fixes to colonful reshape

In several different situations `reshape` had thrown `DivideError`
instead of returning a correct result or throwing.

Fixes JuliaLang#54245

base/reshapedarray.jl

@@ -135,7 +135,17 @@ reshape(parent::AbstractArray, dims::Tuple{Vararg{Union{Int,Colon}}}) = reshape(
     pre = _before_colon(dims...)
     post = _after_colon(dims...)
     _any_colon(post...) && throw1(dims)
-    sz, remainder = divrem(length(A), prod(pre)*prod(post))
+    len = length(A)
+    sz, remainder = if iszero(len)
+        (0, 0)
+    else
+        let pr = Core.checked_dims(pre..., post...)  # safe product
+            if iszero(pr)
+                throw2(A, dims)
+            end
+            divrem(len, pr)
+        end
+    end::NTuple{2,Int}
     remainder == 0 || throw2(A, dims)
     (pre..., Int(sz), post...)
 end

test/abstractarray.jl

@@ -1852,6 +1852,16 @@ function check_pointer_strides(A::AbstractArray)
     return true
 end
 
+@testset "colonful `reshape`, #54245" begin
+    @test reshape([], (0, :)) isa Matrix
+    @test_throws DimensionMismatch reshape([7], (0, :))
+    let b = prevpow(2, typemax(Int))
+        @test iszero(b*b)
+        @test_throws ArgumentError reshape([7], (b, :, b))
+        @test reshape([], (b, :, b)) isa Array{<:Any, 3}
+    end
+end
+
 @testset "strides for ReshapedArray" begin
     # Type-based contiguous Check
     a = vec(reinterpret(reshape, Int16, reshape(view(reinterpret(Int32, randn(10)), 2:11), 5, :)))