Re-create all objects before updating their properties during client_reset::transfer_group() #6291
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jbreams
changed the title
michael-wb
approved these changes
Feb 10, 2023
| @@ -329,8 +329,30 @@ void transfer_group(const Transaction& group_src, Transaction& group_dst, util:: | |||
| } | |||
| } | |||
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| converters::EmbeddedObjectConverter embedded_tracker; | |||
| // We must re-create any missing objects that are abscent in dst before trying to copy | |||
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missing objects or objects that are absent
| // get or create the object | ||
| auto dst = table_dst->create_object_with_primary_key(src_pk, &updated); | ||
| auto dst = table_dst->get_object_with_primary_key(src_pk); |
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This will create the object if it doesn't exist?
Or it should have already been created by your changes above?
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Yup. I updated the comment above.
| @@ -357,11 +379,11 @@ void transfer_group(const Transaction& group_src, Transaction& group_dst, util:: | |||
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| for (const Obj& src : *table_src) { | |||
| auto src_pk = src.get_primary_key(); | |||
| bool updated = false; | |||
| // get or create the object | |||
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should update this comment
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Side note: maybe it should be turned into a CHECK so we see the actual error. |
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What, How & Why?
This fixes a crash in automatic client resets where there are dangling links in the destination realm (i.e. the realm being client reset). The
transfer_group()function takes a fresh copy of a realm and transfers a source realm's contents to a target by comparing each property in each object in each table, and creating/setting properties as needed if they don't exist or do not match. If the target table has a list of links where some of them are dangling, and the dangling link targets exist in the source realm, it will create the target objects, thereby resurrecting the dangling link, and end up with duplicate entries in the list. This violates an invariant in the IntraRealmObjectConverter class.☑️ ToDos