[mark_undoio]

Hallo, I'm an Undo developer wave

Indeed, using GDB's version of tracepoints (dprintf - https://doc.ecoscentric.com/gnutools/doc/gdb/Dynamic-Printf....) is really powerful and replaying a trace with these installed is to generate "logs I wish I'd had" is exciting.

It also has potential use if:

* you'd like to diff two executions (e.g. one successful, one failing) - you probably can't just compare raw execution as there'll be uninteresting variation but comparing extended logs could be useful

* you are debugging something at a customer site - they might not let you debug directly but you could iterate on plain text logs by shipping them additional tracepoints to run on a recording

We thought this was useful enough that we implemented a tool with its own DSL for simply specifying post factor logging "probes": https://docs.undo.io/PostFailureLogging.html