FAILURE MAP
← Case archive

FA-8766 / Direct manipulation / Open access

Resizable panel constraint handling: Resize deltas replace the absolute panel size · case 01

Resize deltas replace the absolute panel size.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The accumulate operation uses `change` where the contract requires `size + change`.

VERIFIED REPAIR

Implement the accumulate operation as `size + change`.

Unsuccessful approach: Subtracting reverses drag meaning.

Case contract

Disabled handles preserve size; trailing-axis handles reverse delta; add deltas to current size and clamp to min/max.

Why this case matters

A deterministic model of resizable panel constraint handling; 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(size, delta, minimum, maximum, reversed_axis, disabled):
    if disabled: return size
    change = -delta if reversed_axis else delta
    wanted = change
    return max(minimum, min(maximum, wanted))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('disabled', solve(50, 10, 20, 100, False, True), 50)
check('forward', solve(50, 10, 20, 100, False, False), 60)
check('reversed', solve(50, 10, 20, 100, True, False), 40)
check('min', solve(30, -50, 20, 100, False, False), 20)
check('max', solve(80, 50, 20, 100, False, False), 100)
check('zero', solve(50, 0, 20, 100, False, False), 50)
check('parameterized resize distance', solve(10*N,N,0,100*N,False,False),11*N)
for repetition in range(N):
    check('repeat zero', solve(50, 0, 20, 100, False, False), 50)
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
disabled5050Passed
forward2060Failed
reversed2040Failed
min2020Passed
max50100Failed
zero2050Failed
parameterized resize distance111Failed
repeat zero2050Failed

SHA-256 / aa578bea6cad591525e334a3a8e378b2f051b8f0f205f0c5c3b4e452b715c5c0

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(size, delta, minimum, maximum, reversed_axis, disabled):
    if disabled: return size
    change = -delta if reversed_axis else delta
    wanted = size - change
    return max(minimum, min(maximum, wanted))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('disabled', solve(50, 10, 20, 100, False, True), 50)
check('forward', solve(50, 10, 20, 100, False, False), 60)
check('reversed', solve(50, 10, 20, 100, True, False), 40)
check('min', solve(30, -50, 20, 100, False, False), 20)
check('max', solve(80, 50, 20, 100, False, False), 100)
check('zero', solve(50, 0, 20, 100, False, False), 50)
check('parameterized resize distance', solve(10*N,N,0,100*N,False,False),11*N)
for repetition in range(N):
    check('repeat zero', solve(50, 0, 20, 100, False, False), 50)
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
disabled5050Passed
forward4060Failed
reversed6040Failed
min8020Failed
max30100Failed
zero5050Passed
parameterized resize distance911Failed
repeat zero5050Passed

SHA-256 / f087910c56883bdb531b016dd162c3b38ea6d9f358bf9de26d0c112cf23a448d

3 / The verified repair

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

N = 1
observations = []
def solve(size, delta, minimum, maximum, reversed_axis, disabled):
    if disabled: return size
    change = -delta if reversed_axis else delta
    wanted = size + change
    return max(minimum, min(maximum, wanted))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('disabled', solve(50, 10, 20, 100, False, True), 50)
check('forward', solve(50, 10, 20, 100, False, False), 60)
check('reversed', solve(50, 10, 20, 100, True, False), 40)
check('min', solve(30, -50, 20, 100, False, False), 20)
check('max', solve(80, 50, 20, 100, False, False), 100)
check('zero', solve(50, 0, 20, 100, False, False), 50)
check('parameterized resize distance', solve(10*N,N,0,100*N,False,False),11*N)
for repetition in range(N):
    check('repeat zero', solve(50, 0, 20, 100, False, False), 50)
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
disabled5050Passed
forward6060Passed
reversed4040Passed
min2020Passed
max100100Passed
zero5050Passed
parameterized resize distance1111Passed
repeat zero5050Passed

SHA-256 / c9c3aef31922fe4ccbb39dbe52a30550f21c31cf7b5cf382a9dd2921ab3e4ac8

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 2026-09-29T14:38:24.255882+00:00.

Case digest / fc2536c1fdc8d534e78c02d2f28935da8c69b03717a38ba64f1f3e6088c2b6ce