What am I doing wrong here? :(
I open Instruments.app, create a new UI Recorder template, select my application's .app bundle from the Target -> Choose Target menu, hit Record, open a couple of documents, type some stuff on them, close the documents, quit the app.
At this point UI Recorder stops and the Record button changes to "Drive & Record". I hit it, I see my application get launched and Instruments start recording data. Then Instruments gets confused (somehow)... my application loses focus, and suddenly UI Recorder is replaying all of my actions in Instruments!!, which just screws with Instruments in all kinds of messy ways. In this state I'm unable to move the mouse (the system just steals the cursor back), and I'm unable to quit instruments, since when I hit CMD+Q I'm prompted to Save the document, which I can't do because I have no control of the keyboard or mouse.
This is really frustrating. Has anyone got experience with this tool who can tell me where I'm going wrong? I'm scared to run it a third time as it literally hijacks my entire system.
So, you have a memory leak, and it happens when you do a specific series of actions.
The hard way to debug this would be to just have the Allocations and/or Leaks instruments and do the actions yourself every time, and every time you screw up (leave something out, do something wrong), kill the process and start over.
The easy way is the UI Recorder.
The first time you record with it, it records your actions (at the events level, not the target-action level). Mouse movements, clicks, etc.
The way UI Recorder differs from other instruments—which is why it surprised you—is that when you record with it thereafter, it plays them back.
It's not just swinging around your mouse cursor willy nilly; it's doing what you did the first time. Every time after you do things the first time, the UI Recorder does the exact same things for you.
That's what UI Recorder is for: Perfect, mechanically-ensured reproducibility. It's doing what it's meant to do; it's working as it should.
And yeah, aborting that is hard. I haven't looked yet, but there may be a stop-recording global system hotkey you can use. There is one when Instruments is in mini mode.
Also, you can set whether UI Recorder is in “drive” (playback) or “record” mode in the little pop-over that comes up when you click on the (i) button for the instrument. Switch it to record mode to re-record your interaction for different results in future runs. (I don't know whether it preserves the recording(s) in past runs.)