Place building blocks with a styled dynamic text or a list view without a source

.claude/skills/fix-issue/findings/mdl-backend/2026-11-12-listview-without-source-refused-not-written-unconfigured.json

@@ -0,0 +1 @@
+{"area": "mdl/backend", "date": "2026-11-12", "symptom": "`use building block PlatformDesignSystem.Avatar_Group_SM` (and Avatar_Group_XS) failed with `CreatePage: encode: CreatePage: ListView source <nil> is not supported by either engine — please file an issue`; a hand-written `listview` with no `DataSource:` passed `mxcli check` and failed the same way at exec", "cause": "listViewSourceToGen had no case for a nil source, so an unconfigured list view fell to the unsupported-type refusal written for unknown $Types. Separately, Forms$ListViewXPathSource registered only SourceVariable as a null field, so an XPath source with no entity omitted its EntityRef key", "file": "mdl/backend/modelsdk/widget_write.go (listViewSourceToGen, Forms$ListViewXPathSource TypeDefaults); mdl/executor/cmd_pages_builder_v3_widgets.go (warnListViewWithoutSource)", "fix": "A nil source is written as Studio Pro's unconfigured source: Forms$ListViewXPathSource with EntityRef and SourceVariable null, XPathConstraint '', ForceFullObjects false, empty SortBar/Search (EntityRef added to NullFields). exec warns; mx check reports CE0488 'No entity configured for the data source of this list view' until the author binds it", "insight": "The reference shape was already on disk: every unconfigured List View in the Atlas page templates of testdata/testapp (13, identical; 13 likewise in PedApp) — scan the Studio Pro-authored templates before asking for a Studio Pro example. A patched copy of a building block (a Studio Pro list view grafted in, $IDs AND the pointers to them renumbered — renumbering $IDs alone made mxbuild throw KeyNotFoundException while loading) reproduces a Marketplace block that is not downloadable. A block's unconfigured list view is not an mx check error in the block itself; only once placed on a page", "refs": "ako/mxcli#2183, mendixlabs/mxcli#1836", "test": "mdl/backend/modelsdk/listview_no_source_2183_test.go; mdl/executor/use_building_block_unauthored_2183_test.go (PlacesSourcelessListView, WithSourceDoesNotWarn)"}

.claude/skills/fix-issue/findings/mdl-executor/2026-11-12-building-block-dynamictext-style-refused-as-hand-written.json

@@ -0,0 +1 @@
+{"area": "mdl/executor", "date": "2026-11-12", "symptom": "`use building block PlatformDesignSystem.Icon_After_Text` (also Wizard_Horizontal_Responsive, Wizard_Mobile, Wizard_Vertical) failed with `failed to build widget: dynamictext \"b_text13\": an inline `style` crashes MxBuild — wrap it in a container and style the container instead` — the block's own text carries Style '--icon-size: auto;'", "cause": "The MDL-WIDGET03 guard in applyWidgetAppearance (#673) refuses any dynamictext with a style. A block is expanded by rendering its stored widgets to MDL and re-parsing them, so the block's Studio Pro-authored style reached the guard indistinguishable from hand-written MDL", "file": "mdl/executor/cmd_pages_builder_v3.go (applyWidgetAppearance, expandBuildingBlockRef/markFromBuildingBlock); mdl/ast/ast_page_v3.go (WidgetV3.FromBuildingBlock)", "fix": "The expander marks every widget it copies in (FromBuildingBlock, carried by cloneWidget's struct copy); the guard skips marked widgets, so the block's stored style is written verbatim. Hand-written MDL is still refused (check and exec)", "insight": "Measured on Mendix 11.12.1 with real mxbuild: a dynamic text with an inline style written by the current modelsdk engine — hand-written via --no-check with the guard stubbed, and via a patched Card block — passes mx check with 0 errors and `mxcli docker build` (BUILD SUCCEEDED); testdata/testapp also has a Studio Pro-authored dynamic text styled 'word-wrap: break-word;'. The #673 crash did not reproduce, so the hand-written refusal may be obsolete (it predates the modelsdk engine); not lifted here. Any guard written for authored MDL also fires on block/fragment expansion unless it knows the widget's origin", "refs": "ako/mxcli#2183, mendixlabs/mxcli#1836, #673", "test": "mdl/executor/use_building_block_unauthored_2183_test.go (CarriesDynamicTextStyle, HandWrittenDynamicTextStyleStillRefused)"}

.claude/skills/mendix/atlas-design/SKILL.md

@@ -422,7 +422,7 @@ row before opening files.
 | `sort by` not allowed on **association-sourced** listviews | sort the parent, or use a DB datasource |
 | Reserved widget identifiers exist (e.g. `v3`) | prefix names (`sv3`); avoid bare `v<n>` |
 | Pluggable widgets impose their own DOM (charts / timeline / treenode) | for pixel-fidelity use a native `listview` / `gallery` you fully style |
-| Inline `style:` on a `dynamictext` crashes MxBuild (NullReferenceException) | use `class:`, or wrap the text in a styled `container` |
+| Inline `style:` on a `dynamictext` crashes MxBuild (NullReferenceException) | use `class:`, or wrap the text in a styled `container` (a block's own stored style is placed as is by `use building block`) |
 | `alter styling` can't find widgets in MDL-builder-created pages | apply classes via `Class:` / `DynamicClasses:` in `create page` / `alter page` |
 | Full-screen page wanted (no Atlas sidebar) but no blank layout resolves | keep a normal Atlas layout; hide the shell per-page with `.mx-page:has(.my-app) .region-sidebar { display:none }` |
 | "Colour by state" (status pills / cards) | one `dynamicclasses` enum→class expression + one `--st` CSS var cascaded into pill/number/dot/border |

.claude/skills/mendix/atlas-design/reference/building-blocks.md

@@ -263,6 +263,10 @@ more idiomatic form to mirror from a `describe building block`. Notes:
 - Compound properties (Spacing, Border) take a **nested list**:
   `['Spacing': ['margin-top': 'Large', 'margin-bottom': 'None']]`.
 - **Never** put inline `style:` on a `dynamictext` — it crashes MxBuild. Use `class:`
-  or wrap in a styled `container`. (`theme-styling`.)
+  or wrap in a styled `container`. (`theme-styling`.) A block's *own* stored style
+  is the exception: `use building block` places it as stored.
+- A block's list view whose data source is not configured is placed unconfigured
+  (`exec` warns); `mx check` then reports CE0488 until you set one — bind it with
+  `use building block … (datasource: database from Module.Entity)`.
 
 ---

.claude/skills/mendix/create-page/SKILL.md

@@ -158,7 +158,7 @@ actionbutton btn (caption: 'Save', class: 'btn-lg')
 container c (style: 'background-color: #f8f9fa; padding: 16px;') { ... }
 ```
 
-> **Warning:** Do NOT use `style` directly on DYNAMICTEXT widgets — it crashes MxBuild with a NullReferenceException. Wrap the DYNAMICTEXT in a styled CONTAINER instead.
+> **Warning:** Do NOT use `style` directly on DYNAMICTEXT widgets — it crashes MxBuild with a NullReferenceException. Wrap the DYNAMICTEXT in a styled CONTAINER instead. (A building block's own styled dynamic text is placed as stored by `use building block`; the refusal is for hand-written MDL.)
 
 **Design Properties** — Atlas UI structured properties (spacing, colors, toggles):
 ```sql

.claude/skills/mendix/theme-styling/SKILL.md

@@ -13,10 +13,10 @@ description: "The SCSS workflow and its traps — where styling actually compile
 | 24-43 | When to Use This Skill |
 | 44-297 | SCSS Compilation Chain |
 | 298-316 | CSS Hot-Reload Workflow |
-| 317-416 | Caveats |
-| 417-431 | Validation with `mxcli check -p` |
-| 432-440 | Checklist |
-| 441-443 | Default styling + runtime theme switching (`mxcli theme list/show/create/apply/remove/switcher`, `mxcli new --theme`) |
+| 317-420 | Caveats |
+| 421-435 | Validation with `mxcli check -p` |
+| 436-444 | Checklist |
+| 445-447 | Default styling + runtime theme switching (`mxcli theme list/show/create/apply/remove/switcher`, `mxcli new --theme`) |
 
 <!-- /skill-index -->
 # Theme & Styling — SCSS Workflow and Caveats
@@ -330,6 +330,10 @@ container ctn (style: 'color: red;') {
 }
 ```
 
+The rule is for hand-written MDL (`mxcli check` refuses it as MDL-WIDGET03). A
+dynamic text that `use building block` copies in keeps the inline style the block
+stores — Studio Pro wrote it, and it is placed as stored (ako/mxcli#2183).
+
 This also applies to `alter styling` and `alter page set style` — never target a DYNAMICTEXT widget with Style.
 
 ### Clipped navigation labels are the CLOSED sidebar, not the theme

CHANGELOG.md

@@ -30,6 +30,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ### Fixed
 
+- **`use building block` places a block's styled dynamic text and its unconfigured list view** (ako/mxcli#2183, mendixlabs/mxcli#1836) — two refusals meant for hand-written MDL also fired on widgets a building block copies in, so one widget the author never wrote blocked the whole block. PlatformDesignSystem's Icon_After_Text and Wizard blocks failed with "an inline `style` crashes MxBuild", because their dynamic text is styled `--icon-size: auto;`; Avatar_Group_SM and Avatar_Group_XS failed with "ListView source <nil> is not supported by either engine", because their list view has no data source configured yet. A block's own style is now written as the block stores it (a hand-written `style:` on a `dynamictext` is still refused, MDL-WIDGET03), and a list view with no data source, from a block or hand-written, is written the way Studio Pro stores one: an XPath source naming no entity. `exec` warns, and `mx check` reports CE0488 "No entity configured for the data source of this list view" until you bind it, e.g. with `use building block … (datasource: database from Module.Entity)`. Measured on Mendix 11.12.1 with a building block carrying both widgets: before, `exec` refused the page; after, `mx check` reports only CE0488, and with the data source bound it passes and `mxcli docker build` succeeds.
 - **`use building block` places a block whose text-template parameters are unbound** (ako/mxcli#2181, mendixlabs/mxcli#1834) — the block's widget tree is expanded by describing it as MDL and parsing that back, and `describe` prints a parameter nobody has bound yet as `{1} = <unbound>`, which did not parse. Building blocks are full of them (PlatformDesignSystem's Gallery_List_Divider, Gallery_Card_Grid_Actions and Gallery_List_Panels; Atlas's ListItem_WithImage), so the whole block was refused with "could not expand widget tree: extraneous input '<'". The same line made `describe page` output of any page with an unbound parameter fail to re-execute. `{1} = <unbound>` now parses and writes the parameter back unbound, in its position, as Studio Pro stores it: the block is placed, mxbuild reports CE0402 "No value specified." for each parameter until it is bound, and describe -> exec of such a page is unchanged.
 - **`check` resolves an `alter page` target against the building blocks the page holds** (ako/mxcli#2182, mendixlabs/mxcli#1835) — an `alter page` / `alter snippet` on a document the same script creates was never resolved, so `set … on a_container99` after `use building block PlatformDesignSystem.Alert_Info as a_` passed `check -p` and exec then stopped on `widget "a_container99" not found`, with the page already created. A plain misspelt widget passed the same way. Check now replays the documents the script creates, expanding each `use building block` and `use fragment` as exec does (prefix included), and refuses a target they do not hold at that point as MDL-ALTER02, suggesting the nearest name (`did you mean a_container1`). On a stored page, the names a block inserted by `alter page … insert` are now its expanded names: `insert after s_container2` after inserting a block `as s_` is no longer refused, and `set … on s_text99` is no longer waived. Without a project a block cannot be expanded, so every name under its prefix is accepted (every name, for an unprefixed block), and a page holding DataGrid 2 columns or object-list items, whose addresses are derived, is not judged. The duplicate-name side (ako/mxcli#559) was already fixed.
 - **A pluggable widget's template is prepared once per widget type** (ako/mxcli#2160) — every data grid, filter and other pluggable widget a script builds loaded its template by deep-cloning the built-in one and merging the project's widget package into the clone, the same work each time. The merged template is now made once for each widget type and package and reused; each widget still gets IDs of its own. Creating 600 pages: 29.5 s before, 26.5 s after; re-running them settled: 83.1 s before, 73.9 s after. The pages written are the same: all 1,719 units of the two projects compare equal once IDs are set aside.

mdl/ast/ast_page_v3.go

@@ -193,6 +193,15 @@ type WidgetV3 struct {
 	// diagnostic. Keyed by the property name as written; read it through
 	// ExpressionSource, which matches case-insensitively.
 	ValueSource map[string]string
+
+	// FromBuildingBlock records that the widget was copied in by `use building
+	// block` rather than written by the author: Studio Pro authored it, and its
+	// values are the block's stored ones. A refusal meant to stop hand-written
+	// MDL from writing something Studio Pro would not (an inline style on a
+	// dynamictext, MDL-WIDGET03) does not apply to a value Studio Pro wrote
+	// itself — refusing it blocked the whole block (ako/mxcli#2183). Set by the
+	// building-block expander only.
+	FromBuildingBlock bool
 }
 
 // ExpressionSource returns the source text the visitor kept for key (see

mdl/backend/modelsdk/listview_no_source_2183_test.go

@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package modelsdkbackend
+
+import (
+	"reflect"
+	"sort"
+	"strings"
+	"testing"
+
+	"go.mongodb.org/mongo-driver/v2/bson"
+
+	"github.com/mendixlabs/mxcli/sdk/pages"
+)
+
+// studioProUnsetListViewSourceKeys is the key set of the DataSource of every
+// Studio Pro-authored List View whose source is not yet configured: 13 of them
+// in the page templates of testdata/testapp, 13 more in testdata/pedapp's (e.g.
+// testapp mprcontents/30/12/30127bfe-68f5-40ca-ba13-a73943dd6285.mxunit,
+// listView1), all identical —
+//
+//	{$ID, $Type: Forms$ListViewXPathSource, EntityRef: null,
+//	 ForceFullObjects: false, Search: {SearchRefs: [2]},
+//	 SortBar: {SortItems: [2]}, SourceVariable: null, XPathConstraint: ""}
+var studioProUnsetListViewSourceKeys = []string{
+	"$ID", "$Type", "EntityRef", "ForceFullObjects", "Search", "SortBar", "SourceVariable", "XPathConstraint",
+}
+
+// TestListViewWithoutSourceWritesStudioProShape is ako/mxcli#2183
+// (mendixlabs/mxcli#1836): `use building block PlatformDesignSystem.Avatar_Group_SM`
+// failed with "ListView source <nil> is not supported by either engine" — the
+// block's list view has no data source configured, which Studio Pro stores as
+// an XPath source naming no entity. Written that way, `mx check` asks the author
+// to pick an entity, instead of mxcli refusing the whole block.
+func TestListViewWithoutSourceWritesStudioProShape(t *testing.T) {
+	lv, err := widgetToGen(&pages.ListView{PageSize: 10})
+	if err != nil {
+		t.Fatalf("list view without a data source: %v", err)
+	}
+	ds, ok := lookup(encodeD(t, lv), "DataSource").(bson.D)
+	if !ok {
+		t.Fatalf("DataSource missing or not a document")
+	}
+	if got := lookup(ds, "$Type"); got != "Forms$ListViewXPathSource" {
+		t.Errorf("DataSource $Type = %v, want Forms$ListViewXPathSource", got)
+	}
+	keys := dKeys(ds)
+	sort.Strings(keys)
+	if !reflect.DeepEqual(keys, studioProUnsetListViewSourceKeys) {
+		t.Errorf("DataSource keys = %v, want Studio Pro's %v", keys, studioProUnsetListViewSourceKeys)
+	}
+	for _, k := range []string{"EntityRef", "SourceVariable"} {
+		if v := lookup(ds, k); v != nil {
+			t.Errorf("%s = %v, want null (no entity configured)", k, v)
+		}
+	}
+	if v := lookup(ds, "XPathConstraint"); v != "" {
+		t.Errorf("XPathConstraint = %v, want empty", v)
+	}
+	if v := lookup(ds, "ForceFullObjects"); v != false {
+		t.Errorf("ForceFullObjects = %v, want false", v)
+	}
+	if m := lvListMarker(t, lookup(ds, "Search").(bson.D), "SearchRefs"); m != int32(2) {
+		t.Errorf("Search.SearchRefs marker = %v, want 2", m)
+	}
+	if m := lvListMarker(t, lookup(ds, "SortBar").(bson.D), "SortItems"); m != int32(2) {
+		t.Errorf("SortBar.SortItems marker = %v, want 2", m)
+	}
+}
+
+// Control: a source type the writer does not know is still refused loudly —
+// only the absent source changed meaning.
+func TestListViewUnknownSourceStillRefused(t *testing.T) {
+	_, err := listViewSourceToGen(&pages.ListenToWidgetSource{})
+	if err == nil || !strings.Contains(err.Error(), "is not supported by either engine") {
+		t.Errorf("want the unsupported-source refusal, got %v", err)
+	}
+}

mdl/backend/modelsdk/widget_write.go

@@ -119,8 +119,11 @@ func init() {
 	// A List View's XPath source always carries its SourceVariable key, null
 	// when the source is not reached from a parameter: 44 of 44 in the
 	// fixtures, as on the pluggable XPath source above (ako/mxcli#721 L5).
+	// EntityRef likewise: a List View with no entity configured yet stores the
+	// key null — every such List View in the testdata/testapp page templates —
+	// and mxcli omitted it (ako/mxcli#2183).
 	codec.RegisterTypeDefaults("Forms$ListViewXPathSource", codec.TypeDefaults{
-		NullFields: []string{"SourceVariable"},
+		NullFields: []string{"EntityRef", "SourceVariable"},
 	})
 	// An association source likewise: 40 of 40 in FactoryManagement carry the
 	// key, null (30) when the source starts from $currentObject (ako/mxcli#2106).
@@ -1839,7 +1842,18 @@ func associationContextVariableToGen(d *pages.AssociationSource) element.Element
 // Forms$ListViewXPathSource (EntityRef + XPathConstraint + a GridSortBar and a
 // ListViewSearch sub-element, matching what Studio Pro/the legacy writer emit);
 // a microflow source uses Forms$MicroflowSource (as DataView does).
+//
+// No source at all is a List View whose data source is not configured yet — a
+// building block's (PlatformDesignSystem's Avatar_Group_SM) or a hand-written
+// `listview` without `DataSource:`. Studio Pro stores that as an XPath source
+// naming no entity: the same element with EntityRef and SourceVariable null and
+// an empty sort bar and search (every such List View in the page templates of
+// testdata/testapp). `mx check` then asks for the entity, which is the author's
+// to choose. Refusing it instead blocked the whole block (ako/mxcli#2183).
 func listViewSourceToGen(ds pages.DataSource) (element.Element, error) {
+	if ds == nil {
+		return listViewSourceToGen(&pages.DatabaseSource{})
+	}
 	switch d := ds.(type) {
 	case *pages.DatabaseSource:
 		src := genPg.NewListViewXPathSource()

mdl/executor/cmd_pages_builder_v3.go

@@ -696,7 +696,14 @@ func applyWidgetAppearance(widget pages.Widget, w *ast.WidgetV3, theme *ThemeReg
 	// A DynamicText with an inline Style crashes MxBuild with a
 	// NullReferenceException. Reject it here (the workaround is to wrap the
 	// widget in a container and style the container instead).
-	if style != "" && strings.EqualFold(w.Type, "dynamictext") {
+	//
+	// Not for a widget a building block copied in: that style is the block's
+	// own, written by Studio Pro and carried through verbatim, and mxbuild
+	// builds it — PlatformDesignSystem's Icon_After_Text styles its text
+	// `--icon-size: auto;`, and refusing it refused the whole block
+	// (ako/mxcli#2183). Measured on 11.12.1: a dynamic text with that style,
+	// written by this engine, passes `mx check` and `mxcli docker build`.
+	if style != "" && strings.EqualFold(w.Type, "dynamictext") && !w.FromBuildingBlock {
 		return mdlerrors.NewValidationf(
 			"dynamictext %q: an inline `style` crashes MxBuild — wrap it in a container and style the container instead",
 			w.Name,
@@ -3351,6 +3358,7 @@ func (pb *pageBuilder) expandBuildingBlockRef(w *ast.WidgetV3) ([]*ast.WidgetV3,
 		return nil, fmt.Errorf("use building block %s: could not expand widget tree", w.Name)
 	}
 	widgets := def.Widgets
+	markFromBuildingBlock(widgets)
 
 	// Apply the optional prefix rename.
 	if prefix, ok := w.Properties["Prefix"].(string); ok && prefix != "" {
@@ -3390,6 +3398,15 @@ func (pb *pageBuilder) expandBuildingBlockRef(w *ast.WidgetV3) ([]*ast.WidgetV3,
 	return widgets, nil
 }
 
+// markFromBuildingBlock flags every widget of an expanded block, children
+// included, as one the author did not write (see ast.WidgetV3.FromBuildingBlock).
+func markFromBuildingBlock(widgets []*ast.WidgetV3) {
+	for _, w := range widgets {
+		w.FromBuildingBlock = true
+		markFromBuildingBlock(w.Children)
+	}
+}
+
 // isDataSourceWidget reports whether a widget is one that takes a datasource,
 // whether or not it currently carries one. The list is the data containers a
 // building block can be built around; anything else in a block is layout or a