make hash(::Xoshiro) compatible with == (#51376)

Author: rfourquet

stdlib/Random/src/Xoshiro.jl

@@ -81,6 +81,8 @@ function ==(a::Xoshiro, b::Xoshiro)
     a.s0 == b.s0 && a.s1 == b.s1 && a.s2 == b.s2 && a.s3 == b.s3 && a.s4 == b.s4
 end
 
+hash(x::Xoshiro, h::UInt) =  hash((x.s0, x.s1, x.s2, x.s3, x.s4), h + 0x49a62c2dda6fa9be % UInt)
+
 rng_native_52(::Xoshiro) = UInt64
 
 @inline function rand(rng::Xoshiro, ::SamplerType{UInt64})
@@ -221,6 +223,12 @@ end
 
 ==(a::TaskLocalRNG, b::Xoshiro) = b == a
 
+function hash(x::TaskLocalRNG, h::UInt)
+    t = current_task()
+    hash((t.rngState0, t.rngState1, t.rngState2, t.rngState3, t.rngState4), h + 0x49a62c2dda6fa9be % UInt)
+end
+
+
 # for partial words, use upper bits from Xoshiro
 
 rand(r::Union{TaskLocalRNG, Xoshiro}, ::SamplerTrivial{UInt52Raw{UInt64}}) = rand(r, UInt64) >>> 12

stdlib/Random/test/runtests.jl

@@ -594,24 +594,41 @@ guardseed() do
     Random.seed!(typemax(UInt128))
 end
 
-# copy, == and hash
-let seed = rand(UInt32, 10)
-    r = MersenneTwister(seed)
-    @test r == MersenneTwister(seed) # r.vals should be all zeros
-    @test hash(r) == hash(MersenneTwister(seed))
-    s = copy(r)
-    @test s == r && s !== r
-    @test hash(s) == hash(r)
-    skip, len = rand(0:2000, 2)
-    for j=1:skip
-        rand(r)
-        rand(s)
+@testset "copy, == and hash" begin
+    for RNG = (MersenneTwister, Xoshiro)
+        seed = rand(UInt32, 10)
+        r = RNG(seed)
+        t = RNG(seed)
+        @test r == t
+        @test hash(r) == hash(t)
+        s = copy(r)
+        @test s == r == t && s !== r
+        @test hash(s) == hash(r)
+        skip, len = rand(0:2000, 2)
+        for j=1:skip
+            rand(r)
+            @test r != s
+            @test hash(r) != hash(s)
+            rand(s)
+        end
+        @test rand(r, len) == rand(s, len)
+        @test s == r
+        @test hash(s) == hash(r)
+        h = rand(UInt)
+        @test hash(s, h) == hash(r, h)
+        if RNG == Xoshiro
+            t = copy(TaskLocalRNG())
+            @test hash(t) == hash(TaskLocalRNG())
+            @test hash(t, h) == hash(TaskLocalRNG(), h)
+            x = rand()
+            @test hash(t) != hash(TaskLocalRNG())
+            @test rand(t) == x
+            @test hash(t) == hash(TaskLocalRNG())
+            copy!(TaskLocalRNG(), r)
+            @test hash(TaskLocalRNG()) == hash(r)
+            @test TaskLocalRNG() == r
+        end
     end
-    @test rand(r, len) == rand(s, len)
-    @test s == r
-    @test hash(s) == hash(r)
-    h = rand(UInt)
-    @test hash(s, h) == hash(r, h)
 end
 
 # MersenneTwister initialization with invalid values