Michael Bayer (@zzzeek) wrote:

looking to do it like this, will commit soon

class _hash_limit_string(compat.text_type):
    """A string subclass that can only be hashed on a maximum amount
    of unique values.

    This is used for warnings so that we can send out parameterized warnings
    without the __warningregistry__ of the module,  or the non-overridable
    "once" registry within warnings.py, overloading memory,


    """
    def __new__(cls, value, args, num):
        interpolated = value % args + \
            (" (max %d of this warning will be registered)" % num)
        self = super(_hash_limit_string, cls).__new__(cls, interpolated)
        self._hash = hash("%s_%d" % (value, hash(interpolated) % num))
        return self

    def __hash__(self):
        return self._hash

    def __eq__(self, other):
        return hash(self) == hash(other)

if someone uses the "once" filter, there's a global dictionary out of our reach. so this is the only way to go.

there's not really any performant solution to the stack trace part of this, just going to leave that.

Michael Bayer (@zzzeek) wrote:

• A new style of warning can be emitted which will "filter" up to
  N occurrences of a parameterized string. This allows parameterized
  warnings that can refer to their arguments to be delivered a fixed
  number of times until allowing Python warning filters to squelch them,
  and prevents memory from growing unbounded within Python's
  warning registries.
  fixes overhaul warning use so that we can parameterize warnings #3178

→ 3c60d3b

Changes by Michael Bayer (@zzzeek):

• changed status to closed

Michael Bayer (@zzzeek) wrote:

• fix a regression from ref overhaul warning use so that we can parameterize warnings #3178, where dialects that don't actually support
  sane multi rowcount (e.g. pyodbc) would fail on multirow update. add
  a test that mocks this breakage into plain dialects

→ f49c367