tree 9ec19b8da62f33b3a71c55310c67dbc875d03d50
parent 9dedc2ac713d23609e4c41068fd5efa175217945
author Andrew Burgess <aburgess@redhat.com> 1726135014 +0100
committer Andrew Burgess <aburgess@redhat.com> 1727691731 +0100

gdb: fix filename completion in the middle of a line

I noticed that filename completion in the middle of a line doesn't
work as I would expect it too.  For example, assuming '/tmp/filename'
exists, and is the only file in '/tmp/' then when I do the following:

  (gdb) file "/tmp/filen<TAB>

GDB completes to:

  (gdb) file "/tmp/filename"

But, if I type this:

  (gdb) file "/tmp/filen "xxx"

Then move the cursor to the end of '/tmp/filen' and press <TAB>, GDB
will complete the line to:

  (gdb) file "/tmp/filename "xxx"

But GDB will not insert the trailing double quote character.

The reason for this is found in readline/readline/complete.c in the
function append_to_match.  This is the function that appends the
trailing closing quote character, however, the closing quote is only
inserted if the cursor (rl_point) is at the end (rl_end) of the line
being completed.

In this patch, what I do instead is add the closing quote in the
function gdb_completer_file_name_quote, which is called from readline
through the rl_filename_quoting_function hook.  The docs for
rl_filename_quoting_function say (see 'info readline'):

  "... The MATCH_TYPE is either 'SINGLE_MATCH', if there is only one
  completion match, or 'MULT_MATCH'.  Some functions use this to
  decide whether or not to insert a closing quote character. ..."

This is exactly what I'm doing in this patch, and clearly this is not
an unusual choice.  Now after completing a filename that is not at the
end of the line GDB will add the closing quote character if
appropriate.

I have managed to write some tests for this.  I send a line of text to
GDB which includes a partial filename followed by a trailing string, I
then send the escape sequence to move the cursor left, and finally I
send the tab character.

Obviously, expect doesn't actually see the complete output with the
extra text "in place", instead expect sees the original line followed
by some escape sequences to reflect the cursor movement, then an
escape sequence to indicate that text is being inserted in the middle
of a line, followed by the new characters ... it's a bit messy, but I
think it holds together.

Reviewed-By: Tom Tromey <tom@tromey.com>