code: do not truncate args when running with -vvv (#12241)

Related to #2871.

AUTHORS

@@ -279,6 +279,7 @@ Michael Droettboom
 Michael Goerz
 Michael Krebs
 Michael Seifert
+Michael Vogt
 Michal Wajszczuk
 Michał Górny
 Michał Zięba

changelog/2871.improvement.rst

@@ -0,0 +1 @@
+Do not truncate arguments to functions in output when running with `-vvv`.

src/_pytest/_code/code.py

@@ -635,6 +635,7 @@ def getrepr(
         ] = True,
         funcargs: bool = False,
         truncate_locals: bool = True,
+        truncate_args: bool = True,
         chain: bool = True,
     ) -> Union["ReprExceptionInfo", "ExceptionChainRepr"]:
         """Return str()able representation of this exception info.
@@ -665,6 +666,9 @@ def getrepr(
         :param bool truncate_locals:
             With ``showlocals==True``, make sure locals can be safely represented as strings.
 
+        :param bool truncate_args:
+            With ``showargs==True``, make sure args can be safely represented as strings.
+
         :param bool chain:
             If chained exceptions in Python 3 should be shown.
 
@@ -691,6 +695,7 @@ def getrepr(
             tbfilter=tbfilter,
             funcargs=funcargs,
             truncate_locals=truncate_locals,
+            truncate_args=truncate_args,
             chain=chain,
         )
         return fmt.repr_excinfo(self)
@@ -809,6 +814,7 @@ class FormattedExcinfo:
     tbfilter: Union[bool, Callable[[ExceptionInfo[BaseException]], Traceback]] = True
     funcargs: bool = False
     truncate_locals: bool = True
+    truncate_args: bool = True
     chain: bool = True
     astcache: Dict[Union[str, Path], ast.AST] = dataclasses.field(
         default_factory=dict, init=False, repr=False
@@ -839,7 +845,11 @@ def repr_args(self, entry: TracebackEntry) -> Optional["ReprFuncArgs"]:
         if self.funcargs:
             args = []
             for argname, argvalue in entry.frame.getargs(var=True):
-                args.append((argname, saferepr(argvalue)))
+                if self.truncate_args:
+                    str_repr = saferepr(argvalue)
+                else:
+                    str_repr = saferepr(argvalue, maxsize=None)
+                args.append((argname, str_repr))
             return ReprFuncArgs(args)
         return None
 

src/_pytest/nodes.py

@@ -448,6 +448,8 @@ def _repr_failure_py(
         else:
             truncate_locals = True
 
+        truncate_args = False if self.config.getoption("verbose", 0) > 2 else True
+
         # excinfo.getrepr() formats paths relative to the CWD if `abspath` is False.
         # It is possible for a fixture/test to change the CWD while this code runs, which
         # would then result in the user seeing confusing paths in the failure message.
@@ -466,6 +468,7 @@ def _repr_failure_py(
             style=style,
             tbfilter=tbfilter,
             truncate_locals=truncate_locals,
+            truncate_args=truncate_args,
         )
 
     def repr_failure(

testing/code/test_excinfo.py

@@ -11,6 +11,7 @@
 import sys
 import textwrap
 from typing import Any
+from typing import cast
 from typing import TYPE_CHECKING
 
 import _pytest._code
@@ -712,6 +713,29 @@ def test_repr_local_truncated(self) -> None:
         assert full_reprlocals.lines
         assert full_reprlocals.lines[0] == "l          = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
 
+    def test_repr_args_not_truncated(self, importasmod) -> None:
+        mod = importasmod(
+            """
+            def func1(m):
+                raise ValueError("hello\\nworld")
+        """
+        )
+        excinfo = pytest.raises(ValueError, mod.func1, "m" * 500)
+        excinfo.traceback = excinfo.traceback.filter(excinfo)
+        entry = excinfo.traceback[-1]
+        p = FormattedExcinfo(funcargs=True, truncate_args=True)
+        reprfuncargs = p.repr_args(entry)
+        assert reprfuncargs is not None
+        arg1 = cast(str, reprfuncargs.args[0][1])
+        assert len(arg1) < 500
+        assert "..." in arg1
+        # again without truncate
+        p = FormattedExcinfo(funcargs=True, truncate_args=False)
+        reprfuncargs = p.repr_args(entry)
+        assert reprfuncargs is not None
+        assert reprfuncargs.args[0] == ("m", repr("m" * 500))
+        assert "..." not in cast(str, reprfuncargs.args[0][1])
+
     def test_repr_tracebackentry_lines(self, importasmod) -> None:
         mod = importasmod(
             """

testing/test_assertion.py

@@ -2045,3 +2045,36 @@ def test_long_text_fail():
             f"E       AssertionError: assert 'hello world' in '{long_text}'",
         ]
     )
+
+
+def test_full_output_vvv(pytester: Pytester) -> None:
+    pytester.makepyfile(
+        r"""
+        def crash_helper(m):
+            assert 1 == 2
+        def test_vvv():
+            crash_helper(500 * "a")
+    """
+    )
+    result = pytester.runpytest("")
+    # without -vvv, the passed args are truncated
+    expected_non_vvv_arg_line = "m = 'aaaaaaaaaaaaaaa*..aaaaaaaaaaaa*"
+    result.stdout.fnmatch_lines(
+        [
+            expected_non_vvv_arg_line,
+            "test_full_output_vvv.py:2: AssertionError",
+        ],
+    )
+    # double check that the untruncated part is not in the output
+    expected_vvv_arg_line = "m = '{}'".format(500 * "a")
+    result.stdout.no_fnmatch_line(expected_vvv_arg_line)
+
+    # but with "-vvv" the args are not truncated
+    result = pytester.runpytest("-vvv")
+    result.stdout.fnmatch_lines(
+        [
+            expected_vvv_arg_line,
+            "test_full_output_vvv.py:2: AssertionError",
+        ]
+    )
+    result.stdout.no_fnmatch_line(expected_non_vvv_arg_line)