Branko Čibej wrote: > On 19.09.2013 12:09, Julian Foad wrote: >> Branko Čibej wrote: >>> On 17.09.2013 12:55, Julian Foad wrote: >>>> branch the trunk: >>>> >>>> r20: >>>> trunk >>>> /A >>>> /B >>>> branch >>>> /A (pointer to /trunk/A) >>>> /B (pointer to /trunk/B) >>>> >>>> modify branch/A: >>>> >>>> r30: >>>> trunk >>>> /A >>>> /B >>>> branch >>>> /A >>>> /B (pointer to /trunk/B) >> [...] >> >> r40: move A to C, and move B to D
I meant on the branch... >> So the repository in r40 looks like: >> >> r40: >> trunk >> /A >> /B >> branch >> /C >> /D ... but it will make the problem even clearer if we also do it on trunk at the same time, ending up with: r40: trunk /C (was moved from /trunk/A@30) /D (was moved from /trunk/B@30) branch /C (was moved from /branch/A@30) /D (was moved from /branch/B@30) >> Now we query: for each path in 'branch' in r20, where is "it" >> (the same node-line) in r40? The query is to be answered without >> scanning all intervening revisions sequentially. > > Fine, but this has nothing at all to do with moves. It's the > forward-history search problem, [...]. I don't know why you're > trying to optimize that as part of the move design. Although I'd *like* a more optimal solution, I acknowledge that talking about the cost may be distracting us from the semantics. So forget I mentioned that. The key point here is that there needs to be a *unique* solution for where branch/B@20 has been moved to in r40. With copies, of course, there is not a unique solution when we follow history forward because there can be multiple copies, but following moves forward through history must produce a unique path (at each revision). The specific difficulty is that branch/B@20 does not yet have its own copy-id, it shares it with trunk/B@20. I'm saying that if you try to specify an algorithm that traces the moves that lead from branch/B@20 to branch/D@40 using just (node-id, copy-id), you will go looking at the parent directories to see if there any copies involved, and if the nodes you're looking at are lazy-copied, and in doing so you will calculate a derived attribute that is equivalent to "node-line-id". - Julian
