[packagekit] yum: detecting file conflicts and using a custom error

[Tim Lauridsen]

Richard Hughes wrote:
> On Mon, 2008-04-14 at 15:48 +0200, Tim Lauridsen wrote:
>> Not in this case, yum call rpm to test a transaction and rpm returns a 
>> return code and a list of errors, if there is an error then yum raises a 
>> exception with the list of errors generated by rpm. It didn't knows what 
>> kind of errors it is.
> 
> Well, we need to parse the proper error types in a fine grained way, see
> below.
> 
>> I don't know all the errors rpm can return in this case, starting to 
>> parse the string, really sucks big time and i don't see the benefit of 
>> doing it, we have an error we can't solve, we cant do any thing else 
>> than abort the task.
> 
> Well, instead of presenting "unknown error" we can present "There were
> file conflicts". Now, you might think that's a waste of time, seeing as
> you can see that in the error details, but if you localise the UI to
> German, the description becomes some foreign gibberish.

We can make a speciel error code for error in test transaction. so we 
can give a sane messages in the UI,  but trying to parse the messages 
from rpm is doom, it is just like doing screenscraping.
Test Transaction errors is rare, so it is not worth the effort, you have 
to track down all cases of error that can occur in a rpm transaction, by 
digging into the rpm source code (DOOM) and you have to track message 
changes in the rpm error (DOOM) and if rpm start to use localized errors 
, like we have introduced in yum, then we are doomed again.

We can do something like
error(ERROR_TRANSACTION_ERROOR,msgs)

And present it as

:----------------[ERROR]------------------------:
: There is error in the transaction ..........  :
:                                               :
: Details:                                      :
:                                               :
: <rpm error messages>                          :
:                                               :
:-----------------------------------------------:

We can translate the first text but leave the details
i the original. Like we don't try to translate Tracebacks

The idea about cut some errors out is very bad idea, rpm transaction 
error are cause be some packaging errors in the repos, and it make it 
hard to find the errors and report it, if we not get all the error 
messages, and it will also be hard for the developers/packagers to see 
what is wrong if the error messages is translated to Japanese.

Tim