Experimental Physics and
Industrial Control System

Niko Kivel via Core-talk <core-talk at aps.anl.gov> · Thu, 26 Aug 2021 17:50:02 -0000

If this limitation stays like that, it's a complete show-stopper for me.
I'd like to create structures for EtherCAT terminal/slave data. There are
potentially hundreds of PVs to add to pva-groups. All based on their PV
names. Since the PV names have to adhere to the naming convention, they
have '-' between entity name and suffix, i.e. BI02-TimeRise,
master7-Online, BO03-Array, ...
Proposal:
I'd be perfectly happy with a replacement mechanism. I.e. upon adding a PV
to the group, replace non-supported characters with '_'.
Maybe with a flag to prevent automatic conversion? And cause the Error to
be thrown?

On Thu, Aug 26, 2021 at 6:25 PM mdavidsaver <1935037 at bugs.launchpad.net>
wrote:

> The character set restriction of PVD fields (in groups or otherwise) is
> meant to mirror that of C89 keywords.
>
> > int abc;
>
> ... is valid
>
> > int a-bc;
>
> ... is not
>
> This was a somewhat arbitrary decision made many years ago.  imo.
> changing it is primarily a question of backwards compatibility.
> Anything rejected by (or crashing) existing/older clients is a non-
> starter.
>
> Be aware that there is no separate versioning for the PVD encoding.
> imo. an oversight in the design.  The negotiated PVA protocol version is
> the only way to communicate handle changes.  You should also be aware
> that the existing pvData (de)serialization APIs don't expose the
> negotiated protocol version.  So making even seemingly small changes to
> the PVD encoding format would be complicated.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1935037
>
> Title:
>   Invalid charactor in field name
>
> Status in EPICS Base:
>   New
>
> Bug description:
>   When creating a group in QSRV, the allowed characters are too
>   restrictive
>
>   error:
>   Error Group not created: Invalid charactor '-' (45) in field name
> "BI02-TimeRise" must be A-Z, a-z, 0-9, or '_'
>
>   expected behaviour:
>   pva structures should allow for a more liberal set of characters that
> just what is covered by \w regex metacharacter.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/epics-base/+bug/1935037/+subscriptions
>
>

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https://bugs.launchpad.net/bugs/1935037

Title:
  Invalid charactor in field name

Status in EPICS Base:
  New

Bug description:
  When creating a group in QSRV, the allowed characters are too
  restrictive

  error:
  Error Group not created: Invalid charactor '-' (45) in field name "BI02-TimeRise" must be A-Z, a-z, 0-9, or '_'

  expected behaviour:
  pva structures should allow for a more liberal set of characters that just what is covered by \w regex metacharacter.

To manage notifications about this bug go to:
https://bugs.launchpad.net/epics-base/+bug/1935037/+subscriptions

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System