The BSON library currently includes 4 BSON-to-Go numeric value conversion functions that can cause silent data loss:

• AsInt32/AsInt32OK
• AsInt64/AsInt64OK

While converting BSON numeric types to a Go int64 can cause data loss in some cases, it's generally for extremely large or extremely small values that most users never encounter (values > 9.2e+18 or < -9.2e+18). However, converting BSON numeric types to a Go int32 can cause data loss for values that users may commonly encounter (values > 2,147,483,647 or < -2,147,483,648). As a result, using AsInt32/AsInt32OK is practically much less safe than AsInt64/AsInt64OK so we should deprecate AsInt32/AsInt32OK and recommend people use AsInt64/AsInt64OK instead. If users really need an int32, they can convert the int64 to an int32 themselves and implement whatever overflow/underflow checking logic they require.

See GODRIVER-2751 for changes to prevent data loss in AsInt64/AsInt64OK.

Definition of done:

• Deprecate frequently lossy bson.RawValue methods AsInt32 and AsInt32OK.