I've written a frame filter that applies a FrameDecorator object to all frames, and it works for backtraces (when using the bt command). However, when I use up, down, or explicitly go to a frame like f 0, gdb prints the undecorated frame.
Is there a way to always apply a FrameDecorator even when stepping through frames?
This is a requested feature but hasn't been implemented yet. There's a bit of discussion in the gdb bug.
One temporary option might be a stop hook that does bt 1. But this is likely to be somewhat intrusive.