FA-7981 / Form lifecycle / Open access

Form dirty-field bookkeeping: Typing rewrites the baseline instead of the draft · case 01

Typing rewrites the baseline instead of the draft.

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

ROOT CAUSE

The input operation uses `initial[name] = value` where the contract requires `current[name] = value`.

VERIFIED REPAIR

Implement the input operation as `current[name] = value`.

Unsuccessful approach: Setdefault ignores edits to existing fields.

Case contract

Edits change draft only; reset restores baseline; commit accepts draft; unmount removal clears both; dirty comparison includes additions and removals.

Why this case matters

A deterministic model of form dirty-field bookkeeping; 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(initial, current, event, name, value):
    initial, current = initial.copy(), current.copy()
    if event == 'input': initial[name] = value
    elif event == 'reset': current = dict(initial)
    elif event == 'commit': initial = dict(current)
    elif event == 'remove': current.pop(name, None); initial.pop(name, None)
    dirty = sorted(k for k in set(initial) | set(current) if initial.get(k, object()) != current.get(k, object()))
    return (initial, current, dirty)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('edit', solve({'a':1}, {'a':1}, 'input', 'a', 2), ({'a': 1}, {'a': 2}, ['a']))
check('reset', solve({'a':1}, {'a':2}, 'reset', None, None), ({'a': 1}, {'a': 1}, []))
check('commit', solve({'a':1}, {'a':2}, 'commit', None, None), ({'a': 2}, {'a': 2}, []))
check('remove', solve({'a':1,'b':2}, {'a':3,'b':2}, 'remove', 'a', None), ({'b': 2}, {'b': 2}, []))
check('new', solve({}, {'new':0}, 'read', None, None), ({}, {'new': 0}, ['new']))
check('removed', solve({'a':1}, {}, 'read', None, None), ({'a': 1}, {}, ['a']))
check('parameterized dirty value', solve({'a':N}, {'a':N}, 'input', 'a', N+1), ({'a':N}, {'a':N+1}, ['a']))
for repetition in range(N):
    check('repeat removed', solve({'a':1}, {}, 'read', None, None), ({'a': 1}, {}, ['a']))
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 fixture	Actual	Expected	Outcome
edit	`[{'a': 2}, {'a': 1}, ['a']]`	`[{'a': 1}, {'a': 2}, ['a']]`	Failed
reset	`[{'a': 1}, {'a': 1}, []]`	`[{'a': 1}, {'a': 1}, []]`	Passed
commit	`[{'a': 2}, {'a': 2}, []]`	`[{'a': 2}, {'a': 2}, []]`	Passed
remove	`[{'b': 2}, {'b': 2}, []]`	`[{'b': 2}, {'b': 2}, []]`	Passed
new	`[{}, {'new': 0}, ['new']]`	`[{}, {'new': 0}, ['new']]`	Passed
removed	`[{'a': 1}, {}, ['a']]`	`[{'a': 1}, {}, ['a']]`	Passed
parameterized dirty value	`[{'a': 2}, {'a': 1}, ['a']]`	`[{'a': 1}, {'a': 2}, ['a']]`	Failed
repeat removed	`[{'a': 1}, {}, ['a']]`	`[{'a': 1}, {}, ['a']]`	Passed

SHA-256 / 22aeab6fb9b954d433157b4c8894f0ee6245a30a6fdb5e26251eef89605822e3

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(initial, current, event, name, value):
    initial, current = initial.copy(), current.copy()
    if event == 'input': current.setdefault(name, value)
    elif event == 'reset': current = dict(initial)
    elif event == 'commit': initial = dict(current)
    elif event == 'remove': current.pop(name, None); initial.pop(name, None)
    dirty = sorted(k for k in set(initial) | set(current) if initial.get(k, object()) != current.get(k, object()))
    return (initial, current, dirty)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('edit', solve({'a':1}, {'a':1}, 'input', 'a', 2), ({'a': 1}, {'a': 2}, ['a']))
check('reset', solve({'a':1}, {'a':2}, 'reset', None, None), ({'a': 1}, {'a': 1}, []))
check('commit', solve({'a':1}, {'a':2}, 'commit', None, None), ({'a': 2}, {'a': 2}, []))
check('remove', solve({'a':1,'b':2}, {'a':3,'b':2}, 'remove', 'a', None), ({'b': 2}, {'b': 2}, []))
check('new', solve({}, {'new':0}, 'read', None, None), ({}, {'new': 0}, ['new']))
check('removed', solve({'a':1}, {}, 'read', None, None), ({'a': 1}, {}, ['a']))
check('parameterized dirty value', solve({'a':N}, {'a':N}, 'input', 'a', N+1), ({'a':N}, {'a':N+1}, ['a']))
for repetition in range(N):
    check('repeat removed', solve({'a':1}, {}, 'read', None, None), ({'a': 1}, {}, ['a']))
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 fixture	Actual	Expected	Outcome
edit	`[{'a': 1}, {'a': 1}, []]`	`[{'a': 1}, {'a': 2}, ['a']]`	Failed
reset	`[{'a': 1}, {'a': 1}, []]`	`[{'a': 1}, {'a': 1}, []]`	Passed
commit	`[{'a': 2}, {'a': 2}, []]`	`[{'a': 2}, {'a': 2}, []]`	Passed
remove	`[{'b': 2}, {'b': 2}, []]`	`[{'b': 2}, {'b': 2}, []]`	Passed
new	`[{}, {'new': 0}, ['new']]`	`[{}, {'new': 0}, ['new']]`	Passed
removed	`[{'a': 1}, {}, ['a']]`	`[{'a': 1}, {}, ['a']]`	Passed
parameterized dirty value	`[{'a': 1}, {'a': 1}, []]`	`[{'a': 1}, {'a': 2}, ['a']]`	Failed
repeat removed	`[{'a': 1}, {}, ['a']]`	`[{'a': 1}, {}, ['a']]`	Passed

SHA-256 / 7505b7a289e0601cd816f5f11d60e2b9133d39a5bb430d73c9a9e929e9a8883a

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(initial, current, event, name, value):
    initial, current = initial.copy(), current.copy()
    if event == 'input': current[name] = value
    elif event == 'reset': current = dict(initial)
    elif event == 'commit': initial = dict(current)
    elif event == 'remove': current.pop(name, None); initial.pop(name, None)
    dirty = sorted(k for k in set(initial) | set(current) if initial.get(k, object()) != current.get(k, object()))
    return (initial, current, dirty)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('edit', solve({'a':1}, {'a':1}, 'input', 'a', 2), ({'a': 1}, {'a': 2}, ['a']))
check('reset', solve({'a':1}, {'a':2}, 'reset', None, None), ({'a': 1}, {'a': 1}, []))
check('commit', solve({'a':1}, {'a':2}, 'commit', None, None), ({'a': 2}, {'a': 2}, []))
check('remove', solve({'a':1,'b':2}, {'a':3,'b':2}, 'remove', 'a', None), ({'b': 2}, {'b': 2}, []))
check('new', solve({}, {'new':0}, 'read', None, None), ({}, {'new': 0}, ['new']))
check('removed', solve({'a':1}, {}, 'read', None, None), ({'a': 1}, {}, ['a']))
check('parameterized dirty value', solve({'a':N}, {'a':N}, 'input', 'a', N+1), ({'a':N}, {'a':N+1}, ['a']))
for repetition in range(N):
    check('repeat removed', solve({'a':1}, {}, 'read', None, None), ({'a': 1}, {}, ['a']))
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 fixture	Actual	Expected	Outcome
edit	`[{'a': 1}, {'a': 2}, ['a']]`	`[{'a': 1}, {'a': 2}, ['a']]`	Passed
reset	`[{'a': 1}, {'a': 1}, []]`	`[{'a': 1}, {'a': 1}, []]`	Passed
commit	`[{'a': 2}, {'a': 2}, []]`	`[{'a': 2}, {'a': 2}, []]`	Passed
remove	`[{'b': 2}, {'b': 2}, []]`	`[{'b': 2}, {'b': 2}, []]`	Passed
new	`[{}, {'new': 0}, ['new']]`	`[{}, {'new': 0}, ['new']]`	Passed
removed	`[{'a': 1}, {}, ['a']]`	`[{'a': 1}, {}, ['a']]`	Passed
parameterized dirty value	`[{'a': 1}, {'a': 2}, ['a']]`	`[{'a': 1}, {'a': 2}, ['a']]`	Passed
repeat removed	`[{'a': 1}, {}, ['a']]`	`[{'a': 1}, {}, ['a']]`	Passed

SHA-256 / b63e8e7931c4bdb9300dcd6b9f00fae2852e95c78e3e5bd58ac37e930f722a94

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 2026-09-29T14:38:17.094770+00:00.

Case digest / ed5e7c975f444235e546903608211fb5cc7032245e3fc33f40221f35f8a47668