IRC log of shapes on 2017-03-08

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13:00:09 [RRSAgent]
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logging to
13:00:11 [trackbot]
RRSAgent, make logs rdf-data-shapes
13:00:11 [Zakim]
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Zakim, this will be SHAPES
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ok, trackbot
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Meeting: RDF Data Shapes Working Group Teleconference
13:00:14 [trackbot]
Date: 08 March 2017
13:00:43 [hknublau]
13:00:52 [Dimitris]
13:01:25 [ipolikof]
13:01:32 [dallemang]
13:02:00 [pano]
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13:03:27 [ipolikof]
chair: ipolikof
13:04:13 [ipolikof]
scribenick: dallemang
13:04:35 [pano]
13:04:37 [TallTed]
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13:04:39 [sandro]
13:05:03 [dallemang]
ipolikof: Approve minutes
13:05:09 [ipolikof]
PROPOSED: Approve minutes of the 01 Mar 2017 Telecon:
13:05:26 [ipolikof]
13:06:05 [hknublau]
13:06:11 [dallemang]
dallemang: is it important to change minutes for dallemang being present
13:06:14 [pano]
13:06:22 [TallTed]
13:06:22 [dallemang]
sandro: not importat to change, since dallemang shows up in ballots
13:06:24 [ipolikof]
RESOLUTION: Approve minutes of the 01 Mar 2017 Telecon:
13:06:29 [dallemang]
13:06:48 [dallemang]
ipolikof: agenda: disposal of isssues. No open issues
13:07:00 [dallemang]
ipolikof: Introduces pfps as special guest
13:07:21 [dallemang]
ipolikof: pfps will explain his objections
13:07:48 [ipolikof]
13:07:55 [dallemang]
pfps: We can do this foromulaic, or to do something good. Which will we do?
13:08:10 [dallemang]
TallTed: We are all trying to achieve something successful, with best results
13:12:36 [dallemang]
pfps: he can discuss the three formal objections, vs. general problems he sees with working group operation. pfps thinks that the latter is more productive
13:13:18 [dallemang]
ipolikof: wants to go through the objections to understand them.
13:14:38 [Nicky]
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13:17:35 [dallemang]
ipolikof: and pfps objections were described on a tight deadline
13:18:24 [dallemang]
pfps: starting with
13:19:20 [simonstey]
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13:19:50 [dallemang]
pfps: removal removes expressive power, further complicates language,
13:20:43 [dallemang]
pfps: lost expressive power threatens future-proofing
13:22:16 [dallemang]
ipolikof: to clarify: Loss of expressive power has to do with future possibliity of subject becoming literals?
13:22:26 [dallemang]
pfps: Not sure that this is true
13:23:08 [dallemang]
ipolikof: was pfps member of that rdf working group? yes, he was. Did he raise objection to that? No, that group was chartered for minor changes.
13:23:21 [dallemang]
ipolikof: can you talk about machine generated shapes?
13:24:30 [dallemang]
pfps: eg., transform DL into shapes. There is already a commercial system that does something like this. This could use a SHACL engine to run this.
13:25:01 [sandro]
(stardog icv)
13:25:06 [dallemang]
pfps: Stardog is the commercial system
13:26:07 [dallemang]
pfps: some DLs allow a /self/ role (Stardog doesn't), so /self/ role restrictions turn into node shapes.
13:26:22 [dallemang]
ipolikof: can you send us some OWL constructs that cause this issue?
13:27:39 [dallemang]
pfps: "at least 2 self Person"
13:28:16 [dallemang]
ipolikof: Have you seen this in practice? (asking about pfps
13:28:30 [dallemang]
ipolikof: have you seen this in practice?
13:28:50 [dallemang]
pfps: Yes, at least one widely, OpenCyc in OWL that uses necessarily empty concepts as part of OWL trnaslation
13:29:52 [dallemang]
sandro: unconfirmed suspicion is that the loss of power has to do with use of generalized RDF. pfps confirms that he believes this to be the case
13:30:24 [ipolikof]
13:30:29 [dallemang]
ipolikof: Next one
13:31:18 [dallemang]
pfps: hasn't had enogh time to look at latest edit
13:31:53 [dallemang]
pfps: earliest time to look at it is March 20
13:32:12 [ipolikof]
13:32:15 [sandro]
(week of March 20)
13:32:19 [dallemang]
move on to
13:32:36 [dallemang]
pfps: this page misses the major point
13:33:19 [dallemang]
pfps: The issues is that it is possibe to build a SHACL graph in such a way that users don't know how they interact with others. There is no way to know if your grpah is valid or not.
13:33:41 [dallemang]
pfps: Rules for validity are difficult - so it is difficult to know if the graph is valid
13:34:22 [dallemang]
pfps: implementations are free to do as they please with invalid graphs. With no indication back to the user.
13:34:35 [Nicky]
13:34:47 [dallemang]
pfps: this is fatal to interoperability
13:34:52 [dallemang]
13:36:05 [dallemang]
pfps: "Usrs of conforming SHACL implementations will have no way to know if their graphs will be processed the same way in other implementations"
13:36:21 [dallemang]
pfps: this is because even for valid grpahs, they don't know if they are valid
13:36:29 [sandro]
13:38:29 [sandro]
dalleman: This issue sounds clear and valid, but I thought we dealt with this 2-3 weeks ago. Did that get reflected in draft?
13:38:30 [dallemang]
dallemang: Didn't we talk about this two or three weeks ago?
13:39:18 [dallemang]
pfps: the change was to allow implemetnations to signal whether it is valid?
13:39:26 [dallemang]
pfps: key problem is "allow" - so it might now
13:40:25 [dallemang]
sandro: finds this compelling, and of course, we'll stick to valid graphs, but for users, there will be mistakes
13:40:28 [TallTed]
13:40:34 [sandro]
ack sandro
13:40:36 [dallemang]
pfps: even with expert users we'll have these mistakes
13:41:14 [dallemang]
ipolikof: what is the amount of work we'll need to make it happen?
13:41:31 [dallemang]
pfps: a one-word change will be sufficient, i.e., allow -> require
13:41:52 [dallemang]
pfps: WG has to write tests so that the implementation can do this
13:42:11 [hknublau]
ack dallemang
13:42:12 [dallemang]
sandro: invalid shapes definition and tests will be needed
13:42:17 [hknublau]
ack sandro
13:43:08 [hknublau]
ack TallTed
13:43:14 [dallemang]
TallTed: Recalls this as a requirement for a linter, akin to the ones we see for RDF and OWL, none of which are required by a SPARQL engine. But Validator is there (instead of the engine)
13:43:36 [dallemang]
sandro: HTML5 fixed this by defining repair behaviors (HTML5 had a problem like this)
13:44:02 [dallemang]
TallTed: Does this really work on all HTML5 failure mode?
13:44:18 [dallemang]
sandro: No, just that this is viewed as an error, and was addressed this way
13:44:33 [dallemang]
13:45:05 [hknublau]
ack dallemang
13:46:04 [dallemang]
ipolikof: we have worried that this raises the bar for implementation. Is that unreasonably high?
13:46:58 [dallemang]
sandro: maybe a middle ground? The implemetnation is only required to reject the errors that SHACL itself can check (e.g., a shape for SHACL)?
13:47:14 [dallemang]
ipolikof: for Core, many things could be checked by SHACL itself (with a SHACL Shape for SHACL)
13:47:24 [dallemang]
sandro: presumably this bar is pretty low
13:47:40 [dallemang]
pfps: the code to do the check isn't much, he's done it, two pages of code
13:48:48 [dallemang]
pfps: also, it is possilbe to check all of CORE easily, except sh:pattern be legal SPARQL , and recursive for paths and shapes, but can be checked with an extension to core that only takes a small implementation change.
13:48:56 [dallemang]
pfps: that is, bar is low
13:49:17 [dallemang]
pfps: has sent comments to this effect to the group (can we find these in our archives?)
13:50:18 [dallemang]
dallemang: I think there might be a proposal we could do from this to resolve it.
13:50:27 [dallemang]
ipolikof: this is an info gathering call
13:50:50 [sandro]
13:52:14 [dallemang]
sandro: There is more going on here than just allow -> require. There will have to be some sort of mode, etc.
13:52:34 [dallemang]
sandro: strict vs loose for instance
13:52:54 [dallemang]
pfps: that was pfps' proposal
13:53:13 [dallemang]
pfps: strict checking is cheap, do ti all the time, but a loose mode is permissible.
13:53:27 [sandro]
ack sandro
13:53:43 [dallemang]
ipolikof: move on to other topics from pfps
13:54:01 [dallemang]
pfps: structurat topics. He has sent into to group that hasn't received responses
13:54:24 [dallemang]
pfps: many comments have only received non-technical responses
13:54:44 [dallemang]
pfps: it is the WG's job to respond to comments.
13:55:04 [dallemang]
TallTed: WG's job is to wokr, there are lots of kinds of work
13:55:46 [dallemang]
ipolikof: regarding pfps' email about implemnting syntax check
13:56:21 [dallemang]
ipolikof: isn't "thank you for the info" appropriat?
13:56:25 [dallemang]
pfps: for this, yes
14:00:48 [dallemang]
TallTed: WG is doing its best to keep up with comments, If we aren't keeping up, we need to go to W3C mgmt, who has asked for issues to be triaged
14:02:33 [dallemang]
pfps: this is a lot of work for pfps to figure out whether changes to the doc have really addressed a comment.
14:05:19 [dallemang]
sandro: can github help us manage this?
14:05:23 [dallemang]
pfps: Probably not
14:05:35 [dallemang]
pfps: this seems like more burden on the commenter
14:06:55 [dallemang]
pfps: sometimes a comments become an issue, and the issue is closed, but he doesn't necessarilly know how it was closed so that he can evaluate if it was responsive
14:07:15 [dallemang]
sandro: github model keeps a trail for this
14:08:15 [dallemang]
ipolikof: this isn't about checking the WG process, but really about the issues and comments on SHACL spec as it is now.
14:09:20 [sandro]
14:09:24 [dallemang]
ipolikof: do we need to track all the back issues, or review the spec as it stands today?
14:10:38 [dallemang]
sandro: process from other groups - if an issue was closed, we only raise it again if there is something new
14:13:43 [sandro]
PROPOSED: In the transition request, we'll be clear that the door is open during CR for any issues that were previously reported and handled in a way which was not fully reported back to the commenter
14:14:53 [dallemang]
pfps: treating the doc as new and looking for issues again is difficult for reviewers, and risks dropping issues through the cracks
14:17:29 [TallTed]
14:17:36 [sandro]
14:17:46 [ipolikof]
RESOLUTION: In the transition request, we'll be clear that the door is open during CR for any issues that were previously reported and handled in a way which was not fully reported back to the commenter
14:17:48 [sandro]
pfps: Or in status of document
14:19:10 [dallemang]
14:19:20 [pano]
14:21:18 [dallemang]
pfps: pre-binding has been and continues to be a problem, is it well-behaved?
14:21:55 [dallemang]
pfps: it isn't his job to convince anyone that it works, since pfps isn't a pre-binding advocate.
14:23:23 [dallemang]
ipolikof: Andy Seaborne is not on the call today, who could respond to this.
14:24:09 [sandro]
14:26:20 [dallemang]
TallTed: This is an early release, and the process is iterative
14:31:46 [dallemang]
ipolikof: Andy is a recognized expert in SPARQL
14:31:56 [dallemang]
pfps: reluctantly agrees
14:32:04 [sandro]
14:32:10 [dallemang]
pfps: we need someone who can review Andy's work
14:34:52 [dallemang]
sandro: there's an academic idea of "peer review" - e.g.,, three reviewers for any item.
14:35:40 [dallemang]
sandro: this process is less than that.
14:36:00 [dallemang]
pfps: pre-binding has had many iterations, and required shouting from pfps to get any attention at all.
14:37:18 [dallemang]
pfps: pre-binding history: SHACL wanted pre-binding, and said "use SPARQL", but the SPARQL spec didn't have details of the meaning, so we couldn't find out what it means.
14:38:06 [dallemang]
ipolikof: if this objection were raised for SPARQL, would it have made it to CR?
14:38:46 [dallemang]
pfps: there is no implementation of SPARQL
14:39:04 [dallemang]
ipolikof: but it is successful and there are many implementations
14:40:01 [dallemang]
pfps: here are probably ways to fix it up, and Andy could do that.
14:40:19 [dallemang]
pfps: what will we do if a problem is found?
14:40:54 [sandro]
Zakim, who is here?
14:40:54 [Zakim]
Present: hknublau, Dimitris, ipolikof, dallemang, pano, sandro, TallTed, Nicky
14:40:56 [Zakim]
On IRC I see TallTed, pano, Zakim, RRSAgent, ipolikof, hknublau, Dimitris, dallemang, pfps, sandro, rhiaro, trackbot
14:41:08 [dallemang]
ipolikof: personal opinion, if SHACL reaches the success level of SPARQL, she's happy, hope for even more success
14:41:25 [dallemang]
ipolikof: that would address industry needs. Maybe not perfect.
14:42:04 [dallemang]
pfps: WG can move ahead with this unknown
14:42:15 [dallemang]
pfps: Another topic. Validation Reports
14:43:12 [dallemang]
pfps: made an earlier objection, and sees that the pendulum has swung the other way
14:43:46 [dallemang]
pfps: it will be possible to produce validation reports that vary from the expectation.
14:45:04 [dallemang]
pfps: suspects that there are issues, but he hasn't had time to find it.
14:45:17 [dallemang]
pfps: WG could deicde to wait for pfps , which won't be for a few weeks
14:46:23 [dallemang]
sandro: checking against the test suite will reveal problems
14:46:32 [dallemang]
pfps: assuming that test suite can check it, which is hard
14:46:46 [dallemang]
ipolikof: test suite will include validation report
14:46:53 [sandro]
If the test suite compares validation reports, this problem should be addressed
14:48:13 [dallemang]
pfps: if writing the tests reveals the issue, then we make a new CR at that level
14:49:14 [dallemang]
sandro: has the WG resolved that the test suite should include validation reports ?
14:49:31 [dallemang]
ipolikof: No formal resolution. OPTIONAL things might not be in
14:50:11 [dallemang]
hknublau: test harness checks output graph isomorphism between output and expectation
14:50:26 [dallemang]
pfps: not sure that graph isomorphis is correct test
14:51:36 [dallemang]
pfps: we have to include "we will check validation reports as part of the test"
14:54:28 [dallemang]
sandro: are you asking for something beyond standard requirement, that if two people implement to the spec, then they can interoperate?
14:54:53 [dallemang]
ipolikof: W3C director has a lower bar - need a test suite, needs to be reasonable, might not be comprehensive
14:55:23 [sandro]
sandro: Every normative statement in the spec should result in 1+ tests
14:55:26 [dallemang]
pfps: every normative statement should have something backing it up
14:55:51 [dallemang]
pfps: end of major things, he's concerned with syntax
14:56:16 [dallemang]
pfps: current syntax is mystifying
14:56:35 [dallemang]
pfps: disjoint shapes is worrisome
14:56:53 [dallemang]
pfps: theres still a lot of work to be done, and this is nobody's day job.
14:57:41 [dallemang]
ipolikof: misalignment between pfps' expectation and WG process, and even W3C process
14:58:50 [dallemang]
ipolikof: time is up. to sandro is there any urgent process issue/
14:59:46 [dallemang]
sandro: internationalization email
14:59:51 [dallemang]
ipolikof: i think that was good
15:00:56 [TallTed]
RRSAgent, draft minutes
15:00:56 [RRSAgent]
I have made the request to generate TallTed
15:01:00 [TallTed]
RRSAgent, make logs public
15:01:11 [TallTed]
trackbot, end meeting
15:01:11 [trackbot]
Zakim, list attendees
15:01:11 [Zakim]
As of this point the attendees have been hknublau, Dimitris, ipolikof, dallemang, pano, sandro, TallTed, Nicky
15:01:19 [trackbot]
RRSAgent, please draft minutes
15:01:19 [RRSAgent]
I have made the request to generate trackbot
15:01:20 [trackbot]
RRSAgent, bye
15:01:20 [RRSAgent]
I see no action items