require python 3.9+, fix pyupgrade issues

Previous python versions have reached end of life,
with 3.9 support ending soon in October: https://endoflife.date/python

Pyupgrade issues were fixed with ruff by opting-in
to the UP rules: https://docs.astral.sh/ruff/rules/#pyupgrade-up

Author: branchvincent

pycomposefile/compose_element/compose_datatype_transformer.py

@@ -11,7 +11,7 @@ def __str__(self) -> str:
         return f"Failed to evaluate mandatory variable {self.variable_name}"
 
 
-class ComposeDataTypeTransformer():
+class ComposeDataTypeTransformer:
     transform = str
     valid_values = None
 

pycomposefile/secrets/__init__.py

@@ -3,7 +3,7 @@
 
 class SecretFile(str):
     def readFile(self):
-        with open(self, "r") as f:
+        with open(self) as f:
             secret = f.read()
         return secret
 

pycomposefile/service/service_environment.py

@@ -11,7 +11,7 @@ def readFile(self):
         env_array = []
 
         for file_name in self:
-            f = open(file_name, "r")
+            f = open(file_name)
 
             for line in f.readlines():
                 if not line.startswith("#"):

pycomposefile/service/service_misc.py

@@ -17,7 +17,7 @@ def __new__(cls, config, key=None, compose_path=None, ) -> None:
             condition = detail["condition"]
         else:
             name = config
-        ob = super(Dependency, cls).__new__(cls, name)
+        ob = super().__new__(cls, name)
         ob.__setattr__('condition', condition)
         return ob
 

pyproject.toml

@@ -6,7 +6,7 @@ readme = "README.md"
 authors = [
     { name = "Steven Murawski", email = "steven.murawski@microsoft.com" },
 ]
-requires-python = ">=3.6"
+requires-python = ">=3.9"
 dependencies = ["pyyaml"]
 keywords = ["docker", "compose"]
 license = "MIT"
@@ -25,7 +25,7 @@ include = ["sample/", "tests/"]
 line-length = 120
 
 [tool.ruff.lint]
-select = ["C9", "E", "F", "W"]
+select = ["C9", "E", "F", "UP", "W"]
 ignore = ["C901", "E501", "E722", "F401", "F811"]
 mccabe = { max-complexity = 10 }