d0b9f9fc27
The rationale is that a passthrough path (= one with no element) behaves as if the switchbin's sink- and srcpad were one. In particular, internal caps queries (needed for computing the allowed caps) then go to the peers instead to path elements. Rework gst_switch_bin_get_allowed_caps () for a clear handling of NULL path elements and for proper dataflow passthrough and caps & accept-caps query handling. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4632>