Bug #16599: did_you_mean is not activated for NameError and KeyError

• Status: Closed
• Assignee: yuki24 (Yuki Nishijima)
• Target version: -
• ruby -v: 2.6, 2.7, perhaps for earlier versions too
• Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN

[sawa (Tsuyoshi Sawada)]

This document claims that the did_you_mean gem responds to NameError, NoMethodError, and KeyError, but it actually seems to only respond to NoMethodError.

foo()
# >> NoMethodError: undefined method `foo' for main:Object
# >> Did you mean?  for

foo
# >> NameError: undefined local variable or method `foo' for main:Object

Foo
# >> NameError: uninitialized constant Foo

{foo: 1}.fetch(:bar)
# >> KeyError: key not found: :bar

[znz (Kazuhiro NISHIYAMA)]

• Assignee set to yuki24 (Yuki Nishijima)

[zverok (Victor Shepelev)]

As far as I can understand, did_you_mean reacts only when it can find contextually appropriate thing with similar name. For me, it is this way:

foo
# NameError (undefined local variable or method `foo' for main:Object) -- did_you_mean can't suggest anything

fox = 1
foo
# NameError (undefined local variable or method `foo' for main:Object)
# Did you mean?  fox

# And similarly:
FOO = 1
Foo
# NameError (uninitialized constant Foo)
# Did you mean?  FOO


# 2.7 only:
{baz: 1}.fetch(:bar)
# KeyError (key not found: :bar)
# Did you mean?  :baz

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Closed

As @zverok (Victor Shepelev) 's analysis shows, did_you_mean does activate for NameError and KeyError if it can find suggestions.

As for not suggesting for for foo in NameError but doing so for NoMethodError, I can't tell if that is a bug in did_you_mean. It doesn't seem to be general behavior for keywords, since did_you_mean recommends while for whil in both cases. If you think it is a bug in did_you_mean, you may want to file it upstream: https://github.com/ruby/did_you_mean/issues