Graceful handling of partial SKOS XL data for concept labels

[osma]

Reasons for creating this PR

This PR changes the way SKOS XL data for labels is handled. The old code expected that if a concept has some SKOS XL labels, it will have SKOS XL data for all labels. This isn't the case in current YSO where SKOS XL information is added only for a small number of labels. This PR makes the checks for SKOS XL data more careful. Result now looks like this (compare with issue #1346):

Link to relevant issue(s), if any

• Closes Partial SKOS XL label data breaks headline on concept page #1346

Description of the changes in this PR

• Concept.hasXlLabel() and ConceptPropertyValueLiteral.hasXlLabel() methods changed to be more specific so that they only return true when there is non-trivial SKOS XL data available specifically for that concept (prefLabel) / literal value
• some logic (filtering of trivial properties rdf:type and skosxl:literalForm) moved from Twig templates to PHP code
• use dc: namespace for gettext lookups for properties in the dc11: namespace also for properties of SKOS XL Labels (this is already done for e.g. regular properties on concepts and it fixes issues displaying the correct labels for Dublin Core metadata)

Known problems or uncertainties in this PR

• when displaying properties of SKOS XL labels with literal values (e.g. dc:source "Kansalliskirjasto"@fi in above screenshot), there is no mechanism for trying to find and select the value with the correct language tag; so if there were many similar values in different languages, only one of them would be shown
• I noticed that if I hover over the "info" symbol many times, eventually the tooltip will become empty; this could be a bug in qtip2 but it should go a way if/when we replace it with CSS (see PR Replace qtip JS library by a pure CSS tooltip #1324)

Checklist

• phpUnit tests pass locally with my changes
• I have added tests that show that the new code works, or tests are not relevant for this PR (e.g. only HTML/CSS changes)
• The PR doesn't reduce accessibility of the front-end code (e.g. tab focus, scaling to different resolutions, use of .sr-only class, color contrast)
• The PR doesn't introduce unintended code changes (e.g. empty lines or useless reindentation)

[codecov]

Codecov Report

Merging #1356 (a1b6e2c) into master (5e6da4b) will increase coverage by 0.47%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #1356      +/-   ##
============================================
+ Coverage     70.68%   71.15%   +0.47%     
- Complexity     1646     1649       +3     
============================================
  Files            32       32              
  Lines          3786     3786              
============================================
+ Hits           2676     2694      +18     
+ Misses         1110     1092      -18     

Impacted Files	Coverage Δ
model/Concept.php	86.41% <100.00%> (+2.77%)	⬆️
model/ConceptPropertyValueLiteral.php	95.55% <100.00%> (-0.10%)	⬇️
model/LabelSkosXL.php	39.13% <100.00%> (+39.13%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[joelit]

The handling of concept.xlLabel.properties tooltip for the title row seems to be broken. Examples in the comments. OTOH, this could be merged as a fix to the original bug of concept preflabels not being shown at all.

[joelit]

I tested his with SKOS-XL data and it is indeed an improvement - the labels work now but the tooltips don't.

With concept data looking like this:

yso:p6095 a skos:Concept,
        yso-meta:Concept ;
    dct:created "1985-01-01"^^xsd:date ;
    skos:altLabel "Betula"@en,
        "birch"@en,
        "koivu"@fi,
        "björk"@sv ;
    skos:broader yso:p14339,
        yso:p3425 ;
    skos:closeMatch <http://id.loc.gov/authorities/subjects/sh85014281>,
        allars:Y16158,
        ysa:Y96273 ;
    skos:inScheme yso: ;
    skos:narrower yso:p16291,
        yso:p26048,
        yso:p6094 ;
    skos:prefLabel "birches"@en,
        "koivut"@fi,
        "soahki"@se,
        "björkar"@sv ;
    skos:related yso:p21624 ;
    skosxl:prefLabel <http://www.yso.fi/onto/yso-meta/p6095#se_1> .

<http://www.yso.fi/onto/yso-meta/p6095#se_1> a skosxl:Label ;
    dc:source "Lähde Giellagáldu"@fi,
        "Gáldu Giellagáldu"@se ;
    skos:inScheme yso: ;
    skosxl:literalForm "soahki"@se .

The result in Skosmos UI looks like this. The labels work and Skosmos picks the right source information from the skosxl:Label object. The tooltips work when they are displayed in the concept information (foreign label info in this case), but the tooltips won't work as part of the title information.

Seems to work fine here!

Oddly, not working here!

[osma]

Thanks for the review and testing @joelit !

I think what you are seeing is a different bug, probably having more to do with qtip2 than the changes in this PR. I hope that replacing qtip2 with CSS in PR #1324 will help solve that issue.

It did work for me, at least briefly (on Firefox):

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
4 Security Hotspots
6 Code Smells

No Coverage information
0.0% Duplication

[osma]

I added more unit tests, now the diff coverage is 100% 📈
Ready for a final round of review.

[joelit]

LGTM! :)