Single Source of Truth

Kind: principle

Layer: Contracts Core

Aliases: SSOT

Record: architecture:single-source-of-truth

Severity: mandatory

Scope: configuration, data, rule, schema

Canonical: Ontology

A design rule that each fact, rule or configuration value has one owning definition, and every other value is derived from it.

Listed in Architecture principles, after Canonicalization and before Normalization.

Requires

• Ownership
• Canonical Definition

Reinforces

• Do Not Repeat Yourself (DRY)
• Consistency

Enables

• Governance
• Correctness

Conflicts with

• Duplicated Authority
• Magic Value

In tension with

• Availability
• Decentralization

Tensions

• Single Source of Truth / Availability
• Single Source of Truth / Decentralization

Contracts

• Structural Core
• Centralization Kernel
• CSS Type-Cascade Kernel

Violated by

• Duplicated Authority

Refactored by

• Centralize the Rule

Severity

• mandatory

Category

• Schema / Canonical Data / Semantics

Enforced by

• codemods/entrypoints/location.entrypoint.ts
• codemods/entrypoints/vocabulary.entrypoint.ts
• rules/entrypoints/writing.entrypoint.ts
• rules/eslint/centralized-strings.eslint.rule.ts
• rules/eslint/closure-no-browser-derivation.eslint.rule.ts
• rules/eslint/closure-paths-via-ssot.eslint.rule.ts
• rules/eslint/closure-rule-declarations-resolve.eslint.rule.ts
• rules/eslint/markup-through-builder.eslint.rule.ts
• rules/eslint/no-exclusion-membership.eslint.rule.ts
• rules/eslint/no-hardcoded-exclusions.eslint.rule.ts
• rules/eslint/no-inline-asset-path.eslint.rule.ts
• rules/eslint/no-inline-icon-options.eslint.rule.ts
• rules/eslint/no-literal-strings.eslint.rule.ts
• rules/eslint/no-redundant-type-shim.eslint.rule.ts
• rules/eslint/no-string-literal-ids.eslint.rule.ts
• rules/eslint/retired-collection-id.eslint.rule.ts
• rules/eslint/strings-derived-numbering.eslint.rule.ts
• rules/eslint/strings-link-construction.eslint.rule.ts
• runtime/entrypoints/coverage.entrypoint.ts
• runtime/entrypoints/config.entrypoint.ts
• runtime/entrypoints/dependency.entrypoint.ts
• runtime/entrypoints/rule.entrypoint.ts
• runtime/entrypoints/dependency.entrypoint.ts

Reinforced by

• Canonical Model
• Database Normalization
• Derived Record State
• Projection Channel
• Two-Direction Index
• Period-Decided Disposition
• Single Aggregate
• Closed Vocabulary
• Declared Jurisdiction
• Collision Consolidation
• Externally Resolved Slot

Required by

• Derived Naming Registry

Linked from

• Integrating algorithms
• The loop
• The stance
• Three encodings
• Rules with names
• The behavior document
• The drop-in
• One home
• Definitions own what, code owns how
• The canon is grouped twice
• The structural domain
• Separate, trade, or mitigate
• Anti-patterns
• Domain Architecture
• Control / Coordination / Centralization
• Correctness / Determinism / Verification
• Core Modular Design
• Schema / Canonical Data / Semantics
• Security / Privacy / Compliance / Governance
• Coordination Surfaces
• Taxonomy / Classification / Naming
• Transactions / State / Concurrency
• Core Modular Design
• Core Vocabulary
• Quality Attributes
• Schema / Canonical Data / Semantics
• Architectural Clusters
• Centralization
• CSS cascade
• Severity levels
• The resolutions

in this codebase

• configuration/strings
• core/ids
• tabLink