Hello all-

Given the following bttest.pike on a recent pike master, I get some unexpected behavior.

int main(int argc, array argv) { mixed bt = backtrace(1)[(int)argv[1]]; write("%O\n", bt->fun); for(int i = 0; i < bt->num_locals; i++) write("%O: %O\n", bt->get_local_name(i), bt->get_local(i)); return 0; }

Run 1: bin/pike bttest 0

master()->_main "debugger": ({ /* 5 elements */ "/Users/hww3/pikedbg/build/darwin-18.7.0-x86_64/pike", "-DPRECOMPILED_SEARCH_MORE", "-m/Users/hww3/pikedbg/build/darwin-18.7.0-x86_64/master.pike", "bttest", "0" }) "argv": ({ /* 2 elements */ "/Users/hww3/pikedbg/bttest", "0" }) "debug": 0 "trace": 0 "run_tool": 0 "tmp": Getopt "postparseaction": 0 "parts": 0 "i": master()->Version(8.1) "have_debugger": 0 "debugger_wait": 0 "debugger_signal": 0 "debugger_port": 0 "t": /Users/hww3/pikedbg/bttest "err": 0 "script": /Users/hww3/pikedbg/bttest() "first_arg": int 0: 0 0: 0 0: 0 0: 0 0: 0 0: 0 0: 0 0: 0

Run 2:

bin/pike bttest 1

/main()->main 0: 2 0: ({ /* 2 elements */ "/Users/hww3/pikedbg/bttest", "1" }) "bt": _static_modules.Builtin()->LiveBacktraceFrame() 0: 3

Some questions:

1. It seems logical to me that out-of-scope locals have a local name of zero. However, it’s strange to me that function arguments, while treated as locals, don’t have names (see both examples). 2. It’s also strange that the for-loop variable ‘i' doesn’t have a name. If I move the definition of ‘i’ ahead of the for loop, it does have a name. 3. The value of “debugger” from the first listing looks more like the value of orig_argv, which doesn’t appear elsewhere in the locals list. I also don’t seem to have a variable called “debugger” in my definition of “_main” (but there is a variable called “debugger” in the containing (master) object.

Am I doing something wrong in my use of these frames? I get similar strange behavior in the debugger itself, when the thread of the backtrace I’m examining is paused.

Bill