Re: Update on the branch surgery

[Daniel J S. <dan...@ie...>]

On 10/26/2017 11:31 AM, sfeam wrote:
> On Wednesday, 25 October 2017 23:16:15 Eric S. Raymond wrote:
>> Ethan A Merritt <sf...@us...>:
>>> On Wednesday, October 25, 2017 3:18:37 PM PDT Eric S. Raymond wrote:
>>>> I have successfully transplanted 4.2, but 4.0 has a problem.  Rebasing
>>>> it on /#include gp_time.h/ yields this diff at the tip:
>>>>
>>>> --- a/demo/gnuplot.rot	1998-04-22 09:38:42.000000000 -0400
>>>> +++ b/demo/gnuplot.rot	2017-10-25 17:39:55.083147765 -0400
>>>> @@ -1,12 +1,5 @@
>>>> -# HBB: revised open-ended animation routine. Used to just turn
>>>> -# round and round by somewhat large steps. Now, it tumbles
>>>> -# back and forth smoothly.
>>>> -# If 'limit_iterations' is set to a nonzero value, it'll stop after that
>>>> -# many iterations (iteration_count=0 has to be set before this -#
>>>> script is called)
>>>>   zrot=(zrot+10)%360
>>>>   xrot=(xrot+17)%180
>>>> -set view (50.+30.*sin(xrot/180.*pi)),60.+45.*sin(zrot/180.*pi)
>>>> +set view xrot,zrot
>>>>   replot
>>>> -iteration_count=iteration_count+1
>>>> -if ((!limit_iterations) || (iteration_count<=limit_iterations)) reread
>>>> +reread
>>>
>>> That file has only been touched twice, once in 1998 and once in 2006.
>>> The diff you list above was the 1998 change.
>>
>> Hm. That's not what I see.
>>
>> reposurgeon% [demo/gnuplot.rot] list
>>    1009 1998-04-15T19:16:47Z  :1008 *** empty log message ***
>>    1370 1998-04-22T13:40:59Z  :1369 Import of beta 344.
>>   18500 2005-01-07T23:21:02Z :18499 Revise gif animation code to comply with
>>
>> That first one looks like the initial import.  Two following changes, all
>> right, first in 1998, but the second early in 2005 rather than in 2006.
> 
> The incorrect date comes from a typo in the ChangeLog.
>    https://sourceforge.net/p/gnuplot/git-main/ci/50bc9c8abfd499a56717ccf324434bdc675e2bea/
> 
> Note, however, that typo is not present in the main branch copy of ChangeLog
> (actually ChangeLog.1) because it was later corrected.  That leads me to wonder
> which era of the ChangeLog text you guys are mining to assign dates during the
> git conversion.

We aren't using any changelog file.  What we are looking at is the 
*changes* to ChangeLog as they are associated with the changes in other 
files.  That is, every time something was checked into CVS there was 
always a small change to the ChangeLog file as well.  That trail 
contains the most information.  So, if there was a typo in the ChangeLog 
entry for a particular checkin, that mistaken date ends up in the git 
changeset.

It's not possible to look at a whole ChangeLog file and infer dates and 
times about myriad checkins because that ChangeLog was constructed in a 
piecemeal fashion, placing an item under some entry days prior, editing 
some past entry, placing a new entry before other entries rather than 
the top of the file, etc.

The typo explains the date discrepancy (thanks).  There's going to be a 
few of those.  After the fact we can attempt a simple rebase/correct and 
if it works, fine, if not just live with those sorts of issues.  That's 
the minor concern aside from getting the graft points correct.

Dan