From 74439a64a22850f16323f1e1e09ace2a909b0b61 Mon Sep 17 00:00:00 2001
From: Sergei Izmailov <sergei.a.izmailov@gmail.com>
Date: Wed, 18 Oct 2023 04:04:46 +0900
Subject: [PATCH] feature: Use typed iterators in `make_*iterator` (#4876)

---
 include/pybind11/pybind11.h           | 19 +++++++++++++------
 tests/test_sequences_and_iterators.py |  9 +++++++++
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/include/pybind11/pybind11.h b/include/pybind11/pybind11.h
index 4c0069bfb..a94f6f0f1 100644
--- a/include/pybind11/pybind11.h
+++ b/include/pybind11/pybind11.h
@@ -15,6 +15,7 @@
 #include "attr.h"
 #include "gil.h"
 #include "options.h"
+#include "typing.h"
 
 #include <cstdlib>
 #include <cstring>
@@ -2447,7 +2448,7 @@ template <return_value_policy Policy = return_value_policy::reference_internal,
           typename Sentinel,
           typename ValueType = typename detail::iterator_access<Iterator>::result_type,
           typename... Extra>
-iterator make_iterator(Iterator first, Sentinel last, Extra &&...extra) {
+typing::Iterator<ValueType> make_iterator(Iterator first, Sentinel last, Extra &&...extra) {
     return detail::make_iterator_impl<detail::iterator_access<Iterator>,
                                       Policy,
                                       Iterator,
@@ -2465,7 +2466,7 @@ template <return_value_policy Policy = return_value_policy::reference_internal,
           typename Sentinel,
           typename KeyType = typename detail::iterator_key_access<Iterator>::result_type,
           typename... Extra>
-iterator make_key_iterator(Iterator first, Sentinel last, Extra &&...extra) {
+typing::Iterator<KeyType> make_key_iterator(Iterator first, Sentinel last, Extra &&...extra) {
     return detail::make_iterator_impl<detail::iterator_key_access<Iterator>,
                                       Policy,
                                       Iterator,
@@ -2483,7 +2484,7 @@ template <return_value_policy Policy = return_value_policy::reference_internal,
           typename Sentinel,
           typename ValueType = typename detail::iterator_value_access<Iterator>::result_type,
           typename... Extra>
-iterator make_value_iterator(Iterator first, Sentinel last, Extra &&...extra) {
+typing::Iterator<ValueType> make_value_iterator(Iterator first, Sentinel last, Extra &&...extra) {
     return detail::make_iterator_impl<detail::iterator_value_access<Iterator>,
                                       Policy,
                                       Iterator,
@@ -2498,8 +2499,10 @@ iterator make_value_iterator(Iterator first, Sentinel last, Extra &&...extra) {
 /// `std::begin()`/`std::end()`
 template <return_value_policy Policy = return_value_policy::reference_internal,
           typename Type,
+          typename ValueType = typename detail::iterator_access<
+              decltype(std::begin(std::declval<Type &>()))>::result_type,
           typename... Extra>
-iterator make_iterator(Type &value, Extra &&...extra) {
+typing::Iterator<ValueType> make_iterator(Type &value, Extra &&...extra) {
     return make_iterator<Policy>(
         std::begin(value), std::end(value), std::forward<Extra>(extra)...);
 }
@@ -2508,8 +2511,10 @@ iterator make_iterator(Type &value, Extra &&...extra) {
 /// `std::begin()`/`std::end()`
 template <return_value_policy Policy = return_value_policy::reference_internal,
           typename Type,
+          typename KeyType = typename detail::iterator_key_access<
+              decltype(std::begin(std::declval<Type &>()))>::result_type,
           typename... Extra>
-iterator make_key_iterator(Type &value, Extra &&...extra) {
+typing::Iterator<KeyType> make_key_iterator(Type &value, Extra &&...extra) {
     return make_key_iterator<Policy>(
         std::begin(value), std::end(value), std::forward<Extra>(extra)...);
 }
@@ -2518,8 +2523,10 @@ iterator make_key_iterator(Type &value, Extra &&...extra) {
 /// `std::begin()`/`std::end()`
 template <return_value_policy Policy = return_value_policy::reference_internal,
           typename Type,
+          typename ValueType = typename detail::iterator_value_access<
+              decltype(std::begin(std::declval<Type &>()))>::result_type,
           typename... Extra>
-iterator make_value_iterator(Type &value, Extra &&...extra) {
+typing::Iterator<ValueType> make_value_iterator(Type &value, Extra &&...extra) {
     return make_value_iterator<Policy>(
         std::begin(value), std::end(value), std::forward<Extra>(extra)...);
 }
diff --git a/tests/test_sequences_and_iterators.py b/tests/test_sequences_and_iterators.py
index acbe9d898..c13f03dd8 100644
--- a/tests/test_sequences_and_iterators.py
+++ b/tests/test_sequences_and_iterators.py
@@ -58,6 +58,15 @@ def test_generalized_iterators_simple():
     assert list(m.IntPairs([(1, 2), (3, 4), (0, 5)]).simple_values()) == [2, 4, 5]
 
 
+def test_iterator_doc_annotations():
+    assert m.IntPairs.nonref.__doc__.endswith("-> Iterator[tuple[int, int]]\n")
+    assert m.IntPairs.nonref_keys.__doc__.endswith("-> Iterator[int]\n")
+    assert m.IntPairs.nonref_values.__doc__.endswith("-> Iterator[int]\n")
+    assert m.IntPairs.simple_iterator.__doc__.endswith("-> Iterator[tuple[int, int]]\n")
+    assert m.IntPairs.simple_keys.__doc__.endswith("-> Iterator[int]\n")
+    assert m.IntPairs.simple_values.__doc__.endswith("-> Iterator[int]\n")
+
+
 def test_iterator_referencing():
     """Test that iterators reference rather than copy their referents."""
     vec = m.VectorNonCopyableInt()