Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Fri, 26 Jan 2007 23:46:07 +0100

On Friday 26 January 2007 22:12, Andrew Johnson wrote:
> The first Release Candidate of EPICS Base version 3.14.9 is now
> available for download from the website.
> 	http://www.aps.anl.gov/epics/base/R3-14/9.php
>
> This code has gone through testing by the EPICS core developers at a
> number of sites on various different architectures without showing any
> significant bugs, and at this point we would like to ask others in the
> community to try it out and report any problems that you find with it.
>
> There are a couple of known problems which we are not currently
> intending to fix - see the KnownProblems documentation for details.
>
> If there are no reports of any significant bugs in the next week
> (actually I'll make that Monday 5th of February) then I will re-release
> this code as the official R3.14.9 release.

>From the release notes:

---------------------------------------------
dbLoadTemplate

The parser for the substitutions file accepted by dbLoadTemplate() has been 
revised, and is now stricter than it used to be â unmatched characters that 
were accepted and discarded without warning before will now generate 
errors. The quote characters at the two ends of a quoted string value must 
now match, although either single or double quotes can be used. Escaped 
characters inside a quoted string should pass safely through to the 
underlying dbLoadRecord() command. The characters permitted in a bareword 
parameter (i.e. a filename or value that is not inside quotes) have been 
reduced from the overly wide set allowed before; the permitted characters 
now comprise: a-z A-Z 0-9 _ - + : . / \ [ ] < > ;
---------------------------------------------

I am a bit astonished about this. This whole change, but especially the last 
one, introduces a major incompatibility. I would have expected at least a 
note to tech-talk beforehand, inviting requests for comments from concerned 
parties. I am astonished about this because in many other respects 
compatibility on the database level has been a top-priority for EPICS 
(sometimes pursued almost to the point of stiffling progress).

I would be interested to hear of the rationale i.e. what is the great 
improvement, considering the possible disruption such an incompatible 
change may cause, and also considering that 3.14.9 has been advertised as 
a 'mostly bug-fix' release?

One further issue that I would be interested in is: will the corresponding 
tool on the host side (MSI) be adapted according to the new rules, so that 
inflating substitutions on host and target side will remain equivalent? (Or 
have they ever been after dbLoadTemplate was no longer available on the 
host side?)

Ben
-- 
"Prevention is better than cure, in particular if the illness is unmastered
complexity, for which no cure exists." [E.W.Dijkstra]

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System