Hash function for immutable struct containing mutable vectors

General Usage
,
1

Suppose I have an immutable struct A containing immutable fields as well as a (mutable) vector of immutable objects (such as Int64 objects),

struct A
    x::Int
    y::Vector{Int}
end

Does Julia automatically define sensible hash and isequal functions for objects of my type A, taking into account the content (not the memory address) of the vector?

2

See the help for ?== and ?isequal and ?hash. For new types you need to implement equality checks, and hash. Base implements the fallback ==(a,b) = a===b so falls back to egal.

3

This is quite easy to check:

julia> struct A
           x::Int
           y::Vector{Int}
       end

julia> A(1, [1, 2]) == A(1, [1, 2])
false

It’s up to you whether you think this is sensible or not. People disagree.

If this is not the behaviour you want, there’s a package AutoHashEquals.jl which automates different equality and hash definitions for you

julia> using AutoHashEquals

julia> @auto_hash_equals struct A
           x::Int
           y::Vector{Int}
       end

julia> A(1, [1, 2]) == A(1, [1, 2])
true
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