Fix mypy type errors by using Mapping instead of Dict (#130)

Changed VariableValueDict to VariableValueMapping and updated type
from Dict to Mapping to properly represent immutable type annotations.
Fixed _merge function to use dict() constructor instead of .copy()
since Mapping types don't have a copy method.

Author: jonathangreen

tests/test_from_fixtures.py

@@ -11,7 +11,7 @@ def fixture_file_path(filename: str) -> str:
     return os.path.join(absolute_dir, "fixtures", filename)
 
 
-ExampleVariables = uritemplate.variable.VariableValueDict
+ExampleVariables = uritemplate.variable.VariableValueMapping
 ExampleTemplatesAndResults = t.List[t.Tuple[str, t.Union[str, t.List[str]]]]
 
 

tests/test_uritemplate.py

@@ -11,16 +11,18 @@
 
 def merge_dicts(
     *args: t.Union[
-        variable.VariableValueDict, t.Dict[str, str], t.Dict[str, t.List[str]]
+        variable.VariableValueMapping,
+        t.Dict[str, str],
+        t.Dict[str, t.List[str]],
     ]
-) -> variable.VariableValueDict:
+) -> variable.VariableValueMapping:
     d: t.Dict[str, variable.VariableValue] = {}
     for arg in args:
         d.update(arg)
     return d
 
 
-ExampleVariables = variable.VariableValueDict
+ExampleVariables = variable.VariableValueMapping
 ExampleTemplatesAndResults = t.List[t.Tuple[str, t.Union[str, t.List[str]]]]
 
 
@@ -582,7 +584,7 @@ def test_hashability(self) -> None:
         self.assertEqual(d, {t: 2})
 
     def test_no_mutate(self) -> None:
-        args: variable.VariableValueDict = {}
+        args: variable.VariableValueMapping = {}
         t = URITemplate("")
         t.expand(args, key=1)
         self.assertEqual(args, {})
@@ -635,7 +637,7 @@ def test_variables(self) -> None:
 
 
 class TestNativeTypeSupport(unittest.TestCase):
-    context: variable.VariableValueDict = {
+    context: variable.VariableValueMapping = {
         "zero": 0,
         "one": 1,
         "digits": list(range(10)),

uritemplate/api.py

@@ -18,7 +18,7 @@
 
 def expand(
     uri: str,
-    var_dict: t.Optional[variable.VariableValueDict] = None,
+    var_dict: t.Optional[variable.VariableValueMapping] = None,
     **kwargs: variable.VariableValue,
 ) -> str:
     """Expand the template with the given parameters.
@@ -46,7 +46,7 @@ def expand(
 
 def partial(
     uri: str,
-    var_dict: t.Optional[variable.VariableValueDict] = None,
+    var_dict: t.Optional[variable.VariableValueMapping] = None,
     **kwargs: variable.VariableValue,
 ) -> URITemplate:
     """Partially expand the template with the given parameters.

uritemplate/template.py

@@ -25,11 +25,11 @@
 
 
 def _merge(
-    var_dict: t.Optional[variable.VariableValueDict],
-    overrides: variable.VariableValueDict,
-) -> variable.VariableValueDict:
+    var_dict: t.Optional[variable.VariableValueMapping],
+    overrides: variable.VariableValueMapping,
+) -> variable.VariableValueMapping:
     if var_dict:
-        opts = var_dict.copy()
+        opts = dict(var_dict)
         opts.update(overrides)
         return opts
     return overrides
@@ -97,7 +97,7 @@ def __hash__(self) -> int:
         return hash(self.uri)
 
     def _expand(
-        self, var_dict: variable.VariableValueDict, replace: bool
+        self, var_dict: variable.VariableValueMapping, replace: bool
     ) -> str:
         if not self.variables:
             return self.uri
@@ -121,7 +121,7 @@ def replace_partial(match: "re.Match[str]") -> str:
 
     def expand(
         self,
-        var_dict: t.Optional[variable.VariableValueDict] = None,
+        var_dict: t.Optional[variable.VariableValueMapping] = None,
         **kwargs: variable.VariableValue,
     ) -> str:
         """Expand the template with the given parameters.
@@ -148,7 +148,7 @@ def expand(
 
     def partial(
         self,
-        var_dict: t.Optional[variable.VariableValueDict] = None,
+        var_dict: t.Optional[variable.VariableValueMapping] = None,
         **kwargs: variable.VariableValue,
     ) -> "URITemplate":
         """Partially expand the template with the given parameters.

uritemplate/variable.py

@@ -29,7 +29,7 @@
     t.Tuple[str, ScalarVariableValue],
     ScalarVariableValue,
 ]
-VariableValueDict = t.Dict[str, VariableValue]
+VariableValueMapping = t.Mapping[str, VariableValue]
 
 
 _UNRESERVED_CHARACTERS: t.Final[str] = (
@@ -451,7 +451,7 @@ def _string_expansion(
         return self.operator.quote(value)
 
     def expand(
-        self, var_dict: t.Optional[VariableValueDict] = None
+        self, var_dict: t.Optional[VariableValueMapping] = None
     ) -> t.Mapping[str, str]:
         """Expand the variable in question.