Use Python 3 type hints for functions

Unfortunately, we can't do the same for variables as that is only
supported in Python 3.6+.

src/dotenv/__init__.py

@@ -4,14 +4,18 @@
                    unset_key)
 
 
-def load_ipython_extension(ipython):
-    # type: (Any) -> None
+def load_ipython_extension(ipython: Any) -> None:
     from .ipython import load_ipython_extension
     load_ipython_extension(ipython)
 
 
-def get_cli_string(path=None, action=None, key=None, value=None, quote=None):
-    # type: (Optional[str], Optional[str], Optional[str], Optional[str], Optional[str]) -> str
+def get_cli_string(
+    path: Optional[str] = None,
+    action: Optional[str] = None,
+    key: Optional[str] = None,
+    value: Optional[str] = None,
+    quote: Optional[str] = None,
+):
     """Returns a string suitable for running as a shell script.
 
     Useful for converting a arguments passed to a fabric task

src/dotenv/cli.py

@@ -26,8 +26,7 @@
               help="Whether to write the dot file as an executable bash script.")
 @click.version_option(version=__version__)
 @click.pass_context
-def cli(ctx, file, quote, export):
-    # type: (click.Context, Any, Any, Any) -> None
+def cli(ctx: click.Context, file: Any, quote: Any, export: Any) -> None:
     '''This script is used to set, get or unset values from a .env file.'''
     ctx.obj = {}
     ctx.obj['QUOTE'] = quote
@@ -37,8 +36,7 @@ def cli(ctx, file, quote, export):
 
 @cli.command()
 @click.pass_context
-def list(ctx):
-    # type: (click.Context) -> None
+def list(ctx: click.Context) -> None:
     '''Display all the stored key/value.'''
     file = ctx.obj['FILE']
     if not os.path.isfile(file):
@@ -55,8 +53,7 @@ def list(ctx):
 @click.pass_context
 @click.argument('key', required=True)
 @click.argument('value', required=True)
-def set(ctx, key, value):
-    # type: (click.Context, Any, Any) -> None
+def set(ctx: click.Context, key: Any, value: Any) -> None:
     '''Store the given key/value.'''
     file = ctx.obj['FILE']
     quote = ctx.obj['QUOTE']
@@ -71,8 +68,7 @@ def set(ctx, key, value):
 @cli.command()
 @click.pass_context
 @click.argument('key', required=True)
-def get(ctx, key):
-    # type: (click.Context, Any) -> None
+def get(ctx: click.Context, key: Any) -> None:
     '''Retrieve the value for the given key.'''
     file = ctx.obj['FILE']
     if not os.path.isfile(file):
@@ -90,8 +86,7 @@ def get(ctx, key):
 @cli.command()
 @click.pass_context
 @click.argument('key', required=True)
-def unset(ctx, key):
-    # type: (click.Context, Any) -> None
+def unset(ctx: click.Context, key: Any) -> None:
     '''Removes the given key.'''
     file = ctx.obj['FILE']
     quote = ctx.obj['QUOTE']
@@ -110,8 +105,7 @@ def unset(ctx, key):
     help="Override variables from the environment file with those from the .env file.",
 )
 @click.argument('commandline', nargs=-1, type=click.UNPROCESSED)
-def run(ctx, override, commandline):
-    # type: (click.Context, bool, List[str]) -> None
+def run(ctx: click.Context, override: bool, commandline: List[str]) -> None:
     """Run command with environment variables present."""
     file = ctx.obj['FILE']
     if not os.path.isfile(file):
@@ -132,8 +126,7 @@ def run(ctx, override, commandline):
     exit(ret)
 
 
-def run_command(command, env):
-    # type: (List[str], Dict[str, str]) -> int
+def run_command(command: List[str], env: Dict[str, str]) -> int:
     """Run command in sub process.
 
     Runs the command in a sub process with the variables from `env`

src/dotenv/main.py

@@ -20,8 +20,7 @@
     _PathLike = Text
 
 
-def with_warn_for_invalid_lines(mappings):
-    # type: (Iterator[Binding]) -> Iterator[Binding]
+def with_warn_for_invalid_lines(mappings: Iterator[Binding]) -> Iterator[Binding]:
     for mapping in mappings:
         if mapping.error:
             logger.warning(
@@ -32,9 +31,14 @@ def with_warn_for_invalid_lines(mappings):
 
 
 class DotEnv():
-
-    def __init__(self, dotenv_path, verbose=False, encoding=None, interpolate=True, override=True):
-        # type: (Union[Text, _PathLike, io.StringIO], bool, Union[None, Text], bool, bool) -> None
+    def __init__(
+        self,
+        dotenv_path: Union[Text, _PathLike, io.StringIO],
+        verbose: bool = False,
+        encoding: Union[None, Text] = None,
+        interpolate: bool = True,
+        override: bool = True,
+    ) -> None:
         self.dotenv_path = dotenv_path  # type: Union[Text,_PathLike, io.StringIO]
         self._dict = None  # type: Optional[Dict[Text, Optional[Text]]]
         self.verbose = verbose  # type: bool
@@ -43,8 +47,7 @@ def __init__(self, dotenv_path, verbose=False, encoding=None, interpolate=True,
         self.override = override  # type: bool
 
     @contextmanager
-    def _get_stream(self):
-        # type: () -> Iterator[IO[Text]]
+    def _get_stream(self) -> Iterator[IO[Text]]:
         if isinstance(self.dotenv_path, io.StringIO):
             yield self.dotenv_path
         elif os.path.isfile(self.dotenv_path):
@@ -55,8 +58,7 @@ def _get_stream(self):
                 logger.info("Python-dotenv could not find configuration file %s.", self.dotenv_path or '.env')
             yield io.StringIO('')
 
-    def dict(self):
-        # type: () -> Dict[Text, Optional[Text]]
+    def dict(self) -> Dict[Text, Optional[Text]]:
         """Return dotenv as dict"""
         if self._dict:
             return self._dict
@@ -70,15 +72,13 @@ def dict(self):
 
         return self._dict
 
-    def parse(self):
-        # type: () -> Iterator[Tuple[Text, Optional[Text]]]
+    def parse(self) -> Iterator[Tuple[Text, Optional[Text]]]:
         with self._get_stream() as stream:
             for mapping in with_warn_for_invalid_lines(parse_stream(stream)):
                 if mapping.key is not None:
                     yield mapping.key, mapping.value
 
-    def set_as_environment_variables(self):
-        # type: () -> bool
+    def set_as_environment_variables(self) -> bool:
         """
         Load the current dotenv as system environment variable.
         """
@@ -90,8 +90,7 @@ def set_as_environment_variables(self):
 
         return True
 
-    def get(self, key):
-        # type: (Text) -> Optional[Text]
+    def get(self, key: Text) -> Optional[Text]:
         """
         """
         data = self.dict()
@@ -105,8 +104,7 @@ def get(self, key):
         return None
 
 
-def get_key(dotenv_path, key_to_get):
-    # type: (Union[Text, _PathLike], Text) -> Optional[Text]
+def get_key(dotenv_path: Union[Text, _PathLike], key_to_get: Text) -> Optional[Text]:
     """
     Gets the value of a given key from the given .env
 
@@ -116,8 +114,7 @@ def get_key(dotenv_path, key_to_get):
 
 
 @contextmanager
-def rewrite(path):
-    # type: (_PathLike) -> Iterator[Tuple[IO[Text], IO[Text]]]
+def rewrite(path: _PathLike) -> Iterator[Tuple[IO[Text], IO[Text]]]:
     try:
         if not os.path.isfile(path):
             with io.open(path, "w+") as source:
@@ -133,8 +130,13 @@ def rewrite(path):
         shutil.move(dest.name, path)
 
 
-def set_key(dotenv_path, key_to_set, value_to_set, quote_mode="always", export=False):
-    # type: (_PathLike, Text, Text, Text, bool) -> Tuple[Optional[bool], Text, Text]
+def set_key(
+    dotenv_path: _PathLike,
+    key_to_set: Text,
+    value_to_set: Text,
+    quote_mode: Text = "always",
+    export: bool = False,
+) -> Tuple[Optional[bool], Text, Text]:
     """
     Adds or Updates a key/value to the given .env
 
@@ -172,8 +174,11 @@ def set_key(dotenv_path, key_to_set, value_to_set, quote_mode="always", export=F
     return True, key_to_set, value_to_set
 
 
-def unset_key(dotenv_path, key_to_unset, quote_mode="always"):
-    # type: (_PathLike, Text, Text) -> Tuple[Optional[bool], Text]
+def unset_key(
+    dotenv_path: _PathLike,
+    key_to_unset: Text,
+    quote_mode: Text = "always",
+) -> Tuple[Optional[bool], Text]:
     """
     Removes a given key from the given .env
 
@@ -199,9 +204,10 @@ def unset_key(dotenv_path, key_to_unset, quote_mode="always"):
     return removed, key_to_unset
 
 
-def resolve_variables(values, override):
-    # type: (Iterable[Tuple[Text, Optional[Text]]], bool) -> Mapping[Text, Optional[Text]]
-
+def resolve_variables(
+    values: Iterable[Tuple[Text, Optional[Text]]],
+    override: bool,
+) -> Mapping[Text, Optional[Text]]:
     new_values = {}  # type: Dict[Text, Optional[Text]]
 
     for (name, value) in values:
@@ -223,8 +229,7 @@ def resolve_variables(values, override):
     return new_values
 
 
-def _walk_to_root(path):
-    # type: (Text) -> Iterator[Text]
+def _walk_to_root(path: Text) -> Iterator[Text]:
     """
     Yield directories starting from the given directory up to the root
     """
@@ -242,8 +247,11 @@ def _walk_to_root(path):
         last_dir, current_dir = current_dir, parent_dir
 
 
-def find_dotenv(filename='.env', raise_error_if_not_found=False, usecwd=False):
-    # type: (Text, bool, bool) -> Text
+def find_dotenv(
+    filename: Text = '.env',
+    raise_error_if_not_found: bool = False,
+    usecwd: bool = False,
+) -> Text:
     """
     Search in increasingly higher folders for the given file
 
@@ -281,14 +289,13 @@ def _is_interactive():
 
 
 def load_dotenv(
-    dotenv_path=None,
-    stream=None,
-    verbose=False,
-    override=False,
-    interpolate=True,
-    encoding="utf-8",
-):
-    # type: (Union[Text, _PathLike, None], Optional[io.StringIO], bool, bool, bool, Optional[Text]) -> bool  # noqa
+    dotenv_path: Union[Text, _PathLike, None] = None,
+    stream: Optional[io.StringIO] = None,
+    verbose: bool = False,
+    override: bool = False,
+    interpolate: bool = True,
+    encoding: Optional[Text] = "utf-8",
+) -> bool:
     """Parse a .env file and then load all the variables found as environment variables.
 
     - *dotenv_path*: absolute or relative path to .env file.
@@ -313,13 +320,12 @@ def load_dotenv(
 
 
 def dotenv_values(
-    dotenv_path=None,
-    stream=None,
-    verbose=False,
-    interpolate=True,
-    encoding="utf-8",
-):
-    # type: (Union[Text, _PathLike, None], Optional[io.StringIO], bool, bool, Optional[Text]) -> Dict[Text, Optional[Text]]  # noqa: E501
+    dotenv_path: Union[Text, _PathLike, None] = None,
+    stream: Optional[io.StringIO] = None,
+    verbose: bool = False,
+    interpolate: bool = True,
+    encoding: Optional[Text] = "utf-8",
+) -> Dict[Text, Optional[Text]]:
     """
     Parse a .env file and return its content as a dict.