v2.ODataModel requires datajs synchronously if created with `preload: true`

[boghyon]

Open https://embed.plnkr.co/nxTR3eO9kNZo42CR?show=Component.js,preview. It has data-sap-ui-xx-nosync="true" enabled as well as preload: true in manifest.json.

The model should be created successfully but fails since sap/ui/thirdparty/datajs.js is apparently fetched synchronously in the above case despite enabling async features everywhere when possible.

• Loading sap/ui/model/odata/v2/ODataModel.js isolated shows no sync XHR problem: https://jsbin.com/lawatow/edit?html,js,output
• The issue remains even after creating Component-preload.js via tooling.

I didn't test other cases but I assume models, in general, that have dependency to third-party module(s) are affected, not only the v2.ODataModel.

App developers would then need to either disable the preload: true setting in manifest.json, or add sap/ui/thirdparty/<lib> to the sap-ui-modules config.

[codeworrior]

That's a consequence of the sync loading of model implementations when preloading models during component loading. We have conflicting goals here: not to (further) bloat the sap.ui.core preload with bigger thirdparty files. That's why we omitted many thirdparty files from the preload when their usage is not guaranteed (jquery, jquery mobile, hasher, signal and crossroads are exceptions as they are used in nearly all apps). datajs was left out as it is only needed for OData V2. On the other side, preloading shall allow early requests for the OData v2 metadata files.

To be honest, the preload mechanism was initially only designed for the FLP scenario and there we have a custom bootstrap including datajs, so it doesn't matter.

We should discuss this and see what can be done. For async component loading, we should be able to asynchronously require the model implementations, but currently, there's no such path, AFAIK.

[kskondov]

Hello @boghyon Thank you for sharing this finding. I've created an internal incident 2180065338. The status of the issue will be updated here in GitHub. Regards, @kskondov

[Thodd]

@codeworrior you're right there is not path for this scenario... which suprised by a bit to be honest... I created a backlog item for this and informed the PO: CPOUI5FRAMEWORK-210

[mauriciolauffer]

It's kinda related: https://github.com/SAP/openui5/issues/3193

[boghyon]

For future readers..:

Open https://embed.plnkr.co/nxTR3eO9kNZo42CR?show=Component.js,preview. It has data-sap-ui-xx-nosync="true" enabled [...]

The sap-ui-xx-nosync option is no longer usable after the change https://github.com/SAP/openui5/commit/86caa923daa73e12a0fa107b4c9609e276e5b443 --> Fixed with b774db7

But the relevant requireSync call is still there: https://github.com/SAP/openui5/blob/0688cce81d90e624351dacadff67aef772343aeb/src/sap.ui.core/src/sap/ui/core/Component.js#L2059

[mauriciolauffer]

any plans to remove requireSync and make it fully async?

[Thodd]

The sap-ui-xx-nosync issue should be fixed with b774db74262d1af1a749b2b23b557557622eecd7.

@mauriciolauffer: all synchronous JS loading paths are deprecated and will be removed with UI5 2.0. The backlog item CPOUI5FRAMEWORK-210 is currently planned and will take care of the sync loading specific to datajs.

[boghyon]

With https://github.com/SAP/openui5/commit/337b1768cff287cf22c3fbfe4458afd66795c894, this issue can be closed. Thanks @Thodd!