DESCRIBE returns <unbound> for ClientTemplateParameter bound to Forms$PageVariable.LocalVariable

[ako]

Discovered while updating fixture PD06 to mirror the corrected Studio-Pro-produced page in test5 (see #547 follow-up).

Symptom

When a column caption (or any TextTemplate parameter) is bound to a page-level variable via Studio Pro's UI, the BSON stores the binding as:

ClientTemplateParameter {
  AttributeRef: null
  Expression: ""
  SourceVariable: Forms$PageVariable {
    LocalVariable: "Col1Label"
    PageParameter: ""
    SnippetParameter: ""
    ...
  }
}

DESCRIBE page returns CaptionParams: [{1} = <unbound>] because the reader only checks SourceVariable.PageParameter and misses LocalVariable.

mxcli's own writer produces the literal expression form (Expression: "$Col1Label") which DOES round-trip, so this only affects projects edited in Studio Pro UI.

Location

mdl/executor/cmd_pages_describe_pluggable.go:extractTextTemplateParameters — around line 575:

if srcVar, ok := pMap["SourceVariable"].(map[string]any); ok && srcVar != nil {
    if paramName, ok := srcVar["PageParameter"].(string); ok && paramName != "" {
        sourceVarName = paramName
    }
}

Only reads PageParameter. Should also read LocalVariable (page variable), SnippetParameter (snippet parameter), and prefix the result with $.

Suggested fix

if srcVar, ok := pMap["SourceVariable"].(map[string]any); ok && srcVar != nil {
    for _, key := range []string{"LocalVariable", "PageParameter", "SnippetParameter"} {
        if name, ok := srcVar[key].(string); ok && name != "" {
            result = append(result, "$"+name)
            // (continue to next parameter — don't fall through to AttributeRef)
        }
    }
}

Discovered

While correcting mdl-examples/doctype-tests/31-pluggable-datagrid-gallery-v010-examples.mdl PD06 after #547. The Studio-Pro-edited test5 reference has Col1Label as LocalVariable (UI path); Col2Label as Expression: "$Col2Label" (text path). Only the first returns <unbound> in DESCRIBE.

Priority

Low. Cosmetic — affects DESCRIBE accuracy for round-tripping Studio-Pro-edited pages, but mxcli's own write path produces the working Expression form.

[github-actions]

Issue Triage

Summary:
The DESCRIBE command incorrectly shows <unbound> for a column caption that is bound to a page‑level variable (Forms$PageVariable.LocalVariable) because the code only checks the PageParameter field when extracting TextTemplate parameters.

Checklist for bug report completeness

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.)	❌	Only describes the symptom; no explicit command or workflow
Expected output (what should have happened)	❌	Implied but not stated clearly
Experienced output (what actually happened – error message, wrong result, crash)	❌	Described as <unbound> but not tied to a specific command output
AI bug report – output of mxcli diag --bundle or at least the session log	❌	Not provided

Polite request for missing information
Hi there! Thanks for opening this issue. To help us investigate and fix the problem, could you please add the following details?

1. The version of mxcli you’re using (mxcli --version or the commit/build hash).
2. The Mendix version of the project you’re working with (e.g., 10.6, 9.24).
3. The exact scenario: which mxcli command you ran (e.g., mxcli describe page …) and any relevant MDL script or project context.
4. What you expected to see in the output (e.g., the caption showing the bound variable name).
5. The actual output you observed (the full line showing CaptionParams: [{1} = <unbound>] and any surrounding log).
6. If possible, run mxcli diag --bundle and attach the resulting archive, or at least share the session log from the command that produced the issue.

Once we have that information, we’ll be able to reproduce the bug and verify the fix. Thanks again for contributing!

---

Automated triage via OpenRouter — workflow source

[ako]

Closed by commit ecf2628 alongside the write-side fix.

While fixing the parallel write-side issue (mxcli was emitting $Col1Label as a literal Expression instead of as a structured Forms$PageVariable.LocalVariable, causing Studio Pro CE0066-style errors), I extended extractTextTemplateParameters in cmd_pages_describe_pluggable.go to recognize all three Forms$PageVariable kinds:

if name, ok := srcVar["LocalVariable"].(string); ok && name != "" {
    sourceVarName = name
    isLocalVariable = true
} else if name, ok := srcVar["PageParameter"].(string); ok && name != "" {
    sourceVarName = name
} else if name, ok := srcVar["SnippetParameter"].(string); ok && name != "" {
    sourceVarName = name
}

Local-variable bindings emit as bare $varName (no .attribute suffix); page parameter / snippet parameter retain the existing $param.Attr formatting. The <unbound> fallback only triggers now when the parameter genuinely has no binding.