Bootstrapping ushell_abap for variant persistence - sapui5

Question

I have a FIORI application (lunched from launchpad) in which I am using unified shell to persist variants.
In my index.html, I first bootstrap the ushell_abap and then ui bootstrap like this
<script id="sap-ushell-bootstrap" src="https://sapui5.hana.ondemand.com/1.90.0/resources/sap/ushell_abap/bootstrap/abap.js"></script>
<script id="sap-ui-bootstrap" src="https://sapui5.hana.ondemand.com/1.90.0/resources/sap-ui-core.js"
data-sap-ui-libs="sap.ushell, sap.collaboration, sap.m, sap.ui.layout, sap.ui.ux3"
data-sap-ui-theme="sap_belize"
data-sap-ui-resourceroots='{"cvg.wallapp": "./"}'
data-sap-ui-compatVersion="edge"
data-sap-ui-async="true"
data-sap-ui-frameOptions="trusted"
data-sap-ui-bindingSyntax="complex"
data-sap-ui-oninit="module:sap/ui/core/ComponentSupport">
</script>
My app works fine, including variant persistence when running in localhost.
I now deploy the APP to my Fiori server and the bootstrapping process falls apart.
It completely fails to load my theme and associated styling (no custom styling just using the belize theme).
In the console I get the following errors:
includeStylesheet-dbg.js:77 GET https://xxxx:yyyy/sap/public/bc/themes/~client-810/~cache-Bo-MdJE9H9k-CMXXsBrbgsL9ZXQ/UI5/sap/suite/ui/commons/themes/Fiori_LP_Home_Theme/library.css net::ERR_ABORTED 404 (Not found)
One or more parameters could not be found. - sap.ui.core.theming.Parameters
As soon as I remove the bootstrapping of ushell_abap everything works (except the persistence of variants of course).
I have exhausted google searches and reading through the ushell documentation here https://sapui5.hana.ondemand.com/sdk/#/api/sap.ushell
Anyone with an idea on why bootstrapping is failing when truing to use ushell_abap ?

Answer 1

The main issue here was that the app was using a different version of the css libraries than the bootstrap libraries which caused errors (in this case core had new elements in css styling not available in the old css library for core).
If your APP is set up as a standalone APP as explained by Benedikt Kromer and you bootstrap to a specific sapui5 version in the index.html, you can force the app to use the same version css libraries by applying the style to the core on init of the main app.
In on init I just added:
sap.ui.getCore().applyTheme("sap_belize");
This forced the app to load css libraries from the same version I used to bootstrap.
You can see this by watching the network tab in developer tools.

Answer 2

I think you missed one key aspect of the launchpad.
"launched from launchpad" could mean:
It is opening a new tab - standalone -> no need to mention launchpad in the question.
Staying in the same tab - standard/desired setup.
If (1) and you try to load the launchpad theme in your 1.90.0 app. Make sure the ui5 version match exactly.
"parameters could not be found" Could indicate your Theme was create for an older UI5 version.
Possible solutions:
You could generate a theme, matching the standalone ui5 version upload it into an own BSP.
You can ignore the error, there may be some
ui-glitches.
In any case 404 errors indicate also that you didn't link the theme correct in the first place.
If (2), then your index.html is never called. UI5 is starting from the component.js. Hence all your bootstrapping there dosen't count.
In this case index.html is only the playground for local development.
For the shell, this is already in place. I'm not sure why you want to load it again.