How to clear regexp-replace history?

Question

I wrote a bad bit of elisp when trying to do a query-replace-regexp.

The text to replace was like this:

* list item

And I wanted it to be

* List item

My query-replace-regexp match was written as:

^\* \([a-z]\{1\}\) 

And the match, where I used the wrong elisp, was:

* \,(upcase-word \1)  ;; should have been * \,(capitalize \1)

I get this error: Wrong type argument: number-or-marker-p, replace-eval-replacement

If I try to run query-replace-regexp again, I get the same error and cannot edit the replacement text. All I can do is exit Emacs and restart it. I assume there must be some way to clear the history, but I can't find it.

Suggested on twitter was (setq regexp-history nil) but no luck.

This is Emacs 25.0.50.

Answer 1

If you only want to clear the default values that come up when restarting query-replace-regexp, you can clobber them with:

(setq query-replace-defaults nil)

If you want to nuke the entire history as well, you can do:

(setq query-replace-history nil)

Answer 2

@Dan's answer is good, and it clears the bad entry out of your history for good.

Just FYI, another possibility would have been to do C-x ESC ESC, and then edit the search pattern.

That brings up the full last command you executed, as a Lisp sexp, which you can edit. (If you had used other commands in the meantime then you could use M-p to move backward in this history (the extended-command history), which is different (and acts differently) from the query-replace-history.)

That would have let you use query-replace-regexp again without clearing its history. Not that there is any reason here not to clear the history, but it can be good to know of more than one way to skin the cat.