Add changenotes.mts assemble command to move changenotes to CHANGELOG.md

pr-checks/bundle-changelog.test.ts

@@ -112,15 +112,15 @@ ${NO_CHANGES_STR}`;
 describe("updateChangelog", async () => {
   await it("removes `NO_CHANGES_STR` if present in [UNRELEASED] section", async () => {
     const result = updateChangelog(EMPTY_CHANGELOG, "");
-    assert.ok(!result.includes(NO_CHANGES_STR.trim()));
+    assert.ok(!result.includes(NO_CHANGES_STR));
   });
 
   await it("doesn't remove `NO_CHANGES_STR` if present in versioned section", async () => {
     const result = updateChangelog(
       EMPTY_CHANGELOG.replace(UNRELEASED_PLACEHOLDER, "1.2.3"),
       "",
     );
-    assert.ok(result.includes(NO_CHANGES_STR.trim()));
+    assert.ok(result.includes(NO_CHANGES_STR));
   });
 
   await it("throws if there are no sections", async () => {

pr-checks/changelog.test.ts

@@ -9,17 +9,46 @@ import * as fs from "node:fs";
 import { describe, it } from "node:test";
 
 import {
+  addBodyLinesToUnreleasedSection,
+  ChangelogSection,
   EMPTY_CHANGELOG,
+  getHeader,
   getReleaseDateString,
+  NO_CHANGES_STR,
   parseChangelog,
   processChangelogForBackports,
   renderChangelog,
   setVersionAndDate,
+  UNRELEASED_PLACEHOLDER,
 } from "./changelog";
 import { CHANGELOG_FILE } from "./config";
 
 const testDate = new Date(2026, 7, 14);
 
+describe("getHeader", async () => {
+  function Section(headerLine: string): ChangelogSection {
+    return {
+      headerLine,
+      bodyLines: [],
+    };
+  }
+  await it("returns non-headers unchanged", () => {
+    assert.equal("foo", getHeader(Section("foo")));
+    assert.equal("- bar", getHeader(Section("- bar")));
+  });
+  await it("strips octothorpes", async () => {
+    assert.equal("foo", getHeader(Section("# foo")));
+    assert.equal("foo", getHeader(Section("## foo")));
+    assert.equal("foo", getHeader(Section("### foo")));
+    assert.equal("foo", getHeader(Section("#### foo")));
+    assert.equal("foo", getHeader(Section("##### foo")));
+    assert.equal("foo", getHeader(Section("###### foo")));
+  });
+  await it("strips whitespace", async () => {
+    assert.equal("foo", getHeader(Section("# foo  ")));
+  });
+});
+
 describe("getReleaseDateString", async () => {
   await it("formats dates as expected", async () => {
     assert.equal(getReleaseDateString(testDate), "14 Aug 2026");
@@ -70,3 +99,73 @@ describe("processChangelogForBackports", async () => {
     assert.deepEqual(result.split("\n"), testChangelogResult.split("\n"));
   });
 });
+
+describe("addBodyLinesToUnreleasedSection", async () => {
+  function newChangelogWithSections(sections: ChangelogSection[]) {
+    return {
+      preamble: [],
+      sections,
+    };
+  }
+
+  await it("throws error if '[UNRELEASED]' section is not first", async () => {
+    const invalidChangelog = newChangelogWithSections([
+      {
+        headerLine: "## Release 1.0.0",
+        bodyLines: [],
+      },
+      {
+        headerLine: `## ${UNRELEASED_PLACEHOLDER}`,
+        bodyLines: [],
+      },
+    ]);
+    assert.throws(() =>
+      addBodyLinesToUnreleasedSection(invalidChangelog, ["foo"]),
+    );
+  });
+
+  await it("overwrites 'No user facing changes.'", async () => {
+    const changelog = newChangelogWithSections([
+      {
+        headerLine: `## ${UNRELEASED_PLACEHOLDER}`,
+        bodyLines: ["", NO_CHANGES_STR, ""],
+      },
+    ]);
+
+    addBodyLinesToUnreleasedSection(changelog, ["- foo"]);
+
+    assert.equal(changelog.sections[0].bodyLines.length, 3);
+    assert.deepEqual(changelog.sections[0].bodyLines, ["", "- foo", ""]);
+  });
+
+  await it("does nothing if lines is empty", async () => {
+    const changelog = newChangelogWithSections([
+      {
+        headerLine: `## ${UNRELEASED_PLACEHOLDER}`,
+        bodyLines: ["", NO_CHANGES_STR, ""],
+      },
+    ]);
+    const changelogClone = structuredClone(changelog);
+
+    addBodyLinesToUnreleasedSection(changelog, []);
+
+    assert.deepEqual(changelog, changelogClone);
+  });
+
+  await it("inserts a line", async () => {
+    const changelog = newChangelogWithSections([
+      {
+        headerLine: `## ${UNRELEASED_PLACEHOLDER}`,
+        bodyLines: ["", "- Added a new dependency.", ""],
+      },
+    ]);
+    const lineToInsert = "- foo";
+
+    addBodyLinesToUnreleasedSection(changelog, [lineToInsert]);
+
+    assert.equal(changelog.sections[0].bodyLines.length, 4);
+    assert.ok(
+      changelog.sections[0].bodyLines.some((line) => line === lineToInsert),
+    );
+  });
+});

pr-checks/changelog.ts

@@ -6,14 +6,16 @@ import { CHANGELOG_FILE, DryRunOption } from "./config";
 export const UNRELEASED_PLACEHOLDER = "[UNRELEASED]";
 
 /** The default contents for a section in the changelog. */
-export const NO_CHANGES_STR = "No user facing changes.\n\n";
+export const NO_CHANGES_STR = "No user facing changes.";
 
 /** Placeholder changelog content for a new release. */
 export const EMPTY_CHANGELOG = `# CodeQL Action Changelog
 
 ## ${UNRELEASED_PLACEHOLDER}
 
-${NO_CHANGES_STR}`;
+${NO_CHANGES_STR}
+
+`;
 
 /**
  * Represents sections in a changelog.
@@ -31,6 +33,13 @@ export interface Changelog {
   sections: ChangelogSection[];
 }
 
+/**
+ * Returns the text of the header (without the '## ' prefix) of the given section.
+ * */
+export function getHeader(section: ChangelogSection): string {
+  return section.headerLine.replace(/^#+\s+/, "").trimEnd();
+}
+
 /** Returns `date` formatted as `DD Mon YYYY`. */
 export function getReleaseDateString(today: Date = new Date()): string {
   return today.toLocaleDateString("en-GB", {
@@ -125,6 +134,38 @@ export function parseChangelog(content: string): Changelog {
   return { preamble, sections };
 }
 
+/**
+ * Inserts the changenotes `notes` under the `[UNRELEASED]` section of `changelog`.
+ * If the section contains the stock message {@link NO_CHANGES_STR}, then
+ * `notes` will be inserted in place and the stock message will be deleted.
+ *
+ * This function will throw an exception if `[UNRELEASED]` does not exist.
+ *
+ * @param changelog The CHANGELOG object to modify.
+ * @param lines The changenotes to insert.
+ */
+export function addBodyLinesToUnreleasedSection(
+  changelog: Changelog,
+  lines: string[],
+) {
+  // Do nothing if there is nothing to insert.
+  if (lines.length === 0) return;
+
+  const unreleasedSection = changelog.sections[0];
+  if (getHeader(unreleasedSection) !== UNRELEASED_PLACEHOLDER) {
+    throw Error("'[UNRELEASED]' is not the first section of 'CHANGELOG.md'");
+  }
+
+  if (unreleasedSection.bodyLines.includes(NO_CHANGES_STR)) {
+    unreleasedSection.bodyLines = ["", ...lines, ""];
+    return;
+  }
+
+  unreleasedSection.bodyLines.pop(); // Remove the last empty line.
+  unreleasedSection.bodyLines.push(...lines);
+  unreleasedSection.bodyLines.push("");
+}
+
 /**
  * Combines an array of lines into a single string by adding line breaks.
  */
@@ -204,7 +245,7 @@ export function processChangelogForBackports(
 
     // Add an entry if we didn't keep any.
     if (!foundContent) {
-      section.bodyLines.push(NO_CHANGES_STR.trim());
+      section.bodyLines.push(NO_CHANGES_STR);
     }
   }
 

pr-checks/changenotes.mts

@@ -3,21 +3,64 @@
 import * as fs from "node:fs";
 import { pathToFileURL } from "node:url";
 import { parseArgs } from "node:util";
+import path from "path";
 
+import { ExitCode } from "@actions/core";
+import { matter } from "lite-matter";
+
+import {
+  addBodyLinesToUnreleasedSection,
+  parseChangelog,
+  renderChangelog,
+  withChangelog,
+} from "./changelog";
 import { isValidAllChangenoteFiles } from "./changelog/validate.mjs";
 import { CHANGENOTES_DIR } from "./config";
 
+/**
+ * Describes a changenote file, including its file path, frontmatter, and content.
+ */
+interface ChangenoteFile {
+  name: string;
+  data: Record<string, any>;
+  content: string;
+}
+
+/**
+ * Returns the absolute file paths of all files in
+ * {@link CHANGENOTES_DIR} (except ".gitkeep").
+ * */
+function listUnreleasedChangenoteDir(): string[] {
+  return fs
+    .readdirSync(CHANGENOTES_DIR)
+    .filter((name) => name !== ".gitkeep")
+    .map((name) => path.join(CHANGENOTES_DIR, name));
+}
+
+/**
+ * Scans the {@link CHANGENOTES_DIR} directory for changenote files
+ * and returns a parsed listing of those changenote files.
+ */
+function getChangenotes(): ChangenoteFile[] {
+  return listUnreleasedChangenoteDir().map((name) => {
+    return {
+      name,
+      ...matter(fs.readFileSync(name, "utf-8")),
+    };
+  });
+}
+
 const entryPoint = process.argv[1];
 if (entryPoint && import.meta.url === pathToFileURL(entryPoint).href) {
   try {
     process.exit(main());
   } catch (error) {
     console.error(error);
-    process.exit(1);
+    process.exit(ExitCode.Failure);
   }
 }
 
-function main(): number {
+function main(): ExitCode {
   const { positionals } = parseArgs({
     allowPositionals: true,
     strict: true,
@@ -27,30 +70,61 @@ function main(): number {
     case undefined:
     case "help":
       return usage();
+    case "assemble":
+      return assemble();
     case "validate":
       return validate();
     default:
       console.error(`Unknown command: ${command}`);
-      return 1;
+      return ExitCode.Failure;
   }
 }
 
-function usage(): number {
-  console.log(`Usage: changenotes.mts validate`);
-  return 0;
+function usage(): ExitCode {
+  const message =
+    "Usage: changenotes.mts assemble\n" +
+    "       changenotes.mts validate\n" +
+    "       changenotes.mts help";
+  console.log(message);
+  return ExitCode.Success;
+}
+
+function assemble(): ExitCode {
+  try {
+    const changenotes = getChangenotes();
+    const changenoteBodies = changenotes.map((c) => c.content);
+    const changenotePaths = changenotes.map((c) => c.name);
+
+    withChangelog((contents) => {
+      const changelog = parseChangelog(contents);
+      addBodyLinesToUnreleasedSection(changelog, changenoteBodies);
+      return renderChangelog(changelog);
+    }, {});
+
+    // Delete changenotes only after successful processing.
+    for (const p of changenotePaths) {
+      fs.unlinkSync(p);
+    }
+
+    return ExitCode.Success;
+  } catch (e) {
+    console.error("Failed to assemble changenotes to 'CHANGELOG.md'", e);
+  }
+
+  return ExitCode.Failure;
 }
 
-function validate(): number {
+function validate(): ExitCode {
   try {
     if (isValidAllChangenoteFiles(fs.readdirSync(CHANGENOTES_DIR))) {
       console.log(`All changenotes in '${CHANGENOTES_DIR}' are valid.`);
-      return 0;
+      return ExitCode.Success;
     }
   } catch (error) {
     console.error(
       `Failed to read changenotes directory '${CHANGENOTES_DIR}'`,
       error,
     );
   }
-  return 1;
+  return ExitCode.Failure;
 }