Reveal debugger commands are not recognized by the debugger

It's possible that Reveal Debugger Commands installed via Help menu would fail to work in certain cases. The issue would usually manifest itself by Reveal commands not recognized by Xcode's debugger, for example:

(lldb) reveal load
error: 'reveal' is not a valid command.
error: Unrecognized command 'reveal'.

This usually means that Reveal commands were not installed into LLDB. There are currently two known causes for this:

.lldbinit-Xcode file is present, but doesn't import .lldbinit

Reveal installs its debugger commands by creating or modifying .lldbinit file in your home directory. This file is loaded by LLDB during debug session startup. However, if your home directory also contains .lldbinit-Xcode file, it takes precedence over .lldbinit when the debug session is started by Xcode. Usually .lldbinit-Xcode includes the contents of .lldbinit by having the following line in it:

command source ~/.lldbinit

If, however, your .lldbinit-Xcode file does not contain that line, .lldbinit file is silently ignored and Reveal debugger commands will not be integrated. To resolve this issue, simply add the aforementioned line at the top of your .lldbinit-Xcode file. After saving the file, please restart your debugged app in Xcode and try using Reveal commands again.

Python interpreter was installed via Homebrew on your machine

To check whether the debugger uses system-provided Python interpreter or one installed using Homebrew, execute commands script and then sys.executable in your debugger console. The result could look like this:

(lldb) script
Python Interactive Interpreter. To exit, type 'quit()', 'exit()'.
>>> sys.executable

Such output shows that system-provided Python is used. However, if you have the following output instead, this means that LLDB uses Homebrew-installed Python:

(lldb) script
Python Interactive Interpreter. To exit, type 'quit()', 'exit()'.
>>> sys.executable

In such case, one known solution to Reveal debugger commands (and other scripted elements of LLDB) not working is to ensure that your Python installation has six module available. To install it, run the following command in your Terminal: pip install six. After that, try restarting your debugged app in Xcode and using Reveal commands again

If after installing six the issue persists, it's possible that Homebrew-provided Python needs to be removed in order for debugger commands to work. This can be done using the Terminal command:

brew remove python@2 --ignore-dependencies

This command only removes Python 2.x.x, which is already present in the system (version 2.7.12 as of macOS 10.14 Mojave), so other Homebrew packages should be able to fall back to the system Python.