FA-76596 / Email MIME structure / Open access

Assemble the structure of a forwarded message: attachment order · case 01

Forwarded attachments are reordered alphabetically.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The attachment order decision evaluates `[body] + sorted(atts)` where the contract requires `[body] + atts`.

THE FAILURE

The attachment order decision evaluates `[body] + sorted(atts)` where the contract requires `[body] + atts`.

Unsuccessful approach: Reversing the list still loses the original order. The attempted `[body] + atts[::-1]` still disagrees with a fixture.

Case contract

original {subject, body_type ("text" or "alternative"), attachments [names], inline [image names]}. Subjects get a "Fwd: " prefix unless they already start with "fwd:" (case-insensitive). mode "attach" produces mixed(text,message/rfc822): the original travels whole, attachments included. mode "inline" copies the body: alternative(text,html), with related(html, images...) when the original has inline images (kept only when html exists), or text; original attachments follow in their original order inside mixed(...).

Why this case matters

Forwarding rebuilds a MIME tree; errors duplicate attachments, lose inline images or stack Fwd: prefixes.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(original, mode):
    s = original['subject']
    subject = s if s[:4].lower() == 'fwd:' else 'Fwd: ' + s
    if mode == 'attach':
        return {'subject': subject, 'structure': 'mixed(text,message/rfc822)'}
    atts = list(original['attachments'])
    if original['body_type'] == 'alternative':
        body = 'alternative(text,html)'
        if original['inline']:
            body = 'alternative(text,related(html,' + ','.join(original['inline']) + '))'
    else:
        body = 'text'
    if atts:
        body = 'mixed(' + ','.join([body] + sorted(atts)) + ')'
    return {'subject': subject, 'structure': body}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_CASES = {1: [('upper-case existing prefix', ({'subject': 'FWD: plan 1', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 1'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a1.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i1.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c1.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c1.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p1.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p1.gif))', 'subject': 'fwd: y'})], 2: [('upper-case existing prefix', ({'subject': 'FWD: plan 2', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 2'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a2.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i2.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c2.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c2.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p2.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p2.gif))', 'subject': 'fwd: y'})], 3: [('upper-case existing prefix', ({'subject': 'FWD: plan 3', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 3'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a3.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i3.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c3.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c3.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p3.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p3.gif))', 'subject': 'fwd: y'})], 4: [('upper-case existing prefix', ({'subject': 'FWD: plan 4', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 4'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a4.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i4.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c4.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c4.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p4.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p4.gif))', 'subject': 'fwd: y'})], 5: [('upper-case existing prefix', ({'subject': 'FWD: plan 5', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 5'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a5.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i5.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c5.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c5.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p5.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p5.gif))', 'subject': 'fwd: y'})]}
for _label, _args, _expected in _CASES[N]:
    check(_label, solve(*_args), _expected)
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
upper-case existing prefix	`{'structure': 'text', 'subject': 'FWD: plan 1'}`	`{'structure': 'text', 'subject': 'FWD: plan 1'}`	Passed
subject starting with Fwd as a word	`{'structure': 'text', 'subject': 'Fwd: Fwd planning review'}`	`{'structure': 'text', 'subject': 'Fwd: Fwd planning review'}`	Passed
attach mode keeps parts inside	`{'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}`	`{'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}`	Passed
text body with inline images	`{'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}`	`{'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}`	Passed
attachment order	`{'structure': 'mixed(alternative(text,html),a.doc,b.pdf,c1.txt)', 'subject': 'Fwd: s'}`	`{'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c1.txt)', 'subject': 'Fwd: s'}`	Failed
html without inline images	`{'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}`	`{'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}`	Passed
html with inline image	`{'structure': 'alternative(text,related(html,p1.gif))', 'subject': 'fwd: y'}`	`{'structure': 'alternative(text,related(html,p1.gif))', 'subject': 'fwd: y'}`	Passed

SHA-256 / 72f1d60d3e5c3df707a943386f4a89a7439a901b9bd14d7f41cc346ba0b424e9

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(original, mode):
    s = original['subject']
    subject = s if s[:4].lower() == 'fwd:' else 'Fwd: ' + s
    if mode == 'attach':
        return {'subject': subject, 'structure': 'mixed(text,message/rfc822)'}
    atts = list(original['attachments'])
    if original['body_type'] == 'alternative':
        body = 'alternative(text,html)'
        if original['inline']:
            body = 'alternative(text,related(html,' + ','.join(original['inline']) + '))'
    else:
        body = 'text'
    if atts:
        body = 'mixed(' + ','.join([body] + atts[::-1]) + ')'
    return {'subject': subject, 'structure': body}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_CASES = {1: [('upper-case existing prefix', ({'subject': 'FWD: plan 1', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 1'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a1.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i1.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c1.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c1.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p1.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p1.gif))', 'subject': 'fwd: y'})], 2: [('upper-case existing prefix', ({'subject': 'FWD: plan 2', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 2'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a2.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i2.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c2.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c2.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p2.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p2.gif))', 'subject': 'fwd: y'})], 3: [('upper-case existing prefix', ({'subject': 'FWD: plan 3', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 3'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a3.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i3.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c3.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c3.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p3.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p3.gif))', 'subject': 'fwd: y'})], 4: [('upper-case existing prefix', ({'subject': 'FWD: plan 4', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 4'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a4.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i4.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c4.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c4.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p4.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p4.gif))', 'subject': 'fwd: y'})], 5: [('upper-case existing prefix', ({'subject': 'FWD: plan 5', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'FWD: plan 5'}), ('subject starting with Fwd as a word', ({'subject': 'Fwd planning review', 'body_type': 'text', 'attachments': [], 'inline': []}, 'inline'), {'structure': 'text', 'subject': 'Fwd: Fwd planning review'}), ('attach mode keeps parts inside', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['a5.pdf'], 'inline': ['logo.png']}, 'attach'), {'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}), ('text body with inline images', ({'subject': 's', 'body_type': 'text', 'attachments': ['a.pdf'], 'inline': ['i5.png', 'j.png']}, 'inline'), {'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}), ('attachment order', ({'subject': 's', 'body_type': 'alternative', 'attachments': ['b.pdf', 'a.doc', 'c5.txt'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c5.txt)', 'subject': 'Fwd: s'}), ('html without inline images', ({'subject': 'Re: x', 'body_type': 'alternative', 'attachments': ['x.pdf'], 'inline': []}, 'inline'), {'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}), ('html with inline image', ({'subject': 'fwd: y', 'body_type': 'alternative', 'attachments': [], 'inline': ['p5.gif']}, 'inline'), {'structure': 'alternative(text,related(html,p5.gif))', 'subject': 'fwd: y'})]}
for _label, _args, _expected in _CASES[N]:
    check(_label, solve(*_args), _expected)
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
upper-case existing prefix	`{'structure': 'text', 'subject': 'FWD: plan 1'}`	`{'structure': 'text', 'subject': 'FWD: plan 1'}`	Passed
subject starting with Fwd as a word	`{'structure': 'text', 'subject': 'Fwd: Fwd planning review'}`	`{'structure': 'text', 'subject': 'Fwd: Fwd planning review'}`	Passed
attach mode keeps parts inside	`{'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}`	`{'structure': 'mixed(text,message/rfc822)', 'subject': 'Fwd: s'}`	Passed
text body with inline images	`{'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}`	`{'structure': 'mixed(text,a.pdf)', 'subject': 'Fwd: s'}`	Passed
attachment order	`{'structure': 'mixed(alternative(text,html),c1.txt,a.doc,b.pdf)', 'subject': 'Fwd: s'}`	`{'structure': 'mixed(alternative(text,html),b.pdf,a.doc,c1.txt)', 'subject': 'Fwd: s'}`	Failed
html without inline images	`{'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}`	`{'structure': 'mixed(alternative(text,html),x.pdf)', 'subject': 'Fwd: Re: x'}`	Passed
html with inline image	`{'structure': 'alternative(text,related(html,p1.gif))', 'subject': 'fwd: y'}`	`{'structure': 'alternative(text,related(html,p1.gif))', 'subject': 'fwd: y'}`	Passed

SHA-256 / 773cef9d84dbd0eb24c3afecca3e25b9c5faf94b5a493bd757ea2ef1305156d5

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 7 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

Stipulated offline model over pre-parsed MIME dictionaries; not a conforming MIME parser, generator or mail client. 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 2026-09-29T14:49:17.811711+00:00.

Case digest / fede932a599e6ae153cd24fe8de94489302f51958b6b3311efcdde56c8d41ef0