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Regardless if an error is wrapped or not, the Cosmos SDK's `errors` package provides a function to determine if
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an error is of a particular kind via `Is`.
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## ABCI
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If a module error is registered, the Cosmos SDK `errors` package allows ABCI information to be extracted
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through the `ABCIInfo` function. The package also provides `ResponseCheckTx` and `ResponseDeliverTx` as
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auxiliary functions to automatically get `CheckTx` and `DeliverTx` responses from an error.
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