bug#2333: 23.0.90; rmail: rmail-summary-by-topic is not reliable

[Glenn Morris <rgm@gnu.org>]

Xavier Maillard wrote:

>  7840D  3-Feb          admin@flosoft.biz [114] { summit } Re: [Summit] Prepaid cellphones
[...]
> Doing C-M-t RET -i.e. choosing default subject as the topic returns:
> No previous message. More generally, rmail-summary-by-topic is
> rather unreliable since less than 50% of the time it will return
> correct results.

One problem is that rmail-summary-by-topic does not regexp-quote the
default expression to search for. This leads to the confusing result
that you can fail to find the current message, if the subject happens
to contain regexp special characters, eg "[ ]" in your example.

The patch for that is trivial, and seems like the right thing to do.

The "no previous message" message indicates that more care needs to be
taken somewhere when there are no matches.


*** rmailsum.el	15 Feb 2009 02:52:16 -0000	1.170
--- rmailsum.el	18 Feb 2009 21:55:17 -0000
***************
*** 155,161 ****
   look in the whole message.
  SUBJECT is a string of regexps separated by commas."
    (interactive
!    (let* ((subject (rmail-simplified-subject))
  	  (prompt (concat "Topics to summarize by (regexp"
  			  (if subject ", default current subject" "")
  			  "): ")))
--- 155,161 ----
   look in the whole message.
  SUBJECT is a string of regexps separated by commas."
    (interactive
!    (let* ((subject (regexp-quote (rmail-simplified-subject)))
  	  (prompt (concat "Topics to summarize by (regexp"
  			  (if subject ", default current subject" "")
  			  "): ")))