Open Radar

 
Summary:  With QC4 in Snow Leopard, it's now possible to create compositions that open without warning in QC3, yet render incorrectly.  As a simple example, the Scale inputs added to the 3D Transformation patch don't exist on Leopard, and are silently ignored.  There are currently no notifications to the host app to indicate that a composition may not be rendering as expected.

Steps to Reproduce:  In QC4, create a composition which uses new ports on a patch that exists in QC3 (3D Transform is an easy one).  Then open the composition on Leopard with QC3 -- no errors are emitted, yet the output can be incorrectly rendered.

Expected Results:  A notification to inform the user that the output may not render as intended.

Actual Results:  No notification.

Regression:  This may also happen with some Leopard (QC3) compositions opened on Tiger (QC2).

Notes: It's possible to check the composition plist's FrameworkVersion key/value, but those can be edited with certain hidden preference enabled.  That key can also be absent, making this method unreliable.