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FA-79326 / Image orientation metadata / Open access

Unknown reconciliation policy prefers the embedded tag · case 01

Libraries migrated from an older config with policy "latest" ignore newer sidecar edits.

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

ROOT CAUSE

Unrecognised policies fall back to embedded-first instead of newest.

VERIFIED REPAIR

Treat unknown policies as "newest".

Unsuccessful approach: Always preferring the sidecar ignores timestamps.

Case contract

A photo manager reconciles the embedded orientation with an XMP sidecar. Values are valid if they are integers 1..8 or strings that are exactly one digit 1..8 after trimming. Policy "sidecar" prefers the sidecar, "embedded" prefers the file, and "newest" (also used for unknown policies) prefers the sidecar when both are valid and sidecar_mtime >= file_mtime; the other valid value is the fallback, then 1.

Why this case matters

Camera, phone and scanner images carry an orientation hint separately from the stored pixels; galleries, thumbnailers, editors and upload pipelines must interpret it consistently or photos appear sideways, mirrored or doubly rotated.

1 / The failure

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

N = 1
observations = []
def solve(d):
    def ok(v):
        if isinstance(v, str) and v.strip() in ('1', '2', '3', '4', '5', '6', '7', '8'):
            return int(v.strip())
        if isinstance(v, int) and not isinstance(v, bool) and 1 <= v <= 8:
            return v
        return None
    e = ok(d.get('embedded'))
    s = ok(d.get('sidecar'))
    pol = d.get('policy')
    if pol not in ('newest', 'sidecar', 'embedded'):
        pol = 'embedded'
    if pol == 'sidecar':
        order = [s, e]
    elif pol == 'embedded':
        order = [e, s]
    elif s is not None and e is not None:
        order = [s, e] if d['sidecar_mtime'] >= d['file_mtime'] else [e, s]
    else:
        order = [s, e]
    for v in order:
        if v is not None:
            return v
    return 1
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[{'embedded': '6', 'sidecar': 5, 'file_mtime': 101, 'sidecar_mtime': 101, 'policy': None}, 5], [{'embedded': 8, 'sidecar': '6', 'file_mtime': 107, 'sidecar_mtime': 102, 'policy': 'latest'}, 8], [{'embedded': 5, 'sidecar': '+3', 'file_mtime': 103, 'sidecar_mtime': 108, 'policy': 'newest'}, 5], [{'embedded': 'x', 'sidecar': 'x', 'file_mtime': 109, 'sidecar_mtime': 109, 'policy': 'embedded'}, 1], [{'embedded': 8, 'sidecar': 'x', 'file_mtime': 102, 'sidecar_mtime': 101, 'policy': 'newest'}, 8], [{'embedded': 9, 'sidecar': 9, 'file_mtime': 108, 'sidecar_mtime': 109, 'policy': None}, 1], [{'embedded': ' 8', 'sidecar': 5, 'file_mtime': 105, 'sidecar_mtime': 105, 'policy': 'newest'}, 5], [{'embedded': ' 8', 'sidecar': 1, 'file_mtime': 103, 'sidecar_mtime': 103, 'policy': None}, 1]], [[{'embedded': 3, 'sidecar': 6, 'file_mtime': 109, 'sidecar_mtime': 110, 'policy': 'latest'}, 6], [{'embedded': 5, 'sidecar': 8, 'file_mtime': 106, 'sidecar_mtime': 105, 'policy': 'latest'}, 5], [{'embedded': 3, 'sidecar': None, 'file_mtime': 106, 'sidecar_mtime': 106, 'policy': 'embedded'}, 3], [{'embedded': 1, 'sidecar': '06', 'file_mtime': 104, 'sidecar_mtime': 105, 'policy': 'sidecar'}, 1], [{'embedded': ' 8', 'sidecar': 8, 'file_mtime': 107, 'sidecar_mtime': 112, 'policy': 'embedded'}, 8], [{'embedded': 3, 'sidecar': 6, 'file_mtime': 101, 'sidecar_mtime': 96, 'policy': 'sidecar'}, 6], [{'embedded': 3, 'sidecar': 'x', 'file_mtime': 102, 'sidecar_mtime': 103, 'policy': 'newest'}, 3], [{'embedded': 6, 'sidecar': 3, 'file_mtime': 106, 'sidecar_mtime': 111, 'policy': None}, 3]], [[{'embedded': 3, 'sidecar': 8, 'file_mtime': 101, 'sidecar_mtime': 106, 'policy': 'latest'}, 8], [{'embedded': 3, 'sidecar': 5, 'file_mtime': 102, 'sidecar_mtime': 97, 'policy': None}, 3], [{'embedded': None, 'sidecar': '06', 'file_mtime': 110, 'sidecar_mtime': 115, 'policy': 'newest'}, 1], [{'embedded': 3, 'sidecar': '+3', 'file_mtime': 109, 'sidecar_mtime': 114, 'policy': None}, 3], [{'embedded': 'x', 'sidecar': ' 8', 'file_mtime': 101, 'sidecar_mtime': 101, 'policy': 'sidecar'}, 8], [{'embedded': 5, 'sidecar': 9, 'file_mtime': 105, 'sidecar_mtime': 110, 'policy': 'latest'}, 5], [{'embedded': ' 8', 'sidecar': '06', 'file_mtime': 100, 'sidecar_mtime': 101, 'policy': 'newest'}, 8], [{'embedded': 8, 'sidecar': 1, 'file_mtime': 108, 'sidecar_mtime': 108, 'policy': None}, 1]], [[{'embedded': ' 8', 'sidecar': '6', 'file_mtime': 100, 'sidecar_mtime': 101, 'policy': None}, 6], [{'embedded': '6', 'sidecar': 8, 'file_mtime': 108, 'sidecar_mtime': 103, 'policy': 'latest'}, 6], [{'embedded': 1, 'sidecar': '6', 'file_mtime': 100, 'sidecar_mtime': 99, 'policy': 'newest'}, 1], [{'embedded': 6, 'sidecar': 6, 'file_mtime': 100, 'sidecar_mtime': 105, 'policy': 'sidecar'}, 6], [{'embedded': 5, 'sidecar': 8, 'file_mtime': 109, 'sidecar_mtime': 114, 'policy': 'newest'}, 8], [{'embedded': None, 'sidecar': '6', 'file_mtime': 104, 'sidecar_mtime': 104, 'policy': 'latest'}, 6], [{'embedded': 'x', 'sidecar': 8, 'file_mtime': 103, 'sidecar_mtime': 102, 'policy': None}, 8], [{'embedded': ' 8', 'sidecar': '6', 'file_mtime': 102, 'sidecar_mtime': 102, 'policy': None}, 6]], [[{'embedded': 1, 'sidecar': 5, 'file_mtime': 102, 'sidecar_mtime': 107, 'policy': None}, 5], [{'embedded': 3, 'sidecar': '6', 'file_mtime': 108, 'sidecar_mtime': 107, 'policy': None}, 3], [{'embedded': ' 8', 'sidecar': 8, 'file_mtime': 110, 'sidecar_mtime': 110, 'policy': 'embedded'}, 8], [{'embedded': 0, 'sidecar': 'x', 'file_mtime': 102, 'sidecar_mtime': 102, 'policy': 'embedded'}, 1], [{'embedded': 0, 'sidecar': 9, 'file_mtime': 100, 'sidecar_mtime': 99, 'policy': 'latest'}, 1], [{'embedded': ' 8', 'sidecar': 0, 'file_mtime': 100, 'sidecar_mtime': 100, 'policy': None}, 8], [{'embedded': 8, 'sidecar': 9, 'file_mtime': 102, 'sidecar_mtime': 101, 'policy': 'sidecar'}, 8], [{'embedded': 8, 'sidecar': 3, 'file_mtime': 108, 'sidecar_mtime': 109, 'policy': 'latest'}, 3]]]
labels = ["regression: unknown policy default", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), 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 fixtureActualExpectedOutcome
regression: unknown policy default 065Failed
repair trap 188Passed
combined fault 255Passed
control 311Passed
control 488Passed
boundary 511Passed
boundary 655Passed
control 781Failed

SHA-256 / 6b0fbb4a3ccdb762d79c340f024541b59e6de9d664fefa5b43bf704a3a3ad1e2

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(d):
    def ok(v):
        if isinstance(v, str) and v.strip() in ('1', '2', '3', '4', '5', '6', '7', '8'):
            return int(v.strip())
        if isinstance(v, int) and not isinstance(v, bool) and 1 <= v <= 8:
            return v
        return None
    e = ok(d.get('embedded'))
    s = ok(d.get('sidecar'))
    pol = d.get('policy')
    if pol not in ('newest', 'sidecar', 'embedded'):
        pol = 'sidecar'
    if pol == 'sidecar':
        order = [s, e]
    elif pol == 'embedded':
        order = [e, s]
    elif s is not None and e is not None:
        order = [s, e] if d['sidecar_mtime'] >= d['file_mtime'] else [e, s]
    else:
        order = [s, e]
    for v in order:
        if v is not None:
            return v
    return 1
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[{'embedded': '6', 'sidecar': 5, 'file_mtime': 101, 'sidecar_mtime': 101, 'policy': None}, 5], [{'embedded': 8, 'sidecar': '6', 'file_mtime': 107, 'sidecar_mtime': 102, 'policy': 'latest'}, 8], [{'embedded': 5, 'sidecar': '+3', 'file_mtime': 103, 'sidecar_mtime': 108, 'policy': 'newest'}, 5], [{'embedded': 'x', 'sidecar': 'x', 'file_mtime': 109, 'sidecar_mtime': 109, 'policy': 'embedded'}, 1], [{'embedded': 8, 'sidecar': 'x', 'file_mtime': 102, 'sidecar_mtime': 101, 'policy': 'newest'}, 8], [{'embedded': 9, 'sidecar': 9, 'file_mtime': 108, 'sidecar_mtime': 109, 'policy': None}, 1], [{'embedded': ' 8', 'sidecar': 5, 'file_mtime': 105, 'sidecar_mtime': 105, 'policy': 'newest'}, 5], [{'embedded': ' 8', 'sidecar': 1, 'file_mtime': 103, 'sidecar_mtime': 103, 'policy': None}, 1]], [[{'embedded': 3, 'sidecar': 6, 'file_mtime': 109, 'sidecar_mtime': 110, 'policy': 'latest'}, 6], [{'embedded': 5, 'sidecar': 8, 'file_mtime': 106, 'sidecar_mtime': 105, 'policy': 'latest'}, 5], [{'embedded': 3, 'sidecar': None, 'file_mtime': 106, 'sidecar_mtime': 106, 'policy': 'embedded'}, 3], [{'embedded': 1, 'sidecar': '06', 'file_mtime': 104, 'sidecar_mtime': 105, 'policy': 'sidecar'}, 1], [{'embedded': ' 8', 'sidecar': 8, 'file_mtime': 107, 'sidecar_mtime': 112, 'policy': 'embedded'}, 8], [{'embedded': 3, 'sidecar': 6, 'file_mtime': 101, 'sidecar_mtime': 96, 'policy': 'sidecar'}, 6], [{'embedded': 3, 'sidecar': 'x', 'file_mtime': 102, 'sidecar_mtime': 103, 'policy': 'newest'}, 3], [{'embedded': 6, 'sidecar': 3, 'file_mtime': 106, 'sidecar_mtime': 111, 'policy': None}, 3]], [[{'embedded': 3, 'sidecar': 8, 'file_mtime': 101, 'sidecar_mtime': 106, 'policy': 'latest'}, 8], [{'embedded': 3, 'sidecar': 5, 'file_mtime': 102, 'sidecar_mtime': 97, 'policy': None}, 3], [{'embedded': None, 'sidecar': '06', 'file_mtime': 110, 'sidecar_mtime': 115, 'policy': 'newest'}, 1], [{'embedded': 3, 'sidecar': '+3', 'file_mtime': 109, 'sidecar_mtime': 114, 'policy': None}, 3], [{'embedded': 'x', 'sidecar': ' 8', 'file_mtime': 101, 'sidecar_mtime': 101, 'policy': 'sidecar'}, 8], [{'embedded': 5, 'sidecar': 9, 'file_mtime': 105, 'sidecar_mtime': 110, 'policy': 'latest'}, 5], [{'embedded': ' 8', 'sidecar': '06', 'file_mtime': 100, 'sidecar_mtime': 101, 'policy': 'newest'}, 8], [{'embedded': 8, 'sidecar': 1, 'file_mtime': 108, 'sidecar_mtime': 108, 'policy': None}, 1]], [[{'embedded': ' 8', 'sidecar': '6', 'file_mtime': 100, 'sidecar_mtime': 101, 'policy': None}, 6], [{'embedded': '6', 'sidecar': 8, 'file_mtime': 108, 'sidecar_mtime': 103, 'policy': 'latest'}, 6], [{'embedded': 1, 'sidecar': '6', 'file_mtime': 100, 'sidecar_mtime': 99, 'policy': 'newest'}, 1], [{'embedded': 6, 'sidecar': 6, 'file_mtime': 100, 'sidecar_mtime': 105, 'policy': 'sidecar'}, 6], [{'embedded': 5, 'sidecar': 8, 'file_mtime': 109, 'sidecar_mtime': 114, 'policy': 'newest'}, 8], [{'embedded': None, 'sidecar': '6', 'file_mtime': 104, 'sidecar_mtime': 104, 'policy': 'latest'}, 6], [{'embedded': 'x', 'sidecar': 8, 'file_mtime': 103, 'sidecar_mtime': 102, 'policy': None}, 8], [{'embedded': ' 8', 'sidecar': '6', 'file_mtime': 102, 'sidecar_mtime': 102, 'policy': None}, 6]], [[{'embedded': 1, 'sidecar': 5, 'file_mtime': 102, 'sidecar_mtime': 107, 'policy': None}, 5], [{'embedded': 3, 'sidecar': '6', 'file_mtime': 108, 'sidecar_mtime': 107, 'policy': None}, 3], [{'embedded': ' 8', 'sidecar': 8, 'file_mtime': 110, 'sidecar_mtime': 110, 'policy': 'embedded'}, 8], [{'embedded': 0, 'sidecar': 'x', 'file_mtime': 102, 'sidecar_mtime': 102, 'policy': 'embedded'}, 1], [{'embedded': 0, 'sidecar': 9, 'file_mtime': 100, 'sidecar_mtime': 99, 'policy': 'latest'}, 1], [{'embedded': ' 8', 'sidecar': 0, 'file_mtime': 100, 'sidecar_mtime': 100, 'policy': None}, 8], [{'embedded': 8, 'sidecar': 9, 'file_mtime': 102, 'sidecar_mtime': 101, 'policy': 'sidecar'}, 8], [{'embedded': 8, 'sidecar': 3, 'file_mtime': 108, 'sidecar_mtime': 109, 'policy': 'latest'}, 3]]]
labels = ["regression: unknown policy default", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), 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 fixtureActualExpectedOutcome
regression: unknown policy default 055Passed
repair trap 168Failed
combined fault 255Passed
control 311Passed
control 488Passed
boundary 511Passed
boundary 655Passed
control 711Passed

SHA-256 / ad3dc68203bb6e02f3a67919375858a66fe6560166e8d8177930a53abe53393c

3 / The verified repair

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

N = 1
observations = []
def solve(d):
    def ok(v):
        if isinstance(v, str) and v.strip() in ('1', '2', '3', '4', '5', '6', '7', '8'):
            return int(v.strip())
        if isinstance(v, int) and not isinstance(v, bool) and 1 <= v <= 8:
            return v
        return None
    e = ok(d.get('embedded'))
    s = ok(d.get('sidecar'))
    pol = d.get('policy')
    if pol not in ('newest', 'sidecar', 'embedded'):
        pol = 'newest'
    if pol == 'sidecar':
        order = [s, e]
    elif pol == 'embedded':
        order = [e, s]
    elif s is not None and e is not None:
        order = [s, e] if d['sidecar_mtime'] >= d['file_mtime'] else [e, s]
    else:
        order = [s, e]
    for v in order:
        if v is not None:
            return v
    return 1
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[{'embedded': '6', 'sidecar': 5, 'file_mtime': 101, 'sidecar_mtime': 101, 'policy': None}, 5], [{'embedded': 8, 'sidecar': '6', 'file_mtime': 107, 'sidecar_mtime': 102, 'policy': 'latest'}, 8], [{'embedded': 5, 'sidecar': '+3', 'file_mtime': 103, 'sidecar_mtime': 108, 'policy': 'newest'}, 5], [{'embedded': 'x', 'sidecar': 'x', 'file_mtime': 109, 'sidecar_mtime': 109, 'policy': 'embedded'}, 1], [{'embedded': 8, 'sidecar': 'x', 'file_mtime': 102, 'sidecar_mtime': 101, 'policy': 'newest'}, 8], [{'embedded': 9, 'sidecar': 9, 'file_mtime': 108, 'sidecar_mtime': 109, 'policy': None}, 1], [{'embedded': ' 8', 'sidecar': 5, 'file_mtime': 105, 'sidecar_mtime': 105, 'policy': 'newest'}, 5], [{'embedded': ' 8', 'sidecar': 1, 'file_mtime': 103, 'sidecar_mtime': 103, 'policy': None}, 1]], [[{'embedded': 3, 'sidecar': 6, 'file_mtime': 109, 'sidecar_mtime': 110, 'policy': 'latest'}, 6], [{'embedded': 5, 'sidecar': 8, 'file_mtime': 106, 'sidecar_mtime': 105, 'policy': 'latest'}, 5], [{'embedded': 3, 'sidecar': None, 'file_mtime': 106, 'sidecar_mtime': 106, 'policy': 'embedded'}, 3], [{'embedded': 1, 'sidecar': '06', 'file_mtime': 104, 'sidecar_mtime': 105, 'policy': 'sidecar'}, 1], [{'embedded': ' 8', 'sidecar': 8, 'file_mtime': 107, 'sidecar_mtime': 112, 'policy': 'embedded'}, 8], [{'embedded': 3, 'sidecar': 6, 'file_mtime': 101, 'sidecar_mtime': 96, 'policy': 'sidecar'}, 6], [{'embedded': 3, 'sidecar': 'x', 'file_mtime': 102, 'sidecar_mtime': 103, 'policy': 'newest'}, 3], [{'embedded': 6, 'sidecar': 3, 'file_mtime': 106, 'sidecar_mtime': 111, 'policy': None}, 3]], [[{'embedded': 3, 'sidecar': 8, 'file_mtime': 101, 'sidecar_mtime': 106, 'policy': 'latest'}, 8], [{'embedded': 3, 'sidecar': 5, 'file_mtime': 102, 'sidecar_mtime': 97, 'policy': None}, 3], [{'embedded': None, 'sidecar': '06', 'file_mtime': 110, 'sidecar_mtime': 115, 'policy': 'newest'}, 1], [{'embedded': 3, 'sidecar': '+3', 'file_mtime': 109, 'sidecar_mtime': 114, 'policy': None}, 3], [{'embedded': 'x', 'sidecar': ' 8', 'file_mtime': 101, 'sidecar_mtime': 101, 'policy': 'sidecar'}, 8], [{'embedded': 5, 'sidecar': 9, 'file_mtime': 105, 'sidecar_mtime': 110, 'policy': 'latest'}, 5], [{'embedded': ' 8', 'sidecar': '06', 'file_mtime': 100, 'sidecar_mtime': 101, 'policy': 'newest'}, 8], [{'embedded': 8, 'sidecar': 1, 'file_mtime': 108, 'sidecar_mtime': 108, 'policy': None}, 1]], [[{'embedded': ' 8', 'sidecar': '6', 'file_mtime': 100, 'sidecar_mtime': 101, 'policy': None}, 6], [{'embedded': '6', 'sidecar': 8, 'file_mtime': 108, 'sidecar_mtime': 103, 'policy': 'latest'}, 6], [{'embedded': 1, 'sidecar': '6', 'file_mtime': 100, 'sidecar_mtime': 99, 'policy': 'newest'}, 1], [{'embedded': 6, 'sidecar': 6, 'file_mtime': 100, 'sidecar_mtime': 105, 'policy': 'sidecar'}, 6], [{'embedded': 5, 'sidecar': 8, 'file_mtime': 109, 'sidecar_mtime': 114, 'policy': 'newest'}, 8], [{'embedded': None, 'sidecar': '6', 'file_mtime': 104, 'sidecar_mtime': 104, 'policy': 'latest'}, 6], [{'embedded': 'x', 'sidecar': 8, 'file_mtime': 103, 'sidecar_mtime': 102, 'policy': None}, 8], [{'embedded': ' 8', 'sidecar': '6', 'file_mtime': 102, 'sidecar_mtime': 102, 'policy': None}, 6]], [[{'embedded': 1, 'sidecar': 5, 'file_mtime': 102, 'sidecar_mtime': 107, 'policy': None}, 5], [{'embedded': 3, 'sidecar': '6', 'file_mtime': 108, 'sidecar_mtime': 107, 'policy': None}, 3], [{'embedded': ' 8', 'sidecar': 8, 'file_mtime': 110, 'sidecar_mtime': 110, 'policy': 'embedded'}, 8], [{'embedded': 0, 'sidecar': 'x', 'file_mtime': 102, 'sidecar_mtime': 102, 'policy': 'embedded'}, 1], [{'embedded': 0, 'sidecar': 9, 'file_mtime': 100, 'sidecar_mtime': 99, 'policy': 'latest'}, 1], [{'embedded': ' 8', 'sidecar': 0, 'file_mtime': 100, 'sidecar_mtime': 100, 'policy': None}, 8], [{'embedded': 8, 'sidecar': 9, 'file_mtime': 102, 'sidecar_mtime': 101, 'policy': 'sidecar'}, 8], [{'embedded': 8, 'sidecar': 3, 'file_mtime': 108, 'sidecar_mtime': 109, 'policy': 'latest'}, 3]]]
labels = ["regression: unknown policy default", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), 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 fixtureActualExpectedOutcome
regression: unknown policy default 055Passed
repair trap 188Passed
combined fault 255Passed
control 311Passed
control 488Passed
boundary 511Passed
boundary 655Passed
control 711Passed

SHA-256 / 40e830e664d9a3f1aca8f18812699302134237fef287372d09a244e0f1dfc559

Verification & scope

A deterministic bounded teaching model with a stipulated contract; it makes no claim of conformance to any published specification. 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 2026-09-29T14:49:43.693578+00:00.

Case digest / d73931d79467fe5ba43cf3fd3cd58f07be9017e6f183aa206428e45fee23b254