Fix inverse_rle with negative lengths (#853)

Author: ararslan

Project.toml

@@ -1,7 +1,7 @@
 name = "StatsBase"
 uuid = "2913bbd2-ae8a-5f71-8c99-4fb6c76f3a91"
 authors = ["JuliaStats"]
-version = "0.33.21"
+version = "0.33.22"
 
 [deps]
 DataAPI = "9a962f9c-6df0-11e9-0e5d-c546b8b5ee8a"

src/misc.jl

@@ -60,11 +60,14 @@ run lengths.
 function inverse_rle(vals::AbstractVector{T}, lens::AbstractVector{<:Integer}) where T
     m = length(vals)
     length(lens) == m || raise_dimerror()
+    n = sum(lens)
+    n >= 0 || throw(ArgumentError("lengths must be non-negative"))
 
-    r = Vector{T}(undef, sum(lens))
+    r = Vector{T}(undef, n)
     p = 0
     @inbounds for i = 1 : m
         j = lens[i]
+        j >= 0 || throw(ArgumentError("lengths must be non-negative"))
         v = vals[i]
         while j > 0
             r[p+=1] = v

test/misc.jl

@@ -8,6 +8,7 @@ z = [1, 1, 2, 2, 2, 3, 1, 2, 2, 3, 3, 3, 3]
 @test vals == [1, 2, 3, 1, 2, 3]
 @test lens == [2, 3, 1, 1, 2, 4]
 @test inverse_rle(vals, lens) == z
+@test_throws ArgumentError inverse_rle(vals, fill(-1, length(lens)))
 
 z = [true, true, false, false, true, false, true, true, true]
 vals, lens = rle(z)