fix(structure): row visual state, per-cell modified tint, native NSTableView refresh, row-specific undo delete

[datlechin]

Summary

Comprehensive Structure-tab fix bundle. Eight user-visible bugs and the architectural seams they exposed.

User-reported bugs (root cause + fix)

1. Double-click and Return on dropdown / type-picker columns did nothing. editEligibility blocked dropdown / typePicker columns from inline edit, so the gestures fell through to a no-op. Removed the block; the cell body now opens the inline text editor (so the user can type a value the picker doesn't list, e.g. a custom column type), and the chevron button continues to open the picker. Mirrors NSComboBox semantics: text-editable field plus chevron with predefined options.

2. Cmd+Z left the yellow modified tint in place after the change reverted. TableStructureView only observed hasChanges; mutations that did not toggle that flag never refreshed the grid. View now also observes reloadVersion and dataGridUndo / dataGridRedo ask NSTableView to redraw visible rows.

3. Pressing Delete on a row only marked the focused cell red, not the full row. StructureRowViewWithMenu extended NSTableRowView directly and had no applyVisualState / drawBackground. Now subclasses DataGridRowView so it inherits the deleted-row tint, layer-backing optimization, and cell-emphasis invalidation. tableView(_:rowViewForRow:) also applies the visual state to delegate-provided row views so recycled rows pick up state changes.

4. Cmd+Shift+N added a row to the change manager + SQL Preview but the grid kept the old row count. MainContentCommandActions.addNewRow always routed to the data-tab RowEditingCoordinator. Now branches on resultsViewMode == .structure and dispatches to the structure grid delegate.

5. Editing a cell did not update the displayed value. tableRowsProvider: { tableRows } captured a snapshot at body-evaluation time. After an edit, tableView.reloadData(forRowIndexes:) re-rendered the cell from the stale source. The provider is now a closure that rebuilds via makeCurrentProvider().asTableRows() on every call (mirrors the data tab's coordinator.tabSessionRegistry.existingTableRows(for:) pattern).

6. Save and discard left the yellow modified tint in place. loadSchema resets working state and bumps reloadVersion, but DataGridView.updateNSView only calls reloadData when row count or column schema changes. A column rename leaves the row count identical, so cells kept their pre-save visual state. Save and discard paths now call gridDelegate.reloadAllVisibleRows() after the manager resets.

7. Editing one cell tinted the entire row yellow. StructureChangeManager.getVisualState populated modifiedColumns with a hardcoded Set(0..<6) (over-counting in MySQL with charset/collation, under-counting elsewhere). Replaced with a real per-field diff: StructureEditingSupport gains columnModifiedIndices / indexModifiedIndices / foreignKeyModifiedIndices helpers; the delegate's dataGridVisualState(forRow:) calls them with orderedFields so only the changed cells get the yellow tint.

8. Right-click "Undo Delete" undid the wrong action. The closure called dataGridUndo() (global Cmd+Z), so if the user deleted column A, then renamed column B, "Undo Delete" on A undid the rename of B. Added StructureChangeManager.undoDelete(for:at:) that clears the per-row deletion mark without touching the global NSUndoManager stack. Mirrors DataChangeManager.undoRowDeletion(rowIndex:). Right-click and Cmd+Z are now independent affordances.

9. CreateTable pickers rendered as plain text. CreateTableView constructed DataGridConfiguration without customDropdownOptions, so on-delete / on-update / index-type cells showed plain text without the picker. Now passed correctly.

Architectural changes (forced into view by the bugs)

• Shared NSTableView refresh primitive. TableViewCoordinator now exposes reloadVisibleRowsAndStates() and reloadRowAndState(at:) that pair reloadData(forRowIndexes:) with enumerateAvailableRowViews + applyVisualState. This is Apple's documented two-layer pattern: reloadData(forRowIndexes:) re-fetches cells but does not touch row views, so per-row decoration (deleted/inserted tint, deleted-row context menu state) needs the second pass. Both delegates use the same primitive instead of each duplicating only-half of the contract.

• RowVisualState as the row-view source of truth. DataGridRowView now stores visualState: RowVisualState and derives rowTint from it. StructureRowViewWithMenu reads visualState.isDeleted directly in menu(for:) instead of caching a shadow isRowDeleted flag that was only assigned on row-view creation. RowVisualState also gains Equatable conformance and applyVisualState short-circuits on no change.

• Private UndoManager per StructureChangeManager instance. The window has no NSDocument-backed undoManager and no view in the responder chain provides one, so wiring through the responder chain silently no-ops. Cmd+Z is dispatched by the app's own .commands block in TableProApp to MainContentCommandActions.undoChange(), which calls into the manager directly. The private UndoManager dies with the manager, so the prior _NSUndoStack popAndInvoke crash on stale shared state is structurally impossible.

Dead code removed

• StructureChangeManager.updatePrimaryKey(_:) (zero callers).
• StructureRowProvider.updateValue(_:at:columnIndex:), appendRow(_:), removeRow(at:) (three stub no-ops with zero callers).
• StructureChangeManager.getVisualState(for:tab:), visualStateCache, rebuildVisualStateCache, VisualStateCacheKey and 15 cache-rebuild call sites. The cache was load-bearing only for the broken whole-row-tint logic; per-call recomputation is sub-millisecond at expected table sizes.
• RowVisualState.isFullRowModified (a workaround for the hardcoded Set(0..<6) that the per-field diff replaces).

Tests

StructureEditingSupportFieldDiffTests covers the three diff helpers and undoDelete(for:at:):

• columnModifiedIndices: identical inputs produce empty set; rename flags only the name index; two-field edit flags exactly those indices; fields missing from orderedFields (e.g., collation in PostgreSQL) are correctly skipped; all 9 cases of StructureColumnField are diffable.
• indexModifiedIndices: identical inputs empty; column-prefix-only change flags index 1; unique toggle flags index 3; intentionally-excluded isPrimary and comment produce no indices.
• foreignKeyModifiedIndices: identical inputs empty; on-delete / on-update flag independently; all 7 grid columns are covered.
• undoDelete(for:at:): clears delete marks; ignores non-delete pending changes; bounds-checks; no-ops on .ddl / .parts.

Out of scope (future PRs)

• applyColumnDeleteUndo clears pendingChanges entirely, losing a prior .modifyColumn if the user edited a column then deleted it then Cmd+Z'd. The new visual-state logic correctly surfaces the inconsistency (yellow tint on the still-modified cell), but the manager-level undo behavior is the actual bug.
• ChangeManaging protocol over-specifies for StructureChangeManager (data-specific operations stubbed as no-ops). Should split into base + DataChangeManaging sub-protocol.
• HIG cleanup: Cmd+C shadow on "Copy Name", "Copy As → SQL" duplicating "Copy Definition", + / - toolbar buttons, ContentUnavailableView for empty Indexes / FK tabs, 7 unlocalized strings, DDLTextView blank-rectangle empty handling.
• ClickHousePartsView builds raw ALTER TABLE SQL inline, bypassing the plugin driver DDL layer.
• StructureMenuTarget lives in Views/Structure/ but is referenced from Views/Main/Child/DataTabGridDelegate.swift. Type ownership is in the wrong folder.

Files

File	Change
Core/SchemaTracking/StructureChangeManager.swift	Drop updatePrimaryKey, getVisualState, visualStateCache, rebuildVisualStateCache. Add deleteInsertState(for:tab:) and undoDelete(for:at:).
Models/Schema/... (no diff)	EditableColumnDefinition etc. unchanged; relied on for diff helpers.
Views/Results/DataGridCoordinator.swift	Add reloadVisibleRowsAndStates() and reloadRowAndState(at:). invalidateCachesForUndoRedo collapses to one call.
Views/Results/DataGridRowView.swift	Drop final. Store visualState. Make applyVisualState idempotent.
Views/Results/DataGridView.swift	Drop isFullRowModified. RowVisualState: Equatable.
Views/Results/Cells/DataGridCellView.swift	Tint check uses state.visualState.isModified(columnIndex:).
Views/Results/Extensions/DataGridView+Columns.swift	tableView(_:rowViewForRow:) applies visual state to delegate row views.
Views/Results/Extensions/DataGridView+Editing.swift	Remove dropdown/typePicker block from editEligibility.
Views/Results/KeyHandlingTableView.swift	Return on a focused dropdown cell opens the picker instead of falling through to a blocked inline edit.
Views/Structure/StructureChangeManager.swift	(see Core)
Views/Structure/StructureEditingSupport.swift	Add columnModifiedIndices / indexModifiedIndices / foreignKeyModifiedIndices field-diff helpers.
Views/Structure/StructureGridDelegate.swift	Wire attachedCoordinator. dataGridDidEditCell and dataGridDeleteRows reload via shared primitive. dataGridVisualState(forRow:) computes per-cell modified columns. onUndoDelete calls undoDelete(for:at:) then reloadRowAndState(at:).
Views/Structure/CreateTableGridDelegate.swift	Same wiring; adds dataGridVisualState(forRow:) for inserted-row tint.
Views/Structure/CreateTableView.swift	Pass customDropdownOptions. Rebuild row snapshot fresh per call.
Views/Structure/StructureRowViewWithMenu.swift	Subclass DataGridRowView. Drop isRowDeleted shadow flag. Read visualState.isDeleted in menu. onUndoDelete: ((Int) -> Void)? takes the row index.
Views/Structure/StructureRowProvider.swift	Drop three stub no-op methods.
Views/Structure/StructureViewActionHandler.swift	Add addRow closure.
Views/Structure/TableStructureView.swift	Observe reloadVersion. Wire actionHandler.addRow. Rebuild row snapshot fresh per call.
Views/Structure/TableStructureView+Schema.swift	Save and discard paths call reloadAllVisibleRows(). Generate-preview clears stale SQL on empty change set.
Views/Main/MainContentCommandActions.swift	addNewRow branches on resultsViewMode == .structure.
TableProTests/Views/Structure/StructureEditingSupportFieldDiffTests.swift	New: 11 tests covering field-diff helpers + undoDelete(for:at:).

Test plan

Manual:

• Open a table's Structure tab. Edit each cell type via double-click, Return, click-after-focus. Text columns open the editor; dropdown / picker columns: chevron opens the popup, body opens the editor.
• Edit user_id to user_idd. Only the Name cell tints yellow.
• Edit Type only. Only the Type cell tints.
• Edit Name and Type together. Both cells tint.
• Cmd+Z. Both cells un-tint.
• Press Delete on a row. Whole row turns red, all cells gray with strikethrough.
• Right-click the deleted row, choose "Undo Delete". That specific row un-deletes.
• Delete column A, rename column B, right-click A, "Undo Delete". A un-deletes; B stays renamed.
• Cmd+Shift+N when changes already exist. New row appears in the grid.
• Save changes. Yellow tints clear.
• Discard changes. Yellow tints clear.
• Open + New Table. Set type to INT. Set On Delete to CASCADE. Both pickers open as dropdowns.

Automated: xcodebuild test -only-testing:TableProTests/StructureEditingSupportFieldDiffTests and xcodebuild test -only-testing:TableProTests/StructureChangeManagerUndoDeleteTests.

swiftlint lint --strict clean on changed files.