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https://issues.apache.org/jira/browse/TINKERPOP-2854?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17679222#comment-17679222
]
Stephen Mallette commented on TINKERPOP-2854:
---------------------------------------------
Using the Gremlin Console's {{:bc}} command we can turn that GraphSON bytecode
into a nice Gremlin string representation:
{code:java}
gremlin> :bc translate g <your-graphson-with-line-breaks-removed>
==>Script[(g.inject(" cypher.start").map(__.project(" GENERATED1","
GENERATED2","
GENERATED3").by(__.constant(1L)).by(__.constant(2L)).by(__.constant(3L)).select(Column.values)).project("r").by(__.project("
GENERATED5"," GENERATED6","
GENERATED7").by(__.identity()).by(__.choose(__.constant(from),__.constant(from),__.constant("
cypher.null"))).by(__.choose(__.constant(to),__.constant(to),__.constant("
cypher.null"))).select(Column.values).map({cypherListSlice().apply(it)})).inject("
cypher.start").map(__.project(" GENERATED1"," GENERATED2","
GENERATED3").by(__.constant(1L)).by(__.constant(2L)).by(__.constant(3L)).select(Column.values)).project("r").by(__.project("
GENERATED5"," GENERATED6","
GENERATED7").by(__.identity()).by(__.choose(__.constant(from),__.constant(from),__.constant("
cypher.null"))).by(__.choose(__.constant(to),__.constant(to),__.constant("
cypher.null"))).select(Column.values).map({cypherListSlice().apply(it)})),Optional.empty)]
{code}
which formats more nicely in Gremlint to:
{code:java}
g.inject(" cypher.start").
map(
__.project(" GENERATED1", " GENERATED2", " GENERATED3").
by(__.constant(1L)).
by(__.constant(2L)).
by(__.constant(3L)).
select(Column.values)).
project("r").
by(
__.project(" GENERATED5", " GENERATED6", " GENERATED7").
by(__.identity()).
by(
__.choose(
__.constant(from),
__.constant(from),
__.constant(" cypher.null"))).
by(
__.choose(__.constant(to), __.constant(to), __.constant("
cypher.null"))).
select(Column.values).
map({cypherListSlice().apply(it)})).
inject(" cypher.start").
map(
__.project(" GENERATED1", " GENERATED2", " GENERATED3").
by(__.constant(1L)).
by(__.constant(2L)).
by(__.constant(3L)).
select(Column.values)).
project("r").
by(
__.project(" GENERATED5", " GENERATED6", " GENERATED7").
by(__.identity()).
by(
__.choose(
__.constant(from),
__.constant(from),
__.constant(" cypher.null"))).
by(
__.choose(__.constant(to), __.constant(to), __.constant("
cypher.null"))).
select(Column.values).
map({cypherListSlice().apply(it)}))
{code}
I believe the problem is that 3.6.x introduces two {{Direction}} alias values
for {{OUT}} and {{IN}} called {{from}} and {{to}} respectively making those
tokens reserved. Rather than treat those tokens as variable bindings (which i
believe cypher-for-gremlin intended them to be) they are now being considered
{{{}Direction{}}}.
As a result, I don't think this is a bug in TinkerPop, but rather a breaking
change that consuming libraries and clients would have to adjust to. I think
that if cypher-for-gremlin were to change its naming of "from" and "to" this
part would start working again.
> Generated Traversal differs from v3.4.13 to v3.6.1
> --------------------------------------------------
>
> Key: TINKERPOP-2854
> URL: https://issues.apache.org/jira/browse/TINKERPOP-2854
> Project: TinkerPop
> Issue Type: Bug
> Affects Versions: 3.6.1
> Reporter: Andrea Santurbano
> Priority: Major
>
> Hi everybody,
> I'm playing with Gremlin and OpenCypher query transpiler by using the
> following bytecode query:
> {code:java}
> [[], [inject( cypher.start), map([[], [project( GENERATED1, GENERATED2,
> GENERATED3), by([[], [constant(1)]]), by([[], [constant(2)]]), by([[],
> [constant(3)]]), select(values)]]), project(r), by([[], [project(
> GENERATED5, GENERATED6, GENERATED7), by([[], [identity()]]), by([[],
> [choose([[], [constant(binding[from=3])]], [[], [constant(binding[from=3])]],
> [[], [constant( cypher.null)]])]]), by([[], [choose([[],
> [constant(binding[to=1])]], [[], [constant(binding[to=1])]], [[], [constant(
> cypher.null)]])]]), select(values),
> map(lambda[cypherListSlice().apply(it)])]])]]{code}
> Using Gremlin 3.4.13 produces the following traversal:
>
>
> {code:java}
> [InjectStep([ cypher.start]), TraversalMapStep([ProjectStep([ GENERATED1,
> GENERATED2, GENERATED3],[[ConstantStep(1)], [ConstantStep(2)],
> [ConstantStep(3)]]), TraversalMapStep(values)]),
> ProjectStep([r],[[ProjectStep([ GENERATED5, GENERATED6,
> GENERATED7],[[IdentityStep], [ChooseStep([ConstantStep(3),
> HasNextStep],[[(eq(true)), [ConstantStep(3), EndStep]], [(eq(false)),
> [ConstantStep( cypher.null), EndStep]]])], [ChooseStep([ConstantStep(1),
> HasNextStep],[[(eq(true)), [ConstantStep(1), EndStep]], [(eq(false)),
> [ConstantStep( cypher.null), EndStep]]])]]), TraversalMapStep(values),
> LambdaMapStep(lambda)]])]{code}
> while 3.6.1 creates this one (we only upgraded the library and changed some
> package name references):
>
>
> {code:java}
> [InjectStep([ cypher.start]), TraversalMapStep([ProjectStep([ GENERATED1,
> GENERATED2, GENERATED3],[[ConstantStep(1)], [ConstantStep(2)],
> [ConstantStep(3)]]), TraversalMapStep(values)]),
> ProjectStep([r],[[ProjectStep([ GENERATED5, GENERATED6,
> GENERATED7],[[IdentityStep], [ChooseStep([ConstantStep(OUT),
> HasNextStep],[[(eq(true)), [ConstantStep(OUT), EndStep]], [(eq(false)),
> [ConstantStep( cypher.null), EndStep]]])], [ChooseStep([ConstantStep(IN),
> HasNextStep],[[(eq(true)), [ConstantStep(IN), EndStep]], [(eq(false)),
> [ConstantStep( cypher.null), EndStep]]])]]), TraversalMapStep(values),
> LambdaMapStep(lambda)]])]{code}
> Indeed the one in 3.6.1 is the wrong one because it adds some extra steps
> like {*}ConstantStep(IN){*}.
>
>
>
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