Simply turn into a string and downcase

[nobu]

Symbol#to_s returns frozen string now.

[eregon]

Looks good to me, thank you for creating the PR.

[yuki24]

Thanks!

[MSP-Greg]

To all,

Thanks for the fix. JFYI, this is causing errors in both spec & test-all when run in Ruby master without --disable=did_you_mean. Probably the reason for the PR.

Due to:
ruby/ruby@6ffc045
[EXPERIMENTAL] Make Symbol#to_s return a frozen String
Thu Sep 26 10:23:02 2019 +0200

[eregon]

@MSP-Greg Could you point to a failure in a CI log? Or is it only happening locally?

[MSP-Greg]

@eregon

ruby/ruby builds are from the build folder, so they may not have did_you_mean enabled, as it is a bundled gem. ruby-loco runs tests from install, so it is enabled. See below:

NoMethodError#message calls receiver.inspect only when calling Exception#message FAILED
Expected [:inspect_called, :inspect_called]
 to equal [:inspect_called]

/ruby/spec/ruby/core/exception/no_method_error_spec.rb:86:in `rescue in block (2 levels) in <top (required)>'
/ruby/spec/ruby/core/exception/no_method_error_spec.rb:80:in `block (2 levels) in <top (required)>'
/ruby/spec/ruby/core/exception/no_method_error_spec.rb:45:in `<top (required)>'

  1) Error:
TestRDocRIDriver#test_display_name_not_found_class:
FrozenError: can't modify frozen String: ""
    /install/lib/ruby/gems/2.7.0/gems/did_you_mean-1.3.0/lib/did_you_mean/spell_checker.rb:47:in `downcase!'
    /install/lib/ruby/gems/2.7.0/gems/did_you_mean-1.3.0/lib/did_you_mean/spell_checker.rb:47:in `normalize'
    /install/lib/ruby/gems/2.7.0/gems/did_you_mean-1.3.0/lib/did_you_mean/spell_checker.rb:13:in `correct'
    /install/lib/ruby/2.7.0/rdoc/ri/driver.rb:1286:in `lookup_method'

I patched the method:

    def normalize(str_or_symbol) #:nodoc:
      str_or_symbol.to_s.downcase.tr("@", "").dup
    end

As you know, it only affects people using very new versions of ruby-head. Didn't you do the commit?

[yuki24]

@MSP-Greg Interesting. I wonder if there is a case where the #downcase method also returns a frozen string. If that's the case, I'd be happy to apply your patch above.

[MSP-Greg]

@yuki24

I've been writing/refactoring too many tests lately. Hence, write bullet-proof code.

where the #downcase method also returns a frozen string

Well, a few days ago, Symbol#to_s wasn't frozen...

It's probably fine the way it is, and @nobu is certainly aware of what may be changing in the future...

EDIT: #downcase really isn't comparable to #to_s, as #to_s normally initializes a new string, where #downcase modifies an existing one.

[nobu]

@MSP-Greg You might want to write #downcase!, I think.

[eregon]

Actually, the did_you_mean tests failed on https://github.com/ruby/ruby/runs/236956239 but nobody noticed since that's run by ignored the exit status (https://github.com/ruby/ruby/blob/550a6a6bc1be4ff9aa6b65f6ad9b45c3fa2d1344/.github/workflows/ubuntu.yml#L83)

[eregon]

@yuki24 Could you make a release of did_you_mean with this fix? 🙏
This seems to be the only way to make the did_you_mean tests in ruby/ruby's CI pass.

[MSP-Greg]

@nobu

You might want to write #downcase!, I think.

I'm probably mistaken, but isn't that true iif str is the final return value?

I ran the tests locally without the final .dup call shown above, and they ran fine. IOW, the method was simply str_or_symbol.to_s.downcase.tr '@', ''

[yuki24]

released as part of v1.3.1.

[eregon]

@yuki24 Thank you, did_you_mean tests pass on ruby/ruby now: ruby/ruby#2503