bundle

Documentation

Overview

Package bundle computes a content digest over a tree of files, so that the frontend compiled into the binary can be compared with the one on disk.

It exists because go:embed reads web/dist at COMPILE time. A binary built before the frontend was rebuilt carries the older bundle, serves it happily, and passes every health check — the E2E suite then fails against a UI that no longer matches the source, and the failures look like anything except what they are. That has happened twice here: once as stale-at-build (the binary compiled before `npm run build`) and once as stale-after-rebase (the bundle left over from before a rebase), the second costing eight phantom E2E failures before anyone suspected the bundle.

Index

• func Count(fsys fs.FS) (int, error)
• func Digest(fsys fs.FS) (string, error)

Functions

func Count

func Count(fsys fs.FS) (int, error)

Count reports how many regular files fsys holds. It is only used to make a mismatch message concrete ("142 files" against "1 file" says immediately that a stub dist was embedded, which a pair of hashes does not).

func Digest

func Digest(fsys fs.FS) (string, error)

Digest returns a hex-encoded SHA-256 over every regular file in fsys.

Both the path and the content of each file go into the hash, in sorted path order, each length-delimited. The path matters because otherwise moving bytes between two files would not change the digest; the length delimiter matters because otherwise concatenation is ambiguous — "ab" + "c" and "a" + "bc" would hash alike.

Directories contribute nothing. An empty one is not a difference worth failing a build over, and go:embed would not carry it across anyway, so counting it would make the two sides disagree for no reason.