bug#7883: [PATCH] comint history expansion fails to process :N or $ modifier

[Roland McGrath]

This has been driving me nuts since I started using 23 and I only just now
bothered to find and fix it.  This worked correctly in 22 and was broken,
apparently just by a careless change.

In a comint/shell buffer, type:
        echo foo bar RET
and then type:
        echo !$ TAB
and you get the expansion:
        echo echo foo bar
i.e., the whole line as if !$ had been !!.
The expansion you should get is just:
        echo bar

The following trivial patch fixes the bug, restoring the behavior of v22
with similar code to what it had originally.  I tested the fix in 23.2.1,
but the relevant comint.el code in the trunk has not changed since then.


Thanks,
Roland


2011-01-21  Roland McGrath  <roland@frob.com>

        * comint.el (comint-replace-by-expanded-history-before-point):
        Fix expansion of !$ and !!:N syntax to pick the indicated word.

--- lisp/comint.el      2011-01-20 22:36:12 +0000
+++ lisp/comint.el      2011-01-21 18:03:09 +0000
@@ -1294,7 +1294,9 @@ than the logical beginning of line."
                   (message "Relative reference exceeds input history size"))))
              ((or (looking-at "!!?:?\\([0-9^$*-]+\\)") (looking-at "!!"))
               ;; Just a number of args from the previous input line.
-              (replace-match (comint-previous-input-string 0) t t)
+              (replace-match (comint-args (comint-previous-input-string 0)
+                                          (match-beginning 1) (match-end 1))
+                             t t)
               (message "History item: previous"))
              ((looking-at
                "!\\??\\({\\(.+\\)}\\|\\(\\sw+\\)\\)\\(:?[0-9^$*-]+\\)?")