size() method returns different result from inside of IF() statement

[v1nsai]

I opened a StackOverflow ticket on this recently but I believe it is actually a bug.

OrientDB Version: 3.0.0

Java Version: 1.8.0_171

OS: Ubuntu 16.04

Expected behavior

$3.size() should be greater than 0 for both of the following scripts

LET $1 = SELECT expand(bothE(Begets)) FROM Creature WHERE uniquename='hildigrimTook';
LET $2 = SELECT expand(bothE(Begets)) FROM Creature WHERE uniquename='adalgrimTook';
LET $3 = SELECT INTERSECT($1, $2).size();
LET $4 = CREATE EDGE Begets FROM (SELECT FROM Creature WHERE uniquename='hildigrimTook') TO (SELECT FROM Creature WHERE uniquename='adalgrimTook');
SELECT $3.size();

LET $1 = SELECT expand(bothE(Begets)) FROM Creature WHERE uniquename='hildigrimTook';
LET $2 = SELECT expand(bothE(Begets)) FROM Creature WHERE uniquename='adalgrimTook';
LET $3 = SELECT INTERSECT($1, $2).size();
LET $4 = CREATE EDGE Begets FROM (SELECT FROM Creature WHERE uniquename='hildigrimTook') TO (SELECT FROM Creature WHERE uniquename='adalgrimTook');
IF($3.size() > 0 {
    return 'Edge already exists'
}
IF($3.size() == 0 {
    return $4;
}

Actual behavior

Calling $3.size() is 0 when called from inside of an IF() statement, but > 0 when called from a SELECT, so $4 is called every time and creates duplicate edges.

Steps to reproduce

The following creates a duplicate edge instead of correctly reading $3.size() and returning 'Edge already exists'.

LET $1 = SELECT expand(bothE(Begets)) FROM Creature WHERE uniquename='hildigrimTook';
LET $2 = SELECT expand(bothE(Begets)) FROM Creature WHERE uniquename='adalgrimTook';
LET $3 = SELECT INTERSECT($1, $2).size();
LET $4 = CREATE EDGE Begets FROM (SELECT FROM Creature WHERE uniquename='hildigrimTook') TO (SELECT FROM Creature WHERE uniquename='adalgrimTook');
IF($3.size() > 0 {
    return 'Edge already exists'
}
IF($3.size() == 0 {
    return $4;
}

[luigidellaquila]

Hi @v1nsai

Thank you very much for reporting, I'm working on this now

Thanks

Luigi

[luigidellaquila]

Hi @v1nsai

I pushed a fix to develop branch, the new snapshot is already available.

Just please consider that the LET statements are evaluated early, so in your case the edge is created anyway.
What you probably need is something as follows:

LET $1 = SELECT expand(bothE(Begets)) FROM Creature WHERE uniquename='hildigrimTook';
LET $2 = SELECT expand(bothE(Begets)) FROM Creature WHERE uniquename='adalgrimTook';
LET $3 = SELECT INTERSECT($1, $2).size();
uniquename='hildigrimTook') TO (SELECT FROM Creature WHERE uniquename='adalgrimTook');
IF($3.size() > 0 {
    return 'Edge already exists'
}
IF($3.size() == 0 {
    LET $4 = CREATE EDGE Begets FROM (SELECT FROM Creature WHERE 
    return $4;
}

Thanks

Luigi

[luigidellaquila]

You can find the snapshot here

https://oss.sonatype.org/content/repositories/snapshots/com/orientechnologies/orientdb-community/3.0.1-SNAPSHOT/

[v1nsai]

Thanks for the code fix, that really helped! I actually was calling $3.INTERSECT.size() just in case anyone from Google happens upon this.