Add rollback-changelog.ts with tests

pr-checks/rollback-changelog.test.ts

@@ -0,0 +1,45 @@
+/**
+ * Tests for `rollback-changelog.ts`.
+ */
+
+import * as assert from "node:assert/strict";
+import * as fs from "node:fs";
+import { describe, it } from "node:test";
+
+import { getReleaseDateString, parseChangelog } from "./changelog";
+import { CHANGELOG_FILE } from "./config";
+import { updateChangelog } from "./rollback-changelog";
+
+describe("updateChangelog", async () => {
+  await it("replaces the first section with one for the rollback release", async () => {
+    const actualChangelog = parseChangelog(
+      fs.readFileSync(CHANGELOG_FILE, "utf-8"),
+    );
+    const existingFirstSection = actualChangelog.sections[0];
+
+    const today = new Date();
+    updateChangelog(actualChangelog, {
+      "new-version": "Test.1.3",
+      "rollback-version": "Test.1.2",
+      "target-version": "Test.1.1",
+      today,
+    });
+
+    // Check that the old, first section is gone.
+    for (const section of actualChangelog.sections) {
+      assert.notDeepEqual(section, existingFirstSection);
+    }
+
+    // Check that the new, first section matches our expectations.
+    const newFirstSection = actualChangelog.sections[0];
+    assert.deepEqual(
+      newFirstSection.headerLine,
+      `## Test.1.3 - ${getReleaseDateString(today)}`,
+    );
+    assert.equal(newFirstSection.bodyLines.length, 3);
+    assert.deepEqual(
+      newFirstSection.bodyLines[1],
+      `This release rolls back Test.1.2 due to issues with that release. It is identical to Test.1.1.`,
+    );
+  });
+});

pr-checks/rollback-changelog.ts

@@ -0,0 +1,94 @@
+#!/usr/bin/env npx tsx
+
+/**
+ * Replaces the current, first section of the changelog with a new one for the rollback release.
+ */
+
+import * as fs from "node:fs";
+import { parseArgs } from "node:util";
+
+import { getErrorMessage } from "../src/util";
+
+import {
+  Changelog,
+  ChangelogSection,
+  getReleaseDateString,
+  parseChangelog,
+  renderChangelog,
+} from "./changelog";
+import { CHANGELOG_FILE } from "./config";
+
+export interface RollbackChangelogInputs {
+  "target-version": string;
+  "rollback-version": string;
+  "new-version": string;
+  today?: Date;
+}
+
+/**
+ * Replaces the current, first section of the changelog with a new one for the rollback release.
+ */
+export function updateChangelog(
+  changelog: Changelog,
+  versions: RollbackChangelogInputs,
+) {
+  // Drop the existing first section.
+  changelog.sections.shift();
+
+  // Construct the section for the rollback version.
+  const newSection: ChangelogSection = {
+    headerLine: `## ${versions["new-version"]} - ${getReleaseDateString(versions.today)}`,
+    bodyLines: [
+      "",
+      `This release rolls back ${versions["rollback-version"]} due to issues with that release. It is identical to ${versions["target-version"]}.`,
+      "",
+    ],
+  };
+
+  // Add the new section at the top of the changelog.
+  changelog.sections.unshift(newSection);
+}
+
+function main() {
+  try {
+    const { values } = parseArgs({
+      options: {
+        "target-version": {
+          type: "string",
+          short: "t",
+        },
+        "rollback-version": {
+          type: "string",
+          short: "r",
+        },
+        "new-version": {
+          type: "string",
+          short: "n",
+        },
+      },
+      strict: true,
+    });
+
+    for (const key of Object.keys(values)) {
+      if (key === undefined || key.trim() === "") {
+        throw new Error(`Argument '--${key}' is required.`);
+      }
+    }
+
+    const changelog = parseChangelog(fs.readFileSync(CHANGELOG_FILE, "utf-8"));
+    updateChangelog(changelog, values as RollbackChangelogInputs);
+    console.info(renderChangelog(changelog));
+
+    return 0;
+  } catch (err) {
+    console.error(
+      `Failed to prepare rollback changelog: ${getErrorMessage(err)}`,
+    );
+    return -1;
+  }
+}
+
+// Only call `main` if this script was run directly.
+if (require.main === module) {
+  process.exit(main());
+}