From d957e75721097f36b61fe17364c36dcfdd8eefdf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20H=C3=B8egh?= <dhoegh91@gmail.com>
Date: Sat, 13 Aug 2016 13:20:09 +0200
Subject: [PATCH] Fix #17956 and add test. The bug was introduced in
 103db50aa6c67d8e732e8e2bd7f5743bae17e369

---
 base/env.jl |  2 +-
 test/env.jl | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/base/env.jl b/base/env.jl
index fc3fe87e78c70..3c77619400b82 100644
--- a/base/env.jl
+++ b/base/env.jl
@@ -94,7 +94,7 @@ end
 function next(hash::EnvHash, block::Tuple{Ptr{UInt16},Ptr{UInt16}})
     pos = block[1]
     blk = block[2]
-    len = ccall(:wcslen, UInt, (Ptr{UInt16},), pos)
+    len = ccall(:wcslen, UInt, (Ptr{UInt16},), pos) + 1
     buf = Array{UInt16}(len)
     unsafe_copy!(pointer(buf), pos, len)
     env = transcode(String, buf)
diff --git a/test/env.jl b/test/env.jl
index 592c378cf65ee..6d57d4217b894 100644
--- a/test/env.jl
+++ b/test/env.jl
@@ -30,3 +30,36 @@ key = randstring(25)
 @test !haskey(ENV,key)
 @test_throws KeyError ENV[key]
 @test get(ENV,key,"default") == "default"
+
+# Test for #17956
+@test length(ENV) > 1
+k1, k2 = "__test__", "__test1__"
+withenv(k1=>k1, k2=>k2) do
+    b_k1, b_k2 = false, false
+    for (k, v) in ENV
+        if k==k1
+            b_k1=true
+        elseif k==k2
+            b_k2=true
+        end
+    end
+    @test b_k1 && b_k2
+    io = IOBuffer()
+    show(io, ENV)
+    s = takebuf_string(io)
+    @test contains(s, k1)
+    @test contains(s, k2)
+
+    @test pop!(ENV, k1) == k1
+    @test !haskey(ENV, k1)
+    ENV[k1] = k1
+    @test pop!(ENV, k1) == k1
+    @test pop!(ENV, k1, "not_there") == "not_there"
+
+    ENV[k1] = k1
+    @test delete!(ENV, k1) == ENV
+    @test !haskey(ENV, k1)
+end
+
+# Test for #10853
+@test withenv(Dict{Any,Any}()...) do; true; end