CONTAINER Visible expression produces CE0117 (needs repro; likely BSON serialization)

[ako]

Problem

Setting conditional visibility on a CONTAINER in MDL (e.g. Visible: [Attribute != '']) produces a CE0117 error in Studio Pro, forcing manual configuration.

Current behavior

The grammar accepts VISIBLE on widgets (mdl/grammar/domains/MDLPage.g4:294-295), and Container carries ConditionalVisibility via BaseWidget (sdk/pages/pages_widgets.go:35). The dispatcher applies conditional settings to built widgets (applyConditionalSettings at mdl/executor/cmd_pages_builder_v3.go:396).

⚠️ Note — a tempting but WRONG hypothesis

Investigation initially suggested buildContainerV3 (cmd_pages_builder_v3_layout.go:190) "never calls applyConditionalSettings". That's misleading — the dispatcher (buildWidgetV3, cmd_pages_builder_v3.go:396) applies it to the returned widget, and containers go through that dispatcher. So the builder does attach the visibility setting.

The CE0117 is more likely in BSON serialization of ConditionalVisibilitySettings for Forms$DivContainer (sdk/mpr/writer_widgets.go). Needs a debug-bson reproduction (.claude/skills/debug-bson.md) against a Studio Pro reference to confirm before fixing.

Request

Fully support Visible expressions on CONTAINER widgets in MDL (no CE0117).

Related

• SHOW_PAGE with parameter binding generates invalid expression (CE0117) #122 (SHOW_PAGE parameter binding generates invalid expression, also CE0117) — different cause, same error code.
• The click property on the Container is not supported by the MDL parser #603 (Container click property unsupported) — adjacent container-property gap.

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Source: customer feedback batch (2026-06). Reporter: Miwa. Reporter severity: 4/5.
Filed after codebase investigation at 297e0b0a.

[github-actions]

Issue Triage

Summary:
The issue reports that applying a Visible expression to a CONTAINER widget in MDL triggers a CE0117 error in Studio Pro, and the user suspects a BSON serialization problem.

Checklist of required bug‑report information

Required info	Present?	Details
mxcli version	❌	Not mentioned
Mendix version	❌	Not mentioned
Scenario (what the user was trying to do)	✅ (implicit)	Setting conditional visibility on a CONTAINER via MDL (Visible: [Attribute != ''])
Expected output	✅	No CE0117 error; the visibility expression should be accepted
Experienced output	✅	CE0117 error in Studio Pro forcing manual configuration
AI bug report (mxcli diag --bundle or session log)	❌	Not provided

Request for missing information
To help us reproduce and fix the issue, could you please add:

1. The version of mxcli you are using (mxcli --version or the commit/build identifier).
2. The Mendix version of the project you are processing (e.g., 10.6.0, 9.24.1).
3. A diagnostic bundle or at least the session log from mxcli diag --bundle (or the relevant log excerpt) so we can see the exact context where the CE0117 arises.

Once we have those details, we’ll be able to investigate the BSON serialization hypothesis and work toward a fix. Thank you for bringing this to our attention!

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