From ded9f65bfd525843675ffd76058f42fce9fe1e0c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Quentin=20Gallou=C3=A9dec?=
 <45557362+qgallouedec@users.noreply.github.com>
Date: Tue, 29 Nov 2022 10:24:44 +0100
Subject: [PATCH] Fix `sb3_contrib/common/utils.py` type hint (#120)

* Update contribution.md

* New loop struct to make mypy happy

* Update setup.cfg

* Update changelog

* Add return statement in cg solver for max_iter=0

Co-authored-by: Antonin Raffin <antonin.raffin@ensta.org>
---
 CONTRIBUTING.md             | 4 ++--
 docs/misc/changelog.rst     | 1 +
 sb3_contrib/common/utils.py | 2 ++
 setup.cfg                   | 1 -
 4 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 1112e98..9013df7 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -152,7 +152,7 @@ To run tests with `pytest`:
 make pytest
 ```
 
-Type checking with `pytype`:
+Type checking with `pytype` and `mypy`:
 
 ```
 make type
@@ -165,7 +165,7 @@ make check-codestyle
 make lint
 ```
 
-To run `pytype`, `format` and `lint` in one command:
+To run `type`, `format` and `lint` in one command:
 ```
 make commit-checks
 ```
diff --git a/docs/misc/changelog.rst b/docs/misc/changelog.rst
index 7a9bdf1..1d7a288 100644
--- a/docs/misc/changelog.rst
+++ b/docs/misc/changelog.rst
@@ -27,6 +27,7 @@ Deprecations:
 Others:
 ^^^^^^^
 - Fixed flake8 config
+- Fixed ``sb3_contrib/common/utils.py`` type hint
 
 Release 1.6.2 (2022-10-10)
 --------------------------
diff --git a/sb3_contrib/common/utils.py b/sb3_contrib/common/utils.py
index d380bb7..8066ccc 100644
--- a/sb3_contrib/common/utils.py
+++ b/sb3_contrib/common/utils.py
@@ -133,6 +133,8 @@ def conjugate_gradient_solver(
         beta = new_residual_squared_norm / residual_squared_norm
         residual_squared_norm = new_residual_squared_norm
         p = residual + beta * p
+    # Note: this return statement is only used when max_iter=0
+    return x
 
 
 def flat_grad(
diff --git a/setup.cfg b/setup.cfg
index 75afed5..dad73ae 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -32,7 +32,6 @@ exclude = (?x)(
 	| sb3_contrib/common/recurrent/type_aliases.py$
 	| sb3_contrib/common/recurrent/policies.py$
 	| sb3_contrib/common/recurrent/buffers.py$
-	| sb3_contrib/common/utils.py$
 	| sb3_contrib/common/maskable/distributions.py$
 	| sb3_contrib/common/maskable/callbacks.py$
 	| sb3_contrib/common/maskable/policies.py$