[binutils-gdb] [gdb/python] Handle error in gdbpy_initialize_gdb_readline
Tom de Vries via Gdb-cvs <[email protected]>
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https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=25f1035f403c929a38d822f0525ec1bb180fffb5 commit 25f1035f403c929a38d822f0525ec1bb180fffb5 Author: Tom de Vries <[email protected]> Date: Wed Aug 12 23:11:46 2026 +0200 [gdb/python] Handle error in gdbpy_initialize_gdb_readline On Fedora Rawhide aarch64-linux, with test-case gdb.python/py-failed-init.exp I ran into: ... builtin_spawn $build/gdb/gdb -nw -nx -q -iex set height 0 -iex set width 0 \ -data-directory $build/gdb/data-directory -iex set interactive-mode on WARN: Could not find the standard library directory! The Python 'home' \ directory was set to 'foo', is this correct? Error occurred computing Python error message. $build/gdb/gdb: warning: Could not load the Python gdb module from `$build/gdb/data-directory/python'. Limited Python support is available from the _gdb module. Suggest passing --data-directory=/path/to/gdb/data-directory. (gdb) set height 0 (gdb) set width 0 (gdb) dir Reinitialize source path to empty? (y or n) y Source directories searched: $cdir:$cwd (gdb) dir $src/gdb/testsuite/gdb.python Source directories searched: $src/gdb/testsuite/gdb.python:$cdir:$cwd (gdb) python print (1) 1 (gdb) FAIL: $exp: gdb-command<python print (1)> quit Exception ignored on threading shutdown: Traceback (most recent call last): File "<string>", line 2, in <module> ModuleNotFoundError: No module named 'importlib' PASS: $exp: quit ... The test-case tries to break python: ... save_vars { env(PYTHONHOME) } { setenv PYTHONHOME foo clean_restart } ... enough to get it to this point: ... gdb_test "python print (1)" \ "Python not initialized" ... but apparently, that doesn't work anymore in this python version: ... $ python --version Python 3.15.0b4 ... The test-case needs updating, and I've submitted a testsuite patch [1] for that. The next question is why we're seeing a ModuleNotFoundError on quit. I investigated this, and found that it originates from gdbpy_initialize_gdb_readline, where we do: ... if (eval_python_command (code, Py_file_input) == 0) PyOS_ReadlineFunctionPointer = gdbpy_readline_wrapper; ... but don't report and reset the python error state, so instead the error is reported by Py_Finalize. Fix this by: - making sure that the error is reported immediately, though in the form of a warning rather than an error, and - disabling the python-interactive command if gdbpy_initialize_gdb_readline fails, to avoid broken readline behavior in a python-interactive session. Also make the test-case a bit stricter by checking that there's no output when quitting. Tested on aarch64-linux. Approved-By: Tom Tromey <[email protected]> Changes in v2: - use gdbpy_print_stack instead of PyErr_Print/PyErr_Clear - Fix error/warning message by ensure that command name is double-quoted and displayed using command_style Versions: - v1 https://sourceware.org/pipermail/gdb-patches/2026-August/229261.html Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=34485 [1] https://sourceware.org/pipermail/gdb-patches/2026-August/229193.html Diff: --- gdb/python/py-gdb-readline.c | 17 +++++++++++++++++ gdb/python/python-internal.h | 5 +++++ gdb/python/python.c | 4 ++++ gdb/testsuite/gdb.python/py-failed-init.exp | 6 ++++++ 4 files changed, 32 insertions(+) diff --git a/gdb/python/py-gdb-readline.c b/gdb/python/py-gdb-readline.c index e8e2c23547c..1bb83adcc42 100644 --- a/gdb/python/py-gdb-readline.c +++ b/gdb/python/py-gdb-readline.c @@ -19,7 +19,9 @@ #include "python-internal.h" #include "top.h" +#include "ui-out.h" #include "cli/cli-utils.h" +#include "cli/cli-style.h" /* Readline function suitable for PyOS_ReadlineFunctionPointer, which is used for Python's interactive parser and raw_input. In both @@ -116,8 +118,23 @@ sys.meta_path.insert(2, GdbRemoveReadlineFinder())\n\ "; if (eval_python_command (code, Py_file_input) == 0) PyOS_ReadlineFunctionPointer = gdbpy_readline_wrapper; + else + { + gdbpy_print_stack (); + + warning (_("Disabling import readline failed, \"%ps\" command disabled"), + styled_string (command_style.style (), "python-interactive")); + } return 0; } +/* See python-internal.h. */ + +bool +gdbpy_import_readline_disabled () +{ + return PyOS_ReadlineFunctionPointer == gdbpy_readline_wrapper; +} + GDBPY_INITIALIZE_FILE (gdbpy_initialize_gdb_readline); diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h index 1165f165e29..3be1cc3ad55 100644 --- a/gdb/python/python-internal.h +++ b/gdb/python/python-internal.h @@ -1391,4 +1391,9 @@ py_notimplemented () #include "py-wrappers.h" #include "py-safety.h" +/* Return true if import readline was successfully disabled during + initialization. */ + +extern bool gdbpy_import_readline_disabled (); + #endif /* GDB_PYTHON_PYTHON_INTERNAL_H */ diff --git a/gdb/python/python.c b/gdb/python/python.c index 7b5de98b903..0d6134ef060 100644 --- a/gdb/python/python.c +++ b/gdb/python/python.c @@ -383,6 +383,10 @@ eval_python_command (const char *command, int start_symbol, static void python_interactive_command (const char *arg, int from_tty) { + if (!gdbpy_import_readline_disabled ()) + error (_("Disabling import readline failed, \"%ps\" command disabled"), + styled_string (command_style.style (), "python-interactive")); + struct ui *ui = current_ui; int err; diff --git a/gdb/testsuite/gdb.python/py-failed-init.exp b/gdb/testsuite/gdb.python/py-failed-init.exp index 622743d8d9b..c2b9c990e29 100644 --- a/gdb/testsuite/gdb.python/py-failed-init.exp +++ b/gdb/testsuite/gdb.python/py-failed-init.exp @@ -24,8 +24,14 @@ save_vars { env(PYTHONHOME) } { gdb_test "python print (1)" \ "Python not initialized" +set output_seen 0 gdb_test_multiple "quit" "" { + -re ^quit\r\n { + exp_continue + } eof { + set output_seen [expr [string length $expect_out(buffer)] != 0] pass $gdb_test_name } } +gdb_assert {!$output_seen} "no output after quit"