Crthuky

Background.
I would like to replace the intentionally blank pages or vacat pages in scrbook with a page which shows a new quote on every new blank page. Thanks to scrbook and LuaTeX this is not that difficult to write.

Here is my problem.
Unfortunately, the index on these pages does not work. The entry does not show up in the .idx-file.

Remarks.

• Choosing a different engine than LuaTeX is not an option.


• The code which accesses the quote from Lua-tables is not shown here to avoid a bloated MWE and a separated .lua-file.


• Choosing a different class than scrbook is not an option.


• The same problem occurs in the header and footer.


• The indexes index does work here A and index does work here B work fine.

My MWE.

documentclass[paper=a4,twoside]scrbook

usepackagefontspec,polyglossia
setdefaultlanguage[variant=usmax]english

usepackagehyperref,makeidx

usepackagescrlayer,scrlayer-scrpage
DeclareNewLayer[
foreground,
align=l,
area=.25paperwidth.37paperheight.5paperwidth.5paperheight,
contents=A quote which is accessed by Lua. But not in the MWE. But the textbfindexindexindex does not work here does not work here!
Just some Lua code: directluatex.sprint(math.exp(-1)).
]intentionallyBlankLayer
DeclareNewPageStyleByLayersintentionallyBlankintentionallyBlankLayer
KOMAoptionscleardoublepage=intentionallyBlank

ihead[bar indexbar head index does not work]foo indexfoo head index does not work
ifoot[bar indexbar foot index does not work]foo indexfoo foot index does not work

makeindex
begindocument

chapterLorem foo
Some text with a working indexindexindex does work here A.
chapterLorem bar
Some other text with a working indexindexindex does work here B.

printindex
enddocument

The page style is used during the output routine and there index is redefined to do nothing. You can try to write the index entry with low level commands, but then you don't get links from hyperref. You could also move the index code to the onselect-hook of the page style. But as pagestyles can be selected in various places without being used at the end you could end with too many index entries. The onevenpage-option looks more logical but doesn't work.

RequirePackageluatex85
documentclass[paper=a4,twoside]scrbook
makeatletter

usepackagefontspec,polyglossia
setdefaultlanguage[variant=usmax]english

usepackagehyperref
usepackagemakeidx

usepackagescrlayer,scrlayer-scrpage

makeatletter
DeclareNewLayer[
foreground,
align=l,
area=.25paperwidth.37paperheight.5paperwidth.5paperheight,
contents=some content with an index entry without link:
 protected@write@indexfile%
 stringindexentryindex entry in contentthepage,
]intentionallyBlankLayer
DeclareNewPageStyleByLayers[
 onselect = 
 ifnumoddvaluepageindexindex quote in onselect]intentionallyBlankintentionallyBlankLayer
KOMAoptionscleardoublepage=intentionallyBlank

makeindex
begindocument
chapterLorem foo
Some text with a working indexindexindex does work here A.
chapterLorem bar
Some other text with a working indexindexindex does work here B.

printindex
enddocument

Ulrike Fischer describes a different solution in her comment Index in KoMa-Layers does not work with a redefinition of cleardoublpage. I hoped for an elegant solution which is not based on overriding something. The following code is based on https://tex.stackexchange.com/a/205536/128553.

documentclass[paper=a4,twoside]scrbook

usepackagefontspec,polyglossia
setdefaultlanguage[variant=usmax]english

usepackagehyperref,makeidx

usepackagescrlayer,scrlayer-scrpage
newcommand*blankpage%
 parvspace*fill%
 A quote which is accessed by Lua. But not in the MWE. But the textbfindexindexindex does now work here does not work here!
Just some Lua code: directluatex.sprint(math.exp(-1)).
 vspacefill%

makeatletter
renewcommand*cleardoubleoddstandardpage%
 clearpage
 if@twoside
 ifoddc@page
 else
 blankpage
 thispagestyleempty%
 newpage
 if@twocolumnhboxnewpagefi
 fi
 fi

makeatother

makeindex
begindocument

chapterLorem foo
Some text with a working indexindexindex does work here A.
chapterLorem bar
Some other text with a working indexindexindex does work here B.

printindex
enddocument

Remark. This answer was part of the question and is now posted as an answer to honor the conventions of this site. The answer https://tex.stackexchange.com/a/360327/128553 is accepted for giving two solutions, this one is a just a realisation of her second suggestion.