Re: apkg -u, the deception?

Hi Erich;

Am Donnerstag, 15. Oktober 2015, 08:27:56 schrieb Erich Titl:
> Hi KP
> 
> > I also _believe_ , that integration of apkg -u into the upgrade script
> > will be easier to accomplish the then smaller changes and more helpful,
> > than reinvent apkg and configdb.
> 
> I have been thinking hard about this and I believe you are wrong in this
> aspect.
> Let me state why I think this is so
> 
> - we have a package A of version 1.0 which we just call A
> - we have a config file AC belonging to package A , call this AC
> - we have an installed package A with a modified config file AC, call
> this AC'
> - we can detect the difference between AC and AC', lets call this D
> - we have a package A of version 1.1, lets call this A1
> - we have a config file AC belonging to package A1, lets call this AC1
> - let us assume that AC <> AC1
> - we want an installed package A1 with the adjusted config file AC1'
> 
> therefore we need a transformation from AC' to AC1'
> 
> - there is no direct transformation from AC' to AC1'
> - we can build AC1' by applying D to AC1
> 
> Right now we do not save D, but we save AC'
> 
> If we replace AC by AC1 (by replacing the corresponding package A by A1)
> then we lose the capability to generate the difference D and as a
> consequence we loose the transformation from AC1 to AC1'
> 
> This leads me to the conclussion that the transformation of AC' to AC1'
> cannot only work if either
> 
> - D is saved, because then we can apply D to AC1
> - AC, AC1 and AC1' are available, because then we can calculate D
> 
> So a tool like apkg -u cannot work unless it is applied from a location
> different from the original boot location, because once the package A
> has been overwritten by A1 the reference to AC is lost.

No; we only need the new package with the AC1 and the AC', which is in 
configdb.lrp.
If you call apkg -u it will detect the changed file and it will offer you to 
either Keep your version, Show differences, Edit a merge file or to go with the 
new version.
I've checked that it even works, if you replace the original package with the 
new version on /mnt.

Pls test.

So what upgrade can do is to copy the package to /mnt and run apkg -u 
afterwards from /mnt. If there are changes, the user can decide how to 
proceed.

There has been introduced a safety feature, that every upgrade needs a 
response (y/n) , even it doesn't touch any config etc..., but if changes in the 
config are detected, you'll be  offered with the menu to deal with the changes.  


> Is there a description how apkg -u is to be used?

Only the source code...

kp

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