Empty DiffSync instance evaluates as false

[smk4664]

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Environment

• DiffSync version: 1.3.0
• Python version: 3.6

Observed Behavior

When using diffsync within Nautobot-plugin-ssot, it would be nice to allow the Destination (Target) to have no data.

An empty DiffSync() evaluates to False. This causes a failure to proceed to the Diff.

the base DiffSync class has a len() method, an object’s default bool() casting must use that to determine whether it evaluates as truthy:

diffsync = DiffSync() bool(diffsync) False diffsync.add(DiffSyncModel()) bool(diffsync) True

Expected Behavior

diffsync proceeds to diff and then syncs data to the Destination (Target).

[glennmatthews]

Workaround is to check explicitly is not None - see https://github.com/nautobot/nautobot-plugin-ssot/pull/18

[Kircheneer]

Having thought about this a little before I merge my fix PR into next-2.0 - I actually consider this the more intuitive behavior as opposed to always returning True. I think the workaround specified in the comment above to me is very acceptable. Opinions on closing without a change?

[Kircheneer]

See above comment.