From c97017dd1d8cdd02c1a7aeae39b7336babc313d7 Mon Sep 17 00:00:00 2001
From: Kyle Edwards <kyle.edwards@kitware.com>
Date: Mon, 14 Aug 2023 15:25:11 -0400
Subject: [PATCH] win,spawn: allow `%PATH%` to be unset (#4116)

Fix: https://github.com/libuv/libuv/issues/4115
---
 src/win/process.c | 29 +++++++++++++----------------
 test/test-list.h  |  2 ++
 test/test-spawn.c | 28 ++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/src/win/process.c b/src/win/process.c
index 3e451e22..3cfa89e7 100644
--- a/src/win/process.c
+++ b/src/win/process.c
@@ -396,7 +396,7 @@ static WCHAR* search_path(const WCHAR *file,
                                   name_has_ext);
 
     while (result == NULL) {
-      if (*dir_end == L'\0') {
+      if (dir_end == NULL || *dir_end == L'\0') {
         break;
       }
 
@@ -1025,22 +1025,19 @@ int uv_spawn(uv_loop_t* loop,
     DWORD path_len, r;
 
     path_len = GetEnvironmentVariableW(L"PATH", NULL, 0);
-    if (path_len == 0) {
-      err = GetLastError();
-      goto done;
-    }
+    if (path_len != 0) {
+      alloc_path = (WCHAR*) uv__malloc(path_len * sizeof(WCHAR));
+      if (alloc_path == NULL) {
+        err = ERROR_OUTOFMEMORY;
+        goto done;
+      }
+      path = alloc_path;
 
-    alloc_path = (WCHAR*) uv__malloc(path_len * sizeof(WCHAR));
-    if (alloc_path == NULL) {
-      err = ERROR_OUTOFMEMORY;
-      goto done;
-    }
-    path = alloc_path;
-
-    r = GetEnvironmentVariableW(L"PATH", path, path_len);
-    if (r == 0 || r >= path_len) {
-      err = GetLastError();
-      goto done;
+      r = GetEnvironmentVariableW(L"PATH", path, path_len);
+      if (r == 0 || r >= path_len) {
+        err = GetLastError();
+        goto done;
+      }
     }
   }
 
diff --git a/test/test-list.h b/test/test-list.h
index 6e6e0824..36de006f 100644
--- a/test/test-list.h
+++ b/test/test-list.h
@@ -504,6 +504,7 @@ TEST_DECLARE   (listen_with_simultaneous_accepts)
 TEST_DECLARE   (listen_no_simultaneous_accepts)
 TEST_DECLARE   (fs_stat_root)
 TEST_DECLARE   (spawn_with_an_odd_path)
+TEST_DECLARE   (spawn_no_path)
 TEST_DECLARE   (ipc_listen_after_bind_twice)
 TEST_DECLARE   (win32_signum_number)
 #else
@@ -1021,6 +1022,7 @@ TASK_LIST_START
   TEST_ENTRY  (listen_no_simultaneous_accepts)
   TEST_ENTRY  (fs_stat_root)
   TEST_ENTRY  (spawn_with_an_odd_path)
+  TEST_ENTRY  (spawn_no_path)
   TEST_ENTRY  (ipc_listen_after_bind_twice)
   TEST_ENTRY  (win32_signum_number)
 #else
diff --git a/test/test-spawn.c b/test/test-spawn.c
index 5e84dcdb..066d5d62 100644
--- a/test/test-spawn.c
+++ b/test/test-spawn.c
@@ -1366,6 +1366,34 @@ TEST_IMPL(spawn_with_an_odd_path) {
   MAKE_VALGRIND_HAPPY(uv_default_loop());
   return 0;
 }
+
+
+TEST_IMPL(spawn_no_path) {
+  char* env[1];
+  WCHAR* old_path = NULL;
+  DWORD old_path_len;
+
+  if ((old_path_len = GetEnvironmentVariableW(L"PATH", NULL, 0)) > 0) {
+    old_path = malloc(old_path_len * sizeof(WCHAR));
+    GetEnvironmentVariableW(L"PATH", old_path, old_path_len);
+    SetEnvironmentVariableW(L"PATH", NULL);
+  }
+
+  init_process_options("spawn_helper1", exit_cb);
+  options.env = env;
+  env[0] = NULL;
+
+  ASSERT(0 == uv_spawn(uv_default_loop(), &process, &options));
+  ASSERT(0 == uv_run(uv_default_loop(), UV_RUN_DEFAULT));
+
+  ASSERT(exit_cb_called == 1);
+  ASSERT(close_cb_called == 1);
+
+  SetEnvironmentVariableW(L"PATH", old_path);
+
+  MAKE_VALGRIND_HAPPY(uv_default_loop());
+  return 0;
+}
 #endif
 
 #ifndef _WIN32