Fix support for 0d arrays (#844)

This was accidentally removed in the PyArray reparametrization.

Co-authored-by: Christopher Rowley <cjdrwly@gmail.com>

Author: JamesWrigley

src/Wrap/PyArray.jl

@@ -644,7 +644,8 @@ function pyarray_offset(x::PyArray{T,N,F}, i::Vararg{Int,N}) where {T,N,F}
     if N >= 1 && (:contiguous in F)
         sum((i .- 1) .* (sizeof(pyarray_get_R(T)), x.strides[2:end]...))
     else
-        sum((i .- 1) .* x.strides)
+        # `init` covers 0-d arrays indexed as `x[]`, where `i` is empty
+        sum((i .- 1) .* x.strides; init=0)
     end
 end
 

test/Wrap.jl

@@ -100,6 +100,16 @@
         )
         @test_throws Exception PyArray(nd; array = false, buffer = true)
     end
+    @testset "0-d" begin
+        tb = pyimport("_testbuffer")
+        nd = tb.ndarray(5, shape = pylist(), flags = tb.ND_WRITABLE)
+        a = PyArray(nd; array = false, buffer = true)
+        @test ndims(a) == 0
+        @test a[] == 5
+        a[] = 6
+        @test a[] == 6
+        @test pyconvert(Int, nd.tolist()) == 6
+    end
     @testset "contiguous 2D" begin
         tb = pyimport("_testbuffer")
         nd = tb.ndarray(