Search for pyproject.toml config file in parent dirs (#7163)

Co-authored-by: Pierre Sassoulas <pierre.sassoulas@gmail.com>
Co-authored-by: Daniël van Noord <13665637+DanielNoord@users.noreply.github.com>

5 files changed, 79 insertions, 1 deletions

diff --git a/.pyenchant_pylint_custom_dict.txt b/.pyenchant_pylint_custom_dict.txt
index 507babde2..6cd91e1ba 100644
--- a/.pyenchant_pylint_custom_dict.txt
+++ b/.pyenchant_pylint_custom_dict.txt
@@ -261,6 +261,7 @@ pylint
 pylintdict
 pylintrc
 pylint's
+pyproject
 pypy
 pyreverse
 pytest
@@ -318,6 +319,8 @@ subtree
 supcls
 superclass
 symilar
+symlink
+symlinks
 sys
 tbump
 tempfile
diff --git a/doc/user_guide/usage/run.rst b/doc/user_guide/usage/run.rst
index b9dfedc88..7e6e1a830 100644
--- a/doc/user_guide/usage/run.rst
+++ b/doc/user_guide/usage/run.rst
@@ -105,6 +105,9 @@ configuration file in the following order and uses the first one it finds:
    providing it has at least one ``pylint.`` section
 #. ``tox.ini`` in the current working directory,
    providing it has at least one ``pylint.`` section
+#. Pylint will search for the ``pyproject.toml`` file up the directories hierarchy
+   unless it's found, or a ``.git``/``.hg`` directory is found, or the file system root
+   is approached.
 #. If the current working directory is in a Python package, Pylint searches \
    up the hierarchy of Python packages until it finds a ``pylintrc`` file. \
    This allows you to specify coding standards on a module-by-module \
diff --git a/doc/whatsnew/fragments/7163.other b/doc/whatsnew/fragments/7163.other
new file mode 100644
index 000000000..93f731aae
--- /dev/null
+++ b/doc/whatsnew/fragments/7163.other
@@ -0,0 +1,3 @@
+Search for ``pyproject.toml`` recursively in parent directories up to a project or file system root.
+
+Refs #7163, Closes #3289
diff --git a/pylint/config/find_default_config_files.py b/pylint/config/find_default_config_files.py
index a121b32a3..3b03f6357 100644
--- a/pylint/config/find_default_config_files.py
+++ b/pylint/config/find_default_config_files.py
@@ -16,7 +16,28 @@ else:
     import tomli as tomllib
 
 RC_NAMES = (Path("pylintrc"), Path(".pylintrc"))
-CONFIG_NAMES = (*RC_NAMES, Path("pyproject.toml"), Path("setup.cfg"))
+PYPROJECT_NAME = Path("pyproject.toml")
+CONFIG_NAMES = (*RC_NAMES, PYPROJECT_NAME, Path("setup.cfg"))
+
+
+def _find_pyproject() -> Path:
+    """Search for file pyproject.toml in the parent directories recursively.
+
+    It resolves symlinks, so if there is any symlink up in the tree, it does not respect them
+    """
+    current_dir = Path.cwd().resolve()
+    is_root = False
+    while not is_root:
+        if (current_dir / PYPROJECT_NAME).is_file():
+            return current_dir / PYPROJECT_NAME
+        is_root = (
+            current_dir == current_dir.parent
+            or (current_dir / ".git").is_dir()
+            or (current_dir / ".hg").is_dir()
+        )
+        current_dir = current_dir.parent
+
+    return current_dir
 
 
 def _toml_has_config(path: Path | str) -> bool:
@@ -100,6 +121,13 @@ def find_default_config_files() -> Iterator[Path]:
         pass
 
     try:
+        parent_pyproject = _find_pyproject()
+        if parent_pyproject.is_file() and _toml_has_config(parent_pyproject):
+            yield parent_pyproject.resolve()
+    except OSError:
+        pass
+
+    try:
         yield from _find_config_in_home_or_environment()
     except OSError:
         pass
diff --git a/tests/config/test_find_default_config_files.py b/tests/config/test_find_default_config_files.py
index f78f640b2..0b513a3d5 100644
--- a/tests/config/test_find_default_config_files.py
+++ b/tests/config/test_find_default_config_files.py
@@ -130,6 +130,47 @@ def test_pylintrc_parentdir() -> None:
 
 
 @pytest.mark.usefixtures("pop_pylintrc")
+def test_pyproject_toml_parentdir() -> None:
+    """Test the search of pyproject.toml file in parent directories"""
+    with tempdir() as chroot:
+        with fake_home():
+            chroot_path = Path(chroot)
+            files = [
+                "pyproject.toml",
+                "git/pyproject.toml",
+                "git/a/pyproject.toml",
+                "git/a/.git",
+                "git/a/b/c/__init__.py",
+                "hg/pyproject.toml",
+                "hg/a/pyproject.toml",
+                "hg/a/.hg",
+                "hg/a/b/c/__init__.py",
+                "none/sub/__init__.py",
+            ]
+            testutils.create_files(files)
+            for config_file in files:
+                if config_file.endswith("pyproject.toml"):
+                    with open(config_file, "w", encoding="utf-8") as fd:
+                        fd.write('[tool.pylint."messages control"]\n')
+            results = {
+                "": chroot_path / "pyproject.toml",
+                "git": chroot_path / "git" / "pyproject.toml",
+                "git/a": chroot_path / "git" / "a" / "pyproject.toml",
+                "git/a/b": chroot_path / "git" / "a" / "pyproject.toml",
+                "git/a/b/c": chroot_path / "git" / "a" / "pyproject.toml",
+                "hg": chroot_path / "hg" / "pyproject.toml",
+                "hg/a": chroot_path / "hg" / "a" / "pyproject.toml",
+                "hg/a/b": chroot_path / "hg" / "a" / "pyproject.toml",
+                "hg/a/b/c": chroot_path / "hg" / "a" / "pyproject.toml",
+                "none": chroot_path / "pyproject.toml",
+                "none/sub": chroot_path / "pyproject.toml",
+            }
+            for basedir, expected in results.items():
+                os.chdir(chroot_path / basedir)
+                assert next(config.find_default_config_files(), None) == expected
+
+
+@pytest.mark.usefixtures("pop_pylintrc")
 def test_pylintrc_parentdir_no_package() -> None:
     """Test that we don't find a pylintrc in sub-packages."""
     with tempdir() as chroot: