Drop isort 4, and clean up the resulting code (#10641)

Author: DanielNoord

doc/whatsnew/fragments/10637.breaking

@@ -0,0 +1,5 @@
+Version requirement for `isort` has been bumped to >=5.0.0.
+The internal compatibility for older `isort` versions exposed via `pylint.utils.IsortDriver` has
+been removed.
+
+Refs #10637

pylint/checkers/imports.py

@@ -17,6 +17,7 @@
 
 import astroid
 import astroid.modutils
+import isort
 from astroid import nodes
 from astroid.nodes._base_nodes import ImportNode
 
@@ -35,7 +36,6 @@
 from pylint.interfaces import HIGH
 from pylint.reporters.ureports.nodes import Paragraph, Section, VerbatimText
 from pylint.typing import MessageDefinitionTuple
-from pylint.utils import IsortDriver
 from pylint.utils.linterstats import LinterStats
 
 if TYPE_CHECKING:
@@ -322,6 +322,7 @@ def _make_graph(
 DEFAULT_PREFERRED_MODULES = ()
 
 
+# pylint: disable-next = too-many-instance-attributes
 class ImportsChecker(DeprecatedMixin, BaseChecker):
     """BaseChecker for import statements.
 
@@ -458,6 +459,15 @@ def __init__(self, linter: PyLinter) -> None:
         )
         self._excluded_edges: defaultdict[str, set[str]] = defaultdict(set)
 
+        self._isort_config = isort.Config(
+            # There is no typo here. EXTRA_standard_library is
+            # what most users want. The option has been named
+            # KNOWN_standard_library for ages in pylint, and we
+            # don't want to break compatibility.
+            extra_standard_library=linter.config.known_standard_library,
+            known_third_party=linter.config.known_third_party,
+        )
+
     def open(self) -> None:
         """Called before visiting project (i.e set of modules)."""
         self.linter.stats.dependencies = {}
@@ -746,7 +756,6 @@ def _is_fallback_import(
         imports = [import_node for (import_node, _) in imports]
         return any(astroid.are_exclusive(import_node, node) for import_node in imports)
 
-    # pylint: disable = too-many-statements
     def _check_imports_order(self, _module_node: nodes.Module) -> tuple[
         list[tuple[ImportNode, str]],
         list[tuple[ImportNode, str]],
@@ -765,7 +774,6 @@ def _check_imports_order(self, _module_node: nodes.Module) -> tuple[
         third_party_not_ignored: list[tuple[ImportNode, str]] = []
         first_party_not_ignored: list[tuple[ImportNode, str]] = []
         local_not_ignored: list[tuple[ImportNode, str]] = []
-        isort_driver = IsortDriver(self.linter.config)
         for node, modname in self._imports_stack:
             if modname.startswith("."):
                 package = "." + modname.split(".")[1]
@@ -775,7 +783,7 @@ def _check_imports_order(self, _module_node: nodes.Module) -> tuple[
             ignore_for_import_order = not self.linter.is_message_enabled(
                 "wrong-import-order", node.fromlineno
             )
-            import_category = isort_driver.place_module(package)
+            import_category = isort.place_module(package, config=self._isort_config)
             node_and_package_import = (node, package)
 
             match import_category:

pylint/checkers/utils.py

@@ -6,7 +6,7 @@
 
 from __future__ import annotations
 
-import _string
+import _string  # pylint: disable=wrong-import-order # Ruff and Isort disagree about the order here
 import builtins
 import fnmatch
 import itertools

pylint/utils/__init__.py

@@ -11,8 +11,6 @@
 from pylint.utils.file_state import FileState
 from pylint.utils.linterstats import LinterStats, ModuleStats, merge_stats
 from pylint.utils.utils import (
-    HAS_ISORT_5,
-    IsortDriver,
     _check_csv,
     _check_regexp_csv,
     _splitstrip,
@@ -29,10 +27,8 @@
 )
 
 __all__ = [
-    "HAS_ISORT_5",
     "ASTWalker",
     "FileState",
-    "IsortDriver",
     "LinterStats",
     "ModuleStats",
     "_check_csv",

pylint/utils/utils.py

@@ -4,17 +4,6 @@
 
 from __future__ import annotations
 
-try:
-    import isort.api
-    import isort.settings
-
-    HAS_ISORT_5 = True
-except ImportError:  # isort < 5
-    import isort
-
-    HAS_ISORT_5 = False
-
-import argparse
 import codecs
 import os
 import re
@@ -344,30 +333,3 @@ def _ini_format(stream: TextIO, options: list[tuple[str, OptionDict, Any]]) -> N
                 # remove trailing ',' from last element of the list
                 value = value[:-1]
             print(f"{optname}={value}", file=stream)
-
-
-class IsortDriver:
-    """A wrapper around isort API that changed between versions 4 and 5."""
-
-    def __init__(self, config: argparse.Namespace) -> None:
-        if HAS_ISORT_5:
-            self.isort5_config = isort.settings.Config(
-                # There is no typo here. EXTRA_standard_library is
-                # what most users want. The option has been named
-                # KNOWN_standard_library for ages in pylint, and we
-                # don't want to break compatibility.
-                extra_standard_library=config.known_standard_library,
-                known_third_party=config.known_third_party,
-            )
-        else:
-            # pylint: disable-next=no-member
-            self.isort4_obj = isort.SortImports(  # type: ignore[attr-defined]
-                file_contents="",
-                known_standard_library=config.known_standard_library,
-                known_third_party=config.known_third_party,
-            )
-
-    def place_module(self, package: str) -> str:
-        if HAS_ISORT_5:
-            return isort.api.place_module(package, self.isort5_config)
-        return self.isort4_obj.place_module(package)  # type: ignore[no-any-return]

pyproject.toml

@@ -45,7 +45,7 @@ dependencies = [
   "dill>=0.2; python_version<'3.11'",
   "dill>=0.3.6; python_version>='3.11'",
   "dill>=0.3.7; python_version>='3.12'",
-  "isort>=4.2.5,!=5.13,<7",
+  "isort>=5,!=5.13,<8",
   "mccabe>=0.6,<0.8",
   "platformdirs>=2.2",
   "tomli>=1.1; python_version<'3.11'",

tests/test_functional.py

@@ -23,21 +23,13 @@
     LintModuleOutputUpdate,
     get_functional_test_files_from_directory,
 )
-from pylint.utils import HAS_ISORT_5
 
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
 FUNCTIONAL_DIR = Path(__file__).parent.resolve() / "functional"
 
 
-# isort 5 has slightly different rules as isort 4. Testing both would be hard: test with isort 5 only.
-TESTS = [
-    t
-    for t in get_functional_test_files_from_directory(FUNCTIONAL_DIR)
-    if not (t.base == "wrong_import_order" and not HAS_ISORT_5)
-]
-TESTS_NAMES = [t.base for t in TESTS]
 TEST_WITH_EXPECTED_DEPRECATION = [
     "anomalous_backslash_escape",
     "anomalous_unicode_escape",
@@ -55,7 +47,11 @@ def revert_stateful_config_changes(linter: PyLinter) -> Iterator[PyLinter]:
 
 
 @pytest.mark.usefixtures("revert_stateful_config_changes")
-@pytest.mark.parametrize("test_file", TESTS, ids=TESTS_NAMES)
+@pytest.mark.parametrize(
+    "test_file",
+    get_functional_test_files_from_directory(FUNCTIONAL_DIR),
+    ids=lambda x: x.base,
+)
 def test_functional(test_file: FunctionalTestFile, pytestconfig: Config) -> None:
     __tracebackhide__ = True  # pylint: disable=unused-variable
     lint_test: LintModuleOutputUpdate | testutils.LintModuleTest