Experimental Physics and
Industrial Control System

Wang Xiaoqiang via Tech-talk <[email protected]> · Fri, 10 Jan 2020 09:37:58 +0100

Hi Andrew,

Here is a test run between 3.14.12.7 and 3.14.12.8, (compiled with HOST_OPT=NO).
  https://xiaoqiangwang.github.io/epics-base-api-checker

It does not show any ABI breaking. Or is there something it does not detect, as

Michael expects?

Best
Xiaoqiang

On 1/9/20 10:51 PM, Johnson, Andrew N. wrote:

Hi Xiaoqiang,

On 1/9/20 2:47 AM, Wang Xiaoqiang wrote:

It is understandable ABI/API compatibility has never been a concern of the

core developers and an extra burden with no immediate benefits. But this

becomes essential for sites (increasingly) using central deployment.

Please note, API (i.e. source-code) compatibility between releases has been a

major concern of core developers for many years, I already described how we

treat that in another email in this thread. Our position on ABI compatibility

though has been that we don't have enough developers to promise that, so users

should recompile from source whenever they upgrade Base. By concentrating on API

compatibility we can reduce the burden on users when they do upgrade despite our

only having a small group of core developers. If ABI compatibility were really

essential to a site they would be throwing effort or money at us to actually

implement it (nobody has yet).

I assume this ABI checking can be one additional step in the CI script, using

tools like abi-compliance-checker. It could then be used as a guideline in

development. e.g. attached is a generated report of pvAccess library between

7.0.2 and 7.0.3.

That output does look good, I'd love to see the tool being run automatically

against all our shared libraries whenever we commit changes to our Git repo's.

It would be interesting to see what results it gives for Michael's challenge.

- Andrew

--
Complexity comes for free, Simplicity you have to work for.