My scenario: I had two empty stores and i inserted "item 1" into both stores. Then I performed a UploadAndDownload sync with local constrian resolution policy set to "destination wins" and remote constrain resolution policy set to "source wins". I traced the store operations and here are what happend:
1. "Item 1" from local store was inserted to remote store. The insertion failed due to id constrain.
2. "Item 1" from remote store was deleted.
3. "Item 1" from local store was inserted into remote store (this time succeeded).
So far so good. But during the download process two things happened
1. "Item 1" from local store is DELETED.
2. "Item 1" from remote store is inserted into local store.
These two operations seemed strange because the local policy is destination wins. Shouldn't the framework just try to insert remote version into local store and ignore the constrain error because destination wins?
I tried to visualize the store knowledge changes but I was not sure if I understood it correctly:
Initial state
Store A: “Value a”,update version = A1, store knowledge = A1
Store B: “Value b”,update version = B1, store knowledge = B1
During upload (conflict detected)
Store A: “Value a”,update version = A1, store knowledge = A1
Store B: “Value b”,update version = B1, store knowledge =B1A1
After upload (conflict resolved)
Store A: “Value a”,update version = A1, store knowledge = A1
Store B: “Value a”,update version = B2, store knowledge = B2A1
After download (so here it should have been one UPDATE, but not one DELETE and one INSERT)
Store A: “Value a”,update version = B2, store knowledge = A1B2
Store B: “Value a”,update version = B2, store knowledge = B2A1
