prevent stack overflows from faulty user-defined constructor methods#59506
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topolarity merged 4 commits intoJuliaLang:masterfrom Sep 17, 2025
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`Base` code often assumes that a constructor will return a value of the stated type. This is false, cross-reference issue JuliaLang#42372. This change prevents several stack overflows that arise when a generic method is called with a newly-defined type with such a weird constructor for some `Base`-defined type.
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The trimming CI failure is issue #59507. |
topolarity
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Good find. Indeed, these implementations assume that these will reach a base case.
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…uliaLang#59506) `Base` code often assumes that a constructor will return a value of the stated type. This is false, cross-reference issue JuliaLang#42372. This change prevents several stack overflows that arise when a generic method is called with a newly-defined type with such a weird constructor for some `Base`-defined type.
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Due to issue JuliaLang#42372, it can not be assumed that a constructor call will return a value of the requested type. Enforce that assumption in code where it matters. Example stack overflows that this change prevents: ```julia struct FaultyInt <: Integer end # new `Int`-like function Base.Int(x::FaultyInt) x end # invalid constructor iterate("", FaultyInt()) # overflows the stack isvalid("", FaultyInt()) # overflows the stack struct MyString <: AbstractString # valid new subtype of `AbstractString` str::String end isvalid(MyString(""), FaultyInt()) # overflows the stack codeunit(MyString(""), FaultyInt()) # overflows the stack ``` Follow up on PR JuliaLang#59506.
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#60876) Due to issue #42372, it can not be assumed that a constructor call will return a value of the requested type. Enforce that assumption in code where it matters. Example stack overflows that this change prevents: ```julia struct FaultyInt <: Integer end # new `Int`-like function Base.Int(x::FaultyInt) x end # invalid constructor iterate("", FaultyInt()) # overflows the stack isvalid("", FaultyInt()) # overflows the stack struct MyString <: AbstractString # valid new subtype of `AbstractString` str::String end isvalid(MyString(""), FaultyInt()) # overflows the stack codeunit(MyString(""), FaultyInt()) # overflows the stack ``` Follow up on PR #59506.
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Basecode often assumes that a constructor will return a value of the stated type. This is false, cross-reference issue #42372.This change prevents several stack overflows that arise when a generic method is called with a newly-defined type with such a weird constructor for some
Base-defined type.