Constrain autofill to a single axis (vertical or horizontal) by ggyuchive · Pull Request #82 · wafflebase/wafflebase

ggyuchive · 2026-03-25T16:10:07Z

Summary

Previously computeAutofillRange created a bounding box that could extend in both row and column directions simultaneously. Now the target is clamped to the dominant axis — whichever direction the drag extends furthest from the source edge — matching Google Sheets behaviour.

Why

Both google sheet and excel supports to autofill vertical or horizontal.
This change will handle number-autofill case easily (future work). It does not just fill repeatly, based on Ordinary Least Squares(OLS).

Linked Issues

Fixes #

Verification

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verify:self — CI comment shows ✅
verify:integration — CI comment shows ✅ (or explicit skip reason below)

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Risk Assessment

User-facing risk:
Data/security risk:
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Notes for Reviewers

UI changes (screenshots/gifs if applicable):
Follow-up work (if any):

Summary by CodeRabbit

Documentation
- Updated frontend and sheet design documentation to clarify autofill behavior constraints.
Bug Fixes
- Modified autofill (fill-handle) to expand along a single axis (vertical or horizontal) based on drag direction distance, with vertical preferred on ties.
Tests
- Updated autofill test cases to validate single-axis expansion behavior.

github-actions · 2026-03-25T16:12:28Z

Verification: verify:self

Result: ✅ PASS in 104.5s

Lane	Status	Duration
sheets:build	✅ pass	13.2s
docs:build	✅ pass	5.4s
verify:fast	✅ pass	48.4s
frontend:build	✅ pass	14.8s
verify:frontend:chunks	✅ pass	0.3s
backend:build	✅ pass	4.3s
cli:build	✅ pass	1.8s
verify:entropy	✅ pass	16.2s

Verification: verify:integration

Result: ✅ PASS

Previously computeAutofillRange created a bounding box that could extend in both row and column directions simultaneously. Now the target is clamped to the dominant axis — whichever direction the drag extends furthest from the source edge — matching Google Sheets behaviour. Ties favour vertical. Co-Authored-By: Claude Opus 4.6 <[email protected]>

coderabbitai · 2026-03-25T16:14:31Z

📝 Walkthrough

Walkthrough

The pull request modifies autofill behavior for fill-handle drag operations, constraining expansion to a single dominant axis (vertical or horizontal) rather than allowing unrestricted rectangular expansion. The dominant axis is determined by which direction extends farthest from the source, with ties favoring vertical. Updates span design documentation, core implementation, and test coverage.

Changes

Cohort / File(s)	Summary
Design Documentation `docs/design/frontend.md`, `docs/design/sheet.md`	Updated documentation to reflect single-axis autofill constraint behavior, specifying how the dominant axis is selected based on drag distance with vertical-tie preference.
Implementation & Tests `packages/sheets/src/model/worksheet/clipboard.ts`, `packages/sheets/test/sheet/autofill.test.ts`	Modified `computeAutofillRange` to compute vertical and horizontal distances from target to source edges, select the dominant axis, and clamp non-dominant coordinates. Updated existing test and added new test asserting single-axis filling and tie-breaking behavior.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~22 minutes

Suggested reviewers

hackerwins

Poem

🐰 Along one axis true, the bunny fills with care,
No diagonal sprawl or rectangular flair!
Vertical wins ties—a rule most fair,
The fill-handle hops with purpose and air. 🎯

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The pull request title clearly and concisely summarizes the main change: constraining autofill behavior to a single axis, matching the primary objective throughout the changeset.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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🧹 Nitpick comments (1)

packages/sheets/test/sheet/autofill.test.ts (1)
42-55: Minor naming inconsistency in test description.

The test name says "vertical wins on tie", but this scenario isn't actually a tie—vertical distance is 2 vs horizontal distance 1. Consider renaming to better reflect what's being tested:
-  it('constrains autofill to single axis (vertical wins on tie)', async () => {
+  it('constrains autofill to single axis (diagonal target)', async () => {
Alternatively, to truly test the tie-breaker behavior, you could use a target where both distances are equal (e.g., { r: 2, c: 2 } for a single-cell source at A1).
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.

In `@packages/sheets/test/sheet/autofill.test.ts` around lines 42 - 55, The test
titled "constrains autofill to single axis (vertical wins on tie)" is misleading
because the target { r: 3, c: 2 } is not a tie (vertical distance 2 vs
horizontal 1); either rename the test to reflect vertical dominance (e.g.,
"constrains autofill to single axis (vertical wins)"), or change the target to a
true tie (e.g., use sheet.autofill({ r: 2, c: 2 })) so it actually exercises the
tie-breaker; update the test title or the autofill target accordingly in the
it(...) block that constructs Sheet and calls sheet.autofill.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@packages/sheets/test/sheet/autofill.test.ts`:
- Around line 42-55: The test titled "constrains autofill to single axis
(vertical wins on tie)" is misleading because the target { r: 3, c: 2 } is not a
tie (vertical distance 2 vs horizontal 1); either rename the test to reflect
vertical dominance (e.g., "constrains autofill to single axis (vertical wins)"),
or change the target to a true tie (e.g., use sheet.autofill({ r: 2, c: 2 })) so
it actually exercises the tie-breaker; update the test title or the autofill
target accordingly in the it(...) block that constructs Sheet and calls
sheet.autofill.

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 97af10de-867b-4cad-bd67-1ae5c12be89f

📥 Commits

Reviewing files that changed from the base of the PR and between c5b64c5 and 272bae5.

📒 Files selected for processing (4)

docs/design/frontend.md
docs/design/sheet.md
packages/sheets/src/model/worksheet/clipboard.ts
packages/sheets/test/sheet/autofill.test.ts

ggyuchive force-pushed the fix-autofill branch from 18f4a10 to 272bae5 Compare March 25, 2026 16:14

coderabbitai Bot reviewed Mar 25, 2026

View reviewed changes

hackerwins merged commit ed79a4d into main Mar 25, 2026
3 checks passed

hackerwins deleted the fix-autofill branch March 25, 2026 18:45

coderabbitai Bot mentioned this pull request Mar 27, 2026

Add to support number autofill with Ordinary Least Squares #85

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Constrain autofill to a single axis (vertical or horizontal)#82

Constrain autofill to a single axis (vertical or horizontal)#82
hackerwins merged 1 commit into
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fix-autofill

ggyuchive commented Mar 25, 2026 •

edited by hackerwins

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ggyuchive commented Mar 25, 2026 • edited by hackerwins Loading Uh oh! There was an error while loading. Please reload this page.

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ggyuchive commented Mar 25, 2026 •

edited by hackerwins

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