feat: add warning when pytest.ini and pyproject.toml are present

AUTHORS

@@ -403,6 +403,7 @@ Sadra Barikbin
 Saiprasad Kale
 Samuel Colvin
 Samuel Dion-Girardeau
+Samuel Gaist
 Samuel Jirovec
 Samuel Searles-Bryant
 Samuel Therrien (Avasam)

changelog/13330.improvement.rst

@@ -0,0 +1,3 @@
+Having both ``pytest.ini`` and ``pyproject.toml`` will now print a warning to make it clearer to the user that the former takes precedence over the latter.
+
+-- by :user:`sgaist`

src/_pytest/terminal.py

@@ -879,7 +879,14 @@ def pytest_report_header(self, config: Config) -> list[str]:
         result = [f"rootdir: {config.rootpath}"]
 
         if config.inipath:
-            result.append("configfile: " + bestrelpath(config.rootpath, config.inipath))
+            warning = ""
+            if config.inipath.name in ["pytest.ini", ".pytest.ini"]:
+                pyproject = config.rootpath / "pyproject.toml"
+                if pyproject.exists():
+                    warning = " (WARNING: ignoring pytest config in pyproject.toml!)"
+            result.append(
+                "configfile: " + bestrelpath(config.rootpath, config.inipath) + warning
+            )
 
         if config.args_source == Config.ArgsSource.TESTPATHS:
             testpaths: list[str] = config.getini("testpaths")

testing/test_terminal.py

@@ -2893,6 +2893,47 @@ def test_format_trimmed() -> None:
     assert _format_trimmed(" ({}) ", msg, len(msg) + 3) == " (unconditional ...) "
 
 
+def test_warning_when_init_trumps_pyproject_toml(
+    pytester: Pytester, monkeypatch: MonkeyPatch
+) -> None:
+    """Regression test for #7814."""
+    tests = pytester.path.joinpath("tests")
+    tests.mkdir()
+    pytester.makepyprojecttoml(
+        f"""
+        [tool.pytest.ini_options]
+        testpaths = ['{tests}']
+    """
+    )
+    pytester.makefile(".ini", pytest="")
+    result = pytester.runpytest()
+    result.stdout.fnmatch_lines(
+        [
+            "configfile: pytest.ini (WARNING: ignoring pytest config in pyproject.toml!)",
+        ]
+    )
+
+
+def test_no_warning_on_terminal_with_a_single_config_file(
+    pytester: Pytester, monkeypatch: MonkeyPatch
+) -> None:
+    """Regression test for #7814."""
+    tests = pytester.path.joinpath("tests")
+    tests.mkdir()
+    pytester.makepyprojecttoml(
+        f"""
+        [tool.pytest.ini_options]
+        testpaths = ['{tests}']
+    """
+    )
+    result = pytester.runpytest()
+    result.stdout.fnmatch_lines(
+        [
+            "configfile: pyproject.toml",
+        ]
+    )
+
+
 class TestFineGrainedTestCase:
     DEFAULT_FILE_CONTENTS = """
             import pytest