fix an empty case, add tests

JuliaLang · Jan 6, 2022 · 2226a01 · 2226a01
1 parent 331d0a7
commit 2226a01
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Showing 2 changed files with 11 additions and 1 deletion.
diff --git a/base/abstractarray.jl b/base/abstractarray.jl
@@ -904,7 +904,7 @@ end
 
 function copyto!(dest::AbstractArray, dstart::Integer, src)
     i = Int(dstart)
-    if haslength(src)
+    if haslength(src) && length(dest) > 0
         checkbounds(dest, i)
         checkbounds(dest, i + length(src) - 1)
         for x in src

diff --git a/test/arrayops.jl b/test/arrayops.jl
@@ -2122,6 +2122,16 @@ end
     @test_throws ArgumentError LinearAlgebra.copy_transpose!(a,2:3,1:3,b,1:5,2:7)
 end
 
+@testset "empty copyto!" begin
+    @test isempty(copyto!(Int[], ()))
+    @test isempty(copyto!(Int[], Int[]))
+    @test copyto!([1,2], ()) == [1,2]
+
+    @test isempty(copyto!(Int[], 1, ()))
+    @test isempty(copyto!(Int[], 1, Int[]))
+    @test_broken copyto!([1,2], 1, ()) == [1,2]
+end
+
 module RetTypeDecl
     using Test
     import Base: +, *, broadcast, convert