bug#11378: 24.1.50; Suggestion: Let M-i in isearch cycle `search-invisible'

[Juri Linkov <juri@jurta.org>]

>>> I was thinking that maybe a cycling behavior would be better than
>>> toggling for these: off / foo-only / foo-excluded.
>>
>> Maybe something like this:
>
> Sounds about right, thank you,

Now that text proprieties on the search string can be saved in the desktop file,
I tried to save the isearch-filter-predicate with advice-functions, and
set it back to the search string, but this fails.

An example of the search string saved in the search ring in the desktop file:

#("string" 0 6 (isearch-filter-predicate #1=#[128 #2="\300\301\2\"\205\13\0\300\302\2\"\207"
              [apply isearch-filter-textual #[128 #3="\301\302\300!\2\"\207"
              [isearch-filter-predicate apply default-value] 4 #4="\n\n(fn &rest ARGS)"]
              #5=((isearch-message-prefix . "textual "))] 4 nil]))

After it's restored by desktop.el using `load' and set from the restored string
with (setq isearch-filter-predicate ...) it goes into an infinite loop:

Debugger entered--Lisp error: (error "Lisp nesting exceeds ‘max-lisp-eval-depth’")
  ...
  apply(#f(compiled-function (&rest args) #<bytecode 0x2958aa5>) (12237 12244))
  #f(advice-wrapper :before-while #f(compiled-function (&rest args) #<bytecode 0x2958aa5>) isearch-filter-nontextual ((isearch-message-prefix . "nontextual ")))(12237 12244)
  apply(#f(advice-wrapper :before-while #f(compiled-function
  #f(compiled-function (&rest args) #<bytecode 0x2958aa5>)(12237 12244)
  apply(#f(compiled-function (&rest args) #<bytecode 0x2958aa5>) (12237 12244))
  #f(advice-wrapper :before-while #f(compiled-function (&rest args) #<bytecode 0x2958aa5>) isearch-filter-nontextual ((isearch-message-prefix . "nontextual ")))(12237 12244)
  apply(#f(advice-wrapper :before-while #f(compiled-function
  #f(compiled-function (&rest args) #<bytecode 0x2958aa5>)(12237 12244)
  apply(#f(compiled-function (&rest args) #<bytecode 0x2958aa5>) (12237 12244))
  #f(advice-wrapper :before-while #f(compiled-function (&rest args) #<bytecode 0x2958aa5>) isearch-filter-nontextual ((isearch-message-prefix . "nontextual ")))(12237 12244)
  funcall(#f(advice-wrapper :before-while #f(compiled-function
  (not (funcall isearch-filter-predicate (nth 0 real-match-data) (nth 1 real-match-data)))

If it's impossible to restore its value, then maybe better to save only
function names, and on restoring explicitly call add-function with restored
function names as symbols?

A complete patch is here:

diff --git a/lisp/isearch.el b/lisp/isearch.el
index 5cbb4c9..70e3e44 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -1136,7 +1141,8 @@ isearch-update-ring
 (defun isearch-string-propertize (string &optional properties)
   "Add isearch properties to the isearch string."
   (unless properties
-    (setq properties `(isearch-case-fold-search ,isearch-case-fold-search))
+    (setq properties `(isearch-case-fold-search ,isearch-case-fold-search
+                       isearch-filter-predicate ,isearch-filter-predicate))
     (unless isearch-regexp
       (setq properties (append properties `(isearch-regexp-function ,isearch-regexp-function)))))
   (apply 'propertize string properties))
@@ -1146,6 +1152,9 @@ isearch-update-from-string-properties
   (when (plist-member (text-properties-at 0 string) 'isearch-case-fold-search)
     (setq isearch-case-fold-search
 	  (get-text-property 0 'isearch-case-fold-search string)))
+  (when (plist-member (text-properties-at 0 string) 'isearch-filter-predicate)
+    (setq isearch-filter-predicate
+	  (get-text-property 0 'isearch-filter-predicate string)))
   (when (plist-member (text-properties-at 0 string) 'isearch-regexp-function)
     (setq isearch-regexp-function
 	  (get-text-property 0 'isearch-regexp-function string))))
@@ -1640,6 +1648,38 @@ isearch--momentary-message
        "match invisible text"
      "match visible text")))
 
+(isearch-define-mode-toggle textual "ft" nil
+  "This determines whether to search inside or outside textual parts.
+Toggles the variable `isearch-filter-predicate' between three states:
+searching inside strings or comments, searching outside of strings or
+comments, the third state removes the filtering altogether."
+  (cond
+   ((advice-function-member-p #'isearch-filter-textual
+                              isearch-filter-predicate)
+    (remove-function (local 'isearch-filter-predicate)
+                     #'isearch-filter-textual)
+    (add-function :before-while (local 'isearch-filter-predicate)
+                  #'isearch-filter-nontextual
+                  '((isearch-message-prefix . "nontextual "))))
+   ((advice-function-member-p #'isearch-filter-nontextual
+                              isearch-filter-predicate)
+    (remove-function (local 'isearch-filter-predicate)
+                     #'isearch-filter-nontextual))
+   (t
+    (add-function :before-while (local 'isearch-filter-predicate)
+                  #'isearch-filter-textual
+                  '((isearch-message-prefix . "textual "))))))
+
+(defun isearch-filter-textual (_beg _end)
+  "Test whether the current search hit inside a string or comment."
+  (save-match-data
+    (or (nth 3 (syntax-ppss))
+        (nth 4 (syntax-ppss)))))
+
+(defun isearch-filter-nontextual (beg end)
+  "Test whether the current search hit outside a string or comment."
+  (not (isearch-filter-textual beg end)))
+
 \f
 ;; Word search
 
@@ -3179,6 +3219,7 @@ isearch-lazy-highlight-window-group
 (defvar isearch-lazy-highlight-window-start nil)
 (defvar isearch-lazy-highlight-window-end nil)
 (defvar isearch-lazy-highlight-case-fold-search nil)
+(defvar isearch-lazy-highlight-filter-predicate nil)
 (defvar isearch-lazy-highlight-regexp nil)
 (defvar isearch-lazy-highlight-lax-whitespace nil)
 (defvar isearch-lazy-highlight-regexp-lax-whitespace nil)
@@ -3218,6 +3259,8 @@ isearch-lazy-highlight-new-loop
                             isearch-lazy-highlight-window-group))
 		 (not (eq isearch-lazy-highlight-case-fold-search
 			  isearch-case-fold-search))
+		 (not (equal isearch-lazy-highlight-filter-predicate
+			     isearch-filter-predicate))
 		 (not (eq isearch-lazy-highlight-regexp
 			  isearch-regexp))
 		 (not (eq isearch-lazy-highlight-regexp-function
@@ -3259,6 +3302,7 @@ isearch-lazy-highlight-new-loop
 	  isearch-lazy-highlight-wrapped      nil
 	  isearch-lazy-highlight-last-string  isearch-string
 	  isearch-lazy-highlight-case-fold-search isearch-case-fold-search
+	  isearch-lazy-highlight-filter-predicate isearch-filter-predicate
 	  isearch-lazy-highlight-regexp       isearch-regexp
 	  isearch-lazy-highlight-lax-whitespace   isearch-lax-whitespace
 	  isearch-lazy-highlight-regexp-lax-whitespace isearch-regexp-lax-whitespace
diff --git a/lisp/replace.el b/lisp/replace.el
index 3503b65..2f297b1 100644
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -2383,7 +2383,10 @@ perform-replace
          ;; If non-nil, it is marker saying where in the buffer to stop.
          (limit nil)
          ;; Use local binding in add-function below.
-         (isearch-filter-predicate isearch-filter-predicate)
+         (isearch-filter-predicate
+          (or (and (plist-member (text-properties-at 0 from-string) 'isearch-filter-predicate)
+                   (get-text-property 0 'isearch-filter-predicate from-string))
+              isearch-filter-predicate))
          (region-bounds nil)
 
          ;; Data for the next match.  If a cons, it has the same format as
@@ -2395,6 +2398,15 @@ perform-replace
               (apply 'propertize
                      (concat "Query replacing "
                              (if backward "backward " "")
+                             (if (not case-fold-search)
+                                 "case-sensitive ")
+                             (let ((prefix ""))
+                               (advice-function-mapc
+                                (lambda (_ props)
+                                  (let ((np (cdr (assq 'isearch-message-prefix props))))
+                                    (if np (setq prefix (concat np prefix)))))
+                                isearch-filter-predicate)
+                               prefix)
                              (if delimited-flag
                                  (or (and (symbolp delimited-flag)
                                           (get delimited-flag