Support TOML v1.0.0 syntax in pyproject.toml

.pre-commit-config.yaml

@@ -58,7 +58,7 @@ repos:
           - py>=1.8.2
           - attrs>=19.2.0
           - packaging
-          - types-toml
+          - tomli
           - types-pkg_resources
 -   repo: local
     hooks:

AUTHORS

@@ -302,6 +302,7 @@ Sven-Hendrik Haase
 Sylvain Marié
 Tadek Teleżyński
 Takafumi Arakaki
+Taneli Hukkinen
 Tanvi Mehta
 Tarcisio Fischer
 Tareq Alayan

changelog/8789.feature.rst

@@ -0,0 +1 @@
+Switch TOML parser from ``toml`` to ``tomli`` for TOML v1.0.0 support in ``pyproject.toml``.

setup.cfg

@@ -47,7 +47,7 @@ install_requires =
     packaging
     pluggy>=0.12,<1.0.0a1
     py>=1.8.2
-    toml
+    tomli>=1.0.0,<2.0.0
     atomicwrites>=1.0;sys_platform=="win32"
     colorama;sys_platform=="win32"
     importlib-metadata>=0.12;python_version<"3.8"

src/_pytest/config/findpaths.py

@@ -64,9 +64,13 @@ def load_config_dict_from_file(
 
     # '.toml' files are considered if they contain a [tool.pytest.ini_options] table.
     elif filepath.suffix == ".toml":
-        import toml
+        import tomli
 
-        config = toml.load(str(filepath))
+        toml_text = filepath.read_text(encoding="utf-8")
+        try:
+            config = tomli.loads(toml_text)
+        except tomli.TOMLDecodeError as exc:
+            raise UsageError(str(exc)) from exc
 
         result = config.get("tool", {}).get("pytest", {}).get("ini_options", None)
         if result is not None:

testing/test_findpaths.py

@@ -77,6 +77,7 @@ def test_valid_toml_file(self, tmp_path: Path) -> None:
             y = 20.0
             values = ["tests", "integration"]
             name = "foo"
+            heterogeneous_array = [1, "str"]
             """
             ),
             encoding="utf-8",
@@ -86,6 +87,7 @@ def test_valid_toml_file(self, tmp_path: Path) -> None:
             "y": "20.0",
             "values": ["tests", "integration"],
             "name": "foo",
+            "heterogeneous_array": [1, "str"],
         }