src/_pytest/_io/pprint.py - main - niceSOFT/python3-pytest

src/_pytest/_io/pprint.py
698 строк21 KB
Pierre Sassoulas
[perf] Make ``PrettyPrinter`` format lazily so output can be budget-capped (#14588)
21 июн 2026, 07:49
21 июн 2026, 07:49d2466e3
# mypy: allow-untyped-defs
# This module was imported from the cpython standard library
# (https://github.com/python/cpython/) at commit
# c5140945c723ae6c4b7ee81ff720ac8ea4b52cfd (python3.12).
#
# It has since been adapted to emit its output lazily as a stream of
# string chunks (``_format`` and the per-type helpers are generators)
# rather than writing to a file-like object. This lets ``pformat_lines``
# stop formatting as soon as a line/char budget is reached, so a huge
# collection a caller is going to truncate anyway is never fully built.
# As a result this copy has diverged structurally from upstream and is
# no longer kept in sync with it.
#
#
#  Original Author:      Fred L. Drake, Jr.
#                        fdrake@acm.org
#
#  This is a simple little module I wrote to make life easier.  I didn't
#  see anything quite like it in the library, though I may have overlooked
#  something.  I wrote this when I was trying to read some heavily nested
#  tuples with fairly non-descriptive content.  This is modeled very much
#  after Lisp/Scheme - style pretty-printing of lists.  If you find it
#  useful, thank small children who sleep at night.
from __future__ import annotations

import collections as _collections
from collections.abc import Callable
from collections.abc import Iterable
from collections.abc import Iterator
import dataclasses as _dataclasses
import re
import types as _types
from typing import Any


class _safe_key:
    """Helper function for key functions when sorting unorderable objects.

    The wrapped-object will fallback to a Py2.x style comparison for
    unorderable types (sorting first comparing the type name and then by
    the obj ids).  Does not work recursively, so dict.items() must have
    _safe_key applied to both the key and the value.

    """

    __slots__ = ["obj"]

    def __init__(self, obj):
        self.obj = obj

    def __lt__(self, other):
        try:
            return self.obj < other.obj
        except TypeError:
            return (str(type(self.obj)), id(self.obj)) < (
                str(type(other.obj)),
                id(other.obj),
            )


def _safe_tuple(t):
    """Helper function for comparing 2-tuples"""
    return _safe_key(t[0]), _safe_key(t[1])


class PrettyPrinter:
    def __init__(
        self,
        indent: int = 4,
        width: int = 80,
        depth: int | None = None,
    ) -> None:
        """Handle pretty printing operations onto a stream using a set of
        configured parameters.

        indent
            Number of spaces to indent for each level of nesting.

        width
            Attempted maximum number of columns in the output.

        depth
            The maximum depth to print out nested structures.

        """
        if indent < 0:
            raise ValueError("indent must be >= 0")
        if depth is not None and depth <= 0:
            raise ValueError("depth must be > 0")
        if not width:
            raise ValueError("width must be != 0")
        self._depth = depth
        self._indent_per_level = indent
        self._width = width

    def pformat(self, object: Any) -> str:
        return "".join(self._format(object, 0, 0, set(), 0))

    def pformat_lines(
        self,
        object: Any,
        *,
        max_lines: int | None = None,
        max_chars: int | None = None,
    ) -> list[str]:
        """Pretty-print ``object`` and return its lines.

        ``max_lines`` / ``max_chars`` bound the two output dimensions
        independently; either may be ``None`` to leave that dimension
        unbounded, and with both ``None`` the whole object is formatted.
        When a bound is given the object is only formatted far enough to
        reach it, so a huge object costs O(budget) rather than O(N).

        The budget is a stopping condition, not a precise cut: formatting
        stops on the first piece of output that reaches it, so the result
        may slightly overshoot the bound.
        """
        if max_lines is None and max_chars is None:
            return self.pformat(object).splitlines()
        n_lines = 0
        n_chars = 0
        chunks: list[str] = []
        for chunk in self._format(object, 0, 0, set(), 0):
            chunks.append(chunk)
            if max_chars is not None:
                n_chars += len(chunk)
            if max_lines is not None and "\n" in chunk:
                # Guard the count: most chunks (brackets, indents, item
                # reprs) have no newline, and skipping the call on them
                # is meaningfully cheaper than counting every chunk.
                n_lines += chunk.count("\n")
            if (max_lines is not None and n_lines >= max_lines) or (
                max_chars is not None and n_chars >= max_chars
            ):
                break
        return "".join(chunks).splitlines()

    def _format(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        objid = id(object)
        if objid in context:
            yield _recursion(object)
            return

        p = self._dispatch.get(type(object).__repr__, None)
        if p is not None:
            context.add(objid)
            yield from p(self, object, indent, allowance, context, level + 1)
            context.remove(objid)
        elif (
            _dataclasses.is_dataclass(object)
            and not isinstance(object, type)
            and object.__dataclass_params__.repr  # type:ignore[attr-defined]
            and
            # Check dataclass has generated repr method.
            hasattr(object.__repr__, "__wrapped__")
            and "__create_fn__" in object.__repr__.__wrapped__.__qualname__
        ):
            context.add(objid)
            yield from self._pprint_dataclass(
                object, indent, allowance, context, level + 1
            )
            context.remove(objid)
        else:
            yield self._repr(object, context, level)

    def _pprint_dataclass(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        cls_name = object.__class__.__name__
        items = [
            (f.name, getattr(object, f.name))
            for f in _dataclasses.fields(object)
            if f.repr
        ]
        yield cls_name + "("
        yield from self._format_namespace_items(
            items, indent, allowance, context, level
        )
        yield ")"

    _dispatch: dict[
        Callable[..., str],
        Callable[[PrettyPrinter, Any, int, int, set[int], int], Iterator[str]],
    ] = {}

    def _pprint_dict(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield "{"
        yield from self._format_dict_items(
            object.items(), indent, allowance, context, level
        )
        yield "}"

    _dispatch[dict.__repr__] = _pprint_dict

    def _pprint_ordered_dict(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        if not len(object):
            yield repr(object)
            return
        cls = object.__class__
        yield cls.__name__ + "("
        yield from self._pprint_dict(object, indent, allowance, context, level)
        yield ")"

    _dispatch[_collections.OrderedDict.__repr__] = _pprint_ordered_dict

    def _pprint_list(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield "["
        yield from self._format_items(object, indent, allowance, context, level)
        yield "]"

    _dispatch[list.__repr__] = _pprint_list

    def _pprint_tuple(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield "("
        yield from self._format_items(object, indent, allowance, context, level)
        yield ")"

    _dispatch[tuple.__repr__] = _pprint_tuple

    def _pprint_set(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        if not len(object):
            yield repr(object)
            return
        typ = object.__class__
        if typ is set:
            yield "{"
            endchar = "}"
        else:
            yield typ.__name__ + "({"
            endchar = "})"
        try:
            # Try a direct sort first; it is faster than the fallback and
            # works for the common homogeneous, orderable case.
            object = sorted(object)
        except TypeError:
            # Heterogeneous element types — fall back to a key that
            # tolerates unorderable pairs by string-comparing their types.
            object = sorted(object, key=_safe_key)
        yield from self._format_items(object, indent, allowance, context, level)
        yield endchar

    _dispatch[set.__repr__] = _pprint_set
    _dispatch[frozenset.__repr__] = _pprint_set

    def _pprint_str(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        if not len(object):
            yield repr(object)
            return
        chunks = []
        lines = object.splitlines(True)
        if level == 1:
            indent += 1
            allowance += 1
        max_width1 = max_width = self._width - indent
        for i, line in enumerate(lines):
            rep = repr(line)
            if i == len(lines) - 1:
                max_width1 -= allowance
            if len(rep) <= max_width1:
                chunks.append(rep)
            else:
                # A list of alternating (non-space, space) strings
                parts = re.findall(r"\S*\s*", line)
                assert parts
                assert not parts[-1]
                parts.pop()  # drop empty last part
                max_width2 = max_width
                current = ""
                for j, part in enumerate(parts):
                    candidate = current + part
                    if j == len(parts) - 1 and i == len(lines) - 1:
                        max_width2 -= allowance
                    if len(repr(candidate)) > max_width2:
                        if current:
                            chunks.append(repr(current))
                        current = part
                    else:
                        current = candidate
                if current:  # pragma: no branch - a wrapped line always ends with a pending chunk
                    chunks.append(repr(current))
        if len(chunks) == 1:
            yield rep
            return
        if level == 1:
            yield "("
        for i, rep in enumerate(chunks):
            if i > 0:
                yield "\n" + " " * indent
            yield rep
        if level == 1:
            yield ")"

    _dispatch[str.__repr__] = _pprint_str

    def _pprint_bytes(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        if len(object) <= 4:
            yield repr(object)
            return
        parens = level == 1
        if parens:
            indent += 1
            allowance += 1
            yield "("
        delim = ""
        for rep in _wrap_bytes_repr(object, self._width - indent, allowance):
            yield delim
            yield rep
            if not delim:
                delim = "\n" + " " * indent
        if parens:
            yield ")"

    _dispatch[bytes.__repr__] = _pprint_bytes

    def _pprint_bytearray(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield "bytearray("
        yield from self._pprint_bytes(
            bytes(object), indent + 10, allowance + 1, context, level + 1
        )
        yield ")"

    _dispatch[bytearray.__repr__] = _pprint_bytearray

    def _pprint_mappingproxy(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield "mappingproxy("
        yield from self._format(object.copy(), indent, allowance, context, level)
        yield ")"

    _dispatch[_types.MappingProxyType.__repr__] = _pprint_mappingproxy

    def _pprint_simplenamespace(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        if type(object) is _types.SimpleNamespace:
            # The SimpleNamespace repr is "namespace" instead of the class
            # name, so we do the same here. For subclasses; use the class name.
            cls_name = "namespace"
        else:
            cls_name = object.__class__.__name__
        items = object.__dict__.items()
        yield cls_name + "("
        yield from self._format_namespace_items(
            items, indent, allowance, context, level
        )
        yield ")"

    _dispatch[_types.SimpleNamespace.__repr__] = _pprint_simplenamespace

    def _format_dict_items(
        self,
        items: Iterable[tuple[Any, Any]],
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        item_indent = indent + self._indent_per_level
        delimnl = "\n" + " " * item_indent
        emitted = False
        for key, ent in items:
            emitted = True
            yield delimnl
            yield self._repr(key, context, level)
            yield ": "
            yield from self._format(ent, item_indent, 1, context, level)
            yield ","

        if emitted:
            yield "\n" + " " * indent

    def _format_namespace_items(
        self,
        items: Iterable[tuple[Any, Any]],
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        item_indent = indent + self._indent_per_level
        delimnl = "\n" + " " * item_indent
        emitted = False
        for key, ent in items:
            emitted = True
            yield delimnl
            yield key
            yield "="
            if id(ent) in context:
                # Special-case representation of recursion to match standard
                # recursive dataclass repr.
                yield "..."
            else:
                yield from self._format(
                    ent,
                    item_indent + len(key) + 1,
                    1,
                    context,
                    level,
                )

            yield ","

        if emitted:
            yield "\n" + " " * indent

    def _format_items(
        self,
        items: Iterable[Any],
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        item_indent = indent + self._indent_per_level
        delimnl = "\n" + " " * item_indent
        emitted = False
        for item in items:
            emitted = True
            yield delimnl
            yield from self._format(item, item_indent, 1, context, level)
            yield ","

        if emitted:
            yield "\n" + " " * indent

    def _repr(self, object: Any, context: set[int], level: int) -> str:
        return self._safe_repr(object, context.copy(), self._depth, level)

    def _pprint_default_dict(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        rdf = self._repr(object.default_factory, context, level)
        yield f"{object.__class__.__name__}({rdf}, "
        yield from self._pprint_dict(object, indent, allowance, context, level)
        yield ")"

    _dispatch[_collections.defaultdict.__repr__] = _pprint_default_dict

    def _pprint_counter(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield object.__class__.__name__ + "("

        if object:
            yield "{"
            items = object.most_common()
            yield from self._format_dict_items(items, indent, allowance, context, level)
            yield "}"

        yield ")"

    _dispatch[_collections.Counter.__repr__] = _pprint_counter

    def _pprint_chain_map(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        if not len(object.maps) or (len(object.maps) == 1 and not len(object.maps[0])):
            yield repr(object)
            return

        yield object.__class__.__name__ + "("
        yield from self._format_items(object.maps, indent, allowance, context, level)
        yield ")"

    _dispatch[_collections.ChainMap.__repr__] = _pprint_chain_map

    def _pprint_deque(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield object.__class__.__name__ + "("
        if object.maxlen is not None:
            yield f"maxlen={object.maxlen}, "
        yield "["

        yield from self._format_items(object, indent, allowance + 1, context, level)
        yield "])"

    _dispatch[_collections.deque.__repr__] = _pprint_deque

    def _pprint_user_dict(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield from self._format(object.data, indent, allowance, context, level - 1)

    _dispatch[_collections.UserDict.__repr__] = _pprint_user_dict

    def _pprint_user_list(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield from self._format(object.data, indent, allowance, context, level - 1)

    _dispatch[_collections.UserList.__repr__] = _pprint_user_list

    def _pprint_user_string(
        self,
        object: Any,
        indent: int,
        allowance: int,
        context: set[int],
        level: int,
    ) -> Iterator[str]:
        yield from self._format(object.data, indent, allowance, context, level - 1)

    _dispatch[_collections.UserString.__repr__] = _pprint_user_string

    def _safe_repr(
        self, object: Any, context: set[int], maxlevels: int | None, level: int
    ) -> str:
        typ = type(object)
        if typ in _builtin_scalars:
            return repr(object)

        r = getattr(typ, "__repr__", None)

        if issubclass(typ, dict) and r is dict.__repr__:
            if not object:
                return "{}"
            objid = id(object)
            if maxlevels and level >= maxlevels:
                return "{...}"
            if objid in context:
                return _recursion(object)
            context.add(objid)
            components: list[str] = []
            append = components.append
            level += 1
            for k, v in object.items():
                krepr = self._safe_repr(k, context, maxlevels, level)
                vrepr = self._safe_repr(v, context, maxlevels, level)
                append(f"{krepr}: {vrepr}")
            context.remove(objid)
            return "{{{}}}".format(", ".join(components))

        if (issubclass(typ, list) and r is list.__repr__) or (
            issubclass(typ, tuple) and r is tuple.__repr__
        ):
            if issubclass(typ, list):
                if not object:
                    return "[]"
                format = "[%s]"
            elif len(object) == 1:
                format = "(%s,)"
            else:
                if not object:
                    return "()"
                format = "(%s)"
            objid = id(object)
            if maxlevels and level >= maxlevels:
                return format % "..."
            if objid in context:
                return _recursion(object)
            context.add(objid)
            components = []
            append = components.append
            level += 1
            for o in object:
                orepr = self._safe_repr(o, context, maxlevels, level)
                append(orepr)
            context.remove(objid)
            return format % ", ".join(components)

        return repr(object)


_builtin_scalars = frozenset(
    {str, bytes, bytearray, float, complex, bool, type(None), int}
)


def _recursion(object: Any) -> str:
    return f"<Recursion on {type(object).__name__} with id={id(object)}>"


def _wrap_bytes_repr(object: Any, width: int, allowance: int) -> Iterator[str]:
    current = b""
    last = len(object) // 4 * 4
    for i in range(0, len(object), 4):
        part = object[i : i + 4]
        candidate = current + part
        if i == last:
            width -= allowance
        if len(repr(candidate)) > width:
            if current:
                yield repr(current)
            current = part
        else:
            current = candidate
    if current:
        yield repr(current)