On Thu, Apr 25, 2019 at 12:52 PM Jean-Paul Calderone <exarkun@twistedmatrix.com> wrote:

Hello all,

I'd like to discuss the project policy/process for dealing with incorrect backward incompatibilities that end up released.

Considering the lack of interest in the topic, I'm going to suppose that there is no policy and the decision is made case-by-case. In the case I referenced, I'm going to approve the change in behavior as "compatible" by on the grounds that it restores the original behavior.

Jean-Paul

As a case study, we could look at https://twistedmatrix.com/trac/ticket/9410 / https://github.com/twisted/twisted/pull/1106

In Twisted 16.3.0 the behavior of Request.write was changed so that it raises an AttributeError if called after the connection has closed. Prior to that release, it silently did nothing in that case.

Now, three years later, we have a PR which proposed restoring the behavior of silently ignoring the write to a closed connection.

The original change was incompatible. The new change is incompatible. What should win out?

Jean-Paul