retrieve with sorting: no more sort in describe statement

[mkrouwel]

MX: 11.8, 11.10
MxCli: 0.13

In the MDL source of a microflow with a DB retrieve with sorting, the sorting statement is currently completely missing.

[ako]

Fixed in cc09d8382.

Root cause

This was a write-side regression from the switch to the modelsdk engine as default (hence "no more sort"). In retrieveSourceToGen (mdl/backend/modelsdk/microflow_write.go), a database retrieve stored an empty SortItemList and never serialized the sort columns:

g.SetSortItemList(genMf.NewSortItemList()) // empty; "sort columns are a later slice"

The comment even admitted the work was left unfinished. With nothing written, the (already-correct) read path had nothing to render, so the sort by … line disappeared entirely.

A subtlety that made this a trap: the generated SortItemList type stores its items under "Items", but Mendix stores retrieve sort columns under "Sortings" — which is why the working Sort list-operation bypasses the gen type and builds the envelope by hand. The retrieve path now does the same.

Fix

Build the Microflows$SortingsList manually, mirroring the working SortOperation branch (newElem("Microflows$SortingsList") + addPartList(sl, "Sortings", …) + SetSortItemList).

Verification

Reproduced and fixed end-to-end on a modern 11.12.0 project (so it wasn't version-specific to 10.8/10.10):

retrieve $Tickets from SortBug.Ticket
  sort by Priority desc, Name asc;

DESCRIBE now keeps sort by … desc, … asc, and the output re-parses cleanly. Added a toGen→encode→decode→fromGen regression test plus a bug-test MDL (mdl-examples/bug-tests/727-retrieve-sort-dropped-on-write.mdl).

One thing to confirm

"Completely missing" points squarely at this write bug (nothing stored), which is fixed. I couldn't get a real Studio-Pro-authored 10.8/10.10 sample, and those older versions use binary attribute references rather than by-name. If after upgrading you see the sort line reappear but with a blank attribute name (rather than missing), that would be a separate read-side name-resolution gap for legacy binary refs — please share a sample microflow and we'll follow up.

[mkrouwel]

Thank you @ako . Where I mentioned 10.8 and 10.10, I meant 11.8 and 11.10