Variable: search-invisible
search-invisible is a customizable variable defined in isearch.el.gz.
Value
open
Documentation
If t incremental search/query-replace can match hidden text.
A nil value means don't match invisible text.
When the value is open, if the text matched is made invisible by
an overlay having a non-nil invisible property, and that overlay
has a non-nil property isearch-open-invisible, then incremental
search will show the hidden text. (This applies when using outline.el
and hideshow.el.)
To temporarily change the value for an active incremental search,
use M-s i (isearch-toggle-invisible).
See also the related option isearch-hide-immediately.
See also reveal-mode(var)/reveal-mode(fun) if you want overlays to automatically be opened
whenever point is in one of them.
Probably introduced at or before Emacs version 20.3.
Source Code
;; Defined in /usr/src/emacs/lisp/isearch.el.gz
(defcustom search-invisible 'open
"If t incremental search/query-replace can match hidden text.
A nil value means don't match invisible text.
When the value is `open', if the text matched is made invisible by
an overlay having a non-nil `invisible' property, and that overlay
has a non-nil property `isearch-open-invisible', then incremental
search will show the hidden text. (This applies when using `outline.el'
and `hideshow.el'.)
To temporarily change the value for an active incremental search,
use \\<isearch-mode-map>\\[isearch-toggle-invisible].
See also the related option `isearch-hide-immediately'.
See also `reveal-mode' if you want overlays to automatically be opened
whenever point is in one of them."
:type '(choice (const :tag "Match hidden text" t)
(const :tag "Open overlays" open)
(const :tag "Don't match hidden text" nil)))