From 935dc9ff652ca256c10672412c1df3da95cadbfb Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Thu, 16 Nov 2023 14:42:56 +0000 Subject: [PATCH] gdb/python: handle completion returning a non-sequence GDB's Python API documentation for gdb.Command.complete() says: The 'complete' method can return several values: * If the return value is a sequence, the contents of the sequence are used as the completions. It is up to 'complete' to ensure that the contents actually do complete the word. A zero-length sequence is allowed, it means that there were no completions available. Only string elements of the sequence are used; other elements in the sequence are ignored. * If the return value is one of the 'COMPLETE_' constants defined below, then the corresponding GDB-internal completion function is invoked, and its result is used. * All other results are treated as though there were no available completions. So, returning a non-sequence, and non-integer from a complete method should be fine; it should just be treated as though there are no completions. However, if I write a complete method that returns None, I see this behaviour: (gdb) complete completefilenone x Python Exception : 'NoneType' object is not iterable warning: internal error: Unhandled Python exception (gdb) Which is caused because we currently assume that anything that is not an integer must be iterable, and we call PyObject_GetIter on it. When this call fails a Python exception is set, but instead of clearing (and therefore ignoring) this exception as we do everywhere else in the Python completion code, we instead just return with the exception set. In this commit I add a PySequence_Check call. If this call returns false (and we've already checked the integer case) then we can assume there are no completion results. I've added a test which checks returning a non-sequence. Approved-By: Tom Tromey --- gdb/python/py-cmd.c | 2 +- gdb/testsuite/gdb.python/py-completion.exp | 5 +++++ gdb/testsuite/gdb.python/py-completion.py | 12 ++++++++++++ 3 files changed, 18 insertions(+), 1 deletion(-) diff --git a/gdb/python/py-cmd.c b/gdb/python/py-cmd.c index 20a384d6907..d3845fc7509 100644 --- a/gdb/python/py-cmd.c +++ b/gdb/python/py-cmd.c @@ -290,7 +290,7 @@ cmdpy_completer (struct cmd_list_element *command, else if (value >= 0 && value < (long) N_COMPLETERS) completers[value].completer (command, tracker, text, word); } - else + else if (PySequence_Check (resultobj.get ())) { gdbpy_ref<> iter (PyObject_GetIter (resultobj.get ())); diff --git a/gdb/testsuite/gdb.python/py-completion.exp b/gdb/testsuite/gdb.python/py-completion.exp index 23f981e944a..89843c96f1f 100644 --- a/gdb/testsuite/gdb.python/py-completion.exp +++ b/gdb/testsuite/gdb.python/py-completion.exp @@ -46,6 +46,11 @@ if { [readline_is_used] && ![is_remote host] } { # Just discarding whatever we typed. gdb_test " " ".*" "discard #[incr discard]" + # This should offer no suggestions - the complete() methods + # returns something that is neither an integer, or a sequence. + gdb_test_no_output "complete completefilenone ${testdir_complete}" \ + "no suggestions given" + # This is the problematic one. send_gdb "completefilemethod ${testdir_complete}\t" gdb_test_multiple "" "completefilemethod completion" { diff --git a/gdb/testsuite/gdb.python/py-completion.py b/gdb/testsuite/gdb.python/py-completion.py index abec06921c0..61b6beffa25 100644 --- a/gdb/testsuite/gdb.python/py-completion.py +++ b/gdb/testsuite/gdb.python/py-completion.py @@ -28,6 +28,17 @@ class CompleteFileInit(gdb.Command): raise gdb.GdbError("not implemented") +class CompleteFileNone(gdb.Command): + def __init__(self): + gdb.Command.__init__(self, "completefilenone", gdb.COMMAND_USER) + + def invoke(self, argument, from_tty): + raise gdb.GdbError("not implemented") + + def complete(self, text, word): + return None + + class CompleteFileMethod(gdb.Command): def __init__(self): gdb.Command.__init__(self, "completefilemethod", gdb.COMMAND_USER) @@ -203,6 +214,7 @@ class CompleteLimit7(gdb.Command): CompleteFileInit() +CompleteFileNone() CompleteFileMethod() CompleteFileCommandCond() CompleteLimit1()