bug in minibuffer-complete-and-exit, fix included

[Ryan Barrett <emacs@ryanb.org>]

hi all. i recently noticed a bug in minibuffer-complete-and-exit. if
completion-ignore-case is t, and the minibuffer contains a valid completion in
the wrong case, its case isn't fixed. it should be.

sorry, that was a mouthful. :P here's an example. if foo is a possible
completion, and you enter FoO in the minibuffer, minibuffer-complete-and-exit
returns FoO. it should return foo instead.

this spreads to other code that uses the minibuffer. for example, read-buffer
has an optional arg require-match. if t, an existing buffer name must be
entered. the list of existing buffer names is used as completions. if
completion-ignore-case is t, and you enter an existing buffer name *in the
wrong case*, it's not completed to the right case. (same with read-file-name
and mustmatch.)

here's a test case. run emacs -q, then evaluate these forms:

   (setq completion-ignore-case t)
   (read-buffer "buffer name: " nil t)

enter *scrATCH* at the prompt. it returns *scrATCH*, but it should return
*scratch*.

the patch below, against CVS, fixes this. if i understand the process right,
it's small enough that you can include it without papers. hopefully it's also
small enough to consider for the emacs 22 release.


*** minibuf.c       21 Dec 2005 17:33:40 -0000      1.297
--- minibuf.c       27 Dec 2005 07:39:07 -0000
***************
*** 2139,2145 ****
           if (STRINGP (compl)
               /* If it weren't for this piece of paranoia, I'd replace
                  the whole thing with a call to do_completion. */
!             && EQ (Flength (val), Flength (compl)))
             {
               del_range (XINT (Fminibuffer_prompt_end ()), ZV);
               Finsert (1, &compl);
--- 2139,2145 ----
           if (STRINGP (compl)
               /* If it weren't for this piece of paranoia, I'd replace
                  the whole thing with a call to do_completion. */
!             && EQ (XFASTINT (Flength (val)), XFASTINT (Flength (compl))))
             {
               del_range (XINT (Fminibuffer_prompt_end ()), ZV);
               Finsert (1, &compl);

-Ryan

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