saferepr: Use an __init__ instead of setting attributes after construction

This will be easier to type-check, and also somewhat clearer.

src/_pytest/_io/saferepr.py

@@ -22,6 +22,12 @@ class SafeRepr(reprlib.Repr):
     and includes information on exceptions raised during the call.
     """
 
+    def __init__(self, maxsize):
+        super().__init__()
+        self.maxstring = maxsize
+        self.maxsize = maxsize
+        self.maxother = 160
+
     def repr(self, x):
         return self._callhelper(reprlib.Repr.repr, self, x)
 
@@ -52,9 +58,4 @@ def saferepr(obj, maxsize=240):
     care to never raise exceptions itself.  This function is a wrapper
     around the Repr/reprlib functionality of the standard 2.6 lib.
     """
-    # review exception handling
-    srepr = SafeRepr()
-    srepr.maxstring = maxsize
-    srepr.maxsize = maxsize
-    srepr.maxother = 160
-    return srepr.repr(obj)
+    return SafeRepr(maxsize).repr(obj)

testing/io/test_saferepr.py

@@ -48,7 +48,7 @@ def test_exceptions():
 def test_big_repr():
     from _pytest._io.saferepr import SafeRepr
 
-    assert len(saferepr(range(1000))) <= len("[" + SafeRepr().maxlist * "1000" + "]")
+    assert len(saferepr(range(1000))) <= len("[" + SafeRepr(0).maxlist * "1000" + "]")
 
 
 def test_repr_on_newstyle():