Bug #1614
closed
Problem with typeswitch in XQuery?
100%
Description
I am seeing Saxon XQuery processor fail with this query. To the best of my knowledge I believe the query is correct, it does seem to pass on eXist-db and Zorba XQuery Processors, although that does not mean it is correct of course!
let $something := 1 cast as xs:integer return
typeswitch($something)
case document-node() return
<result>found a document</result>
case $e as element() return
<result>found an element: {local-name($e)}</result>
case $t as text() return
<result>found the text: {$t}</result>
case $i as xs:integer return
<result>found the integer: {$i}</result>
default return
()
Files
Updated by Adam Retter over 11 years ago
- File typeswitch.xql typeswitch.xql added
As your Bug Tracker seems to have mangled the XQuery I posted in the message. I have attached it in a file also.
Updated by Michael Kay over 11 years ago
- Category set to XQuery conformance
- Assignee set to Michael Kay
- Found in version changed from HE 9.4.0.4 to 9.4
Updated by Michael Kay over 11 years ago
The rules on error handling and optimization in XQuery are sufficiently permissive that one could argue this behaviour is legal; but I agree that it's undesirable. What seems to be happening is that Saxon rewrites the typeswitch expression in terms of primitives such as "if $x instance of element() then local-name($x)", and then applies type checking to this rewritten expression; during this analysis it works out that $x is always an integer and local-name($x) is therefore a type error; and type errors that are detected statically can be reported statically even if they occur in code that is never executed. I'll try to find a way of fixing this; it might not be easy.
Updated by Michael Kay over 11 years ago
- Status changed from New to Resolved
- % Done changed from 0 to 100
I have committed a patch for this in the 9.4 branch. The effect of the patch is that during type checking of a conditional expression, if a condition is statically determined to be false, then a type error in the corresponding branch of the conditional is not reported statically (which means in effect that it is never reported -- it won't be reported dynamically because the code is never executed).
Updated by O'Neil Delpratt over 11 years ago
- Status changed from Resolved to Closed
- Fixed in version set to 9.4.0.6
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