fix: tox_modernizer added for django42 (#388)

* fix: tox_modernizer added for django42
* fix: modified moderniser to add dependencies only for django 4 and above
* fix: console command updated
---------

Co-authored-by: Usama Sadiq <[email protected]>

edx_repo_tools/codemods/django42/tox_moderniser_django42.py

@@ -0,0 +1,123 @@
+import io
+import re
+from configparser import ConfigParser, NoSectionError
+
+import click
+
+TOX_SECTION = "tox"
+ENVLIST = "envlist"
+TEST_ENV_SECTION = "testenv"
+TEST_ENV_DEPS = "deps"
+PYTHON_SUBSTITUTE = "py38"
+DJANGO_SUBSTITUTE = "django{32,40,42}"
+
+DJANGO_40_DEPENDENCY = "django40: Django>=4.0,<4.1\n"
+DJANGO_42_DEPENDENCY = "django42: Django>=4.2,<4.3\n"
+NEW_DJANGO_DEPENDENCIES = DJANGO_40_DEPENDENCY + DJANGO_42_DEPENDENCY
+
+SECTIONS = [TOX_SECTION, TEST_ENV_SECTION]
+
+PYTHON_PATTERN = "(py{.*?}-?|py[0-9]+,|py[0-9]+-)"
+
+DJANGO_PATTERN = "(django[0-9]+,|django[0-9]+\n|django{.*}\n|django{.*?}|django[0-9]+-|django{.*}-)"
+
+DJANGO4_DEPENDENCY_PATTERN = "(django32:.*\n)"
+
+
+class ConfigReader:
+    def __init__(self, file_path=None, config_dict=None):
+        self.config_dict = config_dict
+        self.file_path = file_path
+
+    def get_modernizer(self):
+        config_parser = ConfigParser()
+        if self.config_dict is not None:
+            config_parser.read_dict(self.config_dict)
+        else:
+            config_parser.read(self.file_path)
+        return ToxModernizer(config_parser, self.file_path)
+
+
+class ToxModernizer:
+    def __init__(self, config_parser, file_path):
+        self.file_path = file_path
+        self.config_parser = config_parser
+        self._validate_tox_config_sections()
+
+    def _validate_tox_config_sections(self):
+        if not self.config_parser.sections():
+            raise NoSectionError("Bad Config. No sections found.")
+
+        if all(section not in SECTIONS for section in self.config_parser.sections()):
+            raise NoSectionError("File doesn't contain required sections")
+
+    def _update_env_list(self):
+        tox_section = self.config_parser[TOX_SECTION]
+        env_list = tox_section[ENVLIST]
+
+        env_list = ToxModernizer._replace_runners(PYTHON_PATTERN, PYTHON_SUBSTITUTE, env_list)
+        env_list = ToxModernizer._replace_runners(DJANGO_PATTERN, DJANGO_SUBSTITUTE, env_list)
+        self.config_parser[TOX_SECTION][ENVLIST] = env_list
+
+    @staticmethod
+    def _replace_runners(pattern, substitute, env_list):
+        matches = re.findall(pattern, env_list)
+        if not matches:
+            return env_list
+        substitute = ToxModernizer._get_runner_substitute(matches, substitute)
+        return ToxModernizer._replace_matches(pattern, substitute, env_list, matches)
+
+    @staticmethod
+    def _replace_matches(pattern, substitute, target, matches):
+        if not matches:
+            return target
+        occurrences_to_replace = len(matches) - 1
+        if occurrences_to_replace > 0:
+            target = re.sub(pattern, '', target, occurrences_to_replace)
+
+        # checking if there is any dependency for django32 dont override it
+        if matches[0].startswith('django32:'):
+            substitute = matches[0] + substitute
+        target = re.sub(pattern, substitute, target)
+        return target
+
+    @staticmethod
+    def _get_runner_substitute(matches, substitute):
+        last_match = matches[-1]
+        has_other_runners = last_match.endswith('-')
+        return substitute + "-" if has_other_runners else substitute
+
+    def _replace_django_versions(self):
+        test_environment = self.config_parser[TEST_ENV_SECTION]
+        dependencies = test_environment[TEST_ENV_DEPS]
+        matches = re.findall(DJANGO4_DEPENDENCY_PATTERN, dependencies)
+        dependencies = self._replace_matches(DJANGO4_DEPENDENCY_PATTERN, NEW_DJANGO_DEPENDENCIES, dependencies, matches)
+
+        self.config_parser[TEST_ENV_SECTION][TEST_ENV_DEPS] = dependencies
+
+    def _update_config_file(self):
+        # ConfigParser insists on using tabs for output. We want spaces.
+        with io.StringIO() as configw:
+            self.config_parser.write(configw)
+            new_ini = configw.getvalue()
+        new_ini = new_ini.replace("\t", "    ")
+        with open(self.file_path, 'w') as configfile:
+            configfile.write(new_ini)
+
+    def modernize(self):
+        self._update_env_list()
+        self._replace_django_versions()
+        self._update_config_file()
+
+
+@click.command()
+@click.option(
+    '--path', default='tox.ini',
+    help="Path to target tox config file")
+def main(path):
+    modernizer = ConfigReader(path).get_modernizer()
+    modernizer.modernize()
+
+
+if __name__ == '__main__':
+    main()

setup.py

@@ -109,6 +109,7 @@ def is_requirement(line):
             'repo_checks = edx_repo_tools.repo_checks.repo_checks:main',
             'show_hooks = edx_repo_tools.dev.show_hooks:main',
             'tag_release = edx_repo_tools.release.tag_release:main',
+            'modernize_tox_django42 = edx_repo_tools.codemods.django42.tox_moderniser_django42:main',
         ],
     },
     package_data={