Previous implementation of Scylla lifecycle brought flakiness to the test.
This change leaves lifecycle management up to PythonTest.run_ctx,
which implements more stability logic for setup/teardown.
Replace pexpect-driven GDB interaction with GDB batch mode:
- Avoids DeprecationWarning: "This process is multi-threaded, use of forkpty()
may lead to deadlocks in the child.", which ultimately caused CI deadlocks.
- Removes timeout-driven flakiness on slow systems - no interactive waits/timeouts.
- Produces cleaner, more direct assertions around command execution and output.
- Trade-off: batch mode adds ~10s per command per test,
but with --dist=worksteal this is ~10% overall runtime increase across the suite.
Closesscylladb/scylladb#28484
This commit replaces the previous approach of running pytest inside
GDB’s Python interpreter. Instead, tests are executed by driving a
persistent GDB process externally using pexpect.
- pexpect: Python library for controlling interactive programs
(used here to send commands to GDB and capture its output)
- persistent GDB: keep one GDB session alive across multiple tests
instead of starting a new process for each test
Tests can now be executed via `./test.py gdb` or with
`pytest test/scylla_gdb`. This improves performance and
makes failures easier to debug since pytest no longer runs
hidden inside GDB subprocesses.
Closesscylladb/scylladb#24804
