Fix NoMethodError when encoding with invalid: :replace option#9182
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headius merged 2 commits intojruby:masterfrom Jan 30, 2026
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When encoding a string with `invalid: :replace` and `replace:` options but without `undef: :replace`, JRuby was incorrectly throwing NoMethodError instead of Encoding::UndefinedConversionError. The bug occurred because when `ecopts` hash exists (due to `:replace` option) but doesn't contain a `:fallback` key, the code was setting `fallbackFunc` to `AREF_FALLBACK` with a nil `fallback` value. When an undefined conversion was encountered, it tried to call `nil.[]()` which raised NoMethodError. The fix adds a check for `!fallback.isNil()` before assigning the fallback function, ensuring that the fallback is only used when explicitly provided. Fixes jruby#9009
khasinski
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Nice thanks! I think this can go into 10.0.3.0 if @enebo approves. |
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@khasinski One small nitpick... could you see if there's any equivalent spec under spec/ruby? If it's there and tagged (spec/tags/ruby) we can remove the tag. If it's not there, you can port your code over. This will improve ruby/spec for all impls. |
headius
requested changes
Jan 29, 2026
Move test for UndefinedConversionError behavior from JRuby-specific test suite to shared ruby/spec. Also add spec for the basic case of encoding without options raising UndefinedConversionError. Related to jruby#9009
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Great thanks! I'll check if that existing spec is currently excluded. |
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I tested your branch and did not see any additional specs pass, so I'll merge what we have here. If you would like to work on those other failures, that would be great! |
headius
approved these changes
Jan 30, 2026
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Summary
NoMethodError: undefined method '[]' for nilwhen encoding a string withinvalid: :replaceoption but withoutundef: :replaceEncoding::UndefinedConversionErrormatching MRI behaviorProblem
When calling:
JRuby 10.0.2.0 threw:
Expected (MRI behavior):
Root Cause
In
EncodingUtils.transcodeLoop(), whenecoptshash exists (due to:replaceoption) but doesn't contain a:fallbackkey, the code was settingfallbackFunc = AREF_FALLBACKwithfallback = nil. When an undefined conversion was encountered, it tried to callnil.[]()which raisedNoMethodError.Fix
Added a check for
!fallback.isNil()before assigning the fallback function, ensuring that the fallback is only used when explicitly provided via the:fallbackoption.Test plan
Fixes #9009