Add support for merging unrelated Git histories #119
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When merging unrelated Git histories, the merge driver uses an empty ancestor database. Thus, the SQL `max` function cannot operate and returns a `null` value during the merge, effectively discarding *our* database during the merge. This commit ignores the ancestor database if it is empty, so both histories are full preserved in this corner case.
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When merging unrelated Git histories, the merge driver uses an empty
ancestor database. Thus, the SQL
maxfunction cannot operate andreturns a
nullvalue during the merge, effectively discarding ourdatabase during the merge. This PR ignores the ancestor database if
it is empty, so both histories are fully preserved in this corner case.