List of steps to reproduce (step by step, including full links if applicable):
- Execute the query shown below in WDQS (link to the query in WDQS)
PREFIX linguap: <https://lingualibre.org/prop/direct/>
PREFIX linguae: <https://lingualibre.org/entity/>
SELECT * {
SERVICE <https://lingualibre.org/sparql> {
SELECT ?item {
?item linguap:P2 linguae:Q5.
}
}
}What happens?:
It results in Server error.
What should have happened instead?:
The query should be successfully executed as happens in Sophox (link to the same query in Sophox)
Software version (if not a Wikimedia wiki), browser information, screenshots, other information, etc.:
WDQS at the time of this writing.
Additional information
I was looking into this so I wrote some more examples. I'll paste them here as it'll probably help people that look into this.
The following query (A) results in Server error in WDQS.
PREFIX prop: <https://lingualibre.org/prop/direct/>
PREFIX entity: <https://lingualibre.org/entity/>
SELECT * {
SERVICE <https://lingualibre.org/sparql> {
SELECT ?item ?itemLabel {
?item prop:P2 entity:Q5.
SERVICE wikibase:label {bd:serviceParam wikibase:language "en".}
}
}
}The following query (B) is successfully executed in WDQS. Note that the only thing that changed are the name of the prefixes.
PREFIX linguap: <https://lingualibre.org/prop/direct/>
PREFIX linguae: <https://lingualibre.org/entity/>
SELECT * {
SERVICE <https://lingualibre.org/sparql> {
SELECT ?item ?itemLabel {
?item linguap:P2 linguae:Q5.
SERVICE wikibase:label {bd:serviceParam wikibase:language "en".}
}
}
}I first thought that the root cause for this problem in (A) was the name of the prefixes, but this is not true. Proof is shown below.
The following is another query (C). It uses prop and entity as prefixes, it results in Server error in WDQS.
PREFIX prop: <https://lingualibre.org/prop/direct/>
PREFIX entity: <https://lingualibre.org/entity/>
SELECT * {
SERVICE <https://lingualibre.org/sparql> {
SELECT ?item {
?item prop:P2 entity:Q5.
}
}
}The following query (D) is the one as the query shown above but with different prefixes. It uses linguap and linguae as prefixes, it results in Server error in WDQS too.
PREFIX linguap: <https://lingualibre.org/prop/direct/>
PREFIX linguae: <https://lingualibre.org/entity/>
SELECT * {
SERVICE <https://lingualibre.org/sparql> {
SELECT ?item {
?item linguap:P2 linguae:Q5.
}
}
}The queries (A), (B), (C) and (D) were successfully executed in Sophox, but as was mentioned not in WDQS.