Remove force_uppercase_builtins default from test helpers (#19173)

Mypy only supports Python 3.9+. Update the tests to use lowercase names
for PEP 585 generics in error messages. A followup can consider
deprecating `--force-uppercase-builtins` and making it a no-op.

Author: cdce8p

mypy/test/helpers.py

@@ -258,11 +258,12 @@ def local_sys_path_set() -> Iterator[None]:
 
 
 def testfile_pyversion(path: str) -> tuple[int, int]:
-    m = re.search(r"python3([0-9]+)\.test$", path)
-    if m:
-        return 3, int(m.group(1))
+    if m := re.search(r"python3([0-9]+)\.test$", path):
+        # For older unsupported version like python38,
+        # default to that earliest supported version.
+        return max((3, int(m.group(1))), defaults.PYTHON3_VERSION_MIN)
     else:
-        return defaults.PYTHON3_VERSION
+        return defaults.PYTHON3_VERSION_MIN
 
 
 def normalize_error_messages(messages: list[str]) -> list[str]:
@@ -353,7 +354,6 @@ def parse_options(
         options = Options()
         options.error_summary = False
         options.hide_error_codes = True
-        options.force_uppercase_builtins = True
         options.force_union_syntax = True
 
     # Allow custom python version to override testfile_pyversion.

mypy/test/testcheck.py

@@ -136,8 +136,6 @@ def run_case_once(
             options.hide_error_codes = False
         if "abstract" not in testcase.file:
             options.allow_empty_bodies = not testcase.name.endswith("_no_empty")
-        if "lowercase" not in testcase.file:
-            options.force_uppercase_builtins = True
         if "union-error" not in testcase.file:
             options.force_union_syntax = True
 

mypy/test/testcmdline.py

@@ -61,8 +61,6 @@ def test_python_cmdline(testcase: DataDrivenTestCase, step: int) -> None:
         args.append("--hide-error-codes")
     if "--disallow-empty-bodies" not in args:
         args.append("--allow-empty-bodies")
-    if "--no-force-uppercase-builtins" not in args:
-        args.append("--force-uppercase-builtins")
     if "--no-force-union-syntax" not in args:
         args.append("--force-union-syntax")
     # Type check the program.

mypy/test/testmerge.py

@@ -102,7 +102,6 @@ def build(self, source: str, testcase: DataDrivenTestCase) -> BuildResult | None
         options.export_types = True
         options.show_traceback = True
         options.allow_empty_bodies = True
-        options.force_uppercase_builtins = True
         main_path = os.path.join(test_temp_dir, "main")
 
         self.str_conv.options = options

mypy/test/testparse.py

@@ -38,7 +38,6 @@ def test_parser(testcase: DataDrivenTestCase) -> None:
     The argument contains the description of the test case.
     """
     options = Options()
-    options.force_uppercase_builtins = True
     options.hide_error_codes = True
 
     if testcase.file.endswith("python310.test"):

mypy/test/testpythoneval.py

@@ -52,7 +52,6 @@ def test_python_evaluation(testcase: DataDrivenTestCase, cache_dir: str) -> None
         "--no-error-summary",
         "--hide-error-codes",
         "--allow-empty-bodies",
-        "--force-uppercase-builtins",
         "--test-env",  # Speeds up some checks
     ]
     interpreter = python3_path

mypy/test/testsemanal.py

@@ -44,7 +44,6 @@ def get_semanal_options(program_text: str, testcase: DataDrivenTestCase) -> Opti
     options.semantic_analysis_only = True
     options.show_traceback = True
     options.python_version = PYTHON3_VERSION
-    options.force_uppercase_builtins = True
     return options
 
 

mypy/test/testtransform.py

@@ -38,7 +38,6 @@ def test_transform(testcase: DataDrivenTestCase) -> None:
         options.use_builtins_fixtures = True
         options.semantic_analysis_only = True
         options.show_traceback = True
-        options.force_uppercase_builtins = True
         result = build.build(
             sources=[BuildSource("main", None, src)], options=options, alt_lib_path=test_temp_dir
         )

mypy/test/testtypegen.py

@@ -35,7 +35,6 @@ def run_case(self, testcase: DataDrivenTestCase) -> None:
             options.export_types = True
             options.preserve_asts = True
             options.allow_empty_bodies = True
-            options.force_uppercase_builtins = True
             result = build.build(
                 sources=[BuildSource("main", None, src)],
                 options=options,

mypy/test/testtypes.py

@@ -23,7 +23,6 @@
     Expression,
     NameExpr,
 )
-from mypy.options import Options
 from mypy.plugins.common import find_shallow_matching_overload_item
 from mypy.state import state
 from mypy.subtypes import is_more_precise, is_proper_subtype, is_same_type, is_subtype
@@ -130,17 +129,13 @@ def test_callable_type_with_var_args(self) -> None:
         )
         assert_equal(str(c3), "def (X? =, *Y?) -> Any")
 
-    def test_tuple_type_upper(self) -> None:
-        options = Options()
-        options.force_uppercase_builtins = True
-        assert_equal(TupleType([], self.fx.std_tuple).str_with_options(options), "Tuple[()]")
-        assert_equal(TupleType([self.x], self.fx.std_tuple).str_with_options(options), "Tuple[X?]")
-        assert_equal(
-            TupleType(
-                [self.x, AnyType(TypeOfAny.special_form)], self.fx.std_tuple
-            ).str_with_options(options),
-            "Tuple[X?, Any]",
-        )
+    def test_tuple_type_str(self) -> None:
+        t1 = TupleType([], self.fx.std_tuple)
+        assert_equal(str(t1), "tuple[()]")
+        t2 = TupleType([self.x], self.fx.std_tuple)
+        assert_equal(str(t2), "tuple[X?]")
+        t3 = TupleType([self.x, AnyType(TypeOfAny.special_form)], self.fx.std_tuple)
+        assert_equal(str(t3), "tuple[X?, Any]")
 
     def test_type_variable_binding(self) -> None:
         assert_equal(