def check_static_paths(self):
        """Check Application config for incorrect static paths."""
        # Use the dummy Request object in the main thread.
        request = cherrypy.request
        for sn, app in cherrypy.tree.apps.items():
            if not isinstance(app, cherrypy.Application):
                continue
            request.app = app
            for section in app.config:
                # get_resource will populate request.config
                request.get_resource(section + '/dummy.html')
                conf = request.config.get

                if conf('tools.staticdir.on', False):
                    msg = ''
                    root = conf('tools.staticdir.root')
                    dir = conf('tools.staticdir.dir')
                    if dir is None:
                        msg = 'tools.staticdir.dir is not set.'
                    else:
                        fulldir = ''
                        if os.path.isabs(dir):
                            fulldir = dir
                            if root:
                                msg = (
                                    'dir is an absolute path, even '
                                    'though a root is provided.'
                                )
                                testdir = os.path.join(root, dir[1:])
                                if os.path.exists(testdir):
                                    msg += (
                                        '\nIf you meant to serve the '
                                        'filesystem folder at %r, remove the '
                                        'leading slash from dir.' % (testdir,)
                                    )
                        else:
                            if not root:
                                msg = (
                                    'dir is a relative path and '
                                    'no root provided.'
                                )
                            else:
                                fulldir = os.path.join(root, dir)
                                if not os.path.isabs(fulldir):
                                    msg = '%r is not an absolute path.' % (
                                        fulldir,
                                    )

                        if fulldir and not os.path.exists(fulldir):
                            if msg:
                                msg += '\n'
                            msg += (
                                '%r (root + dir) is not an existing '
                                'filesystem path.' % fulldir
                            )

                    if msg:
                        warnings.warn(
                            '%s\nsection: [%s]\nroot: %r\ndir: %r'
                            % (msg, section, root, dir),
                        )
Check Application config for incorrect static paths.
cherrypy/_cpchecker.py