> In the first case we could easily mitigate the risk by testing and be fairly 
> confident, in the second case the tests are too complex to achieve the same 
> confidence and we should take this kind of risk only if there were a serious 
> benefit to balance it, but in this case, there are other solutions with less 
> risks.

Actually, I think testing the lib389 tooling would be even harder. You would 
need to recreate the logic of the mapping tree and sorting in python, which may 
have subtle differences compared to the C version. So it would be harder to 
test and gain confidence in. It also doesn't solve the issue that may come 
about from manual misconfiguration.

> I can understand it could seem too conservervative and frustrating but that 
> is the price when working on mature projects. If you do not do that, the 
> product becomes unstable, and users quickly abandon it.

I have worked on this project for a number of years, so I'm well aware of the 
culture in the team. We are a team who values the highest quality of code, with 
customers who demand the very best. To satisfy this as engineers we need to be 
confident in what we do and the work we create. But every day we make changes 
that are bigger than this, or have "more unknowns" and more. It's out attitude 
as a team to quality, our attention to testing, and designs, that make us 
excellent at effectively making changes with confidence.

Because just as easily, when a product has subtle traps, unknown configuration 
bugs and lets people mishandle it, then they also abandon us. Our user 
experience is paramount, and part of that experience is not just stability, but 
reliability and correctness, that changes performed by administrators will work 
and not "silently fail". This bug is just as much a risk for people to abandon 
us because when the server allows misconfiguration to exist that is hard to 
isolate and understand that too can cause a negative user experience.

So here, I think we are going to have to "agree to disagree", but as Mark has 
stated - the fix is created, the PR is open. If you have more configuration 
cases to contribute to the test suite, that would benefit the project 
significantly to ensure the quality of the change, and the quality of the 
mapping tree in general. Our job is to qualify and create scenarios that were 
"unknown" and turn them to "knowns" so we can control changes and have 
confidence in our work.

> On 20 Oct 2020, at 06:10, Mark Reynolds <[email protected]> wrote:
> 
> Hi,
> 
> So some of the arguments here is that we are introducing risk for something 
> that is not really a big problem.  Or, simply not worth investing in. From a 
> Red Hat perspective "we" would never fix this, it's just not a problem that 
> comes up enough to justify the work and time.  But...  The initial work has 
> been done by the upstream community (William).

With a corporate interest too, we have a customer at SUSE who has hit this :).

>  So from a RH perspective we are getting this work for free.  Personally I 
> don't see this code change as "very" risky, but this is a very sensitive area 
> of the code.  That being said, I am not opposed to adding it, but...  I think 
> we need much more testing around it to build confidence in the patch.  I 
> would want tests that deal with suffixes of varying size, names, nested 
> levels/complexity:
> 
>     o=my_server.com
> 
>     dc=example,dc=com
> 
>     dc=abcdef,dc=abc  (same length as suffix above - since the patch uses 
> sizing as a way of sorting)
> 
>     dc=test,dc=this,dc=patch


Yep, these are some great test ideas. I can add these.

> 
> 
> 
> I want tests that are adding and removing subsuffixes, and sub-subsuffixes, 
> and making sure ldap ops work, and replication, etc.  I want tests that use 
> many different suffixes at the same time and many subsuffixes - some 
> customers have 50 subsuffixes.  Our current CI test suite does not have these 
> kinds of tests, and we need them.

I have already checked with replication suite too, and of course, with ASAN. I 
think that these also are good to have added in general, so I can expand the 
testing to include more suffixes too. 

Do you see 50 subsuffixes in a single level nesting or deeper? I can do some 
shallow nesting and deep nesting hierarchies with that kind of number if you 
want. I think an interesting test would also be to have 

ou=x,ou=y,dc=example,dc=com

dc=example,dc=com

and then add ou=y,dc=example,dc=com in between. Today I think the pre-patched 
MT code would actually not handle this either, but that's a pretty big edge 
case IMO. The real guarantee is that we do assemble the tree correctly.

We thankfully gain confidence already because the CN is already relied on for 
routing and query matching anyway, so we know these values *must* be correct, 
we just need to guarantee the sorting order and tree assembly.

Thanks for the ideas Mark :) 


> 
> As of today I'm not comfortable with the current CI tests to ack this patch, 
> but if we can ramp it up and cover more scenarios it would be a step in the 
> right direction.  This is all just my humble opinion, we are all still just 
> talking :-)
> 
> Mark
> 
> 
> 

—
Sincerely,

William Brown

Senior Software Engineer, 389 Directory Server
SUSE Labs, Australia
_______________________________________________
389-devel mailing list -- [email protected]
To unsubscribe send an email to [email protected]
Fedora Code of Conduct: 
https://docs.fedoraproject.org/en-US/project/code-of-conduct/
List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
List Archives: 
https://lists.fedoraproject.org/archives/list/[email protected]

Reply via email to