AutistMask/tests/buildForbiddenInputs.test.js

// build.js's FORBIDDEN_INPUTS assertion — the mechanical guarantee that the
// MV3 background bundle cannot contain src/shared/state.js
// (https://git.eeqj.de/sneak/AutistMask/issues/324).
//
// Why this file exists: `make check` does not run `make build`. CI executes
// the assertion (Dockerfile runs `make build`), but executing is not testing —
// invert its condition, or make the table lookup always come back undefined,
// and every check in this repo stays green while the singleton walks back into
// the worker. Five defects, one destroyed wallet, and the whole argument for
// the scoped loud-read guard rest on this assertion, so it is pinned here.
//
// The subject is build.js's exported helpers, driven against SYNTHETIC
// metafiles in esbuild's shape. Nothing here shells out to a build or writes
// dist/: the assertion's job is to read a metafile correctly, and a metafile is
// data. That the real shapes reach it is the build's own business and is
// measured in the PR that introduced it.
//
// Paths are absolute on the way in, because the helpers normalize whatever
// esbuild gave them to repo-relative and this file should not depend on the
// working directory jest was started from.

const path = require("path");

const {
    importChain,
    newForbiddenRecord,
    recordBundledInputs,
    assertNoForbiddenInputs,
    assertForbiddenTableCovered,
} = require("../build");

const ROOT = path.resolve(__dirname, "..");
const abs = (p) => path.join(ROOT, p);

const ENTRY = "src/background/index.js";
const OUT = "dist/chrome/src/background/index.js";
const STATE = "src/shared/state.js";
const HOP = "src/shared/chainSwitchFields.js";

// The real table's shape: entry point -> modules its bundle may not contain.
const TABLE = { [ENTRY]: [STATE] };

// A metafile as esbuild emits one: `outputs[out].inputs` is the flat list of
// every input that contributed to that output, and `inputs[file].imports` is
// the edge list, which is what the chain walk follows.
function metafile({ outputs = {}, imports = {} } = {}) {
    return {
        outputs: Object.fromEntries(
            Object.entries(outputs).map(([out, inputs]) => [
                abs(out),
                {
                    inputs: Object.fromEntries(
                        inputs.map((input) => [
                            abs(input),
                            { bytesInOutput: 1 },
                        ]),
                    ),
                },
            ]),
        ),
        inputs: Object.fromEntries(
            Object.entries(imports).map(([file, targets]) => [
                abs(file),
                { imports: targets.map((target) => ({ path: abs(target) })) },
            ]),
        ),
    };
}

function check(mf, table = TABLE, record = newForbiddenRecord()) {
    recordBundledInputs(mf, record);
    assertNoForbiddenInputs(abs(ENTRY), abs(OUT), mf, record, table);
    return record;
}

describe("assertNoForbiddenInputs()", () => {
    test("a forbidden module in the bundle fails, naming the import chain", () => {
        const mf = metafile({
            outputs: { [OUT]: [ENTRY, HOP, STATE] },
            imports: {
                [ENTRY]: [HOP],
                [HOP]: [STATE],
            },
        });

        expect(() => check(mf)).toThrow(
            `${OUT} bundles ${STATE}, which ${ENTRY} must not reach: ` +
                `${ENTRY} -> ${HOP} -> ${STATE}.`,
        );
    });

    test("a bundle without the forbidden module passes, and is recorded as checked", () => {
        const mf = metafile({
            outputs: { [OUT]: [ENTRY, HOP, "src/background/state.js"] },
            imports: { [ENTRY]: [HOP, "src/background/state.js"] },
        });

        const record = check(mf);
        expect([...record.entriesChecked]).toEqual([ENTRY]);
        expect(record.bundledInputs.has(STATE)).toBe(false);
    });

    test("the failure still names the bundle when no import chain can be shown", () => {
        // esbuild resolves `import("../shared/" + variable)` as a glob: the
        // module is an input of the output, but no single edge leads to it.
        // The message must degrade to no chain rather than crash.
        const mf = metafile({
            outputs: { [OUT]: [ENTRY, STATE] },
            imports: { [ENTRY]: [] },
        });

        expect(() => check(mf)).toThrow(
            `${OUT} bundles ${STATE}, which ${ENTRY} must not reach.`,
        );
    });
});

describe("importChain()", () => {
    test("terminates on a cyclic input graph, and still finds the module", () => {
        const mf = metafile({
            imports: {
                [ENTRY]: [HOP],
                [HOP]: ["src/shared/log.js"],
                // The cycle: log <-> hop, with the target one hop past it.
                "src/shared/log.js": [HOP, STATE],
            },
        });

        expect(importChain(mf, abs(ENTRY), STATE)).toEqual([
            ENTRY,
            HOP,
            "src/shared/log.js",
            STATE,
        ]);
    });

    test("terminates and returns null when a cycle cannot reach the module", () => {
        const mf = metafile({
            imports: {
                [ENTRY]: [HOP],
                [HOP]: ["src/shared/log.js"],
                "src/shared/log.js": [HOP, ENTRY],
            },
        });

        expect(importChain(mf, abs(ENTRY), STATE)).toBeNull();
    });
});

describe("assertForbiddenTableCovered()", () => {
    test("the shipped table is satisfied by a build that checked it", () => {
        const record = newForbiddenRecord();
        record.entriesChecked.add(ENTRY);
        // The popup bundle is what legitimately contains the singleton.
        record.bundledInputs.add(STATE);

        expect(() => assertForbiddenTableCovered(record, TABLE)).not.toThrow();
    });

    test("a key no bundled entry point matched fails", () => {
        const mf = metafile({
            outputs: { [OUT]: [ENTRY] },
            imports: { [ENTRY]: [] },
        });
        const stale = { "src/background/renamed.js": [STATE] };
        const record = check(mf, stale);
        record.bundledInputs.add(STATE);

        expect(() => assertForbiddenTableCovered(record, stale)).toThrow(
            "src/background/renamed.js is listed in FORBIDDEN_INPUTS but was" +
                " not bundled, so nothing checked it",
        );
    });

    test("a forbidden module this build bundled nowhere fails", () => {
        // The other half of the same rot: renaming or moving the singleton
        // leaves a table that names a path nothing resolves to any more, and
        // every bundle then passes it vacuously.
        const mf = metafile({
            outputs: { [OUT]: [ENTRY] },
            imports: { [ENTRY]: [] },
        });
        const stale = { [ENTRY]: ["src/shared/stateRenamed.js"] };
        const record = check(mf, stale);
        record.bundledInputs.add(STATE);

        expect(() => assertForbiddenTableCovered(record, stale)).toThrow(
            "src/shared/stateRenamed.js is listed in FORBIDDEN_INPUTS for" +
                ` ${ENTRY}, but this build bundled it nowhere`,
        );
    });
});