From 75d9e85652ada36137bd74a031ee2e92f918033c Mon Sep 17 00:00:00 2001
From: Andrea <andrea_bianchi@outlook.com>
Date: Sat, 2 Dec 2023 16:31:37 +0100
Subject: [PATCH] BUG: Add external library handling for meson [f2py]

---
 .../f2py/buildtools/distutils-to-meson.rst    | 21 +++++++++++++
 numpy/f2py/_backends/_meson.py                | 30 +++++++++++++++++++
 numpy/f2py/_backends/meson.build.template     |  5 ++++
 3 files changed, 56 insertions(+)

diff --git a/doc/source/f2py/buildtools/distutils-to-meson.rst b/doc/source/f2py/buildtools/distutils-to-meson.rst
index 338413928eda..236436c03d33 100644
--- a/doc/source/f2py/buildtools/distutils-to-meson.rst
+++ b/doc/source/f2py/buildtools/distutils-to-meson.rst
@@ -163,6 +163,27 @@ Here, ``meson`` can actually be used to set dependencies more robustly.
     of dependencies. They can be `customized further <https://mesonbuild.com/Dependencies.html>`_
     to use CMake or other systems to resolve dependencies.
 
+1.2.5 Libraries
+^^^^^^^^^^^^^^^
+
+Both ``meson`` and ``distutils`` are capable of linking against libraries.
+
+.. tab-set::
+
+  .. tab-item:: Distutils
+    :sync: distutils
+
+    .. code-block:: bash
+
+      python -m numpy.f2py -c fib.f90 -m fib --backend distutils -lmylib -L/path/to/mylib
+
+  .. tab-item:: Meson
+    :sync: meson
+
+    .. code-block:: bash
+
+      python -m numpy.f2py -c fib.f90 -m fib --backend meson -lmylib -L/path/to/mylib
+
 1.3 Customizing builds
 ~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/numpy/f2py/_backends/_meson.py b/numpy/f2py/_backends/_meson.py
index 4841bb3d5933..04a3ab0b2031 100644
--- a/numpy/f2py/_backends/_meson.py
+++ b/numpy/f2py/_backends/_meson.py
@@ -21,6 +21,8 @@ def __init__(
         modulename: str,
         sources: list[Path],
         deps: list[str],
+        libraries: list[str],
+        library_dirs: list[Path],
         object_files: list[Path],
         linker_args: list[str],
         c_args: list[str],
@@ -32,12 +34,15 @@ def __init__(
         )
         self.sources = sources
         self.deps = deps
+        self.libraries = libraries
+        self.library_dirs = library_dirs
         self.substitutions = {}
         self.objects = object_files
         self.pipeline = [
             self.initialize_template,
             self.sources_substitution,
             self.deps_substitution,
+            self.libraries_substitution,
         ]
         self.build_type = build_type
 
@@ -67,6 +72,29 @@ def deps_substitution(self) -> None:
             [f"dependency('{dep}')" for dep in self.deps]
         )
 
+    def libraries_substitution(self) -> None:
+        self.substitutions["lib_dir_declarations"] = "\n".join(
+            [
+                f"lib_dir_{i} = declare_dependency(link_args : ['-L{lib_dir}'])"
+                for i, lib_dir in enumerate(self.library_dirs)
+            ]
+        )
+
+        self.substitutions["lib_declarations"] = "\n".join(
+            [
+                f"{lib} = declare_dependency(link_args : ['-l{lib}'])"
+                for lib in self.libraries
+            ]
+        )
+
+        indent = " " * 21
+        self.substitutions["lib_list"] = f"\n{indent}".join(
+            [f"{lib}," for lib in self.libraries]
+        )
+        self.substitutions["lib_dir_list"] = f"\n{indent}".join(
+            [f"lib_dir_{i}," for i in range(len(self.library_dirs))]
+        )
+
     def generate_meson_build(self):
         for node in self.pipeline:
             node()
@@ -111,6 +139,8 @@ def write_meson_build(self, build_dir: Path) -> None:
             self.modulename,
             self.sources,
             self.dependencies,
+            self.libraries,
+            self.library_dirs,
             self.extra_objects,
             self.flib_flags,
             self.fc_flags,
diff --git a/numpy/f2py/_backends/meson.build.template b/numpy/f2py/_backends/meson.build.template
index 99bf42e3cbbc..65e3ecb19c30 100644
--- a/numpy/f2py/_backends/meson.build.template
+++ b/numpy/f2py/_backends/meson.build.template
@@ -32,6 +32,9 @@ inc_np = include_directories(incdir_numpy, incdir_f2py)
 # gh-25000
 quadmath_dep = fc.find_library('quadmath', required: false)
 
+${lib_declarations}
+${lib_dir_declarations}
+
 py.extension_module('${modulename}',
                      [
 ${source_list},
@@ -42,5 +45,7 @@ ${source_list},
                      py_dep,
                      quadmath_dep,
 ${dep_list}
+${lib_list}
+${lib_dir_list}
                      ],
                      install : true)