Re: [tlug] Open-source repository question

["Stephen J. Turnbull" <stephen@example.com>]

John Fremlin writes:

 > > Sure, in the sense that since 1 != 0 and 2 != 0, 1 == 2. 
 > 
 > Sorry for not spelling it out.
 > 
 > Given two patches A and B that are identical on some content, and do not 
 > conflict on other content, the original conflict oracle O would claim 
 > that they conflict. The conflict oracle O' notes that the changes on the 
 > conflicted part are identical and claims that they do not conflict.
 > 
 > You might say that O' is "less correct" than O,

I do say that.  Expression matters in understanding intent.  The fact
that two hunks are grouped together in a patch is presumably intended
(at least in a disciplined development process) to indicate that they
are part of the same conceptual change.

 > However, I say that notion is somewhat illusory.

I agree as far as the math goes.  My point is that by looking at
something outside of the math we can make some inferences about
intent, and we can actually do something to make those inferences
plausible (ie, insist on coherent changesets that leave the tree in a
buildable state).

 > From one Oracle satisfying the reasonable axioms, we can derive a
 > new Oracle that also satisfies the axioms but doesn't care about
 > case. Of course the semantics are very different if the file is not
 > line based or semantically case sensitive, but we started this
 > discussion recognising that the Oracle couldn't pretend to
 > understand the semantics of patches.

On second thought, this whole line of argument is wrong.  The whole
point of an Oracle is that it is outside of the axioms; that's where
the semantics (that current patch theories don't understand) are.