docker build . stamps the git tag or short commit, not dev (closes #154)

script/build writes the version script/version prints into
dist/package.json, which quak --version reports: the VERSION environment
variable or build arg when one is given, otherwise git describe --tags
--always, otherwise package.json's version. A checkout with .git whose
version comes out empty, dev or unknown fails the build.

.dockerignore no longer leaves out .git, and ARG VERSION has no default,
so a plain docker build . of a clone stamps its commit. script/docker and
script/cibuild still pass the host's version. make build-bin bundles the
built dist/, so the single binary reports the same version.

Model: opus-5-5

test/packaging/version.test.ts

@@ -0,0 +1,136 @@
+// `script/version` prints the version `script/build` stamps into
+// `dist/package.json`, which is what `quak --version` reports from a build.
+// A `docker build .` of a clone is given no `VERSION` build arg, so the
+// version has to come from the `.git` in its context: the tag on a tagged
+// commit, otherwise the short commit. A checkout with `.git` that still yields
+// no usable version must fail the build, not ship a version nobody can trace
+// back to its commit.
+//
+// Each test copies the script into a fresh directory, which the script then
+// treats as the checkout, and executes it there.
+import { afterEach, describe, expect, it } from "vitest";
+import { execFileSync, spawnSync } from "node:child_process";
+import {
+    chmodSync,
+    copyFileSync,
+    mkdirSync,
+    mkdtempSync,
+    rmSync,
+    writeFileSync,
+} from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const repoRoot = fileURLToPath(new URL("../../", import.meta.url));
+
+let checkout = "";
+
+afterEach(() => {
+    rmSync(checkout, { recursive: true, force: true });
+});
+
+// A checkout holding the script and a package.json that declares 0.0.0, with
+// no .git yet.
+const makeCheckout = (): void => {
+    checkout = mkdtempSync(join(tmpdir(), "quak-version-"));
+    mkdirSync(join(checkout, "script"));
+    copyFileSync(
+        join(repoRoot, "script/version"),
+        join(checkout, "script/version"),
+    );
+    chmodSync(join(checkout, "script/version"), 0o755);
+    writeFileSync(join(checkout, "package.json"), '{ "version": "0.0.0" }\n');
+};
+
+// git in the checkout, with an identity and no commit signing, whatever the
+// host's own git config says.
+const git = (...args: string[]): string =>
+    execFileSync(
+        "git",
+        [
+            "-c",
+            "user.name=quak",
+            "-c",
+            "user.email=quak@example.invalid",
+            "-c",
+            "commit.gpgsign=false",
+            ...args,
+        ],
+        { cwd: checkout, encoding: "utf-8", stdio: ["ignore", "pipe", "pipe"] },
+    ).trim();
+
+const makeCommittedCheckout = (): void => {
+    makeCheckout();
+    git("init", "-q");
+    git("add", "package.json");
+    git("commit", "-q", "-m", "first");
+};
+
+// Runs the script with nothing in its environment but PATH and, when given,
+// VERSION.
+const runVersion = (version?: string) =>
+    spawnSync(join(checkout, "script/version"), {
+        cwd: checkout,
+        encoding: "utf-8",
+        env: { PATH: process.env.PATH, VERSION: version },
+    });
+
+describe("script/version", () => {
+    it("prints the short commit of an untagged commit", () => {
+        makeCommittedCheckout();
+        expect(runVersion().stdout.trim()).toBe(
+            git("rev-parse", "--short", "HEAD"),
+        );
+    });
+
+    it("prints the tag of a tagged commit", () => {
+        makeCommittedCheckout();
+        git("tag", "v1.2.3");
+        expect(runVersion().stdout.trim()).toBe("v1.2.3");
+    });
+
+    // script/docker and script/cibuild pass the version they resolve on the
+    // host as the VERSION build arg.
+    it("prints the VERSION it is given over what git would derive", () => {
+        makeCommittedCheckout();
+        expect(runVersion("x").stdout.trim()).toBe("x");
+    });
+
+    // `--build-arg VERSION=` must not stamp an empty version.
+    it("treats an empty VERSION as unset", () => {
+        makeCommittedCheckout();
+        expect(runVersion("").stdout.trim()).toBe(
+            git("rev-parse", "--short", "HEAD"),
+        );
+    });
+
+    // A source tarball has no .git: it keeps the version package.json
+    // declares, and must still build.
+    it("prints package.json's version where there is no .git", () => {
+        makeCheckout();
+        const result = runVersion();
+        expect(result.status).toBe(0);
+        expect(result.stdout.trim()).toBe("0.0.0");
+    });
+
+    // A repository with no commits stands in for any .git that git cannot
+    // describe: git missing from the image, or refusing to read the checkout.
+    it("fails where .git yields no version", () => {
+        makeCheckout();
+        git("init", "-q");
+        const result = runVersion();
+        expect(result.status).not.toBe(0);
+        expect(result.stdout).toBe("");
+    });
+
+    it.each(["dev", "unknown"])(
+        "fails where there is .git and the version is %s",
+        (version) => {
+            makeCommittedCheckout();
+            const result = runVersion(version);
+            expect(result.status).not.toBe(0);
+            expect(result.stdout).toBe("");
+        },
+    );
+});