DongHyeonkaandClaude Opus 5
b2963105a8
The keycloak project ended with four open questions that design could not
settle. A two-VM lab was built to answer them by measurement, and this is
that material: 26 experiments, 125 raw command outputs, 22 browser captures.
Follows the import procedure in README.md.
source/ the originating repository verbatim — 78 documents, 28 SVGs,
8 manifests, plus .source-revision recording the commit
final/ the SSOT
document.md 729 lines written from the 29 experiment documents, not
concatenated: what was predicted, what was measured, and
where the measurement itself was wrong
evidence/raw 125 outputs, flattened to <experiment>__<file> because
the originals collided (01-baseline.txt appeared three
times) and the audit only globs the top level
evidence/meta one per raw file; command and exitCode are null and the
README says why rather than inventing them
evidence/browser 22 captures
assets/ three diagrams through techviz
.techviz/ their VizSpecs
A separate project rather than an addition to keycloak: the B-layer answers
that project's four questions, but the A, C and D layers are about cluster
failure, SSO and operations, and one document.md should hold one subject.
The four question records there can point here through 관계.
Recorded rather than papered over: only three of the 28 diagrams were
remade. The repository forbids hand-drawn SVG and forbids titles inside the
canvas; all 28 originals carry both, so converting them is redrawing, not
reformatting. They stay in source/ and the gap is written into the document.
verify-pipeline.py passes. audit-records.py reports no issues.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
52 lines
2.1 KiB
Markdown
52 lines
2.1 KiB
Markdown
---
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kind: CONCEPT
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slug: messaging-claim-check-c06
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title: MessageDigest를 호출마다 새로 만드는 것이 옳다
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topic: state-machines-and-ownership
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project: clean-architecture-backend-template
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status: 게시 전
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sourceRevision: 21234e38cdb9a926cbc92bb97a2aee2e4a7d2916
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rootTreeNode: concept:messaging-claim-check-c06
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evidenceCapturedOn: 2026-09-01
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assets:
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- key: messaging-claim-check-c06
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file: ../../../final/evidence/rendered/messaging-claim-check-c06.svg
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evidence:
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- ../../../final/evidence/raw/messaging-claim-check-c06.txt
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source:
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- 원본 분석 절은 analysis/messaging/messaging-claim-check.md#L286 이다.
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module: messaging-claim-check
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---
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# MessageDigest를 호출마다 새로 만드는 것이 옳다
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`ClaimCheckPublisher`·`ClaimCheckResolver`는 final 필드만 갖는 불변 객체이고, `MessageDigest.getInstance("SHA-256")`은 호출마다 새 인스턴스를 만든다.
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## 관계
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- **leaf의 각 public 클래스는 자기 레인에 테스트를 갖는다**
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같은 분석 리프에서 끌어낸 규칙이다.
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- **같은 튜닝 값이 두 계층에 있으면 어느 쪽이 이기는지 정한다**
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같은 분석 리프에서 끌어낸 규칙이다.
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## 본문
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<!-- body:start -->
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`ClaimCheckPublisher`·`ClaimCheckResolver`는 final 필드만 갖는 불변 객체다. `ClaimCheckIntegrityGuard`는 상태가 없고 `ClaimCheckResolver`가 인스턴스를 필드로 하나 만든다.
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## ClaimCheckPublisher 참조 위치
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:::evidence key="messaging-claim-check-c06" alt="코드베이스에서 ClaimCheckPublisher 를 검색한 출력 12줄. 이 기록이 세는 참조가 그 출력에 그대로 보인다." caption="ClaimCheckPublisher 코드베이스 검색 — 12줄 · exit 0" zoom="true"
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:::
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## 호출마다 새로 만드는 것이 옳은 이유
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`MessageDigest.getInstance("SHA-256")`이 **호출마다** 새 인스턴스를 만든다 — `MessageDigest`는 스레드 안전하지 않으므로 이것이 옳다. 재사용했다면 동시 호출이 서로의 상태를 오염시킨다.
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## 계약에 적히지 않은 요구
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`ClaimCheckStore` 구현의 스레드 안전성 요구는 인터페이스 javadoc에 없다.
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<!-- body:end -->
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