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author | Tom de Vries <tdevries@suse.de> | 2022-09-16 15:53:47 +0200 |
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committer | Tom de Vries <tdevries@suse.de> | 2022-09-16 15:53:47 +0200 |
commit | faf01aee1d03aef5b6f95fd0db358bf5e70578f9 (patch) | |
tree | f6015c486a536822de5eba4c43292414de60d761 /gdb | |
parent | 49c3ed081fed6b8e2b48fdc48f805f11e4589514 (diff) | |
download | gdb-faf01aee1d03aef5b6f95fd0db358bf5e70578f9.zip gdb-faf01aee1d03aef5b6f95fd0db358bf5e70578f9.tar.gz gdb-faf01aee1d03aef5b6f95fd0db358bf5e70578f9.tar.bz2 |
[gdb] Handle pending ^C after rl_callback_read_char
In completion tests in various test-cases, we've been running into these
"clearing input line" timeouts:
...
(gdb) $cmd^GPASS: gdb.gdb/unittest.exp: tab complete "$cmd"
FAIL: gdb.gdb/unittest.exp: tab complete "$cmd" (clearing input line) (timeout)
...
where $cmd == "maintenance selftest name_that_does_not_exist".
AFAIU, the following scenario happens:
- expect sends "$cmd\t"
- gdb detects the stdin event, and calls rl_callback_read_char until it
comes to handle \t
- readline interprets the \t as completion, tries to complete, fails to do so,
outputs a bell (^G)
- expect sees the bell, and proceeds to send ^C
- readline is still in the call to rl_callback_read_char, and stores the
signal in _rl_caught_signal
- readline returns from the call to rl_callback_read_char, without having
handled _rl_caught_signal
- gdb goes to wait for the next event
- expect times out waiting for "Quit", the expected reaction for ^C
Fix this by handling pending signals after each call to rl_callback_read_char.
The fix is only available for readline 8.x, if --with-system-readline provides
an older version, then the fix is disabled due to missing function
rl_check_signals.
Tested on x86_64-linux.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27813
Diffstat (limited to 'gdb')
-rw-r--r-- | gdb/event-top.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/gdb/event-top.c b/gdb/event-top.c index 290c3d8..00adbe8f 100644 --- a/gdb/event-top.c +++ b/gdb/event-top.c @@ -186,6 +186,22 @@ gdb_rl_callback_read_char_wrapper_noexcept () noexcept TRY_SJLJ { rl_callback_read_char (); +#if RL_VERSION_MAJOR >= 8 + /* It can happen that readline (while in rl_callback_read_char) + received a signal, but didn't handle it yet. Make sure it's handled + now. If we don't do that we run into two related problems: + - we have to wait for another event triggering + rl_callback_read_char before the signal is handled + - there's no guarantee that the signal will be processed before the + event. */ + while (rl_pending_signal () != 0) + /* Do this in a while loop, in case rl_check_signals also leaves a + pending signal. I'm not sure if that's possible, but it seems + better to handle the scenario than to assert. */ + rl_check_signals (); +#else + /* Unfortunately, rl_check_signals is not available. */ +#endif if (after_char_processing_hook) (*after_char_processing_hook) (); } |