VersioningTrigger doesn't avoid write conflicts

[dovikos]

What is the problem

The VersioningTrigger doesn't avoir conflicts.

What did you expect

Following document about parameter overwrite as described here, I expect that a user can't overwrite modifications already committed by another one, when they're editing the same document at the same time.

Describe how to reproduce or add a test

• Add xquery-versioning-module in your eXist-db instance.

• In $EXIST_HOME/conf.xml, add the following line in the <builtin-modules> element as explained here (paragraph Direct Installation into eXist-db (.jar)):
  <module uri="http://exist-db.org/xquery/versioning" class="org.exist.versioning.xquery.VersioningModule"/>.

• In $EXIST_HOME/conf.xml, enable the VersioningFilter by adding the following line in the <serializer> element as explained here:
  <custom-filter class="org.exist.versioning.VersioningFilter"/>.

• Restart eXist-db.

• Configure a collection with the versioning trigger registered (see here) with parameter overwrite="no".

• With different accounts, try to overwrite changes of a user and see that one may overwrite the other's changes.

Context information

• eXist-db version + Git Revision hash: eXist-db 3.2.0-SNAPSHOT / c7f6e81
• xquery-versioning-module version + Git Revision hash: 1.1.4 / fbdecdb
• Java version: Java8u121
• Operating system: Windows 7
• 64 bit
• Custom changes: in conf.xml, I added the following line in the <builtin-modules> element as explained here:
  <module uri="http://exist-db.org/xquery/versioning" class="org.exist.versioning.xquery.VersioningModule"/>
  I also enabled the serialized filter VersioningFilter as explained here.
  I configured versioning trigger with parameter <parameter name="overwrite" value="no"/> on my collection, as explained here.

[dizzzz]

"user can't overwrite a file modified by another one." ... maybe we should read this as "user can't overwrite a file when it is being modified by another one." ?

[dovikos]

I clarified : "a user can't overwrite modifications already committed by another one, when they're editing the same document at the same time."

[dovikos]

Example: John and Bob are editing the same document at revision n.
John commits first. The document is now at revision n+1.
When Bob commits, I understand from the documentation that he should get an error. Because setting parameter overwrite to no (in collection config) should cause VersioningTrigger to check if revision dit not change (n+1 ≠ n).