TYPO3 fluid variables - typo3

Question

I upgrade my TYPO3 from 7.6 to 8.6.
Now I cant set variables via style.content.get, my root template loads fluid_styled_content.
some source:
page.10 = FLUIDTEMPLATE
page.10 {
partialRootPath ={$resDir}/Private/Partials
layoutRootPath = {$resDir}/Private/Layouts
variables {
contentMain < styles.content.get
contentMain.select.where = colPos = 0
contentnew < styles.content.get
contentnew.select.where = colPos = 1
contentkat < styles.content.get
contentkat.select.where = colPos = 2
test = TEXT
test.value = loool
}
}
display the variables:
<f:format.raw> {contentMain} </f:format.raw>
<f:format.raw> {contentnew} </f:format.raw>
<f:format.raw> {contentkat} </f:format.raw>
<f:format.raw> {test} </f:format.raw>

Answer 1

styles.content.get is defined in ext:fluid_styled_content but very late so most copies are empty. References are no solution as the modification for colPos would apply to all references.
At the moment the best solution seems to be an own definition of styles.content.get early in your TS:
styles.content.get = CONTENT
styles.content.get {
table = tt_content
select {
orderBy = sorting
where = colPos=0
}
}
but as it is an own definition I would rename it to temp.content.get so it is identifiable as my own version (no confusion if the global definition changes)

Answer 2

There is a Bug in TYPO3 8.6: https://forge.typo3.org/issues/80044
Add this before you assign styles.content.get to your variables:
<INCLUDE_TYPOSCRIPT: source="FILE:EXT:frontend/ext_typoscript_setup.txt">
Then you can use it just as before.

Answer 3

SOLVED
Thanks to Bernd! Solved this problem.
Here a full example:
mystyles.content.get = CONTENT
mystyles.content.get {
table = tt_content
select {
orderBy = sorting
where = colPos=0
}
}
page.10 = FLUIDTEMPLATE
page.10 {
partialRootPath ={$resDir}/Private/Partials
layoutRootPath = {$resDir}/Private/Layouts
variables {
contentMain < mystyles.content.get
contentMain.select.where = colPos = 0
contentnew < mystyles.content.get
contentnew.select.where = colPos = 1
contentkat < mystyles.content.get
contentkat.select.where = colPos = 2
test = TEXT
test.value = loool
}
}