Add blame callback for KeyError
#7803
Conversation
This starts with an initial implementation of the `blame/2` callback for `KeyError` to add some helpful `did_you_mean` feedback for potentially typo'd keys. Right now it's only implemented for maps and keyword lists, and only for string and atom keys.
lib/elixir/lib/exception.ex
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| def message(%{message: message}), do: message | ||
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| def message(key, term) do | ||
| msg = "key #{inspect(key)} not found" |
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Minor nitpick: what do you think about using message instead of msg (like the function above) and distance instead of dist in the functions below?
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Yeah, works for me!
lib/elixir/lib/exception.ex
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| end | ||
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| def blame(exception = %{term: term}, stacktrace) when is_list(term) do | ||
| available_keys = Keyword.keys(term) |
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Unfortunately I think there is a bug here. Keyword.keys assumes a keyword is given. So if you do Keyword.fetch!([1, foo: :bar], :bar), it will invoke this clause which then fails on Keyword.keys. My suggestion is to unify both clauses above and do something like this:
if (is_map(term) or Keyword.keyword?(term)) and Enum.all?(term, fn {k, _} -> is_atom(k) end) do
...
else
{message, stacktrace}
end
I know we can have mixed keys in maps, but I think we should start with a more conservative approach for now.
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Ah - I didn't think it was possible for a non-keyword list to be passed as the term to a KeyError. I'll update.
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Thank you! ❤️ |
It was introduced in elixir-lang#7803, looks like it was accidentally made public (no docs, no specs) It shipped in Elixir v1.7 so technically this would be a breaking change. I'm happy to deprecate/doc false it instead.
It was introduced accidentally in #7803 (no docs, no specs)
It was introduced accidentally in #7803 (no docs, no specs)
4 participants
This starts with an initial implementation of the
blame/2callbackfor
KeyErrorto add some helpfuldid_you_meanfeedback forpotentially typo'd keys. Right now it's only implemented for maps and
keyword lists, and only for string and atom keys.
Resolves #7779