Introduce toReplaceWith()-equivalent to EDModules/Sequences/Paths themselves?

[makortel]

Now that we have some experience of eras (cms.Modifier) with toReplaceWith() and toModify(), I'd like to suggest to add toReplaceWith() mechanism to the EDModules/Sequences/(End)Paths directly (probably named as e.g. replaceWith() as the action can and should be taken immediately).

This would be useful for the remaining use-cases of customize functions (e.g. test recipes or HLTrigger/Configuration/python/customizeHLTforCMSSW.py) when one needs to replace a module with another in all Sequences while keeping the label. Currently the same effect can be achieved with

foo = cms.Modifier()
foo._setChosen()
foo.toReplaceWith(process.bar, cms.EDProducer("BetterBar", ...))

# Below is what I'd like to have
#process.bar.replaceWith(cms.EDProducer("BetterBar", ...))

I'm already using this pattern in Validation/RecoTrack/python/customiseTrackingNtuple.py#L16 (for EndPath), but I'll soon (~week) have another case for EDProducers in customizeHLTforCMSSW.py.

Note that I can live with the use of Modifier as above (the need is not that frequent, and it is already much simpler than the "old way" of first removing the module from all sequences, replacing the module, and re-inserting to all sequences), but I though to raise the question in case the mechanism would have wider interest.

If replaceWith() gets accepted, I'd suggest to consider adding also modify() for EDModules on the same go (for consistency).

@Dr15Jones

[cmsbuild]

A new Issue was created by @makortel Matti Kortelainen.

@davidlange6, @smuzaffar, @Dr15Jones can you please review it and eventually sign/assign? Thanks.

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[Dr15Jones]

assign core

[cmsbuild]

New categories assigned: core

@Dr15Jones,@smuzaffar you have been requested to review this Pull request/Issue and eventually sign? Thanks

[smuzaffar]

@Dr15Jones , @makortel , do we still need this or was it already implemented?

[makortel]

It has not been implemented, in principle it could be useful. On the other hand there is

cmssw/HLTrigger/Configuration/python/common.py

Lines 59 to 61 in b221493

	# logic from Modifier.toModify from FWCore/ParameterSet/python/Config.py
	def replace_with(fromObj, toObj):
	"""Replace one object with a different one of the same type.