[PATCH 02/24] Fix latent bug with custom word point completers

Pedro Alves
2019-05-22T20:53:33Z

Completion routines that use a custom word point, and that then
recurse into complete_line (e.g., if we make "thread apply" a custom
word point completer, and complete on the command passed as argument),
we stumble on this latent bug:

(gdb) thread apply all pri[TAB]
(gdb) thread apply all priprint

The problem is that there's a spot in complete_line_internal_1 that
rewinds the completion word but does not reflect that change in the
custom word point in the tracker. This patch fixes it.

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

* completer.c (complete_line_internal_1): Rewind completion word
point.
(completion_tracker::advance_custom_word_point_by): Change
parameter type to int.
* completer.h (completion_tracker::advance_custom_word_point_by):
Likewise.
---
gdb/completer.c | 5 ++++-
gdb/completer.h | 2 +-
2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/gdb/completer.c b/gdb/completer.c
index ee2eec1a35a..e86b0531f54 100644
--- a/gdb/completer.c
+++ b/gdb/completer.c
@@ -1405,6 +1405,9 @@ complete_line_internal_1 (completion_tracker &tracker,
break;
}

+ /* Move the custom word point back too. */
+ tracker.advance_custom_word_point_by (q - p);
+
if (reason != handle_brkchars)
complete_on_cmdlist (result_list, tracker, q, word,
ignore_help_classes);
@@ -1976,7 +1979,7 @@ completion_tracker::recompute_lowest_common_denominator
/* See completer.h. */

void
-completion_tracker::advance_custom_word_point_by (size_t len)
+completion_tracker::advance_custom_word_point_by (int len)
{
m_custom_word_point += len;
}
diff --git a/gdb/completer.h b/gdb/completer.h
index 38a0132ca4d..27371b63a57 100644
--- a/gdb/completer.h
+++ b/gdb/completer.h
@@ -357,7 +357,7 @@ public:
{ m_custom_word_point = point; }

/* Advance the custom word point by LEN. */
- void advance_custom_word_point_by (size_t len);
+ void advance_custom_word_point_by (int len);

/* Whether to tell readline to skip appending a whitespace after the
completion. See m_suppress_append_ws. */
--
2.14.5