##### SUMMARY
If you have executable files in your source code they are not kept in the tarball.

Could be related to https://github.com/ansible/ansible/blob/99d7f150873011e7515851db9b44ff486efa9d77/lib/ansible/galaxy/collection.py#L763

This was noticed as I had some auxiliary scripts in my repo.

Need to also consider scripts in `files/` if/when Collections support roles.

This seems to fail the "principal of least suprise"

**Proposal 1: Keep on stripping executable flags**

Add some line to the output
`WARNING: tests/coverage.sh: source file has executable flag, though this will be ignored in generated tar.gz`
Update developing a collection documentation page
Update integration tests to ensure that executable mode is always stripped.
Update code to link to this issue

**Proposal 2: Allow executible flags**

Update developing a collection documentation page
Update integration tests to ensure that executable mode is preserved
Update code to link to this issue
Changelog


##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
ansible-galaxy

##### ANSIBLE VERSION
```paste below
2.10
```

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

<!--- HINT: You can paste gist.github.com links for larger files -->


if os.path.isdir(cls.test_dir):
            shutil.rmtree(cls.test_dir)
    def test_metadata(self):
        with open(os.path.join(self.role_dir, 'meta', 'main.yml'), 'r') as mf:
            metadata = yaml.safe_load(mf)
        self.assertIn('galaxy_info', metadata, msg='unable to find galaxy_info in metadata')
        self.assertIn('dependencies', metadata, msg='unable to find dependencies in metadata')
    def test_readme(self):
        readme_path = os.path.join(self.role_dir, 'README.md')
        self.assertTrue(os.path.exists(readme_path), msg='Readme doesn\'t exist')
    def test_main_ymls(self):
        need_main_ymls = set(self.expected_role_dirs) - set(['meta', 'tests', 'files', 'templates'])
        for d in need_main_ymls:
            main_yml = os.path.join(self.role_dir, d, 'main.yml')
            self.assertTrue(os.path.exists(main_yml))
            expected_string = "---\n# {0} file for {1}".format(d, self.role_name)
            with open(main_yml, 'r') as f:
                self.assertEqual(expected_string, f.read().strip())
    def test_role_dirs(self):
        for d in self.expected_role_dirs:
            self.assertTrue(os.path.isdir(os.path.join(self.role_dir, d)), msg="Expected role subdirectory {0} doesn't exist".format(d))
    def test_travis_yml(self):