🐛 Resolve Meson tools through recipe env

MesonRecipe installs meson and ninja as hostpython prerequisites and
PyProjectRecipe exposes those executables by prepending the hostpython
bin directories to the recipe environment PATH.
Recipes that call sh.meson or sh.ninja directly can fail before _env is
applied when those tools are not also visible on the current Python process PATH.

Add shared MesonRecipe helpers that resolve commands against the recipe env PATH
and return explicit sh.Command instances.
Use those helpers in the libthorvg and libcairo manual Meson/Ninja build steps.

Add a regression test that reproduces the environment-sensitive lookup failure and
verifies the helper resolves meson from env PATH.

Author: AndreMiras

pythonforandroid/recipe.py

@@ -1567,6 +1567,18 @@ def ensure_args(self, *args):
             if arg not in self.extra_build_args:
                 self.extra_build_args.append(arg)
 
+    def get_recipe_env_command(self, command, env):
+        command_path = shutil.which(command, path=env["PATH"])
+        if command_path is None:
+            raise sh.CommandNotFound(command)
+        return sh.Command(command_path)
+
+    def get_meson_command(self, env):
+        return self.get_recipe_env_command("meson", env)
+
+    def get_ninja_command(self, env):
+        return self.get_recipe_env_command("ninja", env)
+
     def build_arch(self, arch):
         cross_file = join("/tmp", "android.meson.cross")
         info("Writing cross file at: {}".format(cross_file))

pythonforandroid/recipes/libcairo/__init__.py

@@ -56,7 +56,7 @@ def build_arch(self, arch):
                     _env=env
                 )
 
-            shprint(sh.meson, 'setup', 'builddir',
+            shprint(self.get_meson_command(env), 'setup', 'builddir',
                     '--cross-file', join("/tmp", "android.meson.cross"),
                     f'--prefix={install_dir}',
                     '-Dpng=enabled',
@@ -72,14 +72,22 @@ def build_arch(self, arch):
                     f'-Dfreetype_lib_dir={lib_dir}',
                     _env=env)
 
-            shprint(sh.ninja, '-C', 'builddir', '-j', str(cpu_count()), _env=env)
+            shprint(
+                self.get_ninja_command(env),
+                '-C', 'builddir', '-j', str(cpu_count()),
+                _env=env
+            )
             # macOS fix: sometimes Ninja creates a dummy 'lib' file instead of a directory.
             # So we remove and recreate the install directory using shell commands,
             # since os.remove/os.makedirs behave inconsistently in this build env.
             shprint(sh.rm, '-rf', install_dir)
             shprint(sh.mkdir, install_dir)
 
-            shprint(sh.ninja, '-C', 'builddir', 'install', _env=env)
+            shprint(
+                self.get_ninja_command(env),
+                '-C', 'builddir', 'install',
+                _env=env
+            )
 
 
 recipe = LibCairoRecipe()

pythonforandroid/recipes/libthorvg/__init__.py

@@ -54,7 +54,7 @@ def build_arch(self, arch):
         with current_directory(build_dir):
 
             shprint(
-                sh.meson,
+                self.get_meson_command(env),
                 "setup",
                 "builddir",
                 "--cross-file",
@@ -72,10 +72,18 @@ def build_arch(self, arch):
                 _env=env,
             )
 
-            shprint(sh.ninja, "-C", "builddir", "-j", str(cpu_count()), _env=env)
+            shprint(
+                self.get_ninja_command(env),
+                "-C", "builddir", "-j", str(cpu_count()),
+                _env=env,
+            )
             shprint(sh.rm, "-rf", install_dir)
             shprint(sh.mkdir, install_dir)
-            shprint(sh.ninja, "-C", "builddir", "install", _env=env)
+            shprint(
+                self.get_ninja_command(env),
+                "-C", "builddir", "install",
+                _env=env,
+            )
 
             # copy libomp.so
             arch_map = {

tests/test_recipe.py

@@ -1,13 +1,16 @@
 import os
 import pytest
+import sh
 import tempfile
 import types
 import unittest
 import warnings
 from unittest import mock
 
 from pythonforandroid.build import Context
-from pythonforandroid.recipe import Recipe, TargetPythonRecipe, import_recipe
+from pythonforandroid.recipe import (
+    MesonRecipe, Recipe, TargetPythonRecipe, import_recipe
+)
 from pythonforandroid.archs import ArchAarch_64
 from pythonforandroid.bootstrap import Bootstrap
 from tests.test_bootstrap import BaseClassSetupBootstrap
@@ -198,6 +201,33 @@ class DummyTargetPythonRecipe(TargetPythonRecipe):
         assert recipe.major_minor_version_string == '1.2'
 
 
+class TestMesonRecipe(unittest.TestCase):
+
+    def test_get_recipe_env_command_uses_env_path(self):
+        """
+        Meson commands can be installed in the hostpython environment without
+        being visible on the current Python process PATH.
+        """
+        with tempfile.TemporaryDirectory() as temp_dir:
+            bin_dir = os.path.join(temp_dir, "bin")
+            os.mkdir(bin_dir)
+            meson_path = os.path.join(bin_dir, "meson")
+            with open(meson_path, "w") as file:
+                file.write("#!/bin/sh\necho fake meson\n")
+            os.chmod(meson_path, 0o755)
+
+            env = {"PATH": bin_dir}
+            recipe = MesonRecipe()
+
+            with mock.patch.dict(os.environ, {"PATH": os.devnull}):
+                with pytest.raises(sh.CommandNotFound):
+                    sh.meson("--version", _env=env)
+
+                meson = recipe.get_meson_command(env)
+
+            assert meson("--version").strip() == "fake meson"
+
+
 class TestLibraryRecipe(BaseClassSetupBootstrap, unittest.TestCase):
     def setUp(self):
         """