Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Mon, 5 Feb 2018 18:49:55 +0000

Hi Lewis,

> Or maybe Git submodules should be avoided.  It seems to me that there
> are a number of headaches related to the use of submodules in EPICS Base
> that come up from time to time; now it has come up in areaDetector, and
> I suspect the headaches will continue simply because submodules add
> complexity.  
> I think a Git repo containing all of EPICS Base and another
> one containing all of areaDetector would be much simpler to deal with.
> I'm not a fan of submodules in general.

I think you are mixing up 2 very separate issues:

1) Having multiple repositories for EPICS base or areaDetector
2) Using git submodules to link those repositories

In my opinion it would be a terrible idea to go back to having areaDetector be a single git repository, which is how it was before R2-0.  By having multiple repositories we can independently release the core code (ADCore), the supporting libraries (ADSupport), and each detector (ADPilatus, etc.).  This is essential to producing timely releases.

The use of git submodules in areaDetector is completely optional for the end-user.  They can simply checkout out each repository independently and manually arrange them in the following hierarchy

areaDetector
  ADCore
  ADSupport
  ADPilatus
  etc.

The use of "git clone --recursive" is not required.  It is just a convenience if people want to check out lots of modules at the same time. 

In areaDetector only areaDetector repository and the ADCore repository are released synchronously, i.e. they have the same tags.  All other modules are released independently and have different tags.  So it really does not make sense to check out R3-2 at the top-level and expect it to update the submodules to some specific release (except ADCore).

Mark

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf Of J. Lewis Muir
> Sent: Monday, February 05, 2018 12:23 PM
> To: Jörn Dreyer <[email protected]>
> Cc: [email protected]
> Subject: Re: AreaDetector repository inconsistent
> 
> On 02/05, Jörn Dreyer wrote:
> > if I remember correctly I have seen this problem sometime ago
> > already. Maybe someone should look into implementing a commit hook
> > that prevents such situations.
> 
> Or maybe Git submodules should be avoided.  It seems to me that there
> are a number of headaches related to the use of submodules in EPICS Base
> that come up from time to time; now it has come up in areaDetector, and
> I suspect the headaches will continue simply because submodules add
> complexity.  I think a Git repo containing all of EPICS Base and another
> one containing all of areaDetector would be much simpler to deal with.
> I'm not a fan of submodules in general.
> 
> Lewis

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System