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FA-9056 / Direct manipulation / Open access

Gesture axis locking and cancellation: Cancelled gestures continue delivering movement · case 01

Cancelled gestures continue delivering movement.

Verified by executionVariant 1 · 9 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The cancel operation uses `if False: return (None, 0, 0)` where the contract requires `if cancelled: return (None, 0, 0)`.

VERIFIED REPAIR

Implement the cancel operation as `if cancelled: return (None, 0, 0)`.

Unsuccessful approach: Returning existing lock and deltas still applies cancelled input.

Case contract

Cancelled gestures emit no movement; activate at the maximum absolute-axis threshold; choose dominant magnitude with horizontal tie; lock persists and suppresses cross-axis displacement.

Why this case matters

A deterministic model of gesture axis locking and cancellation; this isolates one interface invariant without requiring a browser.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(dx, dy, threshold, locked, cancelled):
    if False: return (None, 0, 0)
    if locked is None:
        if max(abs(dx), abs(dy)) < threshold: return (None, 0, 0)
        locked = 'x' if abs(dx) >= abs(dy) else 'y'
    if locked == 'x': return ('x', dx, 0)
    return ('y', 0, dy)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cancel', solve(10, 2, 5, 'x', True), (None, 0, 0))
check('negative', solve(-10, 0, 5, None, False), ('x', -10, 0))
check('threshold', solve(5, 0, 5, None, False), ('x', 5, 0))
check('small', solve(2, 1, 5, None, False), (None, 0, 0))
check('dominant negative', solve(-10, 3, 5, None, False), ('x', -10, 0))
check('vertical', solve(2, -10, 5, None, False), ('y', 0, -10))
check('locked', solve(2, 20, 5, "x", False), ('x', 2, 0))
check('parameterized gesture distance', solve(2*N,0,N,None,False), ('x',2*N,0))
for repetition in range(N):
    check('repeat locked', solve(2, 20, 5, "x", False), ('x', 2, 0))
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
cancel['x', 10, 0][None, 0, 0]Failed
negative['x', -10, 0]['x', -10, 0]Passed
threshold['x', 5, 0]['x', 5, 0]Passed
small[None, 0, 0][None, 0, 0]Passed
dominant negative['x', -10, 0]['x', -10, 0]Passed
vertical['y', 0, -10]['y', 0, -10]Passed
locked['x', 2, 0]['x', 2, 0]Passed
parameterized gesture distance['x', 2, 0]['x', 2, 0]Passed
repeat locked['x', 2, 0]['x', 2, 0]Passed

SHA-256 / 4f1bbc01833fffcbbb942cc6958286971c15190010583778e3121b95066351f8

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(dx, dy, threshold, locked, cancelled):
    if cancelled: return (locked, dx, dy)
    if locked is None:
        if max(abs(dx), abs(dy)) < threshold: return (None, 0, 0)
        locked = 'x' if abs(dx) >= abs(dy) else 'y'
    if locked == 'x': return ('x', dx, 0)
    return ('y', 0, dy)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cancel', solve(10, 2, 5, 'x', True), (None, 0, 0))
check('negative', solve(-10, 0, 5, None, False), ('x', -10, 0))
check('threshold', solve(5, 0, 5, None, False), ('x', 5, 0))
check('small', solve(2, 1, 5, None, False), (None, 0, 0))
check('dominant negative', solve(-10, 3, 5, None, False), ('x', -10, 0))
check('vertical', solve(2, -10, 5, None, False), ('y', 0, -10))
check('locked', solve(2, 20, 5, "x", False), ('x', 2, 0))
check('parameterized gesture distance', solve(2*N,0,N,None,False), ('x',2*N,0))
for repetition in range(N):
    check('repeat locked', solve(2, 20, 5, "x", False), ('x', 2, 0))
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
cancel['x', 10, 2][None, 0, 0]Failed
negative['x', -10, 0]['x', -10, 0]Passed
threshold['x', 5, 0]['x', 5, 0]Passed
small[None, 0, 0][None, 0, 0]Passed
dominant negative['x', -10, 0]['x', -10, 0]Passed
vertical['y', 0, -10]['y', 0, -10]Passed
locked['x', 2, 0]['x', 2, 0]Passed
parameterized gesture distance['x', 2, 0]['x', 2, 0]Passed
repeat locked['x', 2, 0]['x', 2, 0]Passed

SHA-256 / ef55b7fcb8c9800290a9dd28fc99f4ada3a4859a5986ccce4703a5d0753d8bdb

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(dx, dy, threshold, locked, cancelled):
    if cancelled: return (None, 0, 0)
    if locked is None:
        if max(abs(dx), abs(dy)) < threshold: return (None, 0, 0)
        locked = 'x' if abs(dx) >= abs(dy) else 'y'
    if locked == 'x': return ('x', dx, 0)
    return ('y', 0, dy)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('cancel', solve(10, 2, 5, 'x', True), (None, 0, 0))
check('negative', solve(-10, 0, 5, None, False), ('x', -10, 0))
check('threshold', solve(5, 0, 5, None, False), ('x', 5, 0))
check('small', solve(2, 1, 5, None, False), (None, 0, 0))
check('dominant negative', solve(-10, 3, 5, None, False), ('x', -10, 0))
check('vertical', solve(2, -10, 5, None, False), ('y', 0, -10))
check('locked', solve(2, 20, 5, "x", False), ('x', 2, 0))
check('parameterized gesture distance', solve(2*N,0,N,None,False), ('x',2*N,0))
for repetition in range(N):
    check('repeat locked', solve(2, 20, 5, "x", False), ('x', 2, 0))
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
cancel[None, 0, 0][None, 0, 0]Passed
negative['x', -10, 0]['x', -10, 0]Passed
threshold['x', 5, 0]['x', 5, 0]Passed
small[None, 0, 0][None, 0, 0]Passed
dominant negative['x', -10, 0]['x', -10, 0]Passed
vertical['y', 0, -10]['y', 0, -10]Passed
locked['x', 2, 0]['x', 2, 0]Passed
parameterized gesture distance['x', 2, 0]['x', 2, 0]Passed
repeat locked['x', 2, 0]['x', 2, 0]Passed

SHA-256 / 1e950a9e1339eff02cbe4bfb5b7debe8996dd5657813e97b40aa53391dcbb184

Verification & scope

This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:38:26.776911+00:00.

Case digest / 86f72ac0878c79e387b1a1986de632aeb46ec506d6274cf25d8d58cd2b4d56a4