From 5f1080b076d5ecaef736e0bb489ceeab26da0a7a Mon Sep 17 00:00:00 2001
From: Lukas Weber <49278367+lukas-weber@users.noreply.github.com>
Date: Wed, 4 Oct 2023 17:12:55 -0400
Subject: [PATCH] random_wrap: update for future Julia versions

---
 src/random_wrap.jl | 38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/src/random_wrap.jl b/src/random_wrap.jl
index 8606010..3a64a64 100644
--- a/src/random_wrap.jl
+++ b/src/random_wrap.jl
@@ -1,21 +1,41 @@
 using Random
 using HDF5
 
-function write_checkpoint(rng::Random.Xoshiro, out::HDF5.Group)
+function guess_xoshiro_version()
+    num_fields = length(fieldnames(Xoshiro))
+    if num_fields == 4
+        return 1
+    elseif num_fields == 5
+        return 2
+    end
+    error(
+        "Carlo wrapper does not support this version of Xoshiro yet. Please file a bug report",
+    )
+end
+
+
+function write_checkpoint(rng::Xoshiro, out::HDF5.Group)
     out["type"] = "xoroshiro256++"
-    out["state"] = [rng.s0, rng.s1, rng.s2, rng.s3]
-    out["rng_version"] = 1
+    out["state"] = collect(getproperty.(rng, fieldnames(Xoshiro)))
+
+    out["rng_version"] = guess_xoshiro_version()
 
     return nothing
 end
 
-function read_checkpoint(::Type{Random.Xoshiro}, in::HDF5.Group)
-    rng_type = in["type"]
-
-    if rng_type == "xoroshiro256++"
+function read_checkpoint(::Type{Xoshiro}, in::HDF5.Group)
+    rng_type = read(in["type"])
+    if rng_type != "xoroshiro256++"
         error("checkpoint was done with a different RNG: $(rng_type)")
     end
 
-    state = in["state"]
-    return Random.Xoshiro(state[1], state[2], state[3], state[4])
+    rng_version = read(in["rng_version"])
+    if rng_version != guess_xoshiro_version()
+        error(
+            "checkpoint was done with a different version of Xoshiro. Try running with the version of Julia you used originally.",
+        )
+    end
+
+    state = read(in["state"])
+    return Random.Xoshiro(state...)
 end