Credo.Check.Warning.MapGetUnsafePass (Credo v1.5.2) View Source

This check has a base priority of normal and works with any version of Elixir.

Explanation

Map.get/2 can lead into runtime errors if the result is passed into a pipe without a proper default value. This happens when the next function in the pipe cannot handle nil values correctly.

Example:

%{foo: [1, 2 ,3], bar: [4, 5, 6]}
|> Map.get(:missing_key)
|> Enum.each(&IO.puts/1)

This will cause a Protocol.UndefinedError, since nil isn't Enumerable. Often times while iterating over enumerables zero iterations is preferrable to being forced to deal with an exception. Had there been a [] default parameter this could have been averted.

If you are sure the value exists and can't be nil, please use Map.fetch!/2. If you are not sure, Map.get/3 can help you provide a safe default value.

Configuration parameters

There are no specific parameters for this check.

Like with all checks, general params can be applied.

Parameters can be configured via the .credo.exs config file.