all ndk paths in config must be strings

The paths in the config must be strings because they are used in things
like env vars where they must be strings.  Plus lots of other places in the
code assumes they are strings.  This is the first step to defining the
border of where paths can be pathlib.Path() and where they must be strings.

fdroidserver/common.py

@@ -116,6 +116,7 @@ env = None
 orig_path = None
 
 
+# All paths in the config must be strings, never pathlib.Path instances
 default_config = {
     'sdk_path': "$ANDROID_HOME",
     'ndk_paths': {},

fdroidserver/metadata.py

@@ -325,12 +325,14 @@ class Build(dict):
                 return f
         return 'ant'
 
-    def ndk_path(self):
-        """Return the path to the first configured NDK or an empty string."""
+    def ndk_path(self) -> str:
+        """Return the path string of the first configured NDK or an empty string."""
         ndk = self.ndk
         if isinstance(ndk, list):
             ndk = self.ndk[0]
         path = common.config['ndk_paths'].get(ndk)
+        if path and not isinstance(path, str):
+            raise TypeError('NDK path is not string')
         if path:
             return path
         for vsn, path in common.config['ndk_paths'].items():

tests/common.TestCase

@@ -2371,6 +2371,37 @@ class CommonTest(unittest.TestCase):
         )
         for f in config['java_paths'].values():
             self.assertTrue(f in java_paths)
+            self.assertTrue(isinstance(f, str))  # paths in config must be str
+
+    @mock.patch.dict(os.environ, clear=True)
+    def test_sdk_path_in_config_must_be_strings(self):
+        """All paths in config must be strings, and never pathlib.Path instances"""
+        os.environ['PATH'] = '/usr/bin:/usr/sbin'
+        config = {'sdk_path': Path('/opt/android-sdk')}
+        fdroidserver.common.fill_config_defaults(config)
+        build = fdroidserver.metadata.Build()
+        with self.assertRaises(TypeError):
+            fdroidserver.common.set_FDroidPopen_env(build)
+
+    @mock.patch.dict(os.environ, clear=True)
+    def test_ndk_paths_in_config_must_be_strings(self):
+        """All paths in config must be strings, and never pathlib.Path instances"""
+        fdroidserver.common.config = {
+            'ndk_paths': {'r21d': Path('/opt/android-sdk/ndk/r21d')}
+        }
+        build = fdroidserver.metadata.Build()
+        build.ndk = 'r21d'
+        os.environ['PATH'] = '/usr/bin:/usr/sbin'
+        with self.assertRaises(TypeError):
+            fdroidserver.common.set_FDroidPopen_env(build)
+
+    @mock.patch.dict(os.environ, clear=True)
+    def test_FDroidPopen_envs_paths_can_be_pathlib(self):
+        os.environ['PATH'] = '/usr/bin:/usr/sbin'
+        envs = {'PATHLIB': Path('/pathlib/path'), 'STRING': '/string/path'}
+        p = fdroidserver.common.FDroidPopen(['/bin/sh', '-c', 'export'], envs=envs)
+        self.assertIn('/string/path', p.output)
+        self.assertIn('/pathlib/path', p.output)
 
     def test_vcs_git_latesttags(self):
         tags = [

tests/metadata.TestCase

@@ -1141,6 +1141,15 @@ class MetadataTest(unittest.TestCase):
             build.ndk = ['r22b', 'r10e']
             self.assertEqual(r22b, build.ndk_path())
 
+    def test_build_ndk_path_only_accepts_str(self):
+        """Paths in the config must be strings, never pathlib.Path instances"""
+        config = {'ndk_paths': {'r24': Path('r24')}}
+        fdroidserver.common.config = config
+        build = fdroidserver.metadata.Build()
+        build.ndk = 'r24'
+        with self.assertRaises(TypeError):
+            build.ndk_path()
+
 
 if __name__ == "__main__":
     parser = optparse.OptionParser()