I know a Swift function by name and wanted to call the function from LLDB for debugging purposes.
I tried doing:
expr -- function_with_a_breakpoint()
This runs the function and parses correctly but doesn't hit the breakpoints I made. Ideally, I want to trigger from within LLDB without having to manually trigger the function from the app UI, for example. This would be more convenient.
I've added this answer with bonus notes since we usually trigger a Swift function from LLDB when we want to reach a breakpoint.
I enjoy working within LLDB for managing breakpoints because I don't break my flow between Xcode and the console.
The answer to your question is here. We have to set the -i flag to trigger a function from LLDB:
(lldb) expr -i 0 -- function_with_a_breakpoint()
We commonly use a function trigger from LLDB to trigger a breakpoint manually.
If we want to set a breakpoint on a function and we know the name:
(lldb) breakpoint set -n function_with_a_breakpoint
Using the file name and line number:
(lldb) breakpoint set --file foo.swift --line 12
// copy the breakpoint number into the modify command below
We can also create the breakpoint as a one-off using the --one-shot flag.
(lldb) breakpoint modify --one-shot 1
An example flow:
(lldb) run
(lldb) kill
... hit breakpoints...
(lldb) continue
So we could trigger the function after kill in the above example.