fix(describe): print a Data grid 2's and a Gallery's settings by their widget key

[stagknee]

Closes #1573 together with #1574 (this is the describe half). Please merge after #1574. That PR makes a no-project check accept the expression-typed settings this one now prints.

What it fixes

describe page printed only a few keyword properties of a Data grid 2 (PageSize, Pagination, …) and of a Gallery. Every other setting that check and exec accept by widget key was dropped, so a describe → exec round trip reset it to the default. That includes refreshInterval, columnsHidable, the personalization settings, row classes, text-template labels, a column's own settings, and the emptyPlaceholder slot.

How

cmd_pages_describe_bykey.go (new):

• Defaults come from the stored widget's own Type.ObjectType.PropertyTypes[].ValueType, and from the columns item type for columns, with no hard-coded list.
• A setting is printed only when it differs from what exec writes when the key is left out. That isn't always the schema's DefaultValue: four text templates have '' there but store their shipped translations. Without this rule, every grid would print four labels.
• Printed forms:
  • an enum or string is quoted, a boolean or integer is bare;
  • a text template is printed with its <key>Params;
  • an expression is unquoted, except a pure string literal, which is quoted so it round-trips;
  • an attribute is bare where exec resolves a bare name, and qualified otherwise.
• Actions were already covered by onClick and the named action slots (Feature: MDL surface for named pluggable-widget action slots beyond onClick/onChange (FileUploader createFileAction / onUploadSuccessFile) #956), and selection-typed keys by Selection:.
• An attribute reached over associations is named in a -- NOT re-executable: comment instead of being lost.
• Gallery had the same loss through the same path, so it's included. An untouched widget's describe output is unchanged.

Evidence

• Tests: cmd_pages_describe_bykey_test.go. With the by-key reads switched off, 9 of 10 fail with the symptom, for example configurationStorageType was not printed. The tenth guards an untouched grid's output. All pass with the fix.

• Real round trip (Mendix 11.12.5 scratch app; five grid pages and one gallery page, from bug-tests/1573-datagrid-by-key-settings-describe.mdl). describe → exec over a stored page only proves pass-through, so the real test is describe → drop page → exec → BSON compare, with ids stripped:

  	pages byte-identical after the round trip
  v0.27.0	0 of 6
  this branch	6 of 6

  mx check reports 0 errors after the round trip. Describing the untouched Studio Pro pages of the scratch app and of PedApp changes exactly one page in each: Administration.Account_Overview now keeps onClickTrigger: 'double', which v0.27.0 lost.

• Round-trip suite: go test -tags integration ./mdl/roundtrip -run TestPedAppRoundTrip is ok. The full package gives 2181 pass and 1 Windows TempDir-lock failure (a microflow test), which is identical on the other branch.

• Tests and vet: go test ./mdl/executor/ shows the same 28 pre-existing Windows failures as main. go vet and gofmt are clean.

• Linux (golang:1.26.6-bookworm, ANTLR 4.13.2): make grammar build test check-mdl check-findings check-conformance check-migration-reference lint-go all pass.

• Also included: a CHANGELOG entry (Fixed), a finding in findings/mdl-executor/, and a widget-types.md note that any Data grid 2 setting can be set by its key, with the personalization example.

Not covered

• Combobox, textfilter, dropdownfilter and image have the same describe loss, each in its own describe branch (see the issue).
• A cleared text template (exportDialogLabel: '') is written as the shipped default text, so that can't be represented in MDL.
• A multi-language text template prints only its first non-empty text, as the existing generic describe does.

🤖 Generated with Claude Code

[github-actions]

AI Code Review

Review Summary

Critical Issues

None found.

Moderate Issues

None found.

Minor Issues

None found.

What Looks Good

• Thoroughly addresses the issue: The PR fixes the core problem where describe page was dropping Data grid 2 and Gallery settings that don't have dedicated MDL keywords, preventing silent resets to defaults during describe→exec roundtrips.
• Comprehensive testing:
  • New unit test file (cmd_pages_describe_bykey_test.go) with 415 lines covers various property types (enumerations, booleans, integers, expressions, text templates, attributes)
  • Real round-trip validation shows 6/6 pages byte-identical after describe→drop→exec→BSON compare (vs 0/6 before)
  • Integration tests pass and existing test suites remain stable
• Correct implementation approach:
  • Defaults are read from the widget's actual BSON schema (Type.ObjectType.PropertyTypes) rather than hardcoded lists
  • Settings are only printed when they differ from what exec writes when omitted (avoiding noise like printing all four text template labels)
  • Proper formatting for different value types (quoted strings/enums, bare booleans/integers, expression handling, attribute resolution)
  • Handles omitted properties (like association paths) via comments rather than losing them silently
• Maintains backward compatibility: Untouched widgets produce identical describe output
• Documentation updates:
  • CHANGELOG entry clearly explains the fix
  • widget-types.md updated to document that any Data grid 2 setting can be set by widget key
• Code quality:
  • Follows existing patterns in the executor package
  • Clean separation of concerns (new bykey.go file for core logic)
  • Proper handling of edge cases (attribute resolution inside/outside data containers)
  • No generated parser files modified (appropriately skipped)

Recommendation

Approve. The PR is well-tested, correctly implements the fix according to the project's architecture and guidelines, and provides strong evidence of resolving the described issue without regressions. The dependency on #1574 should be respected as noted in the PR description, but the code itself is sound.

---

Automated review via OpenRouter (Nemotron Super 120B) — workflow source