Deprecate twisted.internet.utils

[itamarst]

utils modules are ick.

1. Move process stuff to twisted.runner somewhere.
2. Move SRV stuff into twisted.names, twisted.internet
modules should not depend on external packages.

[moshez]

The great downgrading.
Utils modules are ick, but not a bug.

[radix]

#2 now lives in #772.

[radix]

twisted.runner isn't an option any more. How about another suggestion?

twisted.internet.procutils?

[itamarst]

We probably should have some place for process utilities, yes, cause there are a
number of common cases people tend to want.

[exarkun]

I don't know what to do with this.  The best thing I can think of is to delete
the module and pretend it never existed.  The functions it provides are
haphazard at best.

[thijs]

This one looks like it's still under 'active' development though.

[exarkun]

The things in twisted.internet.utils are icky. I think everything in it should be deprecated, then the module should be removed. Some of the APIs it contains provide some functionality, so something better should be provided for those before they're deprecated:

1. getProcessOut / getProcessValue / getProcessOutputAndValue - these are sort of useful, except they're all too broken to use in most serious programs. The problems they have:
   1. Three different APIs for doing the same thing but getting a different return value. Pointless. Should be one API that can return any of the information.
   2. Very bad error handling. For example, sometimes you get back a Deferred which errbacks with a tuple. That shouldn't even be possible.
   3. No timeout support. The underlying transport isn't even exposed, so you can't implement timeouts on top of the API.
   4. No incremental result support. This might be out of scope for these utilities, but it's frequently the case that you want to process results as they come. Being able to get a producer or specify a consumer here would be sensible.
   5. No way to specify most of the parameters to spawnProcess - eg, cannot set up custom FDs.
   6. Bad result reporting. eg, getProcessOutput mixes stdout and stderr together. Unless you set errortoo, then it freaks out at the first sign of stderr (and you generally get a truncated worthless message that tells you only that something went wrong, not what).
2. runWithWarningsSuppressed / suppressWarnings - these are trying to provide additional functionality for the Python warnings module. If we want it, we should try submitting patches to the stdlib. And the Deferred thing doesn't make any sense at all. You can't manage shared mutable resources that way. Twisted uses these a bit, but probably in ways which can be eliminated or changed to use some other API.

[exarkun]

See also #3997

[exarkun]

As a further note on how getProcessOutputAndValue is broken, note that you cannot raise a tuple, so combining the Deferred it returns with any of the Failure-into-exception APIs (inlineCallbacks, blockingCallFromThread) results in broken behavior.