Improved Guessing of boost_python version

ci/ciimage/gentoo/install.sh

@@ -115,7 +115,7 @@ cat <<-EOF > /etc/portage/package.use/ci
 	x11-libs/libxkbcommon X
 	dev-lang/rust clippy rustfmt
 	dev-lang/rust-bin clippy rustfmt
-	dev-libs/boost python
+	dev-libs/boost python numpy
 	sci-libs/hdf5 cxx
 
 	# slimmed binpkg, nomesa

ci/ciimage/opensuse/install.sh

@@ -18,7 +18,7 @@ pkgs=(
   libxml2-devel libxslt-devel libyaml-devel glib2-devel json-glib-devel
   boost-devel libboost_date_time-devel libboost_filesystem-devel libboost_locale-devel
   libboost_headers-devel libboost_test-devel libboost_log-devel libboost_regex-devel
-  libboost_python3-devel libboost_regex-devel libgcrypt-devel
+  libboost_python3-devel libboost_numpy3-devel libboost_regex-devel libgcrypt-devel
   # HACK: remove npm once we switch back to hotdoc sdist
   npm
 )

ci/ciimage/ubuntu-rolling/install.sh

@@ -21,7 +21,7 @@ pkgs=(
   libgcrypt20-dev
   libgpgme-dev
   libhdf5-dev
-  libboost-python-dev libboost-regex-dev
+  libboost-python-dev libboost-numpy-dev libboost-regex-dev
   libblocksruntime-dev
   libperl-dev
   liblapack-dev libscalapack-mpi-dev

docs/markdown/Dependencies.md

@@ -370,6 +370,23 @@ that specifying any of these disables system-wide search for boost.
 You can set the argument `threading` to `single` to use boost
 libraries that have been compiled for single-threaded use instead.
 
+### Boost Python and Boost Numpy
+
+In order to use these libraries you need to link against the version
+that matches the major/minor version of python you are compiling
+against. They are named `boost_pythonXYY` and `libboost_numpyXYY`
+where `X` is the python major version and `YY` is the minor version.
+
+The best way to ensure that you get the correct versions to match get
+the language version from your python installation.
+
+```meson
+py = import('python').find_installation()
+pyver = ''.join(py.language_version().split('.'))
+boost_dep = dependency('boost', modules: ['python'+pyver, 'numpy'+pyver])
+py.extension_module('my_mod', 'my_mod.cpp', dependencies: boost_dep)
+```
+
 ## CUDA
 
 *(added 0.53.0)*

docs/markdown/snippets/improve_boost_numpy_guessing.md

@@ -0,0 +1,8 @@
+## Improve Version Guessing for boost_python and boost_numpy
+
+Previously if you specified `boost_python` or `boost_numpy` as modules to
+`dependency('boost')` it would pick a random version based on which file it
+found first. Now, if there are multiple versions it will first try to find
+the one matches the current python interpreter. If that fails, it will use 
+the most recent version. There is also a warning that this behavior will 
+be removed in a future release.

mesonbuild/dependencies/boost.py

@@ -8,6 +8,7 @@
 import functools
 import typing as T
 from pathlib import Path
+from sys import version_info
 
 from .. import mlog
 from .. import mesonlib
@@ -103,11 +104,6 @@ def __lt__(self, other: object) -> bool:
 
 @functools.total_ordering
 class BoostLibraryFile():
-    # Python libraries are special because of the included
-    # minor version in the module name.
-    boost_python_libs = ['boost_python', 'boost_numpy']
-    reg_python_mod_split = re.compile(r'(boost_[a-zA-Z]+)([0-9]*)')
-
     reg_abi_tag = re.compile(r'^s?g?y?d?p?n?$')
     reg_ver_tag = re.compile(r'^[0-9_]+$')
 
@@ -157,11 +153,20 @@ def __init__(self, path: Path):
         if self.basename.startswith('boost_') and self.nvsuffix == 'lib':
             self.static = False
 
+        # Python libraries are special because of the included
+        # minor version in the module name.
+        # Circa 2019-2020 some distros incorrectly renamed boost_python library files,
+        # meson used to support this but it has been removed
+        self.python_version: tuple[int, int] | None = None
+        for bpl in BoostDependency.boost_python_libs:
+            if self.mod_name.startswith(bpl):
+                python_version_str = self.mod_name[len(bpl):]
+                if not python_version_str.isdigit():
+                    continue
+                self.python_version = (int(python_version_str[:1]), int(python_version_str[1:]))
+
         # Process tags
         tags = self.nametags[1:]
-        # Filter out the python version tag and fix modname
-        if self.is_python_lib():
-            tags = self.fix_python_name(tags)
         if not tags:
             return
 
@@ -233,67 +238,6 @@ def abitag(self) -> str:
     def is_boost(self) -> bool:
         return any(self.name.startswith(x) for x in ['libboost_', 'boost_'])
 
-    def is_python_lib(self) -> bool:
-        return any(self.mod_name.startswith(x) for x in BoostLibraryFile.boost_python_libs)
-
-    def fix_python_name(self, tags: T.List[str]) -> T.List[str]:
-        # Handle the boost_python naming madness.
-        # See https://github.com/mesonbuild/meson/issues/4788 for some distro
-        # specific naming variations.
-        other_tags: T.List[str] = []
-
-        # Split the current modname into the base name and the version
-        m_cur = BoostLibraryFile.reg_python_mod_split.match(self.mod_name)
-        cur_name = m_cur.group(1)
-        cur_vers = m_cur.group(2)
-
-        # Update the current version string if the new version string is longer
-        def update_vers(new_vers: str) -> None:
-            nonlocal cur_vers
-            new_vers = new_vers.replace('_', '')
-            new_vers = new_vers.replace('.', '')
-            if not new_vers.isdigit():
-                return
-            if len(new_vers) > len(cur_vers):
-                cur_vers = new_vers
-
-        for i in tags:
-            if i.startswith('py'):
-                update_vers(i[2:])
-            elif i.isdigit():
-                update_vers(i)
-            elif len(i) >= 3 and i[0].isdigit() and i[2].isdigit() and i[1] == '.':
-                update_vers(i)
-            else:
-                other_tags += [i]
-
-        self.mod_name = cur_name + cur_vers
-        return other_tags
-
-    def mod_name_matches(self, mod_name: str) -> bool:
-        if self.mod_name == mod_name:
-            return True
-        if not self.is_python_lib():
-            return False
-
-        m_cur = BoostLibraryFile.reg_python_mod_split.match(self.mod_name)
-        m_arg = BoostLibraryFile.reg_python_mod_split.match(mod_name)
-
-        if not m_cur or not m_arg:
-            return False
-
-        if m_cur.group(1) != m_arg.group(1):
-            return False
-
-        cur_vers = m_cur.group(2)
-        arg_vers = m_arg.group(2)
-
-        # Always assume python 2 if nothing is specified
-        if not arg_vers:
-            arg_vers = '2'
-
-        return cur_vers.startswith(arg_vers)
-
     def version_matches(self, version_lib: str) -> bool:
         # If no version tag is present, assume that it fits
         if not self.version_lib or not version_lib:
@@ -340,6 +284,18 @@ def get_link_args(self) -> T.List[str]:
         return [self.path.as_posix()]
 
 class BoostDependency(SystemDependency):
+
+    boost_python_libs: list[str] = ['boost_python', 'boost_numpy']
+
+    @staticmethod
+    def is_unversioned_python_lib(mod_name: str) -> bool:
+        """Checks if this is an unversioned python module that might need version detection.
+        """
+        if mod_name[-1] in set(('2', '3')):
+            return mod_name[:-1] in BoostDependency.boost_python_libs
+        else:
+            return mod_name in BoostDependency.boost_python_libs
+
     def __init__(self, name: str, environment: Environment, kwargs: DependencyObjectKWs) -> None:
         kwargs['language'] = 'cpp'
         super().__init__(name, environment, kwargs)
@@ -436,6 +392,34 @@ def detect_boost_machine_file(self, props: 'Properties') -> None:
 
         self.check_and_set_roots(paths, use_system=False)
 
+    @staticmethod
+    def find_python_lib(mod_name: str, f_libs: list[BoostLibraryFile]) -> BoostLibraryFile | None:
+        """
+        If a python lib is specified without its version this will sort through the python libs for the best lib to use.
+        """
+
+        mlog.warning(
+            "Support for ",  mlog.bold(mod_name), ' without specifying the version will be dropped in a future version of ',
+            "meson. For the correct solution for these libraries, please see ",
+            "https://mesonbuild.com/Dependencies.html#boost-python-and-boost-numpy"
+            )
+        pylibs = [lib for lib in f_libs if lib.mod_name.startswith(mod_name)]
+
+        if len(pylibs) == 0:
+            return None
+        elif len(pylibs) == 1:
+            # if only one is found go with that one
+            return pylibs[0]
+
+        # if one of the libs matches the current interperter got with that one
+        for lib in pylibs:
+            if lib.python_version == version_info[:2]:
+                return lib
+
+        # if nothing else works just go with the most recent version
+        pylibs.sort(key= lambda x: x.python_version)
+        return pylibs[-1]
+
     def run_check(self, inc_dirs: T.List[BoostIncludeDir], lib_dirs: T.List[Path]) -> bool:
         mlog.debug('  - potential library dirs: {}'.format([x.as_posix() for x in lib_dirs]))
         mlog.debug('  - potential include dirs: {}'.format([x.path.as_posix() for x in inc_dirs]))
@@ -473,10 +457,17 @@ def run_check(self, inc_dirs: T.List[BoostIncludeDir], lib_dirs: T.List[Path]) -
             for mod in modules:
                 found = False
                 for l in f_libs:
-                    if l.mod_name_matches(mod):
+                    if l.mod_name == mod:
                         selected_modules += [l]
                         found = True
                         break
+
+                if not found and self.is_unversioned_python_lib(mod):
+                    pymod = self.find_python_lib(mod, f_libs)
+                    if pymod:
+                        selected_modules += [pymod]
+                        found = True
+
                 if not found:
                     not_found_as_libs += [mod]
 
@@ -636,19 +627,6 @@ def filter_libraries(self, libs: T.List[BoostLibraryFile], lib_vers: str) -> T.L
         abitag = libs[0].abitag
         libs = [x for x in libs if x.abitag == abitag]
 
-        # Assume that we are building against the latest Python version
-        # and that the other ones are only there for backwards compatibility.
-        # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1141440
-        no_python_libs = []
-        python_libs = []
-        for l in libs:
-            if l.is_python_lib():
-                python_libs.append(l)
-            else:
-                no_python_libs.append(l)
-        sorted_pylibs = sorted(python_libs, key=lambda l: l.name, reverse=True)
-        libs = no_python_libs + sorted_pylibs[:1]
-
         return libs
 
     def detect_libraries(self, libdir: Path) -> T.List[BoostLibraryFile]:

test cases/frameworks/1 boost/meson.build

@@ -29,15 +29,16 @@ python2dep = python2.dependency(required: false                           , embe
 python3dep = python3.dependency(required: require_bp, embed: true, disabler: true)
 
 # compile python 2/3 modules only if we found a corresponding python version
-if(python2dep.found() and require_bp and not s)
-  bpython2dep = dependency('boost', static: s, modules : ['python'], required: false, disabler: true)
-else
+# if(python2dep.found() and require_bp and not s)
+#   bpython2dep = dependency('boost', static: s, modules : ['python'], required: false, disabler: true)
+# else
   python2dep = disabler()
   bpython2dep = disabler()
-endif
+# endif
 
+py3ver = ''.join(python3.language_version().split('.'))
 if(python3dep.found() and require_bp and not s)
-  bpython3dep = dependency('boost', static: s, modules : ['python3'])
+  bpython3dep = dependency('boost', static: s, modules : ['python'+py3ver,'numpy'+py3ver])
 else
   python3dep = disabler()
   bpython3dep = disabler()

test cases/frameworks/35 boost symlinks/boost/lib/boost_python315-vc142-mt-gd-x32-0_3.lib

@@ -0,0 +1 @@
+../Cellar/boost-python/0.3.0/lib/boost_python315-vc142-mt-gd-x32-0_3.lib

test cases/frameworks/35 boost symlinks/boost/lib/boost_python315-vc142-mt-gd-x64-0_3.lib

@@ -0,0 +1 @@
+../Cellar/boost-python/0.3.0/lib/boost_python315-vc142-mt-gd-x64-0_3.lib

test cases/frameworks/35 boost symlinks/boost/lib/libboost_python315.so.0.3.0

@@ -0,0 +1 @@
+../Cellar/boost-python/0.3.0/lib/libboost_python315.so.0.3.0

test cases/frameworks/35 boost symlinks/meson.build

@@ -6,7 +6,19 @@ if bm == 'windows' or bm == 'cygwin'
   error('MESON_SKIP_TEST: Windows and symlinks do not mix.')
 endif
 
-dep = dependency('boost', modules : ['regex', 'python'], required: false)
+dep = dependency('boost', modules : ['regex', 'python315'], required: false)
 
 assert(dep.found(), 'expected to find a fake version of boost')
 assert(dep.version() == '0.3.0', 'expected to find version 0.3.0')
+
+# everything below this can be removed when support for unversioned boost_python is removed 
+
+major_version = dependency('boost', modules : ['regex', 'python3'], required: false)
+
+assert(major_version.found(), 'expected to find a fake version of boost')
+assert(major_version.version() == '0.3.0', 'expected to find version 0.3.0')
+
+no_version = dependency('boost', modules : ['regex', 'python'], required: false)
+
+assert(no_version.found(), 'expected to find a fake version of boost')
+assert(no_version.version() == '0.3.0', 'expected to find version 0.3.0')

test cases/frameworks/42 boost python/boost/include/boost/version.hpp

@@ -0,0 +1,3 @@
+#define BOOST_VERSION 100
+
+#error This is not a real version of boost

test cases/frameworks/42 boost python/meson.build

@@ -0,0 +1,15 @@
+# this test case can be deleted if support for unversioned python libs is removed
+
+project('boost python test', 'cpp')
+
+bm = build_machine.system()
+
+if bm == 'windows' or bm == 'cygwin'
+  error('MESON_SKIP_TEST: Windows uses different library files')
+endif
+
+dependency('boost', modules: ['python', 'numpy'], required: true)
+dependency('boost', modules: ['python3', 'numpy3'], required: true)
+dependency('boost', modules: ['python313', 'numpy313'], required: true)
+dependency('boost', modules: ['python314', 'numpy314'], required: true)
+dependency('boost', modules: ['python315', 'numpy315'], required: true)

test cases/frameworks/42 boost python/nativefile.ini.in

@@ -0,0 +1,2 @@
+[properties]
+boost_root = '@MESON_TEST_ROOT@/boost'

test cases/frameworks/42 boost python/test.json

@@ -0,0 +1,3 @@
+{
+  "expect_skip_on_jobname": ["azure", "windows"]
+}