Obey verbosity level when printing 'msg' part of assertions (#12662)

Seems like we just missed that case when more fine-grained verbosity levels were added.

Fixes #6682, #12307

Author: nicoddemus

changelog/6682.bugfix.rst

@@ -0,0 +1 @@
+Fixed bug where the verbosity levels where not being respected when printing the "msg" part of failed assertion (as in ``assert condition, msg``).

src/_pytest/assertion/rewrite.py

@@ -451,7 +451,7 @@ def _format_assertmsg(obj: object) -> str:
     # However in either case we want to preserve the newline.
     replaces = [("\n", "\n~"), ("%", "%%")]
     if not isinstance(obj, str):
-        obj = saferepr(obj)
+        obj = saferepr(obj, _get_maxsize_for_saferepr(util._config))
         replaces.append(("\\n", "\n~"))
 
     for r1, r2 in replaces:

testing/test_assertrewrite.py

@@ -341,6 +341,34 @@ def test_assertion_messages_bytes(self, pytester: Pytester) -> None:
         assert result.ret == 1
         result.stdout.fnmatch_lines(["*AssertionError: b'ohai!'", "*assert False"])
 
+    def test_assertion_message_verbosity(self, pytester: Pytester) -> None:
+        """
+        Obey verbosity levels when printing the "message" part of assertions, when they are
+        non-strings (#6682).
+        """
+        pytester.makepyfile(
+            """
+            class LongRepr:
+
+                def __repr__(self):
+                    return "A" * 500
+
+            def test_assertion_verbosity():
+                assert False, LongRepr()
+            """
+        )
+        # Normal verbosity: assertion message gets abbreviated.
+        result = pytester.runpytest()
+        assert result.ret == 1
+        result.stdout.re_match_lines(
+            [r".*AssertionError: A+\.\.\.A+$", ".*assert False"]
+        )
+
+        # High-verbosity: do not abbreviate the assertion message.
+        result = pytester.runpytest("-vv")
+        assert result.ret == 1
+        result.stdout.re_match_lines([r".*AssertionError: A+$", ".*assert False"])
+
     def test_boolop(self) -> None:
         def f1() -> None:
             f = g = False