test(util): raise the util scripts' syntax floor to 3.8 (#1103)

docs/source/contributing/workflows.rst

@@ -1440,7 +1440,7 @@ setup-python, ``build`` on conda's base ``python`` under the login shell, from
 :file:`conda/pypcapkit`, and ``upload`` on setup-python's. A project
 pin runs each on the cases the shell it replaced handled and requires the same
 status, output and calls.
-:file:`util/_actions.py` is standard library only, and keeps to 3.7's syntax,
+:file:`util/_actions.py` is standard library only, and keeps to 3.8's syntax,
 since the scripts on ``/usr/bin/python3`` and on every leg's interpreter import it.
 
 The scripts a person runs as well, or alone, sit beside the CI-only ones in

tests/project/test_actions_helper_2047.py

@@ -2,8 +2,9 @@
 """#2047: :file:`util/_actions.py`, the GitHub Actions plumbing the ``util/`` scripts share.
 
 * :class:`TestStandardLibraryOnly` holds the helper to the standard library and
-  to 3.7's syntax, since :file:`util/pip_install.py` imports it on every
-  interpreter the matrices hold, before anything is installed.
+  to the syntax of ``requires-python``'s floor, 3.8, since
+  :file:`util/pip_install.py` imports it on every interpreter the matrices hold,
+  before anything is installed.
 * :class:`TestCommands`, :class:`TestFiles` and :class:`TestRun` pin each
   function's exact output, GitHub's escaping included.
 * :class:`TestScriptsImportIt` loads each script that imports the helper in the
@@ -26,16 +27,16 @@
 import subprocess  # nosec: B404
 import sys
 import tempfile
-import tokenize
 import unittest
 from typing import TYPE_CHECKING
 from unittest import mock
 
 from tests._workflows import WORKFLOWS, load
+from tests.project.test_requires_python_floor_2051 import FLOOR
 from util import _actions
 
 if TYPE_CHECKING:
-    from typing import Any, Iterator, Optional
+    from typing import Any, Iterator
 
 #: Test tier (#1958): reads and runs the tree's own scripts, a question about the tree.
 __tier__ = 'LATEST'
@@ -48,10 +49,10 @@
            'python_versions', 'regenerate_samples', 'release_conda', 'release_published', 'release_reset_build',
            'release_status', 'release_tags', 'release_tiers', 'release_upload', 'superseded',
            'update_python_versions', 'vendor_code_changed', 'vendor_test_gate', 'verdict_covers_checkout')
-#: The top-level modules the helper may import, each in Python 3.7's standard
+#: The top-level modules the helper may import, each in Python 3.8's standard
 #: library: the running interpreter's :data:`sys.stdlib_module_names` would
-#: pass ``tomllib``, which 3.7 lacks.
-STDLIB_37 = frozenset({'__future__', 'contextlib', 'os', 'subprocess', 'sys', 'typing', 'uuid'})
+#: pass ``tomllib``, which 3.8 lacks.
+STDLIB_38 = frozenset({'__future__', 'contextlib', 'os', 'subprocess', 'sys', 'typing', 'uuid'})
 #: A trivial run of each script, ``(arguments, environment)``, that gets past its imports.
 RUNS = {
     'apt_packages': (['--help'], {}),
@@ -106,65 +107,25 @@ def imported(source: 'str') -> 'set[str]':
     return names
 
 
-def self_documenting(source: 'str') -> 'list[str]':
-    """Each f-string replacement field in ``source`` that ends in 3.8's ``=``, as ``line:col``.
-
-    ``ast.parse(..., feature_version=(3, 7))`` accepts ``f'{x=}'``. Since 3.12 an
-    f-string tokenizes into its fields (PEP 701), and there the form is an ``=``
-    token followed at once by the ``}``, ``!`` or ``:`` that ends the expression;
-    ``==``, ``:=`` and a keyword argument's ``=`` are other tokens or are followed
-    by an operand.
-
-    """
-    found = []
-    depth = 0
-    previous = None  # type: Optional[tokenize.TokenInfo]
-    for token in tokenize.generate_tokens(io.StringIO(source).readline):
-        if token.type == tokenize.FSTRING_START:  # pylint: disable=no-member
-            depth += 1
-        elif token.type == tokenize.FSTRING_END:  # pylint: disable=no-member
-            depth -= 1
-        elif depth and token.type == tokenize.OP and token.string in ('}', '!', ':') \
-                and previous is not None and previous.type == tokenize.OP and previous.string == '=':
-            found.append('%d:%d' % previous.start)
-        if token.type not in (tokenize.NL, tokenize.NEWLINE, tokenize.COMMENT):
-            previous = token
-    return found
-
-
 class TestStandardLibraryOnly(unittest.TestCase):
-    """The helper imports nothing but 3.7's standard library, and is written in 3.7's syntax."""
+    """The helper imports nothing but 3.8's standard library, and is written in 3.8's syntax."""
 
     def setUp(self) -> None:
         self.source = HELPER.read_text(encoding='utf-8')
 
-    def test_it_parses_as_python_3_7(self) -> None:
-        ast.parse(self.source, filename=str(HELPER), feature_version=(3, 7))
+    def test_it_parses_as_python_3_8(self) -> None:
+        ast.parse(self.source, filename=str(HELPER), feature_version=FLOOR)
 
-    def test_it_imports_only_what_3_7_has(self) -> None:
-        extra = sorted(imported(self.source) - STDLIB_37)
+    def test_it_imports_only_what_3_8_has(self) -> None:
+        extra = sorted(imported(self.source) - STDLIB_38)
         self.assertEqual(extra, [], f'util/_actions.py imports {extra}: check that each is in the standard '
-                                    'library of Python 3.7 and every interpreter the matrices hold, then add '
-                                    'it to STDLIB_37 in this test')
+                                    'library of Python 3.8 and every interpreter the matrices hold, then add '
+                                    'it to STDLIB_38 in this test')
         self.assertIn('uuid', imported(self.source), 'the import inside a function is seen')
 
     def test_the_import_check_sees_a_newer_module(self) -> None:
-        self.assertEqual(sorted(imported('import tomllib\nfrom os import path\n') - STDLIB_37), ['tomllib'])
-        self.assertEqual(sorted(imported('def f():\n    from . import x\n') - STDLIB_37), ['.'])
-
-    @unittest.skipUnless(hasattr(tokenize, 'FSTRING_START'), 'f-strings tokenize into fields from 3.12 (PEP 701)')
-    def test_it_has_no_self_documenting_f_string(self) -> None:
-        self.assertEqual(self_documenting(self.source), [])
-
-    @unittest.skipUnless(hasattr(tokenize, 'FSTRING_START'), 'f-strings tokenize into fields from 3.12 (PEP 701)')
-    def test_the_f_string_check_tells_the_forms_apart(self) -> None:
-        for source in ('f"{x=}"', 'f"{x = }"', 'f"{x=!r}"', 'f"{x=:>4}"', 'f"a {f(y)=} b"', 'f"{f\'{x=}\'}"'):
-            with self.subTest(source=source):
-                self.assertEqual(len(self_documenting(source + '\n')), 1, source)
-        for source in ('f"{a==b}"', 'f"x={x!r}"', 'f"{x:=^5}"', 'f"{(y:=1)}"', 'f"{g(a=1)}"', 'f"{x!r:=>4}"',
-                       'x = {"a": 1}', 'def f(a=1): return {a: a}', "f'{d[\"k=\"]}'"):
-            with self.subTest(source=source):
-                self.assertEqual(self_documenting(source + '\n'), [], source)
+        self.assertEqual(sorted(imported('import tomllib\nfrom os import path\n') - STDLIB_38), ['tomllib'])
+        self.assertEqual(sorted(imported('def f():\n    from . import x\n') - STDLIB_38), ['.'])
 
 
 class TestCommands(unittest.TestCase):

tests/project/test_release_conda_scripts_1967.py

@@ -13,7 +13,7 @@
   run writes, and the errors for a leg on another platform.
 * :class:`TestTheStepsRunTheScripts` pins each step to its script and its
   ``env:``, both jobs' legs to :data:`release_conda.PLATFORMS`, and the script
-  to Python 3.7's syntax.
+  to Python 3.8's syntax.
 
 """
 
@@ -33,6 +33,7 @@
 from typing import TYPE_CHECKING
 
 from tests._workflows import job, steps
+from tests.project.test_requires_python_floor_2051 import FLOOR
 from util import release_conda
 
 if TYPE_CHECKING:
@@ -561,8 +562,8 @@ def test_every_leg_is_mapped_and_every_mapping_is_a_leg(self) -> None:
                 self.assertLessEqual(set(labels), set(release_conda.PLATFORMS))
         self.assertEqual(set(release_conda.PLATFORMS), legs)
 
-    def test_the_scripts_parse_as_python_3_7(self) -> None:
-        ast.parse((UTIL / 'release_conda.py').read_text(encoding='utf-8'), feature_version=(3, 7))
+    def test_the_scripts_parse_as_python_3_8(self) -> None:
+        ast.parse((UTIL / 'release_conda.py').read_text(encoding='utf-8'), feature_version=FLOOR)
 
 
 if __name__ == '__main__':

tests/project/test_release_reset_build_1967.py

@@ -11,7 +11,7 @@
   shell ends.
 * :class:`TestTheStepRunsTheScript` pins the step to its script and its
   ``env:``, after a whole checkout of the repository, its ``git`` calls to ones
-  that never pull, merge, rebase, reset or force, and the script to Python 3.7's
+  that never pull, merge, rebase, reset or force, and the script to Python 3.8's
   syntax.
 
 The shell ran as a step with no ``shell:`` runs on the runner, ``bash -e``, and
@@ -37,6 +37,7 @@
 from typing import TYPE_CHECKING
 
 from tests._workflows import steps
+from tests.project.test_requires_python_floor_2051 import FLOOR
 
 if TYPE_CHECKING:
     from typing import Callable, Optional
@@ -462,9 +463,9 @@ def test_its_git_never_pulls_merges_rebases_resets_or_forces(self) -> None:
         self.assertEqual(commands, {'rev-parse', 'show', 'fetch', 'merge-base', 'ls-remote', 'switch', 'commit',
                                     'push'})
 
-    def test_it_parses_as_python_3_7(self) -> None:
+    def test_it_parses_as_python_3_8(self) -> None:
         """``tag`` has no setup-python, so it runs on the image's ``python3``."""
-        ast.parse(SCRIPT.read_text(encoding='utf-8'), feature_version=(3, 7))
+        ast.parse(SCRIPT.read_text(encoding='utf-8'), feature_version=FLOOR)
 
 
 if __name__ == '__main__':

tests/project/test_release_scripts_1967.py

@@ -10,7 +10,7 @@
   scripts against the same stand-ins and requires the same status, standard
   output and error, ``$GITHUB_OUTPUT`` and calls.
 * :class:`TestTheStepsRunTheScripts` pins each step to its script, after a whole
-  checkout of the repository, and the scripts to Python 3.7's syntax.
+  checkout of the repository, and the scripts to Python 3.8's syntax.
 
 Their runs against a real repository, and the steps' ``env:``, are
 :mod:`tests.project.test_release_tags_the_run_sha_1634`'s.
@@ -32,6 +32,7 @@
 from typing import TYPE_CHECKING
 
 from tests._workflows import load, steps
+from tests.project.test_requires_python_floor_2051 import FLOOR
 
 if TYPE_CHECKING:
     from typing import Callable
@@ -517,11 +518,11 @@ def test_each_job_checks_the_whole_tree_out_first(self) -> None:
                 self.assertFalse([step for step in found if (step.get('name'), job) in {(n, j) for j, n in STEPS}
                                   and 'working-directory' in step])
 
-    def test_the_scripts_parse_as_python_3_7(self) -> None:
+    def test_the_scripts_parse_as_python_3_8(self) -> None:
         """The steps run them on the image's ``python3``, or on a KTLO leg's."""
         for name in ('release_tags.py', 'release_upload.py'):
             with self.subTest(script=name):
-                ast.parse((UTIL / name).read_text(encoding='utf-8'), feature_version=(3, 7))
+                ast.parse((UTIL / name).read_text(encoding='utf-8'), feature_version=FLOOR)
 
 
 if __name__ == '__main__':

tests/project/test_release_status_scripts_1967.py

@@ -15,7 +15,7 @@
   runs that ``run:`` on its own case table, which reaches each of its branches.
 * :class:`TestTheStepsRunTheScripts` pins ``release_status``'s step to its
   script, after a checkout of :file:`util/` alone, and the script to the
-  standard library and Python 3.7's syntax.
+  standard library and Python 3.8's syntax.
 
 The shell ran as a step with no ``shell:`` runs on the runner, ``bash -e``, and
 ``bash`` prefixes each of its own errors with the script's path and line, which
@@ -43,6 +43,7 @@
 
 from tests._workflows import load, steps
 from tests.project.test_release_gates import job_blocks
+from tests.project.test_requires_python_floor_2051 import FLOOR
 
 if TYPE_CHECKING:
     from typing import Callable, Optional
@@ -615,12 +616,12 @@ def test_no_step_holds_the_former_shell(self) -> None:
                     with self.subTest(job=job, step=step.get('name'), line=line):
                         self.assertNotIn(line, step.get('run', ''))
 
-    def test_the_scripts_need_only_util_and_python_3_7(self) -> None:
+    def test_the_scripts_need_only_util_and_python_3_8(self) -> None:
         """The sparse checkout holds :file:`util/`, and the image's ``python3`` nothing installed."""
         allowed = {'__future__', 'argparse', 'os', 'subprocess', 'sys', 'typing', '_actions', 'util'}
         for name in ('release_status.py',):
             with self.subTest(script=name):
-                tree = ast.parse((UTIL / name).read_text(encoding='utf-8'), feature_version=(3, 7))
+                tree = ast.parse((UTIL / name).read_text(encoding='utf-8'), feature_version=FLOOR)
                 imported = {alias.name.split('.')[0] for node in ast.walk(tree) if isinstance(node, ast.Import)
                             for alias in node.names}
                 imported |= {str(node.module).split('.')[0] for node in ast.walk(tree)

tests/project/test_release_version_check_scripts_1967.py

@@ -13,7 +13,7 @@
 * :class:`TestAPlantedDivergenceIsCaught` changes each script in a copy, one
   plant at a time, and requires the cases to tell it from the shell.
 * :class:`TestTheStepsRunTheScripts` pins each step to its script, and the
-  scripts to the standard library and Python 3.7's syntax.
+  scripts to the standard library and Python 3.8's syntax.
 
 The steps run with no ``shell:``, so on the runner's ``bash -e``, and ``bash``
 prefixes each of its own errors with the script's path and line, which
@@ -39,6 +39,7 @@
 from typing import TYPE_CHECKING
 
 from tests._workflows import load, steps
+from tests.project.test_requires_python_floor_2051 import FLOOR
 
 if TYPE_CHECKING:
     from typing import Optional, Union
@@ -818,11 +819,11 @@ def test_no_step_holds_the_former_shell(self) -> None:
                     with self.subTest(job=job, step=step.get('name'), line=line):
                         self.assertNotIn(line, step.get('run', ''))
 
-    def test_the_scripts_need_only_util_and_python_3_7(self) -> None:
+    def test_the_scripts_need_only_util_and_python_3_8(self) -> None:
         allowed = {'__future__', 'argparse', 'os', 're', 'subprocess', 'sys', 'typing', '_actions', 'util'}
         for name in ('release_tiers.py', 'release_published.py'):
             with self.subTest(script=name):
-                tree = ast.parse((UTIL / name).read_text(encoding='utf-8'), feature_version=(3, 7))
+                tree = ast.parse((UTIL / name).read_text(encoding='utf-8'), feature_version=FLOOR)
                 imported = {alias.name.split('.')[0] for node in ast.walk(tree) if isinstance(node, ast.Import)
                             for alias in node.names}
                 imported |= {str(node.module).split('.')[0] for node in ast.walk(tree)

util/_actions.py

@@ -12,7 +12,7 @@
 The scripts run on the image's ``/usr/bin/python3``, or on a leg's own
 interpreter, which may be an end-of-life KTLO one, GraalPy or a free-threaded
 build, and :file:`util/pip_install.py` is the step that installs anything at
-all. So this module is standard library only and keeps to 3.7's syntax; a
+all. So this module is standard library only and keeps to 3.8's syntax; a
 project test, :file:`tests/project/test_actions_helper_2047.py`, holds it to
 both.
 

util/release_conda.py

@@ -46,7 +46,7 @@
 step: every label is ``main`` or ``dev``. On ``windows-latest`` the paths are
 Windows' own rather than Git Bash's ``/tmp/...``.
 
-The script is standard library only, and keeps to Python 3.7's syntax.
+The script is standard library only, and keeps to Python 3.8's syntax.
 
 """
 

util/release_published.py

@@ -34,7 +34,7 @@
 ``[``'s error and reads ``false``; a variable it reads that is unset, which
 Actions never leaves it, is ``<name>: unbound variable`` and status 1.
 
-It keeps to the standard library and Python 3.7's syntax as the other
+It keeps to the standard library and Python 3.8's syntax as the other
 :file:`util/` scripts do.
 
 """

util/release_reset_build.py

@@ -30,7 +30,7 @@
 ``set -u`` did.
 
 ``tag`` has no setup-python, so this runs on the image's ``python3``: standard
-library only, and Python 3.7's syntax. Its ``git switch`` replaces the checkout,
+library only, and Python 3.8's syntax. Its ``git switch`` replaces the checkout,
 :file:`util/` included, so everything it imports is imported first.
 
 """

util/release_status.py

@@ -34,7 +34,7 @@
 ``set -u`` would have, rather than with a traceback.
 
 The job checks out only :file:`util/` and has no setup-python, so this runs on
-the image's ``python3``: standard library only, and Python 3.7's syntax.
+the image's ``python3``: standard library only, and Python 3.8's syntax.
 
 """
 

util/release_tags.py

@@ -30,7 +30,7 @@
 
 The ``conda`` legs run it before setup-python, so ``python3`` is the image's,
 and ``github`` has no setup-python at all. So the script is standard library
-only, and keeps to Python 3.7's syntax.
+only, and keeps to Python 3.8's syntax.
 
 """
 

util/release_tiers.py

@@ -31,7 +31,7 @@
 -d`` left it.
 
 It runs on setup-python's ``python3``, the interpreter it runs the tag's
-reader on, but keeps to the standard library and Python 3.7's syntax as the
+reader on, but keeps to the standard library and Python 3.8's syntax as the
 other :file:`util/` scripts do.
 
 """

util/release_upload.py

@@ -27,7 +27,7 @@
 that is not then a regular file gets an ``::error`` and exits 1. A failing
 ``gh`` ends the script with its status, as ``set -e`` ended the step.
 
-The script is standard library only, and keeps to Python 3.7's syntax.
+The script is standard library only, and keeps to Python 3.8's syntax.
 
 """