Bump to pybind11>=2.5 to simplify build.

CHANGELOG.rst

@@ -1,7 +1,7 @@
 next
 ====
 
-- Dropped support for Py3.5.
+- Bumped dependencies to Python≥3.6, pybind11≥2.5.
 - ``pybind11`` is now a ``setup_requires`` and ``-march=native`` is no longer
   passed as compilation option by default; drop support for
   ``MPLCAIRO_BUILD_TYPE``.

README.rst

@@ -63,7 +63,7 @@ mplcairo requires
 
 Additionally, building mplcairo from source requires
 
-- pybind11≥2.2.4 [#]_ (declared as ``setup_requires``),
+- pybind11≥2.5.0 [#]_ (declared as ``setup_requires``),
 - on Linux and macOS, pycairo≥1.16.0 (declared as ``setup_requires`` on macOS,
   but not on Linux).
 
@@ -83,8 +83,6 @@ OpenType font features.  Refer to the instructions on that project's
 website for installation on Linux and macOS.  You may want to look at
 https://github.com/HOST-Oman/libraqm-cmake for Windows build scripts.
 
-.. _pybind11-1362: https://github.com/pybind/pybind11/issues/1362
-
 .. [#] pycairo 1.16.0 added ``get_include()``.
 
    We do not actually rely on pycairo's Python bindings.  Rather, specifying a
@@ -114,8 +112,8 @@ https://github.com/HOST-Oman/libraqm-cmake for Windows build scripts.
    of cairo, it is suggested to use a commit ≥dfe3aa6, as the latter further
    fixes another bug that can cause crashes in mplcairo.
 
-.. [#] The version requirement comes from pybind11 issue `#1362
-   <pybind11-1362_>`_.
+.. [#] pybind11 2.5.0 is the earliest version that supports being added as
+   ``setup_requires`` (and read-only buffers).
 
 On Fedora, the package is available as `python-mplcairo <fedora-package_>`_.
 

setup.py

@@ -15,7 +15,6 @@
 """
 
 from distutils.version import LooseVersion
-from enum import Enum
 import functools
 import json
 import os
@@ -78,10 +77,7 @@ def paths_from_link_libpaths():
 class build_ext(build_ext):
 
     def build_extensions(self):
-        try:
-            import importlib.metadata as importlib_metadata
-        except ImportError:
-            import importlib_metadata
+        import pybind11
 
         ext, = self.distribution.ext_modules
 
@@ -95,40 +91,8 @@ def build_extensions(self):
         else:
             ext.sources += [*map(str, Path("src").glob("*.cpp"))]
             ext.sources.remove("src/_unity_build.cpp")
-        ext.language = "c++"
-
-        # pybind11.get_include() is brittle (pybind #1425).
-        pybind11_include_path = next(
-            path for path in importlib_metadata.files("pybind11")
-            if path.name == "pybind11.h").locate().parents[1]
-        if not (pybind11_include_path / "pybind11/pybind11.h").exists():
-            # egg-install from setup_requires:
-            # importlib-metadata thinks the headers are at
-            #   .eggs/pybind11-VER-TAG.egg/pybind11-VER.data/headers/pybind11.h
-            # but they're actually at
-            #   .eggs/pybind11-VER-TAG.egg/pybind11.h
-            # pybind11_include_path is
-            #   /<...>/.eggs/pybind11-VER-TAG.egg/pybind11-VER.data
-            # so just create the proper structure there.
-            try:
-                is_egg = (pybind11_include_path.relative_to(
-                    Path(__file__).resolve().parent).parts[0] == ".eggs")
-            except ValueError:
-                # Arch Linux ships completely wrong metadata, but the headers
-                # are in the default include paths, so just leave things as is.
-                is_egg = False
-            if is_egg:
-                shutil.rmtree(pybind11_include_path / "pybind11",
-                              ignore_errors=True)
-                for file in [*pybind11_include_path.parent.glob("**/*")]:
-                    if file.is_dir():
-                        continue
-                    dest = (pybind11_include_path / "pybind11" /
-                            file.relative_to(pybind11_include_path.parent))
-                    dest.parent.mkdir(parents=True, exist_ok=True)
-                    shutil.copy2(file, dest)
 
-        ext.include_dirs += [pybind11_include_path]
+        ext.include_dirs += [pybind11.get_include()]
 
         tmp_include_dir = Path(self.get_finalized_command("build").build_base,
                                "include")
@@ -272,9 +236,8 @@ def exec_module(module):
     ext_modules=[Extension("mplcairo._mplcairo", [])],
     python_requires=">=3.6",
     setup_requires=[
-        "importlib_metadata>=0.8; python_version<'3.8'",  # Added files().
         "setuptools_scm",
-        "pybind11>=2.2.4",
+        "pybind11>=2.5.0",
         # Actually also a setup_requires on Linux, but in the manylinux build
         # we need to shim it.
         "pycairo>=1.16.0; sys_platform == 'darwin'",

src/_mplcairo.cpp

@@ -388,13 +388,8 @@ cairo_t* GraphicsContextRenderer::cr_from_fileformat_args(
        -> cairo_status_t {
       auto const& write =
         py::reinterpret_borrow<py::object>(static_cast<PyObject*>(closure));
-      // FIXME[pybind11]: Work around lack of const buffers in pybind11.
-      auto const& buf_info = py::buffer_info{
-        const_cast<unsigned char*>(data),
-        sizeof(char), py::format_descriptor<char>::format(),
-        1, {length}, {sizeof(char)}};
       return
-        write(py::memoryview{buf_info}).cast<unsigned int>() == length
+        write(py::memoryview{{data, length}}).cast<unsigned int>() == length
         // NOTE: This does not appear to affect the context status.
         ? CAIRO_STATUS_SUCCESS : CAIRO_STATUS_WRITE_ERROR;
     };