[ako]

Works the silent-property-drop row of the triage board (#1357). Six issues: three fixed here, three already fixed on main.

Closes #1487
Closes #1483
Closes #1230

Changes

One commit per issue, plus a docs commit.

#1487 — container (RenderMode: 'Main') "isn't stored" (mendixlabs#1582)

Reported: describe layout printed container ctnMain (Class: 'app-main') {, and alter layout … set refused the property.

• The write was always correct. bson dump shows RenderMode: "Main" on the stored Forms$DivContainer.
• describe never read it. That made it look dropped, and a describe → exec round trip did drop it. Now describe prints RenderMode: Main, leaving out the default Div.
• alter page|layout … set (RenderMode: …) on a container now writes it. Before, it was refused with not a property of this built-in widget.
• create wrote any string as-is into the enum ('main', 'Banner'). Values are now matched case-insensitively against the generated enum (Div … Address), and an unknown member is refused. The hand-written sdk/pages enum had drifted (Div, Form).

#1483 — Calendar editable / showEventDate fail mx check with CE0642 (mendixlabs#1578)

Reported: [CE0642] "Property 'Editable' is required." and "Property 'Show event date range' is required.". Both are type="expression" defaultValue="true". Four separate gaps:

1. modelsdk/widgets/augment.go: the template generated from the .mpk wrote an expression's defaultValue as an empty expression. It now writes the default, which on its own makes every Calendar page build.
2. GenerateDefJSON: a top-level expression property had no mapping, so it was "known but not persisted" and drew a false MDL-WIDGET06. It is now mapped by its own key. Widget definition generator bumped to v19.
3. editable: is also the generic widget-level editability, which the Calendar's package does not declare. The widget's own editable was therefore unreachable in every spelling. When the package declares no Editability system property, the generator now routes editable: (all value shapes) to the widget's own property, and check (MDL-WIDGET41) and build both read that decision. When the package does declare it, editable: keeps its widget-level meaning.
4. describe had no branch for an Expression value. It now prints stored expressions.

An unset expression mapping keeps the template default instead of writing "" over it.

#1230 — column (Attribute: Name, Filterable: true) (mendixlabs#177)

• Already refused on main, so it is no longer a silent drop. What was left was the message: with a project it listed the column's properties, and without one it suggested did you mean FilterType?, which a column doesn't have.
• New message: a key starting with an item's widgets-slot key now names the slot, the body form, and the widget types it takes: — `filter` is a slot for child widgets, not a property: put the widget in the column's braces, e.g. `column (…) { textfilter w1 (…) }` (it takes textfilter, numberfilter, datefilter, dropdownfilter).

Already fixed on main, no change

• [up#1307] actionbutton tooltip: passes check and exec but is silently dropped; ALTER PAGE SET (Tooltip) is refused #1298 (button tooltip): describe prints Tooltip: 'Close this page', as the reporter also confirmed upstream.
• [up#1521] An existing DateTime attribute cannot be switched to localized by create or modify entity or alter entity #1403 (DateTime localized on modify): the keep-on-unstated rule is documented, and exec prints Note: … keeps its stored 'not localized' … write 'Due: DateTime localized' to change it.
• [up#1567] A quoted Editable: '<expression>' on an input widget is silently dropped: the field stays editable #1467 (quoted Editable:): already closed. describe prints the conditional expression.

Docs

Two short paragraphs on docs-wiki/bug-patterns/silent-property-drop.md: check the stored document before blaming the write path, and a builtin MDL key can shadow a widget's own property of the same name.

Validation

• Tests written first. Each one fails with the reported symptom when its fix is reverted:
  • [up#1582] create layout: a container's RenderMode is silently dropped; check and exec pass #1487: describe dropped the container's RenderMode, RenderMode = "main", want Main, 'Banner' must be refused, property "RenderMode" not found on this widget.
  • [up#1578] Calendar widget: the required editable expression cannot be written; mx check fails CE0642 #1483: editable: no mapping, editable: 'true': expression = "", also read as the widget-level editability, describe = [], and editable Expression = "", want the declared default "true".
  • [up#177] feat: Support Filterable property on DataGrid2 COLUMN in MDL #1230: its properties are attribute, header (Caption) and did you mean FilterType.
• Run against real mxbuild (Mendix 11.13.0) on a mxcli new app with Calendar 245304 v2.6.1 from the Marketplace:
  • main's binary: CE0642 × 2.
  • This branch: The app contains: 0 errors. with neither property set, with both 'true', and with editable: false, showEventDate: 'false'. A describe → exec round trip reports Unchanged page.
  • The column-filter form the new message suggests builds with 0 errors.
• Two existing generator tests updated (TestGenerateDefJSON_SkipsComplexTypes, TestGenerateDefJSON_KnownPropertiesUnmapped). They asserted that expression properties stay unmapped, the behaviour this PR changes. The unmapped example is now an icon property.
• Regression scripts: mdl-examples/bug-tests/1582-container-rendermode.mdl, 1578-calendar-expression-properties.mdl (needs the Calendar package), 177-datagrid-column-filter-slot.mdl.
• One finding file per fix under .claude/skills/fix-issue/findings/mdl-executor/.
• make build && make test && make lint, make check-mdl, make check-findings and make check-wiki-pages pass.

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