Frozen guarantees

Frozen guarantees define the non-negotiable contract of a Strata version line.

Once a guarantee is frozen, it must not change without crossing a version boundary and introducing a new Northstar invariant.

Frozen means immutable, not deprecated.

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What "frozen" means in Strata

A frozen guarantee is:

• enforced by tests

• enforced by CI

• relied upon by downstream systems

• safe to depend on indefinitely within a version line

If a frozen guarantee is violated, the implementation is wrong, not the data.

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Frozen guarantees in v0.3.x

As of v0.3.x, the following guarantees are frozen:

Canonical encoding

• Every Strata value has exactly one valid binary representation

• No alternate encodings are permitted

• No normalization after decoding

Binary layout

• Tag values

• Length encodings

• Byte order

• Structural layout of lists and maps

Value model

• Supported value types

• Absence of floats

• Absence of optional types

• Absence of implicit coercions

Integer semantics

• Signed 64-bit integer range

• SLEB128 encoding rules

• Overflow behavior

String semantics

• UTF-8 encoding

• Invalid UTF-8 rejection

• No normalization or transformation

Map semantics

• String keys only

• Canonical UTF-8 byte ordering

• Unique keys in canonical form

Hashing contract

• Hashes computed over canonical .scb bytes only

• Hash input excludes transport, framing, and metadata

• Hash output length and algorithm

Decode behavior

• Strict decoding

• Exact failure modes

• Error kinds and offsets

• Rejection of trailing bytes

Cross-language determinism

• Rust and JavaScript must produce identical bytes

• Rust and JavaScript must produce identical hashes

• Disagreement is treated as a regression

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What frozen guarantees protect

Frozen guarantees exist to protect:

• content addressing

• cryptographic hashing

• signatures

• distributed consensus

• cache keys

• reproducible builds

• long-term storage

Once data is written, its meaning must never drift.

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What frozen guarantees do NOT include

Frozen guarantees do not cover:

• transport protocols

• framing formats

• envelopes

• compression

• encryption

• schema systems

• developer ergonomics

• CLI UX

These may evolve freely as long as canonical bytes remain unchanged.

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Adding new capabilities safely

New features may be added by:

• introducing new layers above canonical encoding

• introducing new formats that compile into canonical Strata

• introducing new tooling or protocols

• introducing new Northstar invariants

New capabilities must not reinterpret existing bytes.

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Violation rules

If a change:

• alters canonical bytes

• alters hashes

• alters decode acceptance

• alters error semantics

then one of the following is required:

• new MINOR version

• new Northstar

• updated documentation

• explicit CI enforcement

If none of these are present, the change is invalid.

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Stability promise

Frozen guarantees in v0.3.x will not change.

Future versions may extend Strata, but they will do so by adding layers, not by rewriting the past.

This is a promise, not a goal.