fix(gui): reach every table row and choose rows from the keyboard by donislawdev · Pull Request #216 · donislawdev/BeanNetworkTester

donislawdev · 2026-09-28T23:22:39Z

What was wrong

Measured on Tk 9.0.4, in a 700x400 table:

The last rows of every table could not be reached. The virtual table measured its viewport in slots. The window holds the rows on screen plus a partial row and a buffer, and the rows that fit were counted as height // rowheight, with the header and border counted as rows. Tk shows 17 rows in full, the table counted 18 and held 22 slots, and max_offset = len - window() left the last rows in slots nobody sees:
- 200 rows: k196-k199 never shown, by wheel, scrollbar or moveto 1.0;
- 20 rows: no scrolling at all, with k17-k19 out of sight;
- Page Down jumped 22 rows, and End did nothing.
Keys and clicks moved ttk's own view. ttk's class bindings choose a slot and see it. Down past the last full row, or a click on the half row at the bottom, scrolled the Treeview's own view under the window (yview 0 -> 0.045). After 40 presses of Down, rows 0-4 could not be scrolled back to.
A selection scrolled out of view was lost. Every selection_set fires a queued <<TreeviewSelect>>, and _on_select rebuilt the selection from the rows on screen. After a scroll, Ctrl+C copied nothing and Shift+F10 opened nothing. A live table adding rows on top did the same without the user touching anything.
Shift+click measured its range from a slot. It used ttk's focus item, so after a scroll the range started at another row.

What changes (`beantester/gui/widgets/sortable_tree.py`)

rows_shown_in_full(first_box, width, height, region_at), a pure function. It returns the rows Tk draws in full, asked of Tk's own layout: it starts from the height as if nothing sat below the rows, then steps back while the bottom pixel of the last row it counts is not a row to identify_region. The border under the rows is found, not assumed; with a 2 px border that is one or two questions.
- It is read on every <Configure>, after a yview() call (see the follow-up below), and stored in _fits. repaint gains no Tcl call.
max_offset, the page step and the scrollbar thumb use _fits. The old division now only sizes the slots (_rows_upper_bound). A thumb dragged to the end is rounded instead of truncated: truncating lost a row for 2 227 of 233 840 (total, fits) pairs, rounding for none.
Rows are chosen by model position. A cursor and an anchor are kept as model keys. _bind_navigation takes over, each binding ending in break:
- Up, Down, Page Up, Page Down, Home and End, and the same with Shift for a range across pages;
- Left and Right, because ttk's Right re-selects its focus slot;
- Button-1, Shift+Button-1 and Control+Button-1.
A click on a heading or a column separator stays with ttk, since that is sorting and resizing. The widget's own view never moves.
The table ignores its own selection echo, found by comparing with what it last wrote (_written). The event is queued, so a flag could not do it.

Tests

Rewritten on purpose:
- test_scrolling_moves_the_window_and_stays_in_range pinned max_offset() == 1000 - window().
- test_selection_is_by_model_key_and_survives_sorting was green only because the fake Tk never fires the echo. The echo is now delivered by hand.
New, in tests/test_virtual_tables.py:
- the pure function, against a stand-in that answers like Tk;
- a resize measured on the new layout, not the old one;
- the keyboard cursor;
- a Shift range across pages that survives a scroll;
- a click that brings the half row into full view;
- a cleared selection that leaves no anchor behind;
- a huge selection that does not make every scroll pay for it;
- an AST check that CI still runs the table pass.
Tk's answer is injected through bbox and identify_region, and the recorded bindings are fired by hand.
17 mutation entries in this PR, all caught (all 25 tables: entries were run after the follow-up, all caught).
tools/ci_gui_render.py --tables measures the pixel half on real Tk in CI, under Xvfb. It runs a bare SortableTree in the real theme at three sizes and several model sizes, plus a wide table scrolled sideways at every height across one row. It checks that:
- the table's _fits equals what Tk draws, also when scrolled sideways;
- the last row shows;
- Down never hides the cursor or moves ttk's own view;
- Page Down shows every row;
- a half-row click selects the row in full;
- a selection survives a scroll;
- Shift+Down across a page selects all of it.
Checked by hand against five restored bugs, and each run went red. Generated keys reach only the window with the keyboard focus, so the check asks for focus again and reports a lost focus as such, not as a table fault. A table with no row on screen is reported as "nothing was measured", not as a table fault.

The guards found two things, both fixed in the second commit:

_row_under added a silently swallowed exception, which the hygiene inventory counts. It now reuses _region and key_at.
A zip had no strict=.

Follow-up: CI on Tk 8.6 and the review (third commit)

The Linux render step was right. On Tk 8.6.14 under Xvfb, the first --tables run printed "the table counts 5 rows in full where Tk draws 4", and 20 more problems followed from that one number. Reproduced on Tk 8.6.14 with the same 21 lines. Tk 8.6's yview counts the row cut off at the bottom as shown: the count read off it was one row too high at 66 of 470 heights on 8.6.14, and right at all 470 on 9.0.4.

Two other ways were measured and rejected:

the height less the header less a bottom border as wide as the side one: when a wide table is scrolled sideways, the first slot's box starts left of the widget (x = -406), so rows that are not there would count;
identify_row: it does not check the bottom edge, and names a row below the widget on both Tk versions.

identify_region, asked at an x inside the columns that are on screen, found the bottom of the row area on both versions, plain and scrolled sideways.

Tk 8.6.14 lays a treeview out only when idle, and its bbox and identify read the layout as it was. Inside <Configure> that is the old size: a table grown from 4 rows to 10 went on counting 4. yview brings a pending layout up to date first (TtkUpdateScrollInfo in ttkScroll.c; newer Tk does it inside bbox and identify too), so _on_configure calls it before it measures. The table's own count after each <Configure> was then right in 1340 of 1340 resizes, in 1 px steps up and down and in 400 random jumps, for a plain table and one scrolled sideways, on 8.6.14 and 9.0.4.

Review follow-ups:

select_keys([]) and a click on a blank slot now clear the cursor and the anchor. A Shift range after either used to start from a row that had been cleared away.
The selection is an ordered dict that _restore_selection reads as it is. repaint used to copy it into a set: with 200 000 rows selected, a one-row scroll took 9.9 ms (0.07 ms with nothing selected) and a refresh 10.9 ms (1.1 ms). After the change, with all 200 000 selected: 0.06 ms and 1.9 ms. The guarding test measures memory, not time: three one-row scrolls with 100 000 rows selected allocate 920 bytes, against about 4 MiB for the copy.
README: the shortcut row calls the menu the right-click menu, the name the Connections section uses.

Review points left as they are, with the reason:

Building a Shift range per key press (the O(n^2) note). Measured over two runs: 0.17-0.33 ms per press at a 1000-row range, 15-18 ms at 100 000. A range that large arrives in one press (End, or a Shift+click), not by holding a key.
Pruning selected keys that left the model. It needs the key index on every refresh, which is O(rows) and which set_model avoids on purpose. selected_keys() already reports only keys still in the model, and the retained keys are bounded by what the user selected.
ast-grep CWE-78 and CWE-22 hints. The subprocess call is a constant argument list (sys.executable, this file, --tables), and the test opens a fixed file in the repository.

Run locally: internal_tools/guards.py --strong --run --lint, smoke_gui.py, tools/ci_gui_render.py on Tk 9.0.4 at 150% (en, pl, zh and the tables, all OK), and tools/ci_gui_render.py --tables on Tk 8.6.14 (OK).

Not run locally: the full suite, which runs here.

🤖 Generated with Claude Code

Summary by CodeRabbit

Bug Fixes
- Table rows can now be navigated with the keyboard and scrolled into view. Selections remain active when rows leave the visible area, and Shift-based range selection works across screens.
- Clicking a partially visible row brings it fully into view while selecting it.
Documentation
- Updated the keyboard shortcuts reference with table navigation, selection, copy, and row-menu shortcuts.

The virtual table measured its viewport in slots. The window holds the rows on screen plus a partial row and a buffer, and the rows that fit were counted as height // rowheight, header and border included. At the bottom the last rows sat in slots nobody could see: in a 400 px tree Tk shows 17 rows in full, the table counted 18 and held 22 slots, so the last five rows of every table were unreachable, a 20-row table could not scroll, and Page Down jumped 22 rows. The rows shown in full are now read off Tk's own yview on every Configure (rows_shown_in_full), the count see() itself goes by, and the bottom, the page step and the scrollbar thumb use it. A thumb dragged to the end is rounded instead of truncated. ttk's own key and click handlers chose a slot and see()-d it, which moved the widget's own view under the window: after 40 presses of Down the first rows could not be scrolled back to. Tk also answers every selection the table writes with a queued <<TreeviewSelect>>, and the table rebuilt its selection from the rows on screen, so a selected row scrolled out of view was lost. Rows are now chosen by model position, with a cursor and an anchor kept as model keys: Up, Down, Page Up, Page Down, Home and End (with Shift for a range across pages), a click, a Shift+click and a Ctrl+click. The table's own selection echo is ignored. tools/ci_gui_render.py --tables measures all of this on real Tk in CI, because the fake Tk of the suite has no pixels. The two tests that pinned the old behaviour are rewritten on purpose. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

…-and-keys

_row_under swallowed a failing identify call on its own, which the silent-handler inventory counts. It now goes through _region and key_at, which already answer a dying widget with None. The render check's zip states strict=True, as the lint gate asks. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

coderabbitai · 2026-09-28T23:22:48Z

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📝 Walkthrough

Walkthrough

SortableTree now measures fully visible rows and supports keyboard navigation, range selection, and pointer selection by model position. Tests cover scrolling and selection behavior. A real-Tk viewport check is included in the render-check command.

Changes

Virtual table navigation

Layer / File(s)	Summary
Visible-row measurement and scrolling `beantester/gui/widgets/sortable_tree.py`, `tests/test_virtual_tables.py`, `tests/test_mutation_registry.py`	The table measures fully visible rows from `yview` and uses that count for offset limits, scrollbar paging, and thumb fractions. Tests cover viewport measurement and scrolling behavior.
Model-based navigation and selection `beantester/gui/widgets/sortable_tree.py`, `tests/test_virtual_tables.py`, `tests/test_mutation_registry.py`, `README.md`, `CHANGELOG.md`	Keyboard and pointer handlers update selection by model position, reveal rows, and preserve selections across scrolling and queued Treeview selection events. The README lists the shortcuts; the changelog describes the navigation and selection changes.
Real-Tk viewport validation `tools/ci_gui_render.py`, `tests/test_virtual_tables.py`, `tests/test_mutation_registry.py`	The render check tests table visibility and interactions at multiple viewport sizes. The command-line flow runs the check and includes its result in the overall status.

Priority: ⬇️ Low

Estimated code review effort: 4 (Complex) | ~45 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  actor User
  participant SortableTree
  participant Treeview
  User->>SortableTree: Press Shift+Down
  SortableTree->>SortableTree: Update cursor, anchor, and model selection
  SortableTree->>Treeview: Reveal row and restore visible selection
  Treeview-->>SortableTree: Emit queued selection event
  SortableTree->>SortableTree: Ignore event matching written selection

Suggested labels: bug, enhancement, ui

Merge Risk: 🔵 Low · up to a30fa

After the selection is cleared, a later Shift-select can extend from a row the user no longer has selected. This is a small, recoverable glitch and should be fixed, but it does not block merging.

Security Architecture Review

Security architecture risk: 🔵 Low · up to a30fa

The change is confined principally to desktop table interaction and its checks. No new security boundary or verified attack path was found, but selection behavior shared with row actions warrants design-level review.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

inferred — The directly evidenced exposure is local GUI selection across table consumers; no new network, credential, tenant, or service authority was established by the inspected navigation paths.

Trust Boundaries and Controls

inferred — The widget translates local input into selected model keys; inspected action-bearing pages retain ownership of menus, callbacks, and their existing row checks.

Resilience and Maintainability Implications

inferred — The queued-echo marker compares reusable widget-slot tuples. Whether another selection producer can produce an equal tuple after slot reuse, with an action-relevant stale model selection as a result, remains unestablished.

Hardening Proposals

proposed — If other selection producers must be supported, distinguish a specific restoration echo from later events after slot reuse, and verify action targeting when rows are Ctrl-selected out of display order.

🚥 Pre-merge checks | ✅ 11 | ❌ 3

❌ Failed checks (3 warnings)

Check name	Status	Explanation	Resolution
No Obvious Performance Problems	⚠️ Warning	Shift-range keyboard selection introduces clear O(n²) UI-thread work. Each Shift+Down/Up event enters `_choose()` and rebuilds `_selected` from the full model slice (`sortable_tree.py:679-682`). The n…	Keep the anchor and cursor as model positions or keys, and represent a contiguous Shift range compactly. Update only the visible slot selection during keyboard events. Materialize the full selected-key list only when an API such as `selecte…
Clear User-Facing Text	⚠️ Warning	The new README shortcut entry calls the control a “row menu,” while the same README calls the same control the “right-click menu.” The PR adds this inconsistent user-facing name. Existing changelog en…	Use one name everywhere. For example, change README.md’s earlier “right-click menu” label to “row menu,” or change the new shortcut entry to use the established term consistently.
No Resource Leaks	⚠️ Warning	The PR can retain an unbounded history of stale model keys in `SortableTree._selected`. `set_model()` replaces `items` and calls `repaint()`, but it does not prune `_selected`. When a selected row dis…	Prune `self._selected` against the keys in the new model during `set_model()` before `repaint()`, or perform equivalent cleanup when an internal selection echo removes all matching rows. Also clear `_cursor` and `_anchor` when their keys le…

✅ Passed checks (11 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Tests For Changed Behavior	✅ Passed	The PR adds or updates tests for the changed runtime behavior. `tests/test_virtual_tables.py` covers fully visible row measurement, offset and scrollbar calculations, keyboard navigation, Shift ranges…
No Secrets Or Debug Leftovers	✅ Passed	The PR changes six existing files and adds no `CLAUDE.md`, `CLAUDE.local.md`, `AGENTS.md`, `.claude/`, or `.env` path. Scans of added lines found no credentials, tokens, private URLs, local absolute p…
No Hardcoded Ui Styling	✅ Passed	The PR changes Tkinter table behavior and adds a real-Tk render fixture. It does not add product colors, fonts, padding, margins, corner radii, or per-control styling literals. The new `700x700` root …
Desktop Robustness	✅ Passed	No explicit desktop-robustness failure condition is introduced. The changed application code only updates virtual-table measurement, scrolling, selection, and event bindings. It adds no asset loading,…
Safe File Parsing	✅ Passed	No unsafe file parsing was introduced. The only new direct file read is the test’s `open(..., encoding="utf-8")` followed by `ast.parse` on the fixed repository source `tools/ci_gui_render.py`; it doe…
System Changes Are Reversible	✅ Passed	The PR changes Tk table navigation, selection handling, tests, documentation, and a GUI render check. The changed files contain no changes to network filters or proxies, firewalls, system time, proces…
Scope, Duplication And Docs	✅ Passed	The changes stay within the titled table-navigation fix. The source changes, focused tests, mutation entries, and real-Tk render check all support that fix. The PR updates CHANGELOG.md and README.md w…
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the user-facing fix: table users can reach every row and select rows from the keyboard. It is specific, relevant, and 65 characters long.

Full details: No Obvious Performance Problems

Explanation

Shift-range keyboard selection introduces clear O(n²) UI-thread work. Each Shift+Down/Up event enters _choose() and rebuilds _selected from the full model slice (sortable_tree.py:679-682). The next event repeats this for the larger range, so selecting N rows processes 1+2+...+N rows and allocates increasingly large lists. repaint() and _restore_selection() also copy the growing selection on each event (:566 and :630). This affects the widget's intended large models; the repository tests use 50,000–100,000 rows.

Resolution

Keep the anchor and cursor as model positions or keys, and represent a contiguous Shift range compactly. Update only the visible slot selection during keyboard events. Materialize the full selected-key list only when an API such as selected_keys() or copy requires it, or update it incrementally for adjacent cursor moves. Add a large-model test that holds Shift while moving across many rows and asserts bounded or linear total work.

Full details: Clear User-Facing Text

Explanation

The new README shortcut entry calls the control a “row menu,” while the same README calls the same control the “right-click menu.” The PR adds this inconsistent user-facing name. Existing changelog entries also use “row menu.”

Full details: No Resource Leaks

Explanation

The PR can retain an unbounded history of stale model keys in SortableTree._selected. set_model() replaces items and calls repaint(), but it does not prune _selected. When a selected row disappears, the new _restore_selection() records an empty _written tuple and the queued _on_select() returns early when it sees that same empty selection. Therefore _selected is not cleared. Repeated live-table refreshes and Ctrl selections can retain keys for rows that no longer exist. selected_keys() only filters the result; it does not release the stale keys.

Resolution

Prune self._selected against the keys in the new model during set_model() before repaint(), or perform equivalent cleanup when an internal selection echo removes all matching rows. Also clear _cursor and _anchor when their keys leave the model. Add a regression test that selects rows, replaces the model without those keys, processes the queued selection event, and asserts both selected_keys() and the private retained selection state are empty.

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donislawdev · 2026-09-29T06:03:40Z

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coderabbitai · 2026-09-29T06:03:49Z

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Actionable comments posted: 1

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Inline comments:
Review comments at @beantester/gui/widgets/sortable_tree.py:
- Around line 645-650: Update select_keys to clear _cursor and _anchor when the
resulting selection is empty, while keeping them aligned with the first selected
key otherwise. Also update _on_press’s blank-slot selection-clearing path to
reset both fields so later range selection cannot use a stale anchor.

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📒 Files selected for processing (6)

CHANGELOG.md
README.md
beantester/gui/widgets/sortable_tree.py
tests/test_mutation_registry.py
tests/test_virtual_tables.py
tools/ci_gui_render.py

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GitHub Actions: CI / 7_tests (ubuntu-latest, py3.14).txt: fix(gui): reach every table row and choose rows from the keyboard

Conclusion: failure

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 �[36;1m  echo "python3-tk and xvfb are already on the image"�[0m
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