--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/test/test-env-vars.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,178 @@
+/* Copyright libuv contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "task.h"
+#include <string.h>
+
+#define BUF_SIZE 10
+
+TEST_IMPL(env_vars) {
+  const char* name = "UV_TEST_FOO";
+  const char* name2 = "UV_TEST_FOO2";
+  char buf[BUF_SIZE];
+  size_t size;
+  int i, r, envcount, found, found_win_special;
+  uv_env_item_t* envitems;
+
+#if defined(_WIN32) && defined(__ASAN__)
+  /* See investigation in https://github.com/libuv/libuv/issues/4338 */
+  RETURN_SKIP("Test does not currently work on Windows under ASAN");
+#endif
+
+  /* Reject invalid inputs when setting an environment variable */
+  r = uv_os_setenv(NULL, "foo");
+  ASSERT_EQ(r, UV_EINVAL);
+  r = uv_os_setenv(name, NULL);
+  ASSERT_EQ(r, UV_EINVAL);
+  r = uv_os_setenv(NULL, NULL);
+  ASSERT_EQ(r, UV_EINVAL);
+
+  /* Reject invalid inputs when retrieving an environment variable */
+  size = BUF_SIZE;
+  r = uv_os_getenv(NULL, buf, &size);
+  ASSERT_EQ(r, UV_EINVAL);
+  r = uv_os_getenv(name, NULL, &size);
+  ASSERT_EQ(r, UV_EINVAL);
+  r = uv_os_getenv(name, buf, NULL);
+  ASSERT_EQ(r, UV_EINVAL);
+  size = 0;
+  r = uv_os_getenv(name, buf, &size);
+  ASSERT_EQ(r, UV_EINVAL);
+
+  /* Reject invalid inputs when deleting an environment variable */
+  r = uv_os_unsetenv(NULL);
+  ASSERT_EQ(r, UV_EINVAL);
+
+  /* Successfully set an environment variable */
+  r = uv_os_setenv(name, "123456789");
+  ASSERT_OK(r);
+
+  /* Successfully read an environment variable */
+  size = BUF_SIZE;
+  buf[0] = '\0';
+  r = uv_os_getenv(name, buf, &size);
+  ASSERT_OK(r);
+  ASSERT_OK(strcmp(buf, "123456789"));
+  ASSERT_EQ(size, BUF_SIZE - 1);
+
+  /* Return UV_ENOBUFS if the buffer cannot hold the environment variable */
+  size = BUF_SIZE - 1;
+  buf[0] = '\0';
+  r = uv_os_getenv(name, buf, &size);
+  ASSERT_EQ(r, UV_ENOBUFS);
+  ASSERT_EQ(size, BUF_SIZE);
+
+  /* Successfully delete an environment variable */
+  r = uv_os_unsetenv(name);
+  ASSERT_OK(r);
+
+  /* Return UV_ENOENT retrieving an environment variable that does not exist */
+  r = uv_os_getenv(name, buf, &size);
+  ASSERT_EQ(r, UV_ENOENT);
+
+  /* Successfully delete an environment variable that does not exist */
+  r = uv_os_unsetenv(name);
+  ASSERT_OK(r);
+
+  /* Setting an environment variable to the empty string does not delete it. */
+  r = uv_os_setenv(name, "");
+  ASSERT_OK(r);
+  size = BUF_SIZE;
+  r = uv_os_getenv(name, buf, &size);
+  ASSERT_OK(r);
+  ASSERT_OK(size);
+  ASSERT_OK(strlen(buf));
+
+  /* Check getting all env variables. */
+  r = uv_os_setenv(name, "123456789");
+  ASSERT_OK(r);
+  r = uv_os_setenv(name2, "");
+  ASSERT_OK(r);
+#ifdef _WIN32
+  /* Create a special environment variable on Windows in case there are no
+     naturally occurring ones. */
+  r = uv_os_setenv("=Z:", "\\");
+  ASSERT_OK(r);
+#endif
+
+  r = uv_os_environ(&envitems, &envcount);
+  ASSERT_OK(r);
+  ASSERT_GT(envcount, 0);
+
+  found = 0;
+  found_win_special = 0;
+
+  for (i = 0; i < envcount; i++) {
+    /* printf("Env: %s = %s\n", envitems[i].name, envitems[i].value); */
+    if (strcmp(envitems[i].name, name) == 0) {
+      found++;
+      ASSERT_OK(strcmp(envitems[i].value, "123456789"));
+    } else if (strcmp(envitems[i].name, name2) == 0) {
+      found++;
+      ASSERT_OK(strlen(envitems[i].value));
+    } else if (envitems[i].name[0] == '=') {
+      found_win_special++;
+    }
+  }
+
+  ASSERT_EQ(2, found);
+#ifdef _WIN32
+  ASSERT_GT(found_win_special, 0);
+#else
+  /* There's no rule saying a key can't start with '='. */
+  (void) &found_win_special;
+#endif
+
+  uv_os_free_environ(envitems, envcount);
+
+  r = uv_os_unsetenv(name);
+  ASSERT_OK(r);
+
+  r = uv_os_unsetenv(name2);
+  ASSERT_OK(r);
+
+  for (i = 1; i <= 4; i++) {
+    size_t n;
+    char* p;
+
+    n = i * 32768;
+    size = n + 1;
+
+    p = malloc(size);
+    ASSERT_NOT_NULL(p);
+
+    memset(p, 'x', n);
+    p[n] = '\0';
+
+    ASSERT_OK(uv_os_setenv(name, p));
+    ASSERT_OK(uv_os_getenv(name, p, &size));
+    ASSERT_EQ(n, size);
+
+    for (n = 0; n < size; n++)
+      ASSERT_EQ('x', p[n]);
+
+    ASSERT_OK(uv_os_unsetenv(name));
+    free(p);
+  }
+
+  return 0;
+}