From 085580a2c8f303acf1654731ebc7dba7e6e501a7 Mon Sep 17 00:00:00 2001
From: flywind <xzsflywind@gmail.com>
Date: Mon, 29 Mar 2021 16:50:58 +0800
Subject: [PATCH]  fix #14010(fix std/registry + arc) (#17551)

* fix nim js cmp fails at CT

* fix #14010

* Update tests/stdlib/tregistry.nim

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

* Update tregistry.nim

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>
---
 lib/windows/registry.nim   | 18 ++++++++++--------
 tests/stdlib/tregistry.nim | 15 +++++++++++++++
 2 files changed, 25 insertions(+), 8 deletions(-)
 create mode 100644 tests/stdlib/tregistry.nim

diff --git a/lib/windows/registry.nim b/lib/windows/registry.nim
index c17f2f455c..ab7d0b1fee 100644
--- a/lib/windows/registry.nim
+++ b/lib/windows/registry.nim
@@ -54,16 +54,18 @@ proc getUnicodeValue*(path, key: string; handle: HKEY): string =
     var newHandle: HKEY
     call regOpenKeyEx(handle, hh, 0, KEY_READ or KEY_WOW64_64KEY, newHandle)
     call regGetValue(newHandle, nil, kk, flags, nil, nil, addr bufsize)
-    var res = newWideCString("", bufsize)
-    call regGetValue(newHandle, nil, kk, flags, nil, cast[pointer](res),
-                   addr bufsize)
-    result = res $ bufsize
+    if bufSize > 0:
+      var res = newWideCString(bufsize)
+      call regGetValue(newHandle, nil, kk, flags, nil, addr res[0],
+                    addr bufsize)
+      result = res $ bufsize
     call regCloseKey(newHandle)
   else:
-    var res = newWideCString("", bufsize)
-    call regGetValue(handle, hh, kk, flags, nil, cast[pointer](res),
-                   addr bufsize)
-    result = res $ bufsize
+    if bufSize > 0:
+      var res = newWideCString(bufsize)
+      call regGetValue(handle, hh, kk, flags, nil, addr res[0],
+                    addr bufsize)
+      result = res $ bufsize
 
 proc regSetValue(key: HKEY, lpSubKey, lpValueName: WideCString,
                  dwType: int32; lpData: WideCString; cbData: int32): int32 {.
diff --git a/tests/stdlib/tregistry.nim b/tests/stdlib/tregistry.nim
new file mode 100644
index 0000000000..8bf084f6d5
--- /dev/null
+++ b/tests/stdlib/tregistry.nim
@@ -0,0 +1,15 @@
+discard """
+  disabled: "unix"
+  matrix: "--gc:refc; --gc:arc"
+"""
+
+when defined(windows):
+  import std/registry
+
+  block: # bug #14010
+    let path = "Environment"
+    let key = "D20210328T202842_key"
+    let val = "D20210328T202842_val"
+    let handle = HKEY_CURRENT_USER
+    setUnicodeValue("Environment", key, val, handle)
+    doAssert getUnicodeValue(path, key, handle) == val