ci: try to clean up some lint allows (#5577)

* ci: try to clean up some lint `allow`s

* restore one `dead_code` lint

* downgrade one `expect` to `allow`

* another one

Author: davidhewitt

pyo3-benches/benches/bench_frompyobject.rs

@@ -8,7 +8,7 @@ use pyo3::{
 };
 
 #[derive(FromPyObject)]
-#[allow(dead_code)]
+#[expect(dead_code)]
 enum ManyTypes {
     Int(i32),
     Bytes(Vec<u8>),

pyo3-build-config/build.rs

@@ -2,11 +2,11 @@
 // Allow dead code because not all code in the modules is used in this build script.
 
 #[path = "src/impl_.rs"]
-#[allow(dead_code)]
+#[allow(dead_code, reason = "not all code is used in build.rs")]
 mod impl_;
 
 #[path = "src/errors.rs"]
-#[allow(dead_code)]
+#[allow(dead_code, reason = "not all code is used in build.rs")]
 mod errors;
 
 use std::{env, path::Path};

pyo3-build-config/src/lib.rs

@@ -120,8 +120,10 @@ pub fn get() -> &'static InterpreterConfig {
             .map(|path| path.exists())
             .unwrap_or(false);
 
-        // CONFIG_FILE is generated in build.rs, so its content can vary
-        #[allow(unknown_lints, clippy::const_is_empty)]
+        #[allow(
+            clippy::const_is_empty,
+            reason = "CONFIG_FILE is generated in build.rs, content can vary"
+        )]
         if let Some(interpreter_config) = InterpreterConfig::from_cargo_dep_env() {
             interpreter_config
         } else if let Some(interpreter_config) = config_from_pyo3_config_file_env() {
@@ -141,8 +143,10 @@ fn config_from_pyo3_config_file_env() -> Option<InterpreterConfig> {
     #[doc(hidden)]
     const CONFIG_FILE: &str = include_str!(concat!(env!("OUT_DIR"), "/pyo3-build-config-file.txt"));
 
-    // CONFIG_FILE is generated in build.rs, so its content can vary
-    #[allow(clippy::const_is_empty)]
+    #[allow(
+        clippy::const_is_empty,
+        reason = "CONFIG_FILE is generated in build.rs, content can vary"
+    )]
     if !CONFIG_FILE.is_empty() {
         let config = InterpreterConfig::from_reader(Cursor::new(CONFIG_FILE))
             .expect("contents of CONFIG_FILE should always be valid (generated by pyo3-build-config's build.rs)");
@@ -265,8 +269,10 @@ pub mod pyo3_build_script_impl {
     /// Steps 2 and 3 are necessary because `pyo3-ffi`'s build script is the first code run which knows
     /// the correct target triple.
     pub fn resolve_build_config(target: &Triple) -> Result<BuildConfig> {
-        // CONFIG_FILE is generated in build.rs, so it's content can vary
-        #[allow(unknown_lints, clippy::const_is_empty)]
+        #[allow(
+            clippy::const_is_empty,
+            reason = "CONFIG_FILE is generated in build.rs, content can vary"
+        )]
         if let Some(mut interpreter_config) = config_from_pyo3_config_file_env() {
             interpreter_config.apply_default_lib_name_to_config_file(target);
             interpreter_config.generate_import_libs()?;

pyo3-ffi/examples/sequential/src/lib.rs

@@ -6,8 +6,7 @@ mod id;
 mod module;
 use crate::module::MODULE_DEF;
 
-// The module initialization function, which must be named `PyInit_<your_module>`.
-#[allow(non_snake_case)]
+#[allow(non_snake_case, reason = "must be named `PyInit_<your_module>`")]
 #[no_mangle]
 pub unsafe extern "C" fn PyInit_sequential() -> *mut PyObject {
     PyModuleDef_Init(ptr::addr_of_mut!(MODULE_DEF))

pyo3-ffi/examples/string-sum/src/lib.rs

@@ -45,8 +45,8 @@ static mut SLOTS: &[PyModuleDef_Slot] = &[
     },
 ];
 
-// The module initialization function, which must be named `PyInit_<your_module>`.
-#[allow(non_snake_case)]
+// The module initialization function
+#[allow(non_snake_case, reason = "must be named `PyInit_<your_module>`")]
 #[no_mangle]
 pub unsafe extern "C" fn PyInit_string_sum() -> *mut PyObject {
     PyModuleDef_Init(ptr::addr_of_mut!(MODULE_DEF))
@@ -69,7 +69,10 @@ unsafe fn parse_arg_as_i32(obj: *mut PyObject, n_arg: usize) -> Option<i32> {
     let mut overflow = 0;
     let i_long: c_long = PyLong_AsLongAndOverflow(obj, &mut overflow);
 
-    #[allow(irrefutable_let_patterns)] // some platforms have c_long equal to i32
+    #[allow(
+        irrefutable_let_patterns,
+        reason = "some platforms have c_long equal to i32"
+    )]
     if overflow != 0 {
         raise_overflowerror(obj);
         None

pyo3-ffi/src/compat/mod.rs

@@ -36,7 +36,7 @@ macro_rules! compat_function {
             // cfgs line up, then the the two glob imports will resolve to the same item via the
             // re-export. If the cfgs mismatch, then the use of $name will be ambiguous in cases
             // where the function is defined twice, and the test will fail to compile.
-            #[allow(unused_imports)]
+            #[allow(unused_imports, reason = "imports exist to try to trigger name conflicts")]
             mod [<test_ $name _export>] {
                 use $crate::*;
                 use $crate::compat::*;

pyo3-ffi/src/cpython/genobject.rs

@@ -18,7 +18,10 @@ pub struct PyGenObject {
     pub gi_weakreflist: *mut PyObject,
     pub gi_name: *mut PyObject,
     pub gi_qualname: *mut PyObject,
-    #[allow(private_interfaces)]
+    #[allow(
+        private_interfaces,
+        reason = "PyGenObject layout was public until 3.14"
+    )]
     pub gi_exc_state: crate::cpython::pystate::_PyErr_StackItem,
     #[cfg(Py_3_11)]
     pub gi_origin_or_finalizer: *mut PyObject,

pyo3-ffi/src/lib.rs

@@ -160,8 +160,8 @@
 //!     PyMethodDef::zeroed(),
 //! ];
 //!
-//! // The module initialization function, which must be named `PyInit_<your_module>`.
-//! #[allow(non_snake_case)]
+//! // The module initialization function.
+//! #[allow(non_snake_case, reason = "must be named `PyInit_<your_module>`")]
 //! #[no_mangle]
 //! pub unsafe extern "C" fn PyInit_string_sum() -> *mut PyObject {
 //!     let module = PyModule_Create(ptr::addr_of_mut!(MODULE_DEF));
@@ -195,7 +195,7 @@
 //!     let mut overflow = 0;
 //!     let i_long: c_long = PyLong_AsLongAndOverflow(obj, &mut overflow);
 //!
-//!     #[allow(irrefutable_let_patterns)] // some platforms have c_long equal to i32
+//!     #[allow(irrefutable_let_patterns, reason = "some platforms have c_long equal to i32")]
 //!     if overflow != 0 {
 //!         raise_overflowerror(obj);
 //!         None

pyo3-ffi/src/moduleobject.rs

@@ -60,7 +60,10 @@ pub struct PyModuleDef_Base {
     pub m_copy: *mut PyObject,
 }
 
-#[allow(clippy::declare_interior_mutable_const)]
+#[allow(
+    clippy::declare_interior_mutable_const,
+    reason = "contains atomic refcount on free-threaded builds"
+)]
 pub const PyModuleDef_HEAD_INIT: PyModuleDef_Base = PyModuleDef_Base {
     ob_base: PyObject_HEAD_INIT,
     m_init: None,
@@ -94,15 +97,21 @@ pub const Py_mod_gil: c_int = 4;
 // skipped private _Py_mod_LAST_SLOT
 
 #[cfg(Py_3_12)]
-#[allow(clippy::zero_ptr)] // matches the way that the rest of these constants are defined
+#[allow(
+    clippy::zero_ptr,
+    reason = "matches the way that the rest of these constants are defined"
+)]
 pub const Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED: *mut c_void = 0 as *mut c_void;
 #[cfg(Py_3_12)]
 pub const Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED: *mut c_void = 1 as *mut c_void;
 #[cfg(Py_3_12)]
 pub const Py_MOD_PER_INTERPRETER_GIL_SUPPORTED: *mut c_void = 2 as *mut c_void;
 
 #[cfg(Py_3_13)]
-#[allow(clippy::zero_ptr)] // matches the way that the rest of these constants are defined
+#[allow(
+    clippy::zero_ptr,
+    reason = "matches the way that the rest of these constants are defined"
+)]
 pub const Py_MOD_GIL_USED: *mut c_void = 0 as *mut c_void;
 #[cfg(Py_3_13)]
 pub const Py_MOD_GIL_NOT_USED: *mut c_void = 1 as *mut c_void;

pyo3-ffi/src/object.rs

@@ -105,7 +105,10 @@ pub struct PyObject {
     pub ob_type: *mut PyTypeObject,
 }
 
-#[allow(clippy::declare_interior_mutable_const)]
+#[allow(
+    clippy::declare_interior_mutable_const,
+    reason = "contains atomic refcount on free-threaded builds"
+)]
 pub const PyObject_HEAD_INIT: PyObject = PyObject {
     #[cfg(py_sys_config = "Py_TRACE_REFS")]
     _ob_next: std::ptr::null_mut(),