wrap rr macros restart and jump in python

[GitMensch]

fixes #3859 warnings during startup

[GitMensch]

Looks like it is working - CI fails with an unrelated error during build:

/tmp/actions-runner/_work/rr/rr/src/test/open_null.c: In function ‘main’:
/tmp/actions-runner/_work/rr/rr/src/test/open_null.c:8:20: error: ‘SYS_open’ undeclared (first use in this function); did you mean ‘SYS_fsopen’?
    8 |   int fd = syscall(SYS_open, NULL, O_RDONLY);
      |                    ^~~~~~~~
      |                    SYS_fsopen
/tmp/actions-runner/_work/rr/rr/src/test/open_null.c:8:20: note: each undeclared identifier is reported only once for each function it appears in

[sidkshatriya]

This commit causes a regression on both Fedora 40 (has gdb 15.2-1.fc40) and Fedora 41 (has gdb 15.2-1.fc41) .

A few tests start failing. e.g. ctest -R checkpoint_mmap_shared. Reverting this specific commit causes the tests to pass again.

[GitMensch]

Can you please give some details on the failure? "Doesn't work" is hardly something I can work with :-/

[user202729]

I think the problem is you're having \n in C++ code, which passes the literal newline to gdb, which of course will break because then the python command will just be the first line.

Replace \n with \\n might work (or split the whole thing to multiple lines and use triple-quote, see e.g. the Python block below), but I haven't tested locally.

Maybe you need a trailing \n on each python command too.

(On another note, does GitHub Actions not run on Fedora?)

p/s: sorry, didn't have time to send a PR myself.

[sidkshatriya]

@GitMensch

Can you please give some details on the failure? "Doesn't work" is hardly something I can work with :-/

Sorry -- I didn't have time to debug the issue. I simply reverted the commit and saw the tests working again. Are you able to run the test checkpoint_mmap_shared on your local machine ? If the test fails for you also I think you will be able to then debug the error.

[sidkshatriya]

@user202729

(On another note, does GitHub Actions not run on Fedora?)

Looking at the "Details" button where this commit was merged it does not seem the CI tests were run at all.

@GitMensch
Here is the error taken from the gdb log (for ctest -R checkpoint_mmap_shared)

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from /tmp/rr-test-checkpoint_mmap_shared-VbXYvN2mk/mmap_shared-VbXYvN2mk-0/mmap_hardlink_3_mmap_shared-VbXYvN2mk..
  File "<string>", line 1
    gdb.execute('define jump
                ^
SyntaxError: unterminated string literal (detected at line 1)
/proc/4133/fd/5:180: Error in sourced command file:
Error occurred in Python: unterminated string literal (detected at line 1) (<string>, line 1)
...
...

[GitMensch]

Ah, yes, that makes sense: executing python gdb.execute('define restart\nrun c$arg0\nend') in GDB works fine - but we need to escape the \n for the C++ literal. I'm working on that now.

[sidkshatriya]

@user202729 was correct in their analysis. The following diff causes the test to pass again.

--- a/src/launch_debugger.cc
+++ b/src/launch_debugger.cc
@@ -50,8 +50,8 @@ static const string& gdb_rr_macros() {
     ss << DebuggerExtensionCommandHandler::gdb_macros()
        // gdb warns about redefining inbuilt commands, silence that by
        // wrapping it in python code
-       << "python gdb.execute('define jump\nrr-denied jump\nend')"
-       << "python gdb.execute('define restart\nrun c$arg0\nend')"
+       << "python gdb.execute('define jump\\nrr-denied jump\\nend')\n"
+       << "python gdb.execute('define restart\\nrun c$arg0\\nend')\n"
        << "document restart\n"
        << "restart at checkpoint N\n"
        << "checkpoints are created with the 'checkpoint' command\n"

[sidkshatriya]

@GitMensch The commit that you added to GitMensch@9f7c2fc will not work as you need a \n at the end of the C++ string. Please see the diff that I posted above.

---

Nevermind -- I see you added that in GitMensch@fae42c2 -- Cool !

[GitMensch]

Should be fixed with #3869 ... which in the end ended with exactly the diff from above.