[PATCH 37/40] Fix completing an empty string

Pedro Alves
2017-06-02T12:23:27Z

While working on this series, I managed to break

(gdb) [TAB]

locally, and make GDB crash in the big completer rework, but only
notice a few weeks down the road, because we have no test for that...

I also noticed that:

(gdb) [TAB]

didn't work (didn't show all commands as matches), even though
entering a command with leading whitespace works:

(gdb) help

This commit fixes the latter and adds a testcase that covers both issues.

The gdb.base/completion.exp change is necessary because the new test has a
file name that also starts with "gdb.base/complet", making that particular
test ambiguous. Adding another letter disambiguates.

gdb/testsuite/ChangeLog:
yyyy-mm-dd Pedro Alves <palves@redhat.com>

* completer.c (complete_line_internal_1): Skip spaces until the
start of the command.
* gdb.base/complete-empty.exp: New file.
* gdb.base/completion.exp: Adjust.
---
gdb/completer.c | 9 ++++--
gdb/testsuite/gdb.base/complete-empty.exp | 46 +++++++++++++++++++++++++++++++
gdb/testsuite/gdb.base/completion.exp | 6 ++--
3 files changed, 55 insertions(+), 6 deletions(-)
create mode 100644 gdb/testsuite/gdb.base/complete-empty.exp

diff --git a/gdb/completer.c b/gdb/completer.c
index 99e40a3..74269ad 100644
--- a/gdb/completer.c
+++ b/gdb/completer.c
@@ -1286,10 +1286,13 @@ complete_line_internal_1 (completion_tracker &tracker,
word = tmp_command + point - strlen (text);
}

- if (point == 0)
+ /* Move P up to the start of the command. */
+ p = skip_spaces_const (p);
+
+ if (*p == '\0')
{
- /* An empty line we want to consider ambiguous; that is, it
- could be any command. */
+ /* An empty line is ambiguous; that is, it could be any
+ command. */
c = CMD_LIST_AMBIGUOUS;
result_list = 0;
}
diff --git a/gdb/testsuite/gdb.base/complete-empty.exp b/gdb/testsuite/gdb.base/complete-empty.exp
new file mode 100644
index 0000000..79f9629
--- /dev/null
+++ b/gdb/testsuite/gdb.base/complete-empty.exp
@@ -0,0 +1,46 @@
+# Copyright 2017 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+load_lib completion-support.exp
+
+gdb_exit
+gdb_start
+
+set timeout 5
+
+# Start of tests.
+
+# Test TAB with no input.
+proc_with_prefix empty-input-line {} {
+ # Set max-completions to 1 to avoid having to hardcode a set of
+ # command names.
+ gdb_test_no_output "set max-completions 1"
+
+ # Given the completion limit, this completes to the command with
+ # the lowest alphanumeric sort, which is, and is likely to remain,
+ # "!".
+ test_gdb_complete_unique "" "!" " " 1
+
+ # Same, but with some leading whitespace.
+ test_gdb_complete_unique " " " !" " " 1
+}
+
+proc test_driver {} {
+ empty-input-line
+}
+
+test_driver
diff --git a/gdb/testsuite/gdb.base/completion.exp b/gdb/testsuite/gdb.base/completion.exp
index f03bfc3..a9a8e4f 100644
--- a/gdb/testsuite/gdb.base/completion.exp
+++ b/gdb/testsuite/gdb.base/completion.exp
@@ -722,13 +722,13 @@ gdb_test "complete file ./gdb.base/compl" \
"file ./gdb.base/completion\\.exp.*" \
"complete-command 'file ./gdb.base/compl'"

-set test "complete 'file ./gdb.base/complet'"
-send_gdb "file ./gdb.base/complet\t"
+set test "complete 'file ./gdb.base/completi'"
+send_gdb "file ./gdb.base/completi\t"
gdb_test_multiple "" "$test" {
-re "^file ./gdb.base/completion\\.exp $" {
send_gdb "\n"
# Ignore the exact error message.
- gdb_test_multiple "" "complete 'file ./gdb.base/complet'" {
+ gdb_test_multiple "" "complete 'file ./gdb.base/completi'" {
-re "\r\nA program is being debugged already\\.\[\r\n\]+Are you sure you want to change the file\\? \\(y or n\\) $" {
send_gdb "n\n"
exp_continue
--
2.5.5