msrv: bump to 1.48

.github/workflows/ci.yml

@@ -123,7 +123,7 @@ jobs:
                 rust-target: "x86_64-apple-darwin",
               }
           # Test minimal supported Rust version
-          - rust: 1.41.1
+          - rust: 1.48.0
             python-version: "3.10"
             platform:
               {

CHANGELOG.md

@@ -8,6 +8,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Packaging
+
+- Update MSRV to Rust 1.48. [#2004](https://github.com/PyO3/pyo3/pull/2004)
+- Update `indoc` optional dependency to 1.0. [#2004](https://github.com/PyO3/pyo3/pull/2004)
+- Update `paste` optional dependency to 1.0. [#2004](https://github.com/PyO3/pyo3/pull/2004)
+
 ### Added
 
 - Add implementations for `Py::as_ref()` and `Py::into_ref()` for `Py<PySequence>`, `Py<PyIterator>` and `Py<PyMapping>`. [#1682](https://github.com/PyO3/pyo3/pull/1682)

Cargo.toml

@@ -21,9 +21,8 @@ parking_lot = "0.11.0"
 
 # support crates for macros feature
 pyo3-macros = { path = "pyo3-macros", version = "=0.15.0", optional = true }
-# indoc must stay at 0.3.x for Rust 1.41 compatibility
-indoc = { version = "0.3.6", optional = true }
-paste = { version = "0.1.18", optional = true }
+indoc = { version = "1.0.3", optional = true }
+paste = { version = "1.0.6", optional = true }
 unindent = { version = "0.1.4", optional = true }
 
 # support crate for multiple-pymethods feature
@@ -32,7 +31,7 @@ inventory = { version = "0.1.4", optional = true }
 
 # crate integrations that can be added using the eponymous features
 anyhow = { version = "1.0", optional = true }
-eyre = { version = ">= 0.4, < 0.7" , optional = true }
+eyre = { version = ">= 0.4, < 0.7", optional = true }
 hashbrown = { version = ">= 0.9, < 0.12", optional = true }
 indexmap = { version = ">= 1.6, < 1.8", optional = true }
 num-bigint = { version = "0.4", optional = true }
@@ -41,11 +40,7 @@ serde = { version = "1.0", optional = true }
 
 [dev-dependencies]
 assert_approx_eq = "1.1.0"
-# O.3.5 uses the matches! macro, which isn't compatible with Rust 1.41
-criterion = "=0.3.4"
-# half and bitflags use if/match in const fn, which isn't compatible with Rust 1.41
-half = "=1.7.1"
-bitflags = "=1.2.1"
+criterion = "0.3.5"
 trybuild = "1.0.49"
 rustversion = "1.0"
 # 1.0.0 requires Rust 1.50

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 1.41](https://img.shields.io/badge/rustc-1.41+-blue.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
+[![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)
 [![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)
 
@@ -18,7 +18,7 @@
 
 PyO3 supports the following software versions:
   - Python 3.6 and up (CPython and PyPy)
-  - Rust 1.41 and up
+  - Rust 1.48 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.
 

pyo3-macros-backend/src/method.rs

@@ -352,15 +352,12 @@ impl<'a> FnSpec<'a> {
             parse_method_receiver(first_arg)
         };
 
-        #[allow(clippy::manual_strip)] // for strip_prefix replacement supporting rust < 1.45
         // strip get_ or set_
         let strip_fn_name = |prefix: &'static str| {
-            let ident = name.unraw().to_string();
-            if ident.starts_with(prefix) {
-                Some(syn::Ident::new(&ident[prefix.len()..], ident.span()))
-            } else {
-                None
-            }
+            name.unraw()
+                .to_string()
+                .strip_prefix(prefix)
+                .map(|stripped| syn::Ident::new(stripped, name.span()))
         };
 
         let (fn_type, skip_first_arg, fixed_convention) = match fn_type_attr {

pyo3-macros-backend/src/proto_method.rs

@@ -15,13 +15,11 @@ pub struct MethodProto {
 }
 
 impl MethodProto {
-    // TODO: workaround for no unsized casts in const fn on Rust 1.45 (stable in 1.46)
-    const EMPTY_ARGS: &'static [&'static str] = &[];
     pub const fn new(name: &'static str, proto: &'static str) -> Self {
         MethodProto {
             name,
             proto,
-            args: MethodProto::EMPTY_ARGS,
+            args: &[],
             with_self: false,
             with_result: true,
         }

pyo3-macros-backend/src/pymethod.rs

@@ -399,14 +399,9 @@ pub fn impl_py_getter_def(cls: &syn::Type, property_type: PropertyType) -> Resul
 
 /// Split an argument of pyo3::Python from the front of the arg list, if present
 fn split_off_python_arg<'a>(args: &'a [FnArg<'a>]) -> (Option<&FnArg>, &[FnArg]) {
-    if args
-        .get(0)
-        .map(|py| utils::is_python(py.ty))
-        .unwrap_or(false)
-    {
-        (Some(&args[0]), &args[1..])
-    } else {
-        (None, args)
+    match args {
+        [py, args @ ..] if utils::is_python(&py.ty) => (Some(py), args),
+        args => (None, args),
     }
 }
 

pyo3-macros-backend/src/utils.rs

@@ -62,8 +62,6 @@ pub fn option_type_argument(ty: &syn::Type) -> Option<&syn::Type> {
 #[derive(Clone)]
 pub struct PythonDoc(TokenStream);
 
-// TODO(#1782) use strip_prefix on Rust 1.45 or greater
-#[allow(clippy::manual_strip)]
 /// Collects all #[doc = "..."] attributes into a TokenStream evaluating to a null-terminated string
 /// e.g. concat!("...", "\n", "\0")
 pub fn get_doc(
@@ -107,11 +105,11 @@ pub fn get_doc(
                         // Strip single left space from literal strings, if needed.
                         // e.g. `/// Hello world` expands to #[doc = " Hello world"]
                         let doc_line = lit_str.value();
-                        if doc_line.starts_with(' ') {
-                            syn::LitStr::new(&doc_line[1..], lit_str.span()).to_tokens(tokens)
-                        } else {
-                            lit_str.to_tokens(tokens)
-                        }
+                        doc_line
+                            .strip_prefix(' ')
+                            .map(|stripped| syn::LitStr::new(stripped, lit_str.span()))
+                            .unwrap_or(lit_str)
+                            .to_tokens(tokens);
                     } else {
                         // This is probably a macro doc from Rust 1.54, e.g. #[doc = include_str!(...)]
                         token_stream.to_tokens(tokens)

src/buffer.rs

@@ -75,12 +75,7 @@ impl ElementType {
     pub fn from_format(format: &CStr) -> ElementType {
         match format.to_bytes() {
             [char] | [b'@', char] => native_element_type_from_type_char(*char),
-            [modifier, char]
-                if (*modifier == b'='
-                    || *modifier == b'<'
-                    || *modifier == b'>'
-                    || *modifier == b'!') =>
-            {
+            [modifier, char] if matches!(modifier, b'=' | b'<' | b'>' | b'!') => {
                 standard_element_type_from_type_char(*char)
             }
             _ => ElementType::Unknown,

src/class/impl_.rs

@@ -542,7 +542,6 @@ pub unsafe extern "C" fn alloc_with_freelist<T: PyClassWithFreeList>(
 /// # Safety
 /// - `obj` must be a valid pointer to an instance of T (not a subclass).
 /// - The GIL must be held.
-#[allow(clippy::collapsible_if)] // for if cfg!
 pub unsafe extern "C" fn free_with_freelist<T: PyClassWithFreeList>(obj: *mut c_void) {
     let obj = obj as *mut ffi::PyObject;
     debug_assert_eq!(
@@ -560,10 +559,9 @@ pub unsafe extern "C" fn free_with_freelist<T: PyClassWithFreeList>(obj: *mut c_
         };
         free(obj as *mut c_void);
 
-        if cfg!(Py_3_8) {
-            if ffi::PyType_HasFeature(ty, ffi::Py_TPFLAGS_HEAPTYPE) != 0 {
-                ffi::Py_DECREF(ty as *mut ffi::PyObject);
-            }
+        #[cfg(Py_3_8)]
+        if ffi::PyType_HasFeature(ty, ffi::Py_TPFLAGS_HEAPTYPE) != 0 {
+            ffi::Py_DECREF(ty as *mut ffi::PyObject);
         }
     }
 }

src/ffi/ceval.rs

@@ -52,7 +52,6 @@ extern "C" {
     fn _Py_CheckRecursiveCall(_where: *mut c_char) -> c_int;
 }
 
-// TODO
 // skipped Py_EnterRecursiveCall
 // skipped Py_LeaveRecursiveCall
 

src/gil.rs

@@ -69,33 +69,36 @@ pub(crate) fn gil_is_acquired() -> bool {
 /// # }
 /// ```
 #[cfg(not(PyPy))]
-#[allow(clippy::collapsible_if)] // for if cfg!
 pub fn prepare_freethreaded_python() {
     // Protect against race conditions when Python is not yet initialized and multiple threads
     // concurrently call 'prepare_freethreaded_python()'. Note that we do not protect against
     // concurrent initialization of the Python runtime by other users of the Python C API.
     START.call_once_force(|_| unsafe {
-        if cfg!(not(Py_3_7)) {
-            // Use call_once_force because if initialization panics, it's okay to try again.
-            if ffi::Py_IsInitialized() != 0 {
-                if ffi::PyEval_ThreadsInitialized() == 0 {
-                    // We can only safely initialize threads if this thread holds the GIL.
-                    assert!(
-                        !ffi::PyGILState_GetThisThreadState().is_null(),
-                        "Python threading is not initialized and cannot be initialized by this \
-                         thread, because it is not the thread which initialized Python."
-                    );
-                    ffi::PyEval_InitThreads();
-                }
-            } else {
-                ffi::Py_InitializeEx(0);
+        // Use call_once_force because if initialization panics, it's okay to try again.
+
+        // TODO(#1782) - Python 3.6 legacy code
+        #[cfg(not(Py_3_7))]
+        if ffi::Py_IsInitialized() != 0 {
+            if ffi::PyEval_ThreadsInitialized() == 0 {
+                // We can only safely initialize threads if this thread holds the GIL.
+                assert!(
+                    !ffi::PyGILState_GetThisThreadState().is_null(),
+                    "Python threading is not initialized and cannot be initialized by this \
+                     thread, because it is not the thread which initialized Python."
+                );
                 ffi::PyEval_InitThreads();
-
-                // Release the GIL.
-                ffi::PyEval_SaveThread();
             }
-        } else if ffi::Py_IsInitialized() == 0 {
-            // In Python 3.7 and up PyEval_InitThreads is irrelevant.
+        } else {
+            ffi::Py_InitializeEx(0);
+            ffi::PyEval_InitThreads();
+
+            // Release the GIL.
+            ffi::PyEval_SaveThread();
+        }
+
+        // In Python 3.7 and up PyEval_InitThreads is irrelevant.
+        #[cfg(Py_3_7)]
+        if ffi::Py_IsInitialized() == 0 {
             ffi::Py_InitializeEx(0);
 
             // Release the GIL.
@@ -134,7 +137,6 @@ pub fn prepare_freethreaded_python() {
 /// # }
 /// ```
 #[cfg(not(PyPy))]
-#[allow(clippy::collapsible_if)] // for if cfg!
 pub unsafe fn with_embedded_python_interpreter<F, R>(f: F) -> R
 where
     F: for<'p> FnOnce(Python<'p>) -> R,
@@ -149,10 +151,9 @@ where
 
     // Changed in version 3.7: This function is now called by Py_Initialize(), so you don’t have to
     // call it yourself anymore.
-    if cfg!(not(Py_3_7)) {
-        if ffi::PyEval_ThreadsInitialized() == 0 {
-            ffi::PyEval_InitThreads();
-        }
+    #[cfg(not(Py_3_7))]
+    if ffi::PyEval_ThreadsInitialized() == 0 {
+        ffi::PyEval_InitThreads();
     }
 
     // Safe: the GIL is already held because of the Py_IntializeEx call.

src/lib.rs

@@ -111,7 +111,7 @@
 //!
 //! PyO3 supports the following software versions:
 //!   - Python 3.6 and up (CPython and PyPy)
-//!   - Rust 1.41 and up
+//!   - Rust 1.48 and up
 //!
 //! # Example: Building a native Python module
 //!

src/pyclass.rs

@@ -83,7 +83,8 @@ where
         slots.push(ffi::Py_tp_free, free as _);
     }
 
-    if cfg!(Py_3_9) {
+    #[cfg(Py_3_9)]
+    {
         let members = py_class_members::<T>();
         if !members.is_empty() {
             slots.push(ffi::Py_tp_members, into_raw(members))
@@ -155,7 +156,8 @@ fn tp_init_additional<T: PyClass>(type_object: *mut ffi::PyTypeObject) {
 
     // Setting buffer protocols via slots doesn't work until Python 3.9, so on older versions we
     // must manually fixup the type object.
-    if cfg!(not(Py_3_9)) {
+    #[cfg(not(Py_3_9))]
+    {
         if let Some(buffer) = T::get_buffer() {
             unsafe {
                 (*(*type_object).tp_as_buffer).bf_getbuffer = buffer.bf_getbuffer;
@@ -166,7 +168,8 @@ fn tp_init_additional<T: PyClass>(type_object: *mut ffi::PyTypeObject) {
 
     // Setting tp_dictoffset and tp_weaklistoffset via slots doesn't work until Python 3.9, so on
     // older versions again we must fixup the type object.
-    if cfg!(not(Py_3_9)) {
+    #[cfg(not(Py_3_9))]
+    {
         // __dict__ support
         if let Some(dict_offset) = PyCell::<T>::dict_offset() {
             unsafe {
@@ -258,12 +261,6 @@ fn py_class_members<T: PyClass>() -> Vec<ffi::structmember::PyMemberDef> {
     members
 }
 
-// Stub needed since the `if cfg!()` above still compiles contained code.
-#[cfg(not(Py_3_9))]
-fn py_class_members<T: PyClass>() -> Vec<ffi::structmember::PyMemberDef> {
-    vec![]
-}
-
 const PY_GET_SET_DEF_INIT: ffi::PyGetSetDef = ffi::PyGetSetDef {
     name: ptr::null_mut(),
     get: None,
@@ -272,7 +269,6 @@ const PY_GET_SET_DEF_INIT: ffi::PyGetSetDef = ffi::PyGetSetDef {
     closure: ptr::null_mut(),
 };
 
-#[allow(clippy::collapsible_if)] // for if cfg!
 fn py_class_properties(
     is_dummy: bool,
     for_each_method_def: &dyn Fn(&mut dyn FnMut(&[PyMethodDefType])),

src/types/string.rs

@@ -227,8 +227,9 @@ impl PyString {
     pub unsafe fn data(&self) -> PyResult<PyStringData<'_>> {
         let ptr = self.as_ptr();
 
-        if cfg!(not(Py_3_12)) {
-            #[allow(deprecated)]
+        #[cfg(not(Py_3_12))]
+        #[allow(deprecated)]
+        {
             let ready = ffi::PyUnicode_READY(ptr);
             if ready != 0 {
                 // Exception was created on failure.

tests/test_compile_error.rs

@@ -23,22 +23,15 @@ fn _test_compile_errors() {
     t.compile_fail("tests/ui/invalid_pymethods.rs");
     t.compile_fail("tests/ui/invalid_pymethod_names.rs");
     t.compile_fail("tests/ui/invalid_argument_attributes.rs");
+    t.compile_fail("tests/ui/missing_clone.rs");
     t.compile_fail("tests/ui/reject_generics.rs");
+    t.compile_fail("tests/ui/wrong_aspyref_lifetimes.rs");
 
-    tests_rust_1_48(&t);
     tests_rust_1_49(&t);
     tests_rust_1_54(&t);
     tests_rust_1_55(&t);
     tests_rust_1_56(&t);
 
-    #[rustversion::since(1.48)]
-    fn tests_rust_1_48(t: &trybuild::TestCases) {
-        t.compile_fail("tests/ui/missing_clone.rs");
-        t.compile_fail("tests/ui/wrong_aspyref_lifetimes.rs");
-    }
-    #[rustversion::before(1.48)]
-    fn tests_rust_1_48(_t: &trybuild::TestCases) {}
-
     #[rustversion::since(1.49)]
     fn tests_rust_1_49(t: &trybuild::TestCases) {
         t.compile_fail("tests/ui/deprecations.rs");

tests/test_not_msrv.rs

@@ -2,9 +2,7 @@
 //! but can't even be cfg-ed out on MSRV because the compiler doesn't support
 //! the syntax.
 
-// TODO(#1782) rustversion attribute can't go on modules until Rust 1.42, so this
-// funky dance has to happen...
+#[rustversion::since(1.54)]
 mod requires_1_54 {
-    #[rustversion::since(1.54)]
     include!("not_msrv/requires_1_54.rs");
 }