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ASF GitHub Bot commented on TINKERPOP-1397: ------------------------------------------- GitHub user dalaro opened a pull request: https://github.com/apache/tinkerpop/pull/378 TINKERPOP-1397 Fix StarGraph.addEdge See: * old PR #372 * JIRA issue https://issues.apache.org/jira/browse/TINKERPOP-1397 As far as I can tell, GraphFilter did not exist in 3.1, and it may not even be possible to induce the buggy traversal behavior describe in #372 (which was all based on master / 3.2). The underlying datastructure corruption -- putting a StarOutEdge into the `inEdges` map -- does exist on 3.1, and @okram's `addEdge` fix applies cleanly on 3.1, but without `applyGraphFilter`, I'm not sure it even matters for correctness on 3.1. You can merge this pull request into a Git repository by running: $ git pull https://github.com/dalaro/incubator-tinkerpop TINKERPOP-1397-tp31 Alternatively you can review and apply these changes as the patch at: https://github.com/apache/tinkerpop/pull/378.patch To close this pull request, make a commit to your master/trunk branch with (at least) the following in the commit message: This closes #378 ---- commit 0022b7f6be25eb7d3c778b137beb6e8a7d2784ca Author: Dan LaRocque <dal...@hopcount.org> Date: 2016-08-10T22:52:13Z TINKERPOP-1397 Fix StarGraph.addEdge For self-loops, StarGraph.addEdge used to put a single StarOutEdge into both its inEdges and outEdges maps, potentially causing problems in applyGraphFilter. This change makes StarGraph.addEdge put the appropriate type of edge (Star(Out/In)Edge) in the associated map. The IDs for each edge instance are kept in agreement. This change is @okram's, who suggested it in PR #372. I merely reviewed it and added a couple of comments. ---- > StarVertex self edge has buggy interaction with graph filters > ------------------------------------------------------------- > > Key: TINKERPOP-1397 > URL: https://issues.apache.org/jira/browse/TINKERPOP-1397 > Project: TinkerPop > Issue Type: Bug > Components: process > Affects Versions: 3.1.3 > Reporter: Dan LaRocque > Fix For: 3.1.4 > > > When StarVertex adds a self-loop, it adds an instance of concrete type > {{StarOutEdge}} to both its {{outEdges}} map and its {{inEdges}} map. > https://github.com/apache/tinkerpop/blob/8f7218d53a31cf41f4a0269d64ac1c27dfc0907a/gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/util/star/StarGraph.java#L321-L330 > (line 329 adds a {{StarOutEdge}} to the {{inEdges}} map) > Having a {{StarOutEdge}} in the {{inEdges}} map mostly doesn't matter. > However, this does matter in the {{applyGraphFilter}} method. This method > uses {{instanceof StarOutEdge}} to guess whether an edge's original direction > was in or out: > https://github.com/apache/tinkerpop/blob/8f7218d53a31cf41f4a0269d64ac1c27dfc0907a/gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/util/star/StarGraph.java#L470 > If you trace {{applyGraphFilter}} through, you see that a {{StarVertex}} with > a self-loop can pop out of {{applyGraphFilter}} with two out edges > corresponding to the self loop and no in edges. This leads to weird > traversal results. One way to trigger this is to write a > {{GraphFilterAware}} {{InputRDD}} that produces {{StarVertex}} instances and > then run a {{g.V()....inE("somelabel")}}, so that TP pushes down the > "somelabel" constraint, which is how I got here. > I think {{addEdge}} should continue putting a {{StarOutEdge}} into > {{outEdges}}, like it already does. -However, it should put a {{StarInEdge}} > into {{inEdges}}. This would increase the object overhead associated with > StarVertices that have self loops (two edge objs instead of one). If we > wanted to be obsessive about optimizing this case we could probably pervert > the {{inEdge}}/{{outEdge}} datastructure contents to do it, but IMHO that's > not worth it.- Actually, I'm no longer convinced that's safe, since I think > it would alter some of StarVertex's other semantics. For one, I think > retrieving an edge and setting a property on it would probably break. > I'll make a PR soon. > I don't know all of the versions this affects, but I do know it affects 3.2.1. -- This message was sent by Atlassian JIRA (v6.3.4#6332)