Sqlite arithmetic on NULL should be nullable

[eygraber]

Runtime Environment
SQLDelight version: 1.3.0
Application OS: Android

If I perform an arithmetic operation on a non null column, that has an aggregate function applied to it, SqlDelight is expecting the result to be non null, when it could be nullable.

CREATE TABLE Test(
  id INTEGER PRIMARY KEY NOT NULL,
  timestamp INTEGER NOT NULL
);

SELECT MIN(timestamp) - 1 FROM Test WHERE id = <id that doesn't exist>;

min(X)
The min() aggregate function returns the minimum non-NULL value of all values in the group. The minimum value is the first non-NULL value that would appear in an ORDER BY of the column. Aggregate min() returns NULL if and only if there are no non-NULL values in the group.