docs: require docs on all public APIs

.cargo/config

@@ -18,4 +18,4 @@ rustflags = [
     "-Delided_lifetimes_in_paths",
     "-Dunused_lifetimes",
     "-Drust_2021_prelude_collisions"
-]
+]

src/buffer.rs

@@ -58,14 +58,23 @@ impl<T> Debug for PyBuffer<T> {
 /// Represents the type of a Python buffer element.
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub enum ElementType {
-    /// A signed integer type and its width in bytes.
-    SignedInteger { bytes: usize },
-    /// An unsigned integer type and its width in bytes.
-    UnsignedInteger { bytes: usize },
+    /// A signed integer type.
+    SignedInteger {
+        /// The width of the signed integer in bytes.
+        bytes: usize,
+    },
+    /// An unsigned integer type.
+    UnsignedInteger {
+        /// The width of the unsigned integer in bytes.
+        bytes: usize,
+    },
     /// A boolean type.
     Bool,
-    /// A float type and its width in bytes.
-    Float { bytes: usize },
+    /// A float type.
+    Float {
+        /// The width of the float in bytes.
+        bytes: usize,
+    },
     /// An unknown type. This may occur when parsing has failed.
     Unknown,
 }
@@ -607,6 +616,8 @@ impl<T: Element> PyBuffer<T> {
         }
     }
 
+    /// Release the buffer object, freeing the reference to the Python object
+    /// which owns the buffer.
     pub fn release(self, _py: Python<'_>) {
         // First move self into a ManuallyDrop, so that PyBuffer::drop will
         // never be called. (It would acquire the GIL and call PyBuffer_Release

src/err/mod.rs

@@ -53,6 +53,8 @@ pub struct PyDowncastError<'a> {
 }
 
 impl<'a> PyDowncastError<'a> {
+    /// Create a new `PyDowncastError` representing a failure to convert the object
+    /// `from` into the type named in `to`.
     pub fn new(from: &'a PyAny, to: impl Into<Cow<'static, str>>) -> Self {
         PyDowncastError {
             from,

src/impl_.rs

@@ -1,3 +1,5 @@
+#![allow(missing_docs)]
+
 //! Internals of PyO3 which are accessed by code expanded from PyO3's procedural macros.
 //!
 //! Usage of any of these APIs in downstream code is implicitly acknowledging that these

src/impl_/pymethods.rs

@@ -1,8 +1,8 @@
 use crate::internal_tricks::{extract_cstr_or_leak_cstring, NulByteInString};
-use crate::{ffi, AsPyPointer, PyAny, PyObject, PyResult, Python};
+use crate::{ffi, PyAny, PyObject, PyResult, PyTraverseError, Python};
 use std::ffi::CStr;
 use std::fmt;
-use std::os::raw::{c_int, c_void};
+use std::os::raw::c_int;
 
 /// Python 3.8 and up - __ipow__ has modulo argument correctly populated.
 #[cfg(Py_3_8)]
@@ -253,41 +253,6 @@ fn get_doc(doc: &'static str) -> Result<&'static CStr, NulByteInString> {
     extract_cstr_or_leak_cstring(doc, "Document cannot contain NUL byte.")
 }
 
-#[repr(transparent)]
-pub struct PyTraverseError(pub(crate) c_int);
-
-/// Object visitor for GC.
-#[derive(Clone)]
-pub struct PyVisit<'p> {
-    pub(crate) visit: ffi::visitproc,
-    pub(crate) arg: *mut c_void,
-    /// VisitProc contains a Python instance to ensure that
-    /// 1) it is cannot be moved out of the traverse() call
-    /// 2) it cannot be sent to other threads
-    pub(crate) _py: Python<'p>,
-}
-
-impl<'p> PyVisit<'p> {
-    /// Visit `obj`.
-    pub fn call<T>(&self, obj: &T) -> Result<(), PyTraverseError>
-    where
-        T: AsPyPointer,
-    {
-        let r = unsafe { (self.visit)(obj.as_ptr(), self.arg) };
-        if r == 0 {
-            Ok(())
-        } else {
-            Err(PyTraverseError(r))
-        }
-    }
-
-    /// Creates the PyVisit from the arguments to tp_traverse
-    #[doc(hidden)]
-    pub unsafe fn from_raw(visit: ffi::visitproc, arg: *mut c_void, _py: Python<'p>) -> Self {
-        Self { visit, arg, _py }
-    }
-}
-
 /// Unwraps the result of __traverse__ for tp_traverse
 #[doc(hidden)]
 #[inline]

src/inspect/mod.rs

@@ -1,4 +1,4 @@
-/// Runtime inspection of objects exposed to Python.
-///
-/// Tracking issue: <https://github.com/PyO3/pyo3/issues/2454>.
+//! Runtime inspection of objects exposed to Python.
+//!
+//! Tracking issue: <https://github.com/PyO3/pyo3/issues/2454>.
 pub mod types;

src/inspect/types.rs

@@ -1,3 +1,5 @@
+//! Data types used to describe runtime Python types.
+
 use std::borrow::Cow;
 use std::fmt::{Display, Formatter};
 

src/lib.rs

@@ -1,3 +1,4 @@
+#![warn(missing_docs)]
 #![cfg_attr(feature = "nightly", feature(auto_traits, negative_impls))]
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
 #![cfg_attr(
@@ -310,7 +311,13 @@ pub use crate::type_object::PyTypeInfo;
 pub use crate::types::PyAny;
 pub use crate::version::PythonVersionInfo;
 
-// Old directory layout, to be rethought?
+/// Old module which contained some implementation details of the `#[pyproto]` module.
+///
+/// Prefer using the same content from `pyo3::pyclass`, e.g. `use pyo3::pyclass::CompareOp` instead
+/// of `use pyo3::class::basic::CompareOp`.
+///
+/// For compatibility reasons this has not yet been removed, however will be done so
+/// once <https://github.com/rust-lang/rust/issues/30827> is resolved.
 pub mod class {
     #[doc(hidden)]
     pub use crate::impl_::pymethods as methods;
@@ -322,20 +329,48 @@ pub mod class {
         PyClassAttributeDef, PyGetterDef, PyMethodDef, PyMethodDefType, PyMethodType, PySetterDef,
     };
 
+    /// Old module which contained some implementation details of the `#[pyproto]` module.
+    ///
+    /// Prefer using the same content from `pyo3::pyclass`, e.g. `use pyo3::pyclass::CompareOp` instead
+    /// of `use pyo3::class::basic::CompareOp`.
+    ///
+    /// For compatibility reasons this has not yet been removed, however will be done so
+    /// once <https://github.com/rust-lang/rust/issues/30827> is resolved.
     pub mod basic {
         pub use crate::pyclass::CompareOp;
     }
 
+    /// Old module which contained some implementation details of the `#[pyproto]` module.
+    ///
+    /// Prefer using the same content from `pyo3::pyclass`, e.g. `use pyo3::pyclass::IterANextOutput` instead
+    /// of `use pyo3::class::pyasync::IterANextOutput`.
+    ///
+    /// For compatibility reasons this has not yet been removed, however will be done so
+    /// once <https://github.com/rust-lang/rust/issues/30827> is resolved.
     pub mod pyasync {
         pub use crate::pyclass::{IterANextOutput, PyIterANextOutput};
     }
 
+    /// Old module which contained some implementation details of the `#[pyproto]` module.
+    ///
+    /// Prefer using the same content from `pyo3::pyclass`, e.g. `use pyo3::pyclass::IterNextOutput` instead
+    /// of `use pyo3::class::pyasync::IterNextOutput`.
+    ///
+    /// For compatibility reasons this has not yet been removed, however will be done so
+    /// once <https://github.com/rust-lang/rust/issues/30827> is resolved.
     pub mod iter {
         pub use crate::pyclass::{IterNextOutput, PyIterNextOutput};
     }
 
+    /// Old module which contained some implementation details of the `#[pyproto]` module.
+    ///
+    /// Prefer using the same content from `pyo3::pyclass`, e.g. `use pyo3::pyclass::PyTraverseError` instead
+    /// of `use pyo3::class::gc::PyTraverseError`.
+    ///
+    /// For compatibility reasons this has not yet been removed, however will be done so
+    /// once <https://github.com/rust-lang/rust/issues/30827> is resolved.
     pub mod gc {
-        pub use crate::impl_::pymethods::{PyTraverseError, PyVisit};
+        pub use crate::pyclass::{PyTraverseError, PyVisit};
     }
 }
 

src/once_cell.rs

@@ -161,10 +161,12 @@ macro_rules! intern {
 pub struct Interned(&'static str, GILOnceCell<Py<PyString>>);
 
 impl Interned {
+    /// Creates an empty holder for an interned `str`.
     pub const fn new(value: &'static str) -> Self {
         Interned(value, GILOnceCell::new())
     }
 
+    /// Gets or creates the interned `str` value.
     #[inline]
     pub fn get<'py>(&'py self, py: Python<'py>) -> &'py PyString {
         self.1

src/pycell/impl_.rs

@@ -1,3 +1,4 @@
+#![allow(missing_docs)]
 //! Crate-private implementation of pycell
 
 use std::cell::Cell;

src/pyclass.rs

@@ -18,6 +18,10 @@ use std::{
     ptr,
 };
 
+mod gc;
+
+pub use self::gc::{PyTraverseError, PyVisit};
+
 /// Types that can be used as Python classes.
 ///
 /// The `#[pyclass]` attribute implements this trait for your Rust struct -
@@ -502,6 +506,7 @@ pub enum IterNextOutput<T, U> {
     Return(U),
 }
 
+/// Alias of `IterNextOutput` with `PyObject` yield & return values.
 pub type PyIterNextOutput = IterNextOutput<PyObject, PyObject>;
 
 impl IntoPyCallbackOutput<*mut ffi::PyObject> for PyIterNextOutput {

src/pyclass/gc.rs

@@ -0,0 +1,39 @@
+use std::os::raw::{c_int, c_void};
+
+use crate::{ffi, AsPyPointer, Python};
+
+/// Error returned by a `__traverse__` visitor implementation.
+#[repr(transparent)]
+pub struct PyTraverseError(pub(crate) c_int);
+
+/// Object visitor for GC.
+#[derive(Clone)]
+pub struct PyVisit<'p> {
+    pub(crate) visit: ffi::visitproc,
+    pub(crate) arg: *mut c_void,
+    /// VisitProc contains a Python instance to ensure that
+    /// 1) it is cannot be moved out of the traverse() call
+    /// 2) it cannot be sent to other threads
+    pub(crate) _py: Python<'p>,
+}
+
+impl<'p> PyVisit<'p> {
+    /// Visit `obj`.
+    pub fn call<T>(&self, obj: &T) -> Result<(), PyTraverseError>
+    where
+        T: AsPyPointer,
+    {
+        let r = unsafe { (self.visit)(obj.as_ptr(), self.arg) };
+        if r == 0 {
+            Ok(())
+        } else {
+            Err(PyTraverseError(r))
+        }
+    }
+
+    /// Creates the PyVisit from the arguments to tp_traverse
+    #[doc(hidden)]
+    pub unsafe fn from_raw(visit: ffi::visitproc, arg: *mut c_void, _py: Python<'p>) -> Self {
+        Self { visit, arg, _py }
+    }
+}

src/type_object.rs

@@ -96,6 +96,7 @@ pub struct LazyStaticType {
 }
 
 impl LazyStaticType {
+    /// Creates an uninitialized `LazyStaticType`.
     pub const fn new() -> Self {
         LazyStaticType {
             value: GILOnceCell::new(),
@@ -104,6 +105,7 @@ impl LazyStaticType {
         }
     }
 
+    /// Gets the type object contained by this `LazyStaticType`, initializing it if needed.
     pub fn get_or_init<T: PyClass>(&self, py: Python<'_>) -> *mut ffi::PyTypeObject {
         fn inner<T: PyClass>() -> *mut ffi::PyTypeObject {
             // Safety: `py` is held by the caller of `get_or_init`.

src/types/datetime.rs

@@ -234,6 +234,7 @@ pyobject_native_type!(
 );
 
 impl PyDateTime {
+    /// Creates a new `datetime.datetime` object.
     #[allow(clippy::too_many_arguments)]
     pub fn new<'p>(
         py: Python<'p>,

src/types/dict.rs

@@ -262,6 +262,7 @@ impl PyDict {
     }
 }
 
+/// PyO3 implementation of an iterator for a Python `dict` object.
 pub struct PyDictIterator<'py> {
     dict: &'py PyDict,
     ppos: ffi::Py_ssize_t,

src/types/frozenset.rs

@@ -89,6 +89,7 @@ mod impl_ {
         }
     }
 
+    /// PyO3 implementation of an iterator for a Python `frozenset` object.
     pub struct PyFrozenSetIterator<'p> {
         it: &'p PyIterator,
     }
@@ -116,6 +117,7 @@ mod impl_ {
         }
     }
 
+    /// PyO3 implementation of an iterator for a Python `frozenset` object.
     pub struct PyFrozenSetIterator<'py> {
         set: &'py PyAny,
         pos: ffi::Py_ssize_t,

src/types/set.rs

@@ -143,6 +143,7 @@ mod impl_ {
         }
     }
 
+    /// PyO3 implementation of an iterator for a Python `set` object.
     pub struct PySetIterator<'p> {
         it: &'p PyIterator,
     }
@@ -165,6 +166,8 @@ mod impl_ {
 #[cfg(not(Py_LIMITED_API))]
 mod impl_ {
     use super::*;
+
+    /// PyO3 implementation of an iterator for a Python `set` object.
     pub struct PySetIterator<'py> {
         set: &'py super::PyAny,
         pos: ffi::Py_ssize_t,

src/types/slice.rs

@@ -18,16 +18,21 @@ pyobject_native_type!(
     #checkfunction=ffi::PySlice_Check
 );
 
-/// Represents Python `slice` indices.
+/// Return value from [`PySlice::indices`].
 #[derive(Debug, Eq, PartialEq)]
 pub struct PySliceIndices {
+    /// Start of the slice
     pub start: isize,
+    /// End of the slice
     pub stop: isize,
+    /// Increment to use when iterating the slice from `start` to `stop`.
     pub step: isize,
+    /// The length of the slice calculated from the original input sequence.
     pub slicelength: isize,
 }
 
 impl PySliceIndices {
+    /// Creates a new `PySliceIndices`.
     pub fn new(start: isize, stop: isize, step: isize) -> PySliceIndices {
         PySliceIndices {
             start,