Refactor ``LinterStats`` (#5074)

* Refactor ``self.stats`` on linter and checker
This adds a new class ``LinterStats`` which is used to store all
kinds of stats during a run of ``pylint``. Tests have been changed
slightly to be able to use the new class.

Co-authored-by: Marc Mueller <30130371+cdce8p@users.noreply.github.com>

4 files changed, 128 insertions, 139 deletions

diff --git a/tests/lint/unittest_lint.py b/tests/lint/unittest_lint.py
index 277799676..79437e987 100644
--- a/tests/lint/unittest_lint.py
+++ b/tests/lint/unittest_lint.py
@@ -48,7 +48,7 @@ from io import StringIO
 from os import chdir, getcwd
 from os.path import abspath, basename, dirname, isdir, join, sep
 from shutil import rmtree
-from typing import Dict, Iterable, Iterator, List, Optional, Tuple
+from typing import Iterable, Iterator, List, Optional, Tuple
 
 import platformdirs
 import pytest
@@ -870,7 +870,7 @@ def test_by_module_statement_value(init_linter: PyLinter) -> None:
     linter = init_linter
     linter.check([os.path.join(os.path.dirname(__file__), "data")])
 
-    by_module_stats: Dict[str, Dict[str, int]] = linter.stats["by_module"]  # type: ignore
+    by_module_stats = linter.stats.by_module
     for module, module_stats in by_module_stats.items():
 
         linter2 = init_linter
@@ -881,4 +881,4 @@ def test_by_module_statement_value(init_linter: PyLinter) -> None:
 
         # Check that the by_module "statement" is equal to the global "statement"
         # computed for that module
-        assert module_stats["statement"] == linter2.stats["statement"]
+        assert module_stats["statement"] == linter2.stats.statement
diff --git a/tests/test_check_parallel.py b/tests/test_check_parallel.py
index c0fbe00fd..be250d892 100644
--- a/tests/test_check_parallel.py
+++ b/tests/test_check_parallel.py
@@ -10,7 +10,6 @@
 
 # pylint: disable=protected-access,missing-function-docstring,no-self-use
 
-import collections
 import os
 from typing import List
 
@@ -25,7 +24,8 @@ from pylint.lint.parallel import _worker_check_single_file as worker_check_singl
 from pylint.lint.parallel import _worker_initialize as worker_initialize
 from pylint.lint.parallel import check_parallel
 from pylint.testutils import GenericTestReporter as Reporter
-from pylint.typing import CheckerStats, FileItem
+from pylint.typing import FileItem
+from pylint.utils import LinterStats, ModuleStats
 
 
 def _gen_file_data(idx: int = 0) -> FileItem:
@@ -103,11 +103,10 @@ class ParallelTestChecker(BaseChecker):
         super().__init__(linter)
         self.data: List[str] = []
         self.linter = linter
-        self.stats: CheckerStats = {}
 
     def open(self) -> None:
         """init the checkers: reset statistics information"""
-        self.stats = self.linter.add_stats()
+        self.linter.stats.reset_node_count()
         self.data = []
 
     def close(self) -> None:
@@ -202,26 +201,24 @@ class TestCheckParallelFramework:
         no_errors_status = 0
         assert no_errors_status == msg_status
         assert {
-            "by_module": {
-                "--test-file_data-name-0--": {
-                    "convention": 0,
-                    "error": 0,
-                    "fatal": 0,
-                    "info": 0,
-                    "refactor": 0,
-                    "statement": 18,
-                    "warning": 0,
-                }
-            },
-            "by_msg": {},
-            "convention": 0,
-            "error": 0,
-            "fatal": 0,
-            "info": 0,
-            "refactor": 0,
-            "statement": 18,
-            "warning": 0,
-        } == stats
+            "--test-file_data-name-0--": {
+                "convention": 0,
+                "error": 0,
+                "fatal": 0,
+                "info": 0,
+                "refactor": 0,
+                "statement": 18,
+                "warning": 0,
+            }
+        } == stats.by_module
+        assert {} == stats.by_msg
+        assert stats.convention == 0
+        assert stats.error == 0
+        assert stats.fatal == 0
+        assert stats.info == 0
+        assert stats.refactor == 0
+        assert stats.statement == 18
+        assert stats.warning == 0
 
     def test_worker_check_sequential_checker(self) -> None:
         """Same as test_worker_check_single_file_no_checkers with SequentialTestChecker"""
@@ -248,26 +245,24 @@ class TestCheckParallelFramework:
         no_errors_status = 0
         assert no_errors_status == msg_status
         assert {
-            "by_module": {
-                "--test-file_data-name-0--": {
-                    "convention": 0,
-                    "error": 0,
-                    "fatal": 0,
-                    "info": 0,
-                    "refactor": 0,
-                    "statement": 18,
-                    "warning": 0,
-                }
-            },
-            "by_msg": {},
-            "convention": 0,
-            "error": 0,
-            "fatal": 0,
-            "info": 0,
-            "refactor": 0,
-            "statement": 18,
-            "warning": 0,
-        } == stats
+            "--test-file_data-name-0--": {
+                "convention": 0,
+                "error": 0,
+                "fatal": 0,
+                "info": 0,
+                "refactor": 0,
+                "statement": 18,
+                "warning": 0,
+            }
+        } == stats.by_module
+        assert {} == stats.by_msg
+        assert stats.convention == 0
+        assert stats.error == 0
+        assert stats.fatal == 0
+        assert stats.info == 0
+        assert stats.refactor == 0
+        assert stats.statement == 18
+        assert stats.warning == 0
 
 
 class TestCheckParallel:
@@ -299,52 +294,48 @@ class TestCheckParallel:
             "checkers registered"
         )
         assert {
-            "by_module": {
-                "--test-file_data-name-0--": {
-                    "convention": 0,
-                    "error": 0,
-                    "fatal": 0,
-                    "info": 0,
-                    "refactor": 0,
-                    "statement": 18,
-                    "warning": 0,
-                }
-            },
-            "by_msg": {},
-            "convention": 0,
-            "error": 0,
-            "fatal": 0,
-            "info": 0,
-            "refactor": 0,
-            "statement": 18,
-            "warning": 0,
-        } == linter.stats
+            "--test-file_data-name-0--": {
+                "convention": 0,
+                "error": 0,
+                "fatal": 0,
+                "info": 0,
+                "refactor": 0,
+                "statement": 18,
+                "warning": 0,
+            }
+        } == linter.stats.by_module
+        assert linter.stats.by_msg == {}
+        assert linter.stats.convention == 0
+        assert linter.stats.error == 0
+        assert linter.stats.fatal == 0
+        assert linter.stats.info == 0
+        assert linter.stats.refactor == 0
+        assert linter.stats.statement == 18
+        assert linter.stats.warning == 0
 
         # now run the regular mode of checking files and check that, in this proc, we
         # collect the right data
         filepath = [single_file_container[0][1]]  # get the filepath element
         linter.check(filepath)
         assert {
-            "by_module": {
-                "input.similar1": {  # module is the only change from previous
-                    "convention": 0,
-                    "error": 0,
-                    "fatal": 0,
-                    "info": 0,
-                    "refactor": 0,
-                    "statement": 18,
-                    "warning": 0,
-                }
-            },
-            "by_msg": {},
-            "convention": 0,
-            "error": 0,
-            "fatal": 0,
-            "info": 0,
-            "refactor": 0,
-            "statement": 18,
-            "warning": 0,
-        } == linter.stats
+            "input.similar1": {  # module is the only change from previous
+                "convention": 0,
+                "error": 0,
+                "fatal": 0,
+                "info": 0,
+                "refactor": 0,
+                "statement": 18,
+                "warning": 0,
+            }
+        } == linter.stats.by_module
+        assert linter.stats.by_msg == {}
+        assert linter.stats.convention == 0
+        assert linter.stats.error == 0
+        assert linter.stats.fatal == 0
+        assert linter.stats.info == 0
+        assert linter.stats.refactor == 0
+        assert linter.stats.statement == 18
+        assert linter.stats.warning == 0
 
     def test_invoke_single_job(self) -> None:
         """Tests basic checkers functionality using just a single workderdo
@@ -365,26 +356,24 @@ class TestCheckParallel:
         )
 
         assert {
-            "by_module": {
-                "--test-file_data-name-0--": {
-                    "convention": 0,
-                    "error": 0,
-                    "fatal": 0,
-                    "info": 0,
-                    "refactor": 0,
-                    "statement": 18,
-                    "warning": 0,
-                }
-            },
-            "by_msg": collections.Counter(),
-            "convention": 0,
-            "error": 0,
-            "fatal": 0,
-            "info": 0,
-            "refactor": 0,
-            "statement": 18,
-            "warning": 0,
-        } == linter.stats
+            "--test-file_data-name-0--": {
+                "convention": 0,
+                "error": 0,
+                "fatal": 0,
+                "info": 0,
+                "refactor": 0,
+                "statement": 18,
+                "warning": 0,
+            }
+        } == linter.stats.by_module
+        assert linter.stats.by_msg == {}
+        assert linter.stats.convention == 0
+        assert linter.stats.error == 0
+        assert linter.stats.fatal == 0
+        assert linter.stats.info == 0
+        assert linter.stats.refactor == 0
+        assert linter.stats.statement == 18
+        assert linter.stats.warning == 0
         assert linter.msg_status == 0, "We expect a single-file check to exit cleanly"
 
     @pytest.mark.parametrize(
@@ -425,30 +414,30 @@ class TestCheckParallel:
 
         # define the stats we expect to get back from the runs, these should only vary
         # with the number of files.
-        expected_stats = {
-            "by_module": {
+        expected_stats = LinterStats(
+            by_module={
                 # pylint: disable-next=consider-using-f-string
                 "--test-file_data-name-%d--"
-                % idx: {
-                    "convention": 0,
-                    "error": 0,
-                    "fatal": 0,
-                    "info": 0,
-                    "refactor": 0,
-                    "statement": 18,
-                    "warning": 0,
-                }
+                % idx: ModuleStats(
+                    convention=0,
+                    error=0,
+                    fatal=0,
+                    info=0,
+                    refactor=0,
+                    statement=18,
+                    warning=0,
+                )
                 for idx in range(num_files)
-            },
-            "by_msg": {},
-            "convention": 0,
-            "error": 0,
-            "fatal": 0,
-            "info": 0,
-            "refactor": 0,
-            "statement": 18 * num_files,
-            "warning": 0,
-        }
+            }
+        )
+        expected_stats.by_msg = {}
+        expected_stats.convention = 0
+        expected_stats.error = 0
+        expected_stats.fatal = 0
+        expected_stats.info = 0
+        expected_stats.refactor = 0
+        expected_stats.statement = 18 * num_files
+        expected_stats.warning = 0
 
         file_infos = _gen_file_datas(num_files)
 
@@ -482,11 +471,11 @@ class TestCheckParallel:
                 stats_check_parallel = linter.stats
                 assert linter.msg_status == 0, "We should not fail the lint"
 
-        assert (
-            stats_single_proc == stats_check_parallel
+        assert str(stats_single_proc) == str(
+            stats_check_parallel
         ), "Single-proc and check_parallel() should return the same thing"
-        assert (
-            stats_check_parallel == expected_stats
+        assert str(stats_check_parallel) == str(
+            expected_stats
         ), "The lint is returning unexpected results, has something changed?"
 
     @pytest.mark.parametrize(
@@ -551,6 +540,6 @@ class TestCheckParallel:
                     arguments=None,
                 )
                 stats_check_parallel = linter.stats
-        assert (
-            stats_single_proc["by_msg"] == stats_check_parallel["by_msg"]
+        assert str(stats_single_proc.by_msg) == str(
+            stats_check_parallel.by_msg
         ), "Single-proc and check_parallel() should return the same thing"
diff --git a/tests/test_import_graph.py b/tests/test_import_graph.py
index 42e3baf56..6035601bf 100644
--- a/tests/test_import_graph.py
+++ b/tests/test_import_graph.py
@@ -48,7 +48,7 @@ POSSIBLE_DOT_FILENAMES = ["foo.dot", "foo.gv", "tests/regrtest_data/foo.dot"]
 @pytest.mark.parametrize("dest", POSSIBLE_DOT_FILENAMES, indirect=True)
 def test_dependencies_graph(dest: str) -> None:
     """DOC files are correctly generated, and the graphname is the basename"""
-    imports._dependencies_graph(dest, {"labas": ["hoho", "yep"], "hoho": ["yep"]})
+    imports._dependencies_graph(dest, {"labas": {"hoho", "yep"}, "hoho": {"yep"}})
     with open(dest, encoding="utf-8") as stream:
         assert (
             stream.read().strip()
@@ -75,7 +75,7 @@ URL="." node[shape="box"]
 def test_missing_graphviz(filename: str) -> None:
     """Raises if graphviz is not installed, and defaults to png if no extension given"""
     with pytest.raises(RuntimeError, match=r"Cannot generate `graph\.png`.*"):
-        imports._dependencies_graph(filename, {"a": ["b", "c"], "b": ["c"]})
+        imports._dependencies_graph(filename, {"a": {"b", "c"}, "b": {"c"}})
 
 
 @pytest.fixture
diff --git a/tests/test_regr.py b/tests/test_regr.py
index 07385a64d..6dadcf2c6 100644
--- a/tests/test_regr.py
+++ b/tests/test_regr.py
@@ -114,12 +114,12 @@ def modify_path() -> Iterator:
 def test_check_package___init__(finalize_linter: PyLinter) -> None:
     filename = ["package.__init__"]
     finalize_linter.check(filename)
-    checked = list(finalize_linter.stats["by_module"].keys())  # type: ignore # Refactor of PyLinter.stats necessary
-    assert checked == filename
+    checked = list(finalize_linter.stats.by_module.keys())
+    assert sorted(checked) == sorted(filename)
 
     os.chdir(join(REGR_DATA, "package"))
     finalize_linter.check(["__init__"])
-    checked = list(finalize_linter.stats["by_module"].keys())  # type: ignore
+    checked = list(finalize_linter.stats.by_module.keys())
     assert checked == ["__init__"]