check_env_var_len

Author: youknowone

Lib/test/test_os.py

@@ -1152,7 +1152,6 @@ def test_putenv_unsetenv(self):
             self.assertEqual(proc.stdout.rstrip(), repr(None))
 
     # On OS X < 10.6, unsetenv() doesn't return a value (bpo-13415).
-    @unittest.expectedFailureIfWindows('TODO: RUSTPYTHON; (AssertionError: ValueError not raised by putenv)')
     @support.requires_mac_ver(10, 6)
     def test_putenv_unsetenv_error(self):
         # Empty variable name is invalid.

crates/common/src/windows.rs

@@ -3,6 +3,9 @@ use std::{
     os::windows::ffi::{OsStrExt, OsStringExt},
 };
 
+/// _MAX_ENV from Windows CRT stdlib.h - maximum environment variable size
+pub const _MAX_ENV: usize = 32767;
+
 pub trait ToWideString {
     fn to_wide(&self) -> Vec<u16>;
     fn to_wide_with_nul(&self) -> Vec<u16>;

crates/vm/src/stdlib/os.rs

@@ -428,6 +428,20 @@ pub(super) mod _os {
         }
     }
 
+    /// Check if environment variable length exceeds Windows limit.
+    /// size should be key.len() + value.len() + 2 (for '=' and null terminator)
+    #[cfg(windows)]
+    fn check_env_var_len(size: usize, vm: &VirtualMachine) -> PyResult<()> {
+        use crate::common::windows::_MAX_ENV;
+        if size > _MAX_ENV {
+            return Err(vm.new_value_error(format!(
+                "the environment variable is longer than {} characters",
+                _MAX_ENV
+            )));
+        }
+        Ok(())
+    }
+
     #[pyfunction]
     fn putenv(
         key: Either<PyStrRef, PyBytesRef>,
@@ -442,6 +456,8 @@ pub(super) mod _os {
         if key.is_empty() || key.contains(&b'=') {
             return Err(vm.new_value_error("illegal environment variable name"));
         }
+        #[cfg(windows)]
+        check_env_var_len(key.len() + value.len() + 2, vm)?;
         let key = super::bytes_as_os_str(key, vm)?;
         let value = super::bytes_as_os_str(value, vm)?;
         // SAFETY: requirements forwarded from the caller
@@ -464,6 +480,9 @@ pub(super) mod _os {
                 ),
             ));
         }
+        // For unsetenv, size is key + '=' (no value, just clearing)
+        #[cfg(windows)]
+        check_env_var_len(key.len() + 1, vm)?;
         let key = super::bytes_as_os_str(key, vm)?;
         // SAFETY: requirements forwarded from the caller
         unsafe { env::remove_var(key) };