Bump MSRV to 1.56 and minimum Python version to 3.8

.github/workflows/build.yml

@@ -201,7 +201,3 @@ jobs:
       # TODO: this is a hack to workaround compile_error! warnings about auto-initialize on PyPy
       # Once cargo's `resolver = "2"` is stable (~ MSRV Rust 1.52), remove this.
       PYO3_CI: 1
-      # This is a hack to make CARGO_PRIMARY_PACKAGE always set even for the
-      # msrv job. MSRV is currently 1.48, but CARGO_PRIMARY_PACKAGE only came in
-      # 1.49.
-      CARGO_PRIMARY_PACKAGE: 1

.github/workflows/ci.yml

@@ -81,7 +81,7 @@ jobs:
           },
         ]
         include:
-          - rust: 1.48.0
+          - rust: 1.56.0
             python-version: "3.11"
             platform:
               {
@@ -178,12 +178,10 @@ jobs:
         extra-features: ["multiple-pymethods"]  # Because MSRV doesn't support this
         rust: [stable]
         python-version: [
-          "3.7",
           "3.8",
           "3.9",
           "3.10",
           "3.11",
-          "pypy-3.7",
           "pypy-3.8",
           "pypy-3.9"
         ]
@@ -207,7 +205,7 @@ jobs:
           ]
         include:
           # Test minimal supported Rust version
-          - rust: 1.48.0
+          - rust: 1.56.0
             python-version: "3.11"
             platform:
               {

Cargo.toml

@@ -12,6 +12,7 @@ categories = ["api-bindings", "development-tools::ffi"]
 license = "Apache-2.0"
 exclude = ["/.gitignore", ".cargo/config", "/codecov.yml", "/Makefile", "/pyproject.toml", "/noxfile.py", "/.github", "/tests/test_compile_error.rs", "/tests/ui"]
 edition = "2018"
+rust-version = "1.56"
 
 [dependencies]
 cfg-if = "1.0"

README.md

@@ -4,7 +4,7 @@
 [![benchmark](https://github.com/PyO3/pyo3/actions/workflows/bench.yml/badge.svg)](https://pyo3.rs/dev/bench/)
 [![codecov](https://codecov.io/gh/PyO3/pyo3/branch/main/graph/badge.svg)](https://codecov.io/gh/PyO3/pyo3)
 [![crates.io](https://img.shields.io/crates/v/pyo3)](https://crates.io/crates/pyo3)
-[![minimum rustc 1.48](https://img.shields.io/badge/rustc-1.48+-blue.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
+[![minimum rustc 1.56](https://img.shields.io/badge/rustc-1.56+-blue.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
 [![dev chat](https://img.shields.io/gitter/room/nwjs/nw.js.svg)](https://gitter.im/PyO3/Lobby)
 [![contributing notes](https://img.shields.io/badge/contribute-on%20github-Green)](https://github.com/PyO3/pyo3/blob/main/Contributing.md)
 
@@ -17,8 +17,8 @@
 ## Usage
 
 PyO3 supports the following software versions:
-  - Python 3.7 and up (CPython and PyPy)
-  - Rust 1.48 and up
+  - Python 3.8 and up (CPython and PyPy)
+  - Rust 1.56 and up
 
 You can use PyO3 to write a native Python module in Rust, or to embed Python in a Rust binary. The following sections explain each of these in turn.
 

examples/plugin/plugin_api/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [project]
 name = "plugin_api"
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 classifiers = [
     "Programming Language :: Rust",
     "Programming Language :: Python :: Implementation :: CPython",

guide/src/getting_started.md

@@ -4,13 +4,13 @@ To get started using PyO3 you will need three things: a Rust toolchain, a Python
 
 ## Rust
 
-First, make sure you have Rust installed on your system. If you haven't already done so, try following the instructions [here](https://www.rust-lang.org/tools/install). PyO3 runs on both the `stable` and `nightly` versions so you can choose whichever one fits you best. The minimum required Rust version is 1.48.
+First, make sure you have Rust installed on your system. If you haven't already done so, try following the instructions [here](https://www.rust-lang.org/tools/install). PyO3 runs on both the `stable` and `nightly` versions so you can choose whichever one fits you best. The minimum required Rust version is 1.56.
 
 If you can run `rustc --version` and the version is new enough you're good to go!
 
 ## Python
 
-To use PyO3, you need at least Python 3.7. While you can simply use the default Python interpreter on your system, it is recommended to use a virtual environment.
+To use PyO3, you need at least Python 3.8. While you can simply use the default Python interpreter on your system, it is recommended to use a virtual environment.
 
 ## Virtualenvs
 
@@ -128,7 +128,7 @@ build-backend = "maturin"
 
 [project]
 name = "pyo3_example"
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 classifiers = [
     "Programming Language :: Rust",
     "Programming Language :: Python :: Implementation :: CPython",

guide/src/migration.md

@@ -3,6 +3,12 @@
 This guide can help you upgrade code through breaking changes from one PyO3 version to the next.
 For a detailed list of all changes, see the [CHANGELOG](changelog.md).
 
+## from 0.19.* to 0.20
+
+### Drop support for older technologies
+
+PyO3 0.20 has increased minimum Rust version to 1.56 and minimum Python version to 3.8. This enables use of newer language features and simplifies maintenance of the project.
+
 ## from 0.18.* to 0.19
 
 ### Access to `Python` inside `__traverse__` implementations are now forbidden

newsfragments/3204.changed.md

@@ -0,0 +1 @@
+Update MSRV to Rust 1.56 and the minimum Python version to 3.8.

noxfile.py

@@ -16,8 +16,8 @@
 
 
 PYO3_DIR = Path(__file__).parent
-PY_VERSIONS = ("3.7", "3.8", "3.9", "3.10", "3.11")
-PYPY_VERSIONS = ("3.7", "3.8", "3.9")
+PY_VERSIONS = ("3.8", "3.9", "3.10", "3.11")
+PYPY_VERSIONS = ("3.8", "3.9")
 
 
 @nox.session(venv_backend="none")

pyo3-ffi/README.md

@@ -2,7 +2,6 @@
 
 This crate provides [Rust](https://www.rust-lang.org/) FFI declarations for Python 3.
 It supports both the stable and the unstable component of the ABI through the use of cfg flags.
-Python Versions 3.7+ are supported.
 It is meant for advanced users only - regular PyO3 users shouldn't
 need to interact with this crate at all.
 
@@ -13,8 +12,8 @@ Manual][capi] for up-to-date documentation.
 # Minimum supported Rust and Python versions
 
 PyO3 supports the following software versions:
-  - Python 3.7 and up (CPython and PyPy)
-  - Rust 1.48 and up
+  - Python 3.8 and up (CPython and PyPy)
+  - Rust 1.56 and up
 
 # Example: Building Python Native modules
 

pyo3-ffi/src/lib.rs

@@ -50,8 +50,8 @@
 //! # Minimum supported Rust and Python versions
 //!
 //! PyO3 supports the following software versions:
-//!   - Python 3.7 and up (CPython and PyPy)
-//!   - Rust 1.48 and up
+//!   - Python 3.8 and up (CPython and PyPy)
+//!   - Rust 1.56 and up
 //!
 //! # Example: Building Python Native modules
 //!

pyo3-macros-backend/src/pyfunction/signature.rs

@@ -27,10 +27,11 @@ pub struct Signature {
 impl Parse for Signature {
     fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
         let content;
-        Ok(Signature {
-            paren_token: syn::parenthesized!(content in input),
-            items: content.parse_terminated(SignatureItem::parse)?,
-        })
+        let paren_token = syn::parenthesized!(content in input);
+
+        let items = content.parse_terminated(SignatureItem::parse)?;
+
+        Ok(Signature { paren_token, items })
     }
 }
 

src/lib.rs

@@ -121,8 +121,8 @@
 //! # Minimum supported Rust and Python versions
 //!
 //! PyO3 supports the following software versions:
-//!   - Python 3.7 and up (CPython and PyPy)
-//!   - Rust 1.48 and up
+//!   - Python 3.8 and up (CPython and PyPy)
+//!   - Rust 1.56 and up
 //!
 //! # Example: Building a native Python module
 //!

xtask/src/cli.rs

@@ -5,7 +5,7 @@ use std::process::{Command, Output};
 use std::time::Instant;
 use structopt::StructOpt;
 
-pub const MSRV: &str = "1.48";
+pub const MSRV: &str = "1.56";
 
 #[derive(StructOpt)]
 pub enum Subcommand {