Don't go though a shell in gdb.debug

gdbserver starts a shell and runs the target process through it.
This behavior was added in gdbserver 8.0 together with the
commandline flag --no-startup-with-shell to disable it.

Author: peace-maker

pwnlib/gdb.py

@@ -323,7 +323,9 @@ def _gdbserver_args(pid=None, path=None, args=None, which=None, env=None, python
 
     orig_args = args
 
-    gdbserver_args = [gdbserver, '--multi']
+    # --no-startup-with-shell is required for forking shells like SHELL=/bin/fish
+    # https://github.com/Gallopsled/pwntools/issues/2377
+    gdbserver_args = [gdbserver, '--multi', '--no-startup-with-shell']
     if context.aslr:
         gdbserver_args += ['--no-disable-randomization']
     else: