When building gdb on ubuntu 16.04 with gcc 5.4.0, and running the gdb
testsuite we run into:
...
FAIL: gdb.linespec/explicit.exp: complete after -line: \
cmd complete "b -line argument " (timeout)
...
The failure is reproducible outside the testsuite like this:
...
$ gdb -q build/gdb/testsuite/outputs/gdb.linespec/explicit/explicit \
-ex "complete b -line argument"
Reading symbols from \
build/gdb/testsuite/outputs/gdb.linespec/explicit/explicit...
terminate called after throwing an instance of 'std::length_error'
what(): basic_string::_M_create
Aborted (core dumped)
...
The problem is here in complete_command:
...
completion_result result = complete (arg, &word, "e_char);
std::string arg_prefix (arg, word - arg);
if (result.number_matches != 0)
...
The problem is that the word variable is not initialized when
result.number_matches == 0, but the variable is still used in the arg_prefix
initialization.
Fix this by guarding the arg_prefix initialization with the
'result.number_matches != 0' test.
Build and tested on x86_64-linux.
gdb/ChangeLog:
2019-05-21 Tom de Vries <tdevries@suse.de>
PR cli/24587
* cli/cli-cmds.c (complete_command): Fix use of unitialized variable.
fb7806c7a4