[jira] [Commented] (OAK-7388) MergingNodeStateDiff may recreate nodes that were previously removed to resolve conflicts
[ https://issues.apache.org/jira/browse/OAK-7388?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16427015#comment-16427015 ] Alex Deparvu commented on OAK-7388: --- +1 good stuff! > MergingNodeStateDiff may recreate nodes that were previously removed to > resolve conflicts > - > > Key: OAK-7388 > URL: https://issues.apache.org/jira/browse/OAK-7388 > Project: Jackrabbit Oak > Issue Type: Improvement > Components: core >Reporter: Francesco Mari >Assignee: Francesco Mari >Priority: Major > Fix For: 1.9.0, 1.10 > > > {{MergingNodeStateDiff}} might behave incorrectly when the resolution of a > conflict involves the deletion of the conflicting node. I spotted this issue > in a use case that can be expressed by the following code. > {noformat} > NodeState root = EmptyNodeState.EMPTY_NODE; > NodeState withProperty; > { > NodeBuilder builder = root.builder(); > builder.child("c").setProperty("foo", "bar"); > withProperty = builder.getNodeState(); > } > NodeState withUpdatedProperty; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").setProperty("foo", "baz"); > withUpdatedProperty = builder.getNodeState(); > } > NodeState withRemovedChild; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").remove(); > withRemovedChild = builder.getNodeState(); > } > NodeBuilder mergedBuilder = withUpdatedProperty.builder(); > withRemovedChild.compareAgainstBaseState(withProperty, new > ConflictAnnotatingRebaseDiff(mergedBuilder)); > NodeState merged = > ConflictHook.of(DefaultThreeWayConflictHandler.OURS).processCommit( > mergedBuilder.getBaseState(), > mergedBuilder.getNodeState(), > CommitInfo.EMPTY > ); > assertFalse(merged.hasChildNode("c")); > {noformat} > The assertion at the end of the code fails becauuse `merged` actually has a > child node named `c`, and `c` is an empty node. After digging into the issue, > I figured out that the problem is caused by the following steps. > # {{MergingNodeStateDiff#childNodeAdded}} is invoked because of > {{:conflicts}}. This eventually results in the deletion of the conflicting > child node. > # {{MergingNodeStateDiff#childNodeChanged}} is called because in > {{ModifiedNodeState#compareAgainstBaseState}} the children are compared with > the {{!=}} operator instead of using {{Object#equals}}. > # {{org.apache.jackrabbit.oak.spi.state.NodeBuilder#child}} is called in > order to setup a new {{MergingNodeStateDiff}} to descend into the subtree > that was detected as modified. > # {{MemoryNodeBuilder#hasChildNode}} correctly returns {{false}}, because the > child was removed in step 1. The return value of {{false}} triggers the next > step. > # {{MemoryNodeBuilder#setChildNode(java.lang.String)}} is invoked in order to > setup a new, empty child node. > In other words, the snippet above can be rewritten like the following. > {noformat} > NodeState root = EmptyNodeState.EMPTY_NODE; > NodeState withProperty; > { > NodeBuilder builder = root.builder(); > builder.child("c").setProperty("foo", "bar"); > withProperty = builder.getNodeState(); > } > NodeState withUpdatedProperty; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").setProperty("foo", "baz"); > withUpdatedProperty = builder.getNodeState(); > } > NodeState withRemovedChild; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").remove(); > withRemovedChild = builder.getNodeState(); > } > NodeBuilder mergedBuilder = withUpdatedProperty.builder(); > // As per MergingNodeStateDiff.childNodeAdded() > mergedBuilder.child("c").remove(); > // As per ModifiedNodeState#compareAgainstBaseState() > if (withUpdatedProperty.getChildNode("c") != > withRemovedChild.getChildNode("c")) { > // As per MergingNodeStateDiff.childNodeChanged() > mergedBuilder.child("c"); > } > NodeState merged = mergedBuilder.getNodeState(); > assertFalse(merged.hasChildNode("c")); > {noformat} > The end result is that {{MergingNodeStateDiff}} inadvertently adds the node > that was removed in order to resolve a conflict. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-7388) MergingNodeStateDiff may recreate nodes that were previously removed to resolve conflicts
[ https://issues.apache.org/jira/browse/OAK-7388?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16425526#comment-16425526 ] Francesco Mari commented on OAK-7388: - I added a failing unit test at r1828343. > MergingNodeStateDiff may recreate nodes that were previously removed to > resolve conflicts > - > > Key: OAK-7388 > URL: https://issues.apache.org/jira/browse/OAK-7388 > Project: Jackrabbit Oak > Issue Type: Improvement > Components: core >Reporter: Francesco Mari >Assignee: Francesco Mari >Priority: Major > Fix For: 1.10 > > > {{MergingNodeStateDiff}} might behave incorrectly when the resolution of a > conflict involves the deletion of the conflicting node. I spotted this issue > in a use case that can be expressed by the following code. > {noformat} > NodeState root = EmptyNodeState.EMPTY_NODE; > NodeState withProperty; > { > NodeBuilder builder = root.builder(); > builder.child("c").setProperty("foo", "bar"); > withProperty = builder.getNodeState(); > } > NodeState withUpdatedProperty; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").setProperty("foo", "baz"); > withUpdatedProperty = builder.getNodeState(); > } > NodeState withRemovedChild; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").remove(); > withRemovedChild = builder.getNodeState(); > } > NodeBuilder mergedBuilder = withUpdatedProperty.builder(); > withRemovedChild.compareAgainstBaseState(withProperty, new > ConflictAnnotatingRebaseDiff(mergedBuilder)); > NodeState merged = > ConflictHook.of(DefaultThreeWayConflictHandler.OURS).processCommit( > mergedBuilder.getBaseState(), > mergedBuilder.getNodeState(), > CommitInfo.EMPTY > ); > assertFalse(merged.hasChildNode("c")); > {noformat} > The assertion at the end of the code fails becauuse `merged` actually has a > child node named `c`, and `c` is an empty node. After digging into the issue, > I figured out that the problem is caused by the following steps. > # {{MergingNodeStateDiff#childNodeAdded}} is invoked because of > {{:conflicts}}. This eventually results in the deletion of the conflicting > child node. > # {{MergingNodeStateDiff#childNodeChanged}} is called because in > {{ModifiedNodeState#compareAgainstBaseState}} the children are compared with > the {{!=}} operator instead of using {{Object#equals}}. > # {{org.apache.jackrabbit.oak.spi.state.NodeBuilder#child}} is called in > order to setup a new {{MergingNodeStateDiff}} to descend into the subtree > that was detected as modified. > # {{MemoryNodeBuilder#hasChildNode}} correctly returns {{false}}, because the > child was removed in step 1. The return value of {{false}} triggers the next > step. > # {{MemoryNodeBuilder#setChildNode(java.lang.String)}} is invoked in order to > setup a new, empty child node. > In other words, the snippet above can be rewritten like the following. > {noformat} > NodeState root = EmptyNodeState.EMPTY_NODE; > NodeState withProperty; > { > NodeBuilder builder = root.builder(); > builder.child("c").setProperty("foo", "bar"); > withProperty = builder.getNodeState(); > } > NodeState withUpdatedProperty; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").setProperty("foo", "baz"); > withUpdatedProperty = builder.getNodeState(); > } > NodeState withRemovedChild; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").remove(); > withRemovedChild = builder.getNodeState(); > } > NodeBuilder mergedBuilder = withUpdatedProperty.builder(); > // As per MergingNodeStateDiff.childNodeAdded() > mergedBuilder.child("c").remove(); > // As per ModifiedNodeState#compareAgainstBaseState() > if (withUpdatedProperty.getChildNode("c") != > withRemovedChild.getChildNode("c")) { > // As per MergingNodeStateDiff.childNodeChanged() > mergedBuilder.child("c"); > } > NodeState merged = mergedBuilder.getNodeState(); > assertFalse(merged.hasChildNode("c")); > {noformat} > The end result is that {{MergingNodeStateDiff}} inadvertently adds the node > that was removed in order to resolve a conflict. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Commented] (OAK-7388) MergingNodeStateDiff may recreate nodes that were previously removed to resolve conflicts
[ https://issues.apache.org/jira/browse/OAK-7388?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16425486#comment-16425486 ] Michael Dürig commented on OAK-7388: Excellent analysis! The first snipped of code should be made into a unit test. And of course we should try to fix this! > MergingNodeStateDiff may recreate nodes that were previously removed to > resolve conflicts > - > > Key: OAK-7388 > URL: https://issues.apache.org/jira/browse/OAK-7388 > Project: Jackrabbit Oak > Issue Type: Improvement > Components: core >Reporter: Francesco Mari >Assignee: Francesco Mari >Priority: Major > Fix For: 1.10 > > > {{MergingNodeStateDiff}} might behave incorrectly when the resolution of a > conflict involves the deletion of the conflicting node. I spotted this issue > in a use case that can be expressed by the following code. > {noformat} > NodeState root = EmptyNodeState.EMPTY_NODE; > NodeState withProperty; > { > NodeBuilder builder = root.builder(); > builder.child("c").setProperty("foo", "bar"); > withProperty = builder.getNodeState(); > } > NodeState withUpdatedProperty; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").setProperty("foo", "baz"); > withUpdatedProperty = builder.getNodeState(); > } > NodeState withRemovedChild; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").remove(); > withRemovedChild = builder.getNodeState(); > } > NodeBuilder mergedBuilder = withUpdatedProperty.builder(); > withRemovedChild.compareAgainstBaseState(withProperty, new > ConflictAnnotatingRebaseDiff(mergedBuilder)); > NodeState merged = > ConflictHook.of(DefaultThreeWayConflictHandler.OURS).processCommit( > mergedBuilder.getBaseState(), > mergedBuilder.getNodeState(), > CommitInfo.EMPTY > ); > assertFalse(merged.hasChildNode("c")); > {noformat} > The assertion at the end of the code fails becauuse `merged` actually has a > child node named `c`, and `c` is an empty node. After digging into the issue, > I figured out that the problem is caused by the following steps. > # {{MergingNodeStateDiff#childNodeAdded}} is invoked because of > {{:conflicts}}. This eventually results in the deletion of the conflicting > child node. > # {{MergingNodeStateDiff#childNodeChanged}} is called because in > {{ModifiedNodeState#compareAgainstBaseState}} the children are compared with > the {{!=}} operator instead of using {{Object#equals}}. > # {{org.apache.jackrabbit.oak.spi.state.NodeBuilder#child}} is called in > order to setup a new {{MergingNodeStateDiff}} to descend into the subtree > that was detected as modified. > # {{MemoryNodeBuilder#hasChildNode}} correctly returns {{false}}, because the > child was removed in step 1. The return value of {{false}} triggers the next > step. > # {{MemoryNodeBuilder#setChildNode(java.lang.String)}} is invoked in order to > setup a new, empty child node. > In other words, the snippet above can be rewritten like the following. > {noformat} > NodeState root = EmptyNodeState.EMPTY_NODE; > NodeState withProperty; > { > NodeBuilder builder = root.builder(); > builder.child("c").setProperty("foo", "bar"); > withProperty = builder.getNodeState(); > } > NodeState withUpdatedProperty; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").setProperty("foo", "baz"); > withUpdatedProperty = builder.getNodeState(); > } > NodeState withRemovedChild; > { > NodeBuilder builder = withProperty.builder(); > builder.child("c").remove(); > withRemovedChild = builder.getNodeState(); > } > NodeBuilder mergedBuilder = withUpdatedProperty.builder(); > // As per MergingNodeStateDiff.childNodeAdded() > mergedBuilder.child("c").remove(); > // As per ModifiedNodeState#compareAgainstBaseState() > if (withUpdatedProperty.getChildNode("c") != > withRemovedChild.getChildNode("c")) { > // As per MergingNodeStateDiff.childNodeChanged() > mergedBuilder.child("c"); > } > NodeState merged = mergedBuilder.getNodeState(); > assertFalse(merged.hasChildNode("c")); > {noformat} > The end result is that {{MergingNodeStateDiff}} inadvertently adds the node > that was removed in order to resolve a conflict. -- This message was sent by Atlassian JIRA (v7.6.3#76005)