Column-level CaptionParams / ContentParams / ShowContentAs dropped in datagrid_builder

[ako]

Discovered while cleaning up v0.10.0 fixture loose ends (commit 4069b601)

Symptom

MDL with a templated column caption + parameters silently loses CaptionParams, ContentParams, ShowContentAs, and Content properties on round-trip.

Input MDL (mirrors Studio-Pro-generated Main.Product_Select from LatoProductInventory):

column Name (
  Attribute: Name,
  Caption: '{1}',
  CaptionParams: [{1} = Name],
  ShowContentAs: dynamicText,
  Content: 'Name',
  ColumnWidth: manual,
  Size: 8
) {
  textfilter tfName
}

DESCRIBE output after mxcli exec:

column Name (Attribute: Name, Caption: '{1}', ColumnWidth: manual, Size: 8) {
  textfilter tfName
}

CaptionParams, ShowContentAs, and Content are silently dropped.

Studio Pro consequence

mx check reports CE0720 "Place holder index 1 is greater than 0, the number of parameter(s)." — the BSON has Caption: '{1}' set as a TextTemplate, but the TextTemplate's parameter bindings list is empty.

Root cause location

mdl/backend/mpr/datagrid_builder.go → cloneAndUpdateColumnProperties → case "header": (around line 294):

case "header":
    entry := columnPropertyIDs["header"]
    result = append(result, buildColumnHeaderProperty(entry, caption))

buildColumnHeaderProperty receives the literal caption string but no parameter list. CaptionParams arrive at the column spec via child.Properties in the executor (see cmd_pages_builder_v3_widgets.go: buildDataGridV3 around line 110), but aren't propagated through DataGridColumnSpec to the backend.

Same issue likely applies to:

• case "content": when ShowContentAs: dynamicText is set with Content + ContentParams
• case "tooltip": if Tooltip is a TextTemplate

Acceptance

• DataGridColumnSpec carries optional CaptionParams, ContentParams (map[string]string of placeholder → attribute path)
• buildColumnHeaderProperty (and equivalent for content, tooltip) build TextTemplate values with the parameter list populated
• Fixture feat(tui): check enhancements, command palette, session restore #31 PD06 restored to the templated-caption pattern matching Studio Pro reference
• DESCRIBE round-trips Caption: '{1}', CaptionParams: [{1} = Name] losslessly
• mx check no longer reports CE0720 on the restored fixture

Out of scope

• TextTemplate parameter support outside DataGrid columns (likely already works for top-level widget properties via SetTextTemplateWithParams — verify and document)

Priority

Medium. Cosmetic for end users (column headers can use plain text); blocks DESCRIBE/edit round-trip for projects that already have templated column captions (most production projects do — see LatoIntegrations.Products_Overview, Main.Product_Select etc. in test fixtures).

🤖 Generated with Claude Code

[github-actions]

Issue Triage

Summary:
The issue reports that when processing an MDL file with templated column captions, mxcli exec silently drops CaptionParams, ContentParams, ShowContentAs, and Content properties, causing round‑trip loss and a Studio Pro validation error.

Checklist of required bug‑report information

Required info	Present?	Notes
mxcli version (output of mxcli --version or commit/build)	❌	Not mentioned
Mendix version of the project being processed	❌	Not mentioned
Scenario (what the user was trying to do – MDL script, CLI command, etc.)	✅	Implicit: running mxcli exec on the provided MDL snippet
Expected output (what should have happened)	✅	The MDL should retain CaptionParams, ContentParams, ShowContentAs, and Content after round‑trip
Experienced output (what actually happened)	✅	Those properties are missing in the DESCRIBE output; Studio Pro reports CE0720
AI bug report (output of mxcli diag --bundle or session log)	❌	Not provided

Polite request for missing information
Could you please add the following details to help us reproduce and fix the issue?

1. The version of mxcli you are using (e.g., output of mxcli --version or the commit/build identifier).
2. The Mendix version of the project you are processing (e.g., 10.6.x, 9.24.x).
3. If possible, attach the session log or run mxcli diag --bundle and share the resulting archive (or at least the relevant log excerpt).

Thank you for the thorough description—adding the above will let us verify the behavior and move toward a fix.

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