--config-file incorrectly expects [tool.pytest] instead of [pytest] in TOML config on pytest 9 #14705

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1. The-Compiler commented on Jul 14, 2026

   

   The-Compiler

   on Jul 14, 2026

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   Good catch, indeed the code hardcodes the names for [pytest] headers:

   pytest/src/_pytest/config/findpaths.py

   Lines 93 to 161 in 67a174f

   	# '.toml' files are considered if they contain a [tool.pytest] table (toml mode)
   	# or [tool.pytest.ini_options] table (ini mode) for pyproject.toml,
   	# or [pytest] table (toml mode) for pytest.toml/.pytest.toml.
   	elif filepath.suffix == ".toml":
   	if sys.version_info >= (3, 11):
   	import tomllib
   	else:
   	import tomli as tomllib
   	toml_text = filepath.read_text(encoding="utf-8")
   	try:
   	config = tomllib.loads(toml_text)
   	except tomllib.TOMLDecodeError as exc:
   	raise UsageError(f"{filepath}: {exc}") from exc
   	# pytest.toml and .pytest.toml use [pytest] table directly.
   	if filepath.name in ("pytest.toml", ".pytest.toml"):
   	if "pytest" in config:
   	# TOML mode - preserve native TOML types.
   	return {
   	k: ConfigValue(v, origin="file", mode="toml")
   	for k, v in config["pytest"].items()
   	}
   	top_level_options = [
   	key for key, value in config.items() if not isinstance(value, dict)
   	]
   	if top_level_options:
   	raise UsageError(
   	f"{filepath}: pytest configuration must be under a "
   	f"[pytest] table (found top-level options: "
   	f"{', '.join(top_level_options)})"
   	)
   	# "pytest.toml" files are always the source of configuration, even if empty.
   	return {}
   	# pyproject.toml uses [tool.pytest] or [tool.pytest.ini_options].
   	else:
   	tool_pytest = config.get("tool", {}).get("pytest", {})
   	# Check for toml mode config: [tool.pytest] with content outside of ini_options.
   	toml_config = {k: v for k, v in tool_pytest.items() if k != "ini_options"}
   	# Check for ini mode config: [tool.pytest.ini_options].
   	ini_config = tool_pytest.get("ini_options", None)
   	if toml_config and ini_config:
   	raise UsageError(
   	f"{filepath}: Cannot use both [tool.pytest] (native TOML types) and "
   	"[tool.pytest.ini_options] (string-based INI format) simultaneously. "
   	"Please use [tool.pytest] with native TOML types (recommended) "
   	"or [tool.pytest.ini_options] for backwards compatibility."
   	)
   	if toml_config:
   	# TOML mode - preserve native TOML types.
   	return {
   	k: ConfigValue(v, origin="file", mode="toml")
   	for k, v in toml_config.items()
   	}
   	elif ini_config is not None:
   	# INI mode - TOML supports richer data types than INI files, but we need to
   	# convert all scalar values to str for compatibility with the INI system.
   	def make_scalar(v: object) -> str | list[str]:
   	return v if isinstance(v, list) else str(v)
   	return {
   	k: ConfigValue(make_scalar(v), origin="file", mode="ini")
   	for k, v in ini_config.items()
   	}

   The comments sound a bit like this is intentional, but I'm not entirely sure it is. In any case, fixing it in a backwards-compatible way is unfortunately going to make that logic even more complex, most likely it would need to consider both [tool.pytest] and [pytest] in any custom TOML files.
2. francis-clairicia commented on Jul 14, 2026

   

   francis-clairicia

   on Jul 14, 2026

   Last edited by francis-clairicia

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   I don't think the fix needs to be backward-compatible because:

   1. the behavior has never been documented in this way,
   2. even with the ini format, the section [tool:pytest] is read only with the setup.cfg file.

   Until now, the "tool" section has always been dedicated to the project file.
3. The-Compiler commented on Jul 14, 2026

   

   The-Compiler

   on Jul 14, 2026

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   From a cursory GitHub code search, I suppose it might indeed be fine. Still a corner case though.
4. molloyzak13 commented on Jul 14, 2026

   

   molloyzak13

   on Jul 14, 2026

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   reply_target: #14705
   The comment at line 128 names pyproject.toml only (it says the else branch handles "pyproject.toml" and reads from [tool.pytest]) but the condition at line 109 checks for pytest.toml and .pytest.toml. A custom TOML file passed with --config-file falls into that else branch and reads the wrong section. The comments document a three-way split but the branching only implements two.

   PR #14707 has the right approach, keeping the [tool.pytest] lookup for pyproject.toml and routing custom TOML files to [pytest].
5. RonnyPfannschmidt

   added 3 commits that reference this issue on Jul 31, 2026

   fix: validate -c/--config-file and read [pytest] from custom TOML files

   ...

   5db0551

   fix: validate -c/--config-file and read [pytest] from custom TOML files

   ...

   6df5f88

   fix: validate -c/--config-file and read [pytest] from custom TOML files

   ...

   d5ef28c
6. RonnyPfannschmidt

   closed this as completedin #14807on Aug 6, 2026