External OSS Attribution: Two Executed Repro Cards - 2026-06-15

This artifact is not a claim that Mimesis becomes correct by citing famous code.

It is the opposite:

Strong external OSS can expose load-bearing structure, but attribution is not validation transfer.

The useful public claim is narrower and stronger:

Digital Factory has two executed local repro cards showing how selected external
OSS artifacts can expose load-bearing structure under objective oracles.

This is source-level attribution under reproduction, not downstream lift, not
maintainer endorsement, not legal clearance, and not external validation.

Claim

Allowed public claim:

Mimesis can use selected external OSS artifacts as attribution anchors for
load-bearing structure when a local repro card includes a source pointer,
objective oracle, defect control, wrong-anchor control, command transcript,
and forbidden-claim boundary.

Forbidden public claim:

external OSS validation transfers to Mimesis outputs,
source-level attribution is downstream lift,
Go or Rust maintainers endorsed Mimesis,
the repro cards are legal clearance,
the repro cards prove production readiness,
the two examples prove universal method validity,
or the extracted structure is safe to market without downstream gates.

Verified Originals

These sources are attribution anchors. They do not validate Mimesis Engineering.

source	what it contributes
golang/go issue 67470	Concrete Go `time.Parse` defect report for out-of-range timezone offsets such as `+99:99`, plus the repair shape: reject impossible offset hour/minute fields instead of silently constructing a broken offset.
Go time parser source	Parser structure and timezone offset validation context for `Parse`, `ParseInLocation`, and the internal parser functions.
Go RFC3339 parser source	Fixed-width range-guard style for date, time, and timezone fields.
Go strconv docs	The public contract that `ParseFloat returns the nearest floating-point number` under IEEE 754 unbiased rounding.
Go Eisel-Lemire source	Fast-path float parsing structure that returns to a slower exact path on half-way ambiguity.
Rust PR 86761	Prior-art context for Eisel-Lemire / decimal-to-float half-way handling in a production language runtime.
CPython strtod tests	Independent nearest-even parsing test tradition used as an oracle reference for float parsing behavior.
Number Parsing at a Gigabyte per Second	Original Eisel-Lemire algorithm paper lineage for fast decimal-to-binary floating-point conversion.

Attribution Boundary

This packet records source-level attribution, not implementation ownership.

Safe wording:

Validated against Go standard-library parsing behavior and Eisel-Lemire /
Go strconv prior-art references for nearest-even float parsing.

Unsafe wording:

Because Go and Rust are verified, Mimesis output is verified.

Executed Repro Card A - P-EXT-03 / Go time.Parse

field	value
Card	`P-EXT-03`
Source anchor	`golang/go issue 67470` plus Go `time.Parse` source context.
Load-bearing structure	Insert an explicit timezone offset range guard before constructing the parsed zone offset.
Objective oracle	Out-of-range timezone offsets such as `+99:99` must error, not round-trip into a malformed formatted offset.
Defect control	A parser that accepts and constructs `+99:99` fails the oracle.
Wrong-anchor control	A clamp/normalize-style repair fails because the oracle requires rejection, not repair.
Local result	Go standard library fix behavior passed, local fix-structure passed, defect failed, wrong-anchor failed.
Boundary	This proves a local reproduction of one parser-guard structure, not general parser correctness.

Observed command sequence:

go version
go run parse_attribution.go
go build -o .\parse_attribution_local.exe parse_attribution.go
.\parse_attribution_local.exe

Observed environment and result summary:

go version go1.26.2 windows/amd64
go run temp-exe was blocked
go build -o local executable workaround succeeded
stdlib(FIX) PASS
fix-structure PASS
defect FAIL
wrong-anchor FAIL

The interesting part is not that Go exists. The interesting part is that the defect and wrong-anchor controls both fail under the same objective oracle.

Executed Repro Card B - P-EXT-06 / Eisel-Lemire

field	value
Card	`P-EXT-06`
Source anchor	Eisel-Lemire / Go `strconv` / Rust decimal-to-float prior-art references.
Load-bearing structure	Half-way ambiguity must not be guessed by the fast path; it must defer to exact nearest-even behavior.
Objective oracle	Python `float()` bit pattern comparison and nearest-even expectations for half-way cases.
Defect control	A no-guard, round-up implementation mis-rounds tie cases.
Wrong-anchor control	A round-half-to-odd policy produces distinct failures.
Local result	Fix passed, defect failed, wrong-anchor failed, controls passed.
Boundary	This proves one load-bearing rounding guard under local oracle tests, not universal float-parser conformance.

Observed command:

python -B p_ext_06_repro.py

Observed result summary:

DEFECT (no guard, round-up): FAIL(2)
FIX (guard->round-half-even): PASS
WRONG_ANCHOR (round-half-to-ODD): FAIL(3)
VERDICT: REPRODUCTION CONFIRMED -- halfway guard is load-bearing

The phrase that matters from the Go public contract is simple: ParseFloat returns the nearest floating-point number. The local card uses that kind of oracle boundary: when the value is halfway, the fast attractive shortcut must not invent a different rounding policy.

Commands / Redlines

Local workbench verification commands observed after the repro cards:

python -B verify_workbench_surface.py
cd mimesis-plugin
python -B verify_evidence_references.py
python -B tools\validate_module.py --all

Observed result:

Digital Factory workbench surface checks passed.
Mimesis evidence-reference checks passed.
14/14 valid

Redlines:

no source anchor without a local oracle,
no local oracle without defect and wrong-anchor controls,
no reproduction claim from file presence,
no inherited validation claim,
no claim that source attribution is downstream lift,
no maintainer endorsement claim,
no legal clearance claim.

Allowed Claim

Safe sentence:

Mimesis external OSS attribution now has two executed repro cards: Go
time.Parse timezone range guarding and Eisel-Lemire nearest-even float parsing.
Both cards keep the source anchor, objective oracle, defect control,
wrong-anchor control, command result, and forbidden claims together.

Forbidden Claim

Unsafe sentence:

Mimesis is validated because it is based on Go, Rust, and Eisel-Lemire.

This is specifically forbidden because source-level attribution is not downstream lift, not maintainer endorsement, not legal clearance, and not external validation.

Claim Boundary

What this artifact proves:

two local external OSS attribution repro cards were executed,
P-EXT-03 records a Go time.Parse timezone range-guard reproduction,
P-EXT-06 records an Eisel-Lemire / nearest-even float parsing reproduction,
both cards use an objective oracle plus defect and wrong-anchor controls,
and both cards preserve forbidden claims beside the evidence.

What this artifact does not prove:

external validation,
downstream output improvement,
production readiness,
universal method validity,
legal clearance,
maintainer endorsement,
full parser conformance,
or public adoption.

Next Proof

The next stronger artifact is not more dramatic language.

It should be either:

a public-safe casebook card that turns these two repro cards into a reusable worksheet,
a third repro card in a different source domain with the same oracle/control structure,
or one downstream case where this attribution structure changes a target output and then passes a separate downstream gate.

Until then, this remains a proof-bounded external OSS attribution packet, not external validation.