From d2a82b1acdcb83fac8c7ab7f02482611ea29f66a Mon Sep 17 00:00:00 2001
From: Aviv Palivoda <palaviv@gmail.com>
Date: Fri, 7 Jun 2019 15:14:27 +0300
Subject: [PATCH 1/2] Add _warnings

---
 tests/snippets/warnings.py |  3 +++
 vm/src/stdlib/mod.rs       |  2 ++
 vm/src/stdlib/warnings.rs  | 37 +++++++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 tests/snippets/warnings.py
 create mode 100644 vm/src/stdlib/warnings.rs

diff --git a/tests/snippets/warnings.py b/tests/snippets/warnings.py
new file mode 100644
index 0000000000..95092e5066
--- /dev/null
+++ b/tests/snippets/warnings.py
@@ -0,0 +1,3 @@
+import _warnings
+
+_warnings.warn("Test")
diff --git a/vm/src/stdlib/mod.rs b/vm/src/stdlib/mod.rs
index ef2d7f3a53..096d148458 100644
--- a/vm/src/stdlib/mod.rs
+++ b/vm/src/stdlib/mod.rs
@@ -16,6 +16,7 @@ mod string;
 mod thread;
 mod time_module;
 mod tokenize;
+mod warnings;
 mod weakref;
 use std::collections::HashMap;
 
@@ -55,6 +56,7 @@ pub fn get_module_inits() -> HashMap<String, StdlibInitFunc> {
     modules.insert("tokenize".to_string(), Box::new(tokenize::make_module));
     modules.insert("_weakref".to_string(), Box::new(weakref::make_module));
     modules.insert("_imp".to_string(), Box::new(imp::make_module));
+    modules.insert("_warnings".to_string(), Box::new(warnings::make_module));
 
     // disable some modules on WASM
     #[cfg(not(target_arch = "wasm32"))]
diff --git a/vm/src/stdlib/warnings.rs b/vm/src/stdlib/warnings.rs
new file mode 100644
index 0000000000..bf0055d900
--- /dev/null
+++ b/vm/src/stdlib/warnings.rs
@@ -0,0 +1,37 @@
+use crate::function::OptionalArg;
+use crate::obj::objstr::PyStringRef;
+use crate::pyobject::PyObjectRef;
+use crate::vm::VirtualMachine;
+
+#[derive(FromArgs)]
+struct WarnArgs {
+    #[pyarg(positional_only, optional = false)]
+    message: PyStringRef,
+    #[pyarg(positional_or_keyword, optional = true)]
+    category: OptionalArg<PyObjectRef>,
+    #[pyarg(positional_or_keyword, optional = true)]
+    stacklevel: OptionalArg<u32>,
+}
+
+fn warnings_warn(args: WarnArgs, _vm: &VirtualMachine) {
+    // TODO: Implement correctly
+    let level = match args.stacklevel {
+        OptionalArg::Present(l) => l,
+        OptionalArg::Missing => 1,
+    };
+    println!(
+        "Warning: {} , category: {:?}, level: {}",
+        args.message.as_str(),
+        args.category,
+        level
+    )
+}
+
+pub fn make_module(vm: &VirtualMachine) -> PyObjectRef {
+    let ctx = &vm.ctx;
+    let module = py_module!(vm, "_warnings", {
+         "warn" => ctx.new_rustfunc(warnings_warn),
+    });
+
+    module
+}

From 8fccad1e09a5c1bf34ef292fee5379b5891c747e Mon Sep 17 00:00:00 2001
From: Aviv Palivoda <palaviv@gmail.com>
Date: Fri, 7 Jun 2019 18:59:41 +0300
Subject: [PATCH 2/2] Print warning to stderr

Co-Authored-By: coolreader18 <33094578+coolreader18@users.noreply.github.com>
---
 vm/src/stdlib/warnings.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vm/src/stdlib/warnings.rs b/vm/src/stdlib/warnings.rs
index bf0055d900..cb97ead480 100644
--- a/vm/src/stdlib/warnings.rs
+++ b/vm/src/stdlib/warnings.rs
@@ -19,7 +19,7 @@ fn warnings_warn(args: WarnArgs, _vm: &VirtualMachine) {
         OptionalArg::Present(l) => l,
         OptionalArg::Missing => 1,
     };
-    println!(
+    eprintln!(
         "Warning: {} , category: {:?}, level: {}",
         args.message.as_str(),
         args.category,