Documentation / @etherfold/core / processorCodeFingerprint
Function: processorCodeFingerprint() ​
processorCodeFingerprint(
processor):string|undefined
Defined in: packages/core/src/utils/fingerprint.ts:73
What a code fingerprint is, and the ONE arrival it names ​
A processor's identity is DERIVED FROM WHAT IT IS and never declared by its author (ADR-0086), and HOW it is derived belongs to the ARRIVAL. Every arrival that has BYTES is named by the SHA-256 of those octets. Exactly one has none: a browser tab handed a MODULE OBJECT by a dev server serving unbundled ESM. That arrival names its fold with THIS derivation, over the author's handler sources (moduleProcessorIdentity, @etherfold/browser), because there is nothing else to be. That arrival was built by a-module-handed-to-a-tab-is-identified-by-its-handler-sources, which is the record of what it survives and why a dev server is the only runtime it is sound in; this file is its derivation and must not be deleted out from under it.
What it USED to be, since the measurements below were taken for that role ​
It was an ADVISORY second opinion sitting beside an author-declared getVersionHash(), reported as a drift report when the two disagreed, and it deliberately stayed OUT of the identity: folding it in "would be safer in principle and unusable in practice: a bundler or minifier that re-emits the same behaviour differently would invalidate every deployment's state and force a full replay with no logic change". (That was recorded here as a deviation from docs/adr/0008, which asked for the folding-in.)
ADR-0086 ANSWERS that objection rather than overruling it, and the answer is why this file survived the deletion of the declared identity and of the drift report with it. A PRODUCTION identity is now the hash of a bundle's octets, so the bundler-and-minifier case never reaches this derivation at all; and the one runtime that does reach it is a dev server serving the page the source text it was written from, where a spurious re-fold is a developer's own save. The measurements below are that decision's whole licence -- the cases this does NOT survive are a bundler's and a minifier's, and neither exists between a dev server and the page it is serving.
What it survives, and what it does not ​
The source is Function.prototype.toString(), normalised by collapsing every run of whitespace to a single space. Measured against this repo's own toolchain (tsc 6.0.3, esbuild 0.28 as vitest uses it):
- Survives: process restarts (the string is a pure function of the loaded source), re-indentation and reformatting, and re-ordering the handlers on the object (the payload is keyed and sorted by property name).
- Does NOT survive: minification (identifiers are renamed), a change of transpiler or target (tsc keeps comments and indents with four spaces, esbuild strips comments and indents with two), or editing a COMMENT inside a handler under a toolchain that keeps comments. Each of those RENAMES a fold that did not change, which costs a re-fold of stored data and nothing else.
Why it is tagged fp- ​
So that a value found in a stored cursor says what it is: a fold named this way carries the tag into GenerationId.processor, where it sits beside the digest-prefixed identity of every arrival that had bytes. The structural protection it used to provide (a fingerprint must never read as a "123n" BigInt to the storage adapters that revived them) moved one level down, into simple_hash, which prefixes every digest for that reason and so protects context.processor and context.config too -- and is now belt and braces on top of that, since no adapter revives the suffix form at all. See utils/bigint.ts for the bug that motivated all three.
Comments ​
Comments are left in rather than stripped, and that is a choice about which way to be wrong. Stripping them from arbitrary source text needs a JS lexer that gets regex-vs-division right; a lexer that gets it wrong deletes real code from the payload, and a change inside the deleted region then reads as the SAME fold. Over-naming costs a re-fold; under-naming serves state computed by code that no longer exists, which is the exact failure this exists to prevent.
Parameters ​
processor ​
unknown
Returns ​
string | undefined