Use the internal pretty-printer consistently

AUTHORS

@@ -375,6 +375,7 @@ Omri Golan
 Ondřej Súkup
 Oscar Benjamin
 Parth Patel
+Parzival235
 Patrick Hayes
 Patrick Lannigan
 Paul Müller

changelog/14859.improvement.rst

@@ -0,0 +1,2 @@
+Pytest's uses of ``pprint`` now consistently expand nested data structures on
+all supported Python versions.

src/_pytest/_io/saferepr.py

@@ -1,9 +1,10 @@
 from __future__ import annotations
 
 from itertools import islice
-import pprint
 import reprlib
 
+from _pytest._io.pprint import PrettyPrinter
+
 
 def _try_repr_or_str(obj: object) -> str:
     try:
@@ -112,7 +113,7 @@ def safeformat(obj: object) -> str:
     with a short exception info.
     """
     try:
-        return pprint.pformat(obj)
+        return PrettyPrinter().pformat(obj)
     except Exception as exc:
         return _format_repr_exception(exc, obj)
 

src/_pytest/approx.py

@@ -14,7 +14,6 @@
 from decimal import Decimal
 import math
 from numbers import Complex
-import pprint
 import sys
 from typing import Any
 from typing import Generic
@@ -23,6 +22,8 @@
 from typing import TypeGuard
 from typing import TypeVar
 
+from _pytest._io.pprint import PrettyPrinter
+
 
 if TYPE_CHECKING:
     from numpy import ndarray
@@ -262,7 +263,9 @@ def __init__(
         for key, value in expected.items():
             if isinstance(value, type(expected)):
                 msg = "pytest.approx() does not support nested dictionaries: key={!r} value={!r}\n  full mapping={}"
-                raise TypeError(msg.format(key, value, pprint.pformat(expected)))
+                raise TypeError(
+                    msg.format(key, value, PrettyPrinter().pformat(expected))
+                )
 
         super().__init__(expected, rel=rel, abs=abs, nan_ok=nan_ok)
 
@@ -360,7 +363,7 @@ def __init__(
         for index, x in enumerate(expected):
             if isinstance(x, type(expected)):
                 msg = "pytest.approx() does not support nested data structures: {!r} at index {}\n  full sequence: {}"
-                raise TypeError(msg.format(x, index, pprint.pformat(expected)))
+                raise TypeError(msg.format(x, index, PrettyPrinter().pformat(expected)))
 
         super().__init__(expected, rel=rel, abs=abs, nan_ok=nan_ok)
 

src/_pytest/assertion/_compare_any.py

@@ -2,8 +2,8 @@
 
 from collections.abc import Iterator
 import dataclasses
-import pprint
 
+from _pytest._io.pprint import PrettyPrinter
 from _pytest.assertion._compare_mapping import _compare_eq_mapping
 from _pytest.assertion._compare_sequence import _compare_eq_iterable
 from _pytest.assertion._compare_sequence import _compare_eq_sequence
@@ -105,6 +105,7 @@ def _compare_eq_cls(
         assert False
 
     indent = "  "
+    pp = PrettyPrinter()
     same = []
     diff = []
     for field in fields_to_check:
@@ -119,10 +120,10 @@ def _compare_eq_cls(
         yield f"Omitting {len(same)} identical items, use -vv to show"
     elif same:
         yield "Matching attributes:"
-        yield from highlighter(pprint.pformat(same)).splitlines()
+        yield from (highlighter(line) for line in pp.pformat_lines(same))
     if diff:
         yield "Differing attributes:"
-        yield from highlighter(pprint.pformat(diff)).splitlines()
+        yield from (highlighter(line) for line in pp.pformat_lines(diff))
         for field in diff:
             field_left = getattr(left, field)
             field_right = getattr(right, field)

src/_pytest/assertion/_compare_mapping.py

@@ -4,9 +4,9 @@
 from collections.abc import Iterator
 from collections.abc import Mapping
 import heapq
-import pprint
 
 from _pytest._io.pprint import _safe_key
+from _pytest._io.pprint import PrettyPrinter
 from _pytest._io.saferepr import saferepr
 from _pytest.assertion._typing import _HighlightFunc
 from _pytest.assertion._typing import NO_TRUNCATION_BUDGET
@@ -23,12 +23,13 @@ def _compare_eq_mapping(
     set_left = set(left)
     set_right = set(right)
     common = set_left.intersection(set_right)
-    same = {k: left[k] for k in common if left[k] == right[k]}
+    same = {k: left[k] for k in sorted(common, key=_safe_key) if left[k] == right[k]}
+    pp = PrettyPrinter()
     if same and verbose < 2:
         yield f"Omitting {len(same)} identical items, use -vv to show"
     elif same:
         yield "Common items:"
-        yield from highlighter(pprint.pformat(same)).splitlines()
+        yield from (highlighter(line) for line in pp.pformat_lines(same))
     diff = {k for k in common if left[k] != right[k]}
     if diff:
         yield "Differing items:"
@@ -61,12 +62,13 @@ def _format_extra_items(
     """Render the "X contains N more items" subdict."""
     max_lines = truncation_budget.max_lines
     if max_lines == 0 or len(keys) <= max_lines:
-        # If no need to truncate, let pprint handle it.
-        yield from highlighter(
-            pprint.pformat({k: mapping[k] for k in keys})
-        ).splitlines()
+        # If no need to truncate, let the pretty printer handle it.
+        lines = PrettyPrinter().pformat_lines(
+            {k: mapping[k] for k in sorted(keys, key=_safe_key)}
+        )
+        yield from (highlighter(line) for line in lines)
     else:
         # To avoid spending effort on formatting entries that would be truncated,
-        # only format the needed entries, keeping the sorting that pprint would use.
+        # only format the needed entries, keeping deterministic key sorting.
         for k in heapq.nsmallest(max_lines, keys, key=_safe_key):
             yield highlighter(saferepr({k: mapping[k]}))

src/_pytest/cacheprovider.py

@@ -21,6 +21,7 @@
 from .reports import CollectReport
 from _pytest import nodes
 from _pytest._io import TerminalWriter
+from _pytest._io.pprint import PrettyPrinter
 from _pytest.config import Config
 from _pytest.config import ExitCode
 from _pytest.config import hookimpl
@@ -614,8 +615,6 @@ def cacheshow(config: Config, session: Session) -> int:
     :param session: pytest session object.
     :returns: Exit code (0 for success).
     """
-    from pprint import pformat
-
     assert config.cache is not None
 
     tw = TerminalWriter()
@@ -638,6 +637,7 @@ def globfiles(base: Path) -> Iterable[Path]:
                 yield x
 
     dummy = object()
+    pp = PrettyPrinter()
     basedir = config.cache._cachedir
     vdir = basedir / Cache._CACHE_PREFIX_VALUES
     tw.sep("-", f"cache values for {glob!r}")
@@ -648,7 +648,7 @@ def globfiles(base: Path) -> Iterable[Path]:
             tw.line(f"{key} contains unreadable content, will be ignored")
         else:
             tw.line(f"{key} contains:")
-            for line in pformat(val).splitlines():
+            for line in pp.pformat_lines(val):
                 tw.line("  " + line)
 
     ddir = basedir / Cache._CACHE_PREFIX_DIRS

src/_pytest/recwarn.py

@@ -6,7 +6,6 @@
 from collections.abc import Callable
 from collections.abc import Generator
 from collections.abc import Iterator
-from pprint import pformat
 import re
 from types import TracebackType
 from typing import Any
@@ -24,6 +23,7 @@
 
 import warnings
 
+from _pytest._io.pprint import PrettyPrinter
 from _pytest.deprecated import check_ispytest
 from _pytest.fixtures import fixture
 from _pytest.outcomes import Exit
@@ -317,7 +317,7 @@ def __exit__(
             return
 
         def found_str() -> str:
-            return pformat([record.message for record in self], indent=2)
+            return PrettyPrinter(indent=2).pformat([record.message for record in self])
 
         try:
             if not any(issubclass(w.category, self.expected_warning) for w in self):

testing/code/test_excinfo.py

@@ -758,7 +758,20 @@ def test_repr_local_truncated(self) -> None:
         full_reprlocals = q.repr_locals(loc)
         assert full_reprlocals is not None
         assert full_reprlocals.lines
-        assert full_reprlocals.lines[0] == "l          = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
+        assert full_reprlocals.lines[0] == (
+            "l          = [\n"
+            "    0,\n"
+            "    1,\n"
+            "    2,\n"
+            "    3,\n"
+            "    4,\n"
+            "    5,\n"
+            "    6,\n"
+            "    7,\n"
+            "    8,\n"
+            "    9,\n"
+            "]"
+        )
 
     def test_repr_args_not_truncated(self, importasmod) -> None:
         mod = importasmod(

testing/io/test_saferepr.py

@@ -2,6 +2,7 @@
 from __future__ import annotations
 
 from _pytest._io.saferepr import DEFAULT_REPR_MAX_SIZE
+from _pytest._io.saferepr import safeformat
 from _pytest._io.saferepr import SafeRepr
 from _pytest._io.saferepr import saferepr
 from _pytest._io.saferepr import saferepr_unlimited
@@ -13,6 +14,19 @@ def test_simple_repr():
     assert saferepr(None) == "None"
 
 
+def test_safeformat_expands_nested_collections() -> None:
+    assert safeformat({"outer": [1, {"inner": 2}]}) == (
+        "{\n"
+        "    'outer': [\n"
+        "        1,\n"
+        "        {\n"
+        "            'inner': 2,\n"
+        "        },\n"
+        "    ],\n"
+        "}"
+    )
+
+
 def test_maxsize():
     s = saferepr("x" * 50, maxsize=25)
     assert len(s) == 25

testing/python/approx.py

@@ -933,6 +933,20 @@ def test_expected_value_type_error(self, x, name):
         ):
             approx(x)
 
+    def test_nested_mapping_error_uses_expanded_format(self) -> None:
+        with pytest.raises(TypeError) as excinfo:
+            approx({"outer": {"inner": 1}})
+
+        assert str(excinfo.value) == (
+            "pytest.approx() does not support nested dictionaries: "
+            "key='outer' value={'inner': 1}\n"
+            "  full mapping={\n"
+            "    'outer': {\n"
+            "        'inner': 1,\n"
+            "    },\n"
+            "}"
+        )
+
     @pytest.mark.parametrize(
         "x",
         [