Compare minimum python version requirement between requires-python and bindings crate

Changelog.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * **Breaking Change**: Drop support for python 3.6, which is end of life
 * Fix incompatibility with cibuildwheel for 32-bit Windows in [#951](https://github.com/PyO3/maturin/pull/951)
 * Don't require `pip` error messages to be utf-8 encoding in [#953](https://github.com/PyO3/maturin/pull/953)
+* Compare minimum python version requirement between `requires-python` and bindings crate in [#954](https://github.com/PyO3/maturin/pull/954)
 
 ## [0.12.19] - 2022-06-05
 

src/python_interpreter/mod.rs

@@ -626,10 +626,28 @@ impl PythonInterpreter {
         bridge: &BridgeModel,
         min_python_minor: Option<usize>,
     ) -> Result<Vec<PythonInterpreter>> {
-        let min_python_minor = min_python_minor.unwrap_or(match bridge {
-            BridgeModel::Bindings(_, minor) => *minor,
-            _ => MINIMUM_PYTHON_MINOR,
-        });
+        let min_python_minor = match min_python_minor {
+            Some(requires_python_minor) => match bridge {
+                BridgeModel::Bindings(bridge_name, minor)
+                | BridgeModel::Bin(Some((bridge_name, minor))) => {
+                    // requires-python minor version might be lower than bridge crate required minor version
+                    if requires_python_minor >= *minor {
+                        requires_python_minor
+                    } else {
+                        eprintln!(
+                            "⚠️  Warning: 'requires-python' (3.{}) is lower than the requirement of {} crate (3.{}).",
+                            requires_python_minor, bridge_name, *minor
+                        );
+                        *minor
+                    }
+                }
+                _ => requires_python_minor,
+            },
+            None => match bridge {
+                BridgeModel::Bindings(_, minor) | BridgeModel::Bin(Some((_, minor))) => *minor,
+                _ => MINIMUM_PYTHON_MINOR,
+            },
+        };
         let executables = if target.is_windows() {
             find_all_windows(target, min_python_minor)?
         } else {

src/templates/Cargo.toml.j2

@@ -13,7 +13,7 @@ crate-type = ["cdylib"]
 
 [dependencies]
 {%- if bindings == "pyo3" -%}
-pyo3 = { version = "0.16.3", features = ["extension-module"] }
+pyo3 = { version = "0.16.5", features = ["extension-module"] }
 {%- elif bindings == "rust-cpython" -%}
 cpython = { version = "0.7.0", features = ["extension-module"] }
 {%- endif -%}

src/templates/pyproject.toml.j2

@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [project]
 name = "{{ name }}"
-requires-python = ">=3.6"
+requires-python = ">=3.7"
 classifiers = [
     "Programming Language :: Rust",
     "Programming Language :: Python :: Implementation :: CPython",