Allow int for truncation_limit_lines and truncation_limit_chars in TOML

changelog/14675.bugfix.rst

@@ -0,0 +1 @@
+The :confval:`truncation_limit_lines` and :confval:`truncation_limit_chars` configuration options now accept integer values in TOML configuration files, while still accepting strings for backward compatibility.

src/_pytest/assertion/__init__.py

@@ -49,11 +49,13 @@ def pytest_addoption(parser: Parser) -> None:
 
     parser.addini(
         "truncation_limit_lines",
+        type=("int", "string"),
         default=None,
         help="Set threshold of LINES after which truncation will take effect",
     )
     parser.addini(
         "truncation_limit_chars",
+        type=("int", "string"),
         default=None,
         help=("Set threshold of CHARS after which truncation will take effect"),
     )

src/_pytest/assertion/_typing.py

@@ -1,8 +1,14 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
+from typing import ClassVar
 from typing import Literal
 from typing import Protocol
+from typing import TYPE_CHECKING
+
+
+if TYPE_CHECKING:
+    from _pytest.config import Config
 
 
 _AssertionTextDiffStyle = Literal["ndiff", "block"]
@@ -17,8 +23,29 @@ class TruncationBudget:
     dimension; ``0`` leaves it unbounded (the limit is disabled).
     """
 
-    max_lines: int
-    max_chars: int
+    #: Default limits applied when the corresponding ini option is left unset.
+    DEFAULT_MAX_LINES: ClassVar[int] = 8
+    DEFAULT_MAX_CHARS: ClassVar[int] = DEFAULT_MAX_LINES * 80
+
+    max_lines: int = DEFAULT_MAX_LINES
+    max_chars: int = DEFAULT_MAX_CHARS
+
+    @classmethod
+    def from_config(cls, config: Config) -> TruncationBudget:
+        """Build a budget from the ``truncation_limit_*`` ini options.
+
+        Both options are registered with ``type=("int", "string")`` for
+        backward compatibility, so :meth:`~_pytest.config.Config.getini` may
+        return an ``int`` (native TOML value) or a ``str`` (INI files, ``-o``
+        overrides); it returns ``None`` when the option is unset, which falls
+        back to the default limit.
+        """
+        max_lines = config.getini("truncation_limit_lines")
+        max_chars = config.getini("truncation_limit_chars")
+        return cls(
+            max_lines=cls.DEFAULT_MAX_LINES if max_lines is None else int(max_lines),
+            max_chars=cls.DEFAULT_MAX_CHARS if max_chars is None else int(max_chars),
+        )
 
 
 class _HighlightFunc(Protocol):  # noqa: PYI046

src/_pytest/assertion/truncate.py

@@ -12,38 +12,25 @@
 from _pytest.nodes import Item
 
 
-DEFAULT_MAX_LINES = 8
-DEFAULT_MAX_CHARS = DEFAULT_MAX_LINES * 80
 USAGE_MSG = "use '-vv' to show"
 
 
 def truncate_if_required(explanation: list[str], item: Item) -> list[str]:
     """Truncate this assertion explanation if the given test item is eligible."""
-    should_truncate, budget = _get_truncation_parameters(item)
-    if should_truncate:
-        return _truncate_explanation(explanation, budget)
-    return explanation
-
-
-def _get_truncation_parameters(item: Item) -> tuple[bool, TruncationBudget]:
-    """Return the truncation parameters related to the given item, as (should truncate, budget)."""
-    # We do not need to truncate if one of conditions is met:
+    # We do not need to truncate if one of these conditions is met:
     # 1. Verbosity level is 2 or more;
     # 2. Test is being run in CI environment;
     # 3. Both truncation_limit_lines and truncation_limit_chars
-    #    .ini parameters are set to 0 explicitly.
-    max_lines = item.config.getini("truncation_limit_lines")
-    max_lines = int(max_lines if max_lines is not None else DEFAULT_MAX_LINES)
-
-    max_chars = item.config.getini("truncation_limit_chars")
-    max_chars = int(max_chars if max_chars is not None else DEFAULT_MAX_CHARS)
-
+    #    are set to 0 explicitly.
     verbose = item.config.get_verbosity(Config.VERBOSITY_ASSERTIONS)
+    if verbose >= 2 or running_on_ci():
+        return explanation
 
-    should_truncate = verbose < 2 and not running_on_ci()
-    should_truncate = should_truncate and (max_lines > 0 or max_chars > 0)
+    budget = TruncationBudget.from_config(item.config)
+    if budget.max_lines <= 0 and budget.max_chars <= 0:
+        return explanation
 
-    return should_truncate, TruncationBudget(max_lines=max_lines, max_chars=max_chars)
+    return _truncate_explanation(explanation, budget)
 
 
 def _truncate_explanation(
@@ -60,7 +47,7 @@ def _truncate_explanation(
     If max_lines=0, no truncation by line count is performed.
 
     When this function is launched we know max_lines > 0 or max_chars > 0
-    because _get_truncation_parameters was called first.
+    because truncate_if_required checked it before calling.
     """
     # The length of the truncation explanation depends on the number of lines
     # removed but is at least 68 characters:

src/_pytest/config/__init__.py

@@ -1747,14 +1747,29 @@ def _getini(self, name: str):
         value = selected.value
         mode = selected.mode
 
-        if mode == "ini":
-            # In ini mode, values are always str | list[str].
-            assert isinstance(value, (str, list))
-            return self._getini_ini(name, canonical_name, type, value, default)
-        elif mode == "toml":
-            return self._getini_toml(name, canonical_name, type, value, default)
-        else:
-            assert_never(mode)
+        # A tuple type means "accept any of these types"; try each in order and
+        # return the first that accepts the value.
+        tags = type if isinstance(type, tuple) else (type,)
+        errors = []
+        for tag in tags:
+            try:
+                if mode == "ini":
+                    # In ini mode, values are always str | list[str].
+                    assert isinstance(value, (str, list))
+                    return self._getini_ini(name, canonical_name, tag, value, default)
+                elif mode == "toml":
+                    return self._getini_toml(name, canonical_name, tag, value, default)
+                else:
+                    assert_never(mode)
+            except (TypeError, ValueError) as exc:
+                errors.append(exc)
+        if len(tags) == 1:
+            raise errors[0]
+        value_type = builtins.type(value).__name__
+        raise TypeError(
+            f"{self.inipath}: config option '{name}' expects one of "
+            f"{' | '.join(tags)}, got {value_type}: {value!r}"
+        )
 
     def _getini_ini(
         self,

src/_pytest/config/argparsing.py

@@ -20,6 +20,26 @@
 
 FILE_OR_DIR = "file_or_dir"
 
+#: The string tags accepted by :meth:`Parser.addini` for its ``type`` argument.
+_IniTypeTag = Literal[
+    "string", "paths", "pathlist", "args", "linelist", "bool", "int", "float"
+]
+
+#: An ini option type: either a single tag, or a tuple of tags meaning "accept
+#: a value of any of these types" (e.g. ``("int", "string")``).
+IniType = _IniTypeTag | tuple[_IniTypeTag, ...]
+
+_INI_TYPE_TAGS: tuple[str, ...] = (
+    "string",
+    "paths",
+    "pathlist",
+    "args",
+    "linelist",
+    "bool",
+    "int",
+    "float",
+)
+
 
 @final
 class Parser:
@@ -54,7 +74,7 @@ def __init__(
         file_or_dir_arg = self.optparser.add_argument(FILE_OR_DIR, nargs="*")
         file_or_dir_arg.completer = filescompleter  # type: ignore
 
-        self._inidict: dict[str, tuple[str, str, Any]] = {}
+        self._inidict: dict[str, tuple[str, IniType, Any]] = {}
         # Maps alias -> canonical name.
         self._ini_aliases: dict[str, str] = {}
 
@@ -182,10 +202,7 @@ def addini(
         self,
         name: str,
         help: str,
-        type: Literal[
-            "string", "paths", "pathlist", "args", "linelist", "bool", "int", "float"
-        ]
-        | None = None,
+        type: _IniTypeTag | tuple[_IniTypeTag, ...] | None = None,
         default: Any = NOTSET,
         *,
         aliases: Sequence[str] = (),
@@ -210,6 +227,16 @@ def addini(
 
                     The ``float`` and ``int`` types.
 
+            A tuple of the above tags may also be passed to accept a value of
+            any of those types, for example ``("int", "string")``. In TOML
+            configuration files the value may then be any of the member types;
+            string-based formats (INI files, ``-o`` overrides) coerce it to the
+            first member that accepts it.
+
+            .. versionadded:: 9.1
+
+                Passing a tuple of types.
+
             For ``paths`` and ``pathlist`` types, they are considered relative to the config-file.
             In case the execution is happening without a config-file defined,
             they will be considered relative to the current working directory (for example with ``--override-ini``).
@@ -233,19 +260,10 @@ def addini(
         The value of configuration keys can be retrieved via a call to
         :py:func:`config.getini(name) <pytest.Config.getini>`.
         """
-        assert type in (
-            None,
-            "string",
-            "paths",
-            "pathlist",
-            "args",
-            "linelist",
-            "bool",
-            "int",
-            "float",
-        )
         if type is None:
             type = "string"
+        tags = type if isinstance(type, tuple) else (type,)
+        assert tags and all(tag in _INI_TYPE_TAGS for tag in tags), type
         if default is NOTSET:
             default = get_ini_default_for_type(type)
 
@@ -261,16 +279,15 @@ def addini(
             self._ini_aliases[alias] = name
 
 
-def get_ini_default_for_type(
-    type: Literal[
-        "string", "paths", "pathlist", "args", "linelist", "bool", "int", "float"
-    ],
-) -> Any:
+def get_ini_default_for_type(type: IniType) -> Any:
     """
     Used by addini to get the default value for a given config option type, when
     default is not supplied.
     """
-    if type in ("paths", "pathlist", "args", "linelist"):
+    if isinstance(type, tuple):
+        # A union has no unambiguous implicit default; require an explicit one.
+        return None
+    elif type in ("paths", "pathlist", "args", "linelist"):
         return []
     elif type == "bool":
         return False

src/_pytest/helpconfig.py

@@ -200,7 +200,8 @@ def showhelp(config: Config) -> None:
         help, type, _default = config._parser._inidict[name]
         if help is None:
             raise TypeError(f"help argument cannot be None for {name}")
-        spec = f"{name} ({type}):"
+        type_repr = " | ".join(type) if isinstance(type, tuple) else type
+        spec = f"{name} ({type_repr}):"
         tw.write(f"  {spec}")
         spec_len = len(spec)
         if spec_len > (indent_len - 3):

testing/test_assertion.py

@@ -1742,6 +1742,68 @@ def test():
                 ]
             )
 
+    @pytest.mark.parametrize(
+        "config",
+        [
+            # Native [tool.pytest] uses TOML types, so an int is accepted (#14675).
+            pytest.param(
+                """
+                [tool.pytest]
+                truncation_limit_lines = 3
+                truncation_limit_chars = 0
+                """,
+                id="native-toml-int",
+            ),
+            # A string in native [tool.pytest] must keep working (backward compat).
+            pytest.param(
+                """
+                [tool.pytest]
+                truncation_limit_lines = "3"
+                truncation_limit_chars = "0"
+                """,
+                id="native-toml-string",
+            ),
+            # [tool.pytest.ini_options] keeps the string-based INI behaviour.
+            pytest.param(
+                """
+                [tool.pytest.ini_options]
+                truncation_limit_lines = "3"
+                truncation_limit_chars = "0"
+                """,
+                id="ini-options-string",
+            ),
+            # ... and also accepts a bare int, coerced like the INI format does.
+            pytest.param(
+                """
+                [tool.pytest.ini_options]
+                truncation_limit_lines = 3
+                truncation_limit_chars = 0
+                """,
+                id="ini-options-int",
+            ),
+        ],
+    )
+    def test_truncation_limits_accept_int_and_string(
+        self, monkeypatch, pytester: Pytester, config: str
+    ) -> None:
+        """Truncation limits accept both int and string values in TOML (#14675)."""
+        pytester.makepyfile(
+            """\
+            string_a = "123456789\\n23456789\\n3"
+            string_b = "123456789\\n23456789\\n4"
+
+            def test():
+                assert string_a == string_b
+            """
+        )
+        monkeypatch.delenv("CI", raising=False)
+        pytester.makepyprojecttoml(config)
+
+        result = pytester.runpytest()
+
+        result.stdout.no_fnmatch_line("*TypeError*")
+        result.stdout.fnmatch_lines(["*truncated (3 lines hidden)*"])
+
 
 def test_python25_compile_issue257(pytester: Pytester) -> None:
     pytester.makepyfile(