Issue 3219: attributes and system exceptions (orb_revision) Source: Triodia Technologies Pty Ltd (Mr. Michi Henning, michi(at)triodia.com) Nature: Uncategorized Issue Severity: Summary: The components spec permits attributes to raise user exceptions, to bring them in line with operations. That's a really nice idea, but raises yet another versioning problem. In particular, no new IDL that uses an attribute with a raises clause can be compiled by an older IDL compiler. (Simply deleting the raises clause and then compiling with an older compiler is risky at best -- marshaling code won't in general expect to get a user exception in reply to accessing an attribute...) Resolution: withdrawn by submitter Revised Text: Actions taken: January 18, 2000: received issue February 3, 2000: closed issue Discussion: End of Annotations:===== Date: Tue, 18 Jan 2000 15:30:28 +1000 (EST) From: Michi Henning Reply-To: Core Revision Task Force , components-ftf@omg.org To: Core Revision Task Force , components-ftf@omg.org cc: issues@omg.org Subject: attributes and system exceptions Message-ID: Organization: Object Oriented Concepts MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-UIDL: S0?!!6,c!!Ll!"!n2W!! The components spec permits attributes to raise user exceptions, to bring them in line with operations. That's a really nice idea, but raises yet another versioning problem. In particular, no new IDL that uses an attribute with a raises clause can be compiled by an older IDL compiler. (Simply deleting the raises clause and then compiling with an older compiler is risky at best -- marshaling code won't in general expect to get a user exception in reply to accessing an attribute...) How do we address this? Cheers, Michi. -- Michi Henning +61 7 3891 5744 Object Oriented Concepts +61 4 1118 2700 (mobile) Suite 4, 904 Stanley St +61 7 3891 5009 (fax) East Brisbane 4169 michi@ooc.com.au AUSTRALIA http://www.ooc.com.au/staff/michi-henning.html From: Jeffrey Mischkinsky Message-Id: <200001180704.XAA18268@wheel.dcn.davis.ca.us> Subject: Re: attributes and system exceptions To: orb_revision@omg.org Date: Mon, 17 Jan 2000 23:04:52 -0800 (PST) Cc: components-ftf@omg.org In-Reply-To: from "Michi Henning" at Jan 18, 2000 03:30:28 PM X-Mailer: ELM [version 2.5 PL2] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii X-UIDL: e]Je9d > > The components spec permits attributes to raise user exceptions, to > bring them in line with operations. That's a really nice idea, but > raises yet another versioning problem. In particular, no new IDL > that > uses an attribute with a raises clause can be compiled by an older > IDL > compiler. (Simply deleting the raises clause and then compiling with > an older compiler is risky at best -- marshaling code won't in > general > expect to get a user exception in reply to accessing an > attribute...) > > How do we address this? Michi, I'm not seeing the problem, at least from the way i understand the description. No (new) IDL that uses any new syntax can be compiled with an older compiler. I don't think that, in itself, is a problem. It's a new feature, so existing compilers won't understand it. But that's just a consequence of adding a new feature. Are you thinking that there might be a backward compatility problem if you invoke a getter/setter w/ exceptions from "old" code? I'm not sure that can happen since if you were to "add" to the IDL, it wouldn't compile and it's repid should change so there woudl be a type mismatch. Do you have some other problem in mind? jeff -- Jeff Mischkinsky jmischki@dcn.davis.ca.us +1 530-758-9850 jeff@persistence.com +1 650-372-3604 From: butek@us.ibm.com X-Lotus-FromDomain: IBMUS To: orb_revision@omg.org, components-ftf@omg.org Message-ID: <8525686A.004A0C6E.00@d54mta08.raleigh.ibm.com> Date: Tue, 18 Jan 2000 07:23:09 -0600 Subject: Re: attributes and system exceptions Mime-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset=us-ascii X-UIDL: (>"e9&3jd9Qb3e9LET!! I agree with Jeff. We should be concerned about backward compatibility, which isn't broken here since new compilers will still compile 'old' code. It's unusual to be concerned about forward compatibility. Or did I just misunderstand your question? Russell Butek butek@us.ibm.com Jeffrey Mischkinsky on 01/18/2000 01:04:52 AM To: orb_revision@omg.org cc: components-ftf@omg.org Subject: Re: attributes and system exceptions 'Michi Henning' writes: > > > The components spec permits attributes to raise user exceptions, to > bring them in line with operations. That's a really nice idea, but > raises yet another versioning problem. In particular, no new IDL that > uses an attribute with a raises clause can be compiled by an older IDL > compiler. (Simply deleting the raises clause and then compiling with > an older compiler is risky at best -- marshaling code won't in general > expect to get a user exception in reply to accessing an attribute...) > > How do we address this? Michi, I'm not seeing the problem, at least from the way i understand the description. No (new) IDL that uses any new syntax can be compiled with an older compiler. I don't think that, in itself, is a problem. It's a new feature, so existing compilers won't understand it. But that's just a consequence of adding a new feature. Are you thinking that there might be a backward compatility problem if you invoke a getter/setter w/ exceptions from "old" code? I'm not sure that can happen since if you were to "add" to the IDL, it wouldn't compile and it's repid should change so there woudl be a type mismatch. Do you have some other problem in mind? jeff -- Jeff Mischkinsky jmischki@dcn.davis.ca.us +1 530-758-9850 jeff@persistence.com +1 650-372-3604 Sender: jbiggar@corvette.floorboard.com Message-ID: <3884CEF9.EFF11490@floorboard.com> Date: Tue, 18 Jan 2000 12:37:13 -0800 From: Jonathan Biggar X-Mailer: Mozilla 4.7 [en] (X11; U; SunOS 5.6 sun4u) X-Accept-Language: en MIME-Version: 1.0 To: Core Revision Task Force , components-ftf@omg.org CC: issues@omg.org Subject: Re: attributes and system exceptions References: Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii X-UIDL: 4b2!!15T!!o:l!!CnY!! Michi Henning wrote: > > The components spec permits attributes to raise user exceptions, to > bring them in line with operations. That's a really nice idea, but > raises yet another versioning problem. In particular, no new IDL > that > uses an attribute with a raises clause can be compiled by an older > IDL > compiler. (Simply deleting the raises clause and then compiling with > an older compiler is risky at best -- marshaling code won't in > general > expect to get a user exception in reply to accessing an > attribute...) I agree with the other comments that there is no issue here. If someone upgrades their IDL and adds user exceptions to attribute definitions, then he has the same problems with interoperability as any other change in IDL. Otherwise, if this is new IDL, then he has to get a newer ORB that supports the feature. -- Jon Biggar Floorboard Software jon@floorboard.com jon@biggar.org Date: Wed, 19 Jan 2000 06:43:43 +1000 (EST) From: Michi Henning To: Jeffrey Mischkinsky cc: orb_revision@omg.org, components-ftf@omg.org Subject: Re: attributes and system exceptions In-Reply-To: <200001180704.XAA18268@wheel.dcn.davis.ca.us> Message-ID: Organization: Object Oriented Concepts MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-UIDL: ZEjd9~$Ke9_`S!!1eXd9 On Mon, 17 Jan 2000, Jeffrey Mischkinsky wrote: > Michi, > I'm not seeing the problem, at least from the way i understand the > description. No, having listened to you and Russell and Jishnu, I can't see the problem either :-) Sorry, brain-lock on my part. I got distracted by the wrong mental picture -- I was in the mindset of thinking of this as a modification to an existing feature rather than a new feature. Of course, because the raises clause is optional, there is no problem. (And no, I wasn't trying to enforce forward compatibility ;-) Sorry for the noise... Cheers, Michi. -- Michi Henning +61 7 3891 5744 Object Oriented Concepts +61 4 1118 2700 (mobile) Suite 4, 904 Stanley St +61 7 3891 5009 (fax) East Brisbane 4169 michi@ooc.com.au AUSTRALIA http://www.ooc.com.au/staff/michi-henning.html