add release-notes output

.gitattributes

@@ -0,0 +1,2 @@
+# Use LF as default EOL marker
+* text=auto eol=lf

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add a new `release-notes` output to the action containing the release notes for the newly released versions.
+
 ## [3.0.0] - 2024-04-08
 
 ### Fixed

__tests__/fixtures/first_release/release-notes.expected.md

@@ -0,0 +1,3 @@
+### Added
+
+- Everything since the beginning!

__tests__/fixtures/standard/release-notes.expected.md

@@ -0,0 +1,3 @@
+### Changed
+
+- Our main theme is now blue instead of red.

__tests__/fixtures/tag_on_tag/release-notes.expected.md

@@ -0,0 +1,3 @@
+### Changed
+
+- Our main theme is now blue instead of red.

__tests__/fixtures/tag_release/release-notes.expected.md

@@ -0,0 +1,3 @@
+### Changed
+
+- Our main theme is now blue instead of red.

__tests__/getReleaseNotes.test.ts

@@ -0,0 +1,35 @@
+import getReleaseNotes from "../src/getReleaseNotes";
+import { read } from "to-vfile";
+
+interface Fixture {
+  tag: string;
+  version: string;
+  date: string;
+  genesisHash: string;
+  owner: string;
+  repo: string;
+}
+
+it.each(["empty_release", "standard", "first_release", "lowercase_link_reference", "tag_release", "tag_on_tag"])(
+  `should extract %s release-notes output`,
+  async function(testcase) {
+    const expectedChangelog = await read(
+      `./__tests__/fixtures/${testcase}/CHANGELOG.expected.md`,
+      {
+        encoding: "utf-8"
+      }
+    );
+    const release: Fixture = await import(
+      `./fixtures/${testcase}/fixture`
+    ).then(module => module.default);
+
+    const expectedReleaseNotes = await read(
+      `./__tests__/fixtures/${testcase}/release-notes.expected.md`,
+      {
+        encoding: "utf-8"
+      }
+    ).then(expected => expected.toString("utf-8"));
+    const actualReleaseNotes = getReleaseNotes(expectedChangelog, release.version);
+    expect(actualReleaseNotes).toEqual(expectedReleaseNotes);
+  }
+);

action.yml

@@ -17,6 +17,9 @@ inputs:
   changelogPath:
     description: 'The path to the changelog file. Defaults to `./CHANGELOG.md`'
     required: false
+outputs:
+  release-notes:
+    description: 'The release notes of the newly released version'
 runs:
   using: 'node20'
   main: 'dist/index.js'

src/getReleaseNotes.ts

@@ -0,0 +1,55 @@
+import unified, { Transformer } from "unified";
+import markdown from "remark-parse";
+import stringify from "remark-stringify";
+import { VFile } from "vfile";
+import { Node } from "unist";
+import { MarkdownRootNode } from "markdown-nodes";
+
+function releaseNotesExtraction(version: string) {
+  return transformer as unknown as Transformer;
+
+  function transformer(tree: MarkdownRootNode, _file: VFile) {
+    const children = tree.children;
+
+    const firstNodeIndex = children.findIndex(
+      node => node.type === "heading" && node.depth === 2 &&
+        node.children.length > 1 && node.children[0].type === "linkReference" &&
+        node.children[0].identifier === version
+    ) + 1;
+    const firstNode = children.slice(firstNodeIndex);
+
+    let lastNodeIndex = firstNode.findIndex(
+      node => node.type === "heading" && node.depth === 2
+    );
+    // special case: release notes for first release will not end with another
+    // section, instead they end with the compare URLs
+    if (lastNodeIndex === -1) {
+      lastNodeIndex = firstNode.findIndex(
+        node => node.type === "definition" && node.identifier === "unreleased"
+      );
+    }
+
+    const releaseNotesNodes = firstNode.slice(0, lastNodeIndex);
+    tree.children = releaseNotesNodes;
+    return tree as Node;
+  }
+}
+
+export default function getReleaseNotes(
+  file: VFile,
+  version: string
+): string {
+  // @ts-ignore
+  return unified()
+    .use(markdown)
+    .use(releaseNotesExtraction, version)
+    .data("settings", {
+      listItemIndent: "1",
+      tightDefinitions: true,
+      bullet: "-"
+    })
+    .use(stringify)
+    .processSync(file)
+    .toString("utf-8")
+    .trim();
+}

src/index.ts

@@ -1,8 +1,10 @@
 import { setFailed } from "@actions/core";
+import { setOutput } from "@actions/core/lib/core";
 import { read, write } from "to-vfile";
 import updateChangelog from "./updateChangelog";
 import getInputs from "./getInputs";
 import getGenesisHash from "./getGenesisHash";
+import getReleaseNotes from "./getReleaseNotes";
 
 async function run(): Promise<void> {
   try {
@@ -20,8 +22,10 @@ async function run(): Promise<void> {
       owner,
       repo
     );
-
     await write(newChangelog, { encoding: "utf-8" });
+
+    const releaseNotes = getReleaseNotes(newChangelog, version);
+    setOutput("release-notes", releaseNotes);
   } catch (error) {
     setFailed(error.message);
   }

src/updateChangelog.ts

@@ -3,65 +3,7 @@ import markdown from "remark-parse";
 import stringify from "remark-stringify";
 import { VFile } from "vfile";
 import { Node, Position } from "unist";
-
-type MarkdownRootNode = {
-  type: "root";
-  children: MarkdownNode[];
-};
-
-interface HeadingNode {
-  type: "heading";
-  depth: number;
-  children: MarkdownNode[];
-  position: Position;
-}
-
-interface DefinitionNode {
-  type: "definition";
-  identifier: string;
-  label: string;
-  url: string;
-  position?: Position;
-}
-
-interface ListNode {
-  type: "list";
-  ordered: boolean;
-  start: any;
-  spread: boolean;
-  url: string;
-  children: object[];
-  position: Position;
-}
-
-interface ParagraphNode {
-  type: "paragraph";
-  children: object[];
-  position: Position;
-}
-
-interface LinkReferenceNode {
-  type: "linkReference";
-  identifier: string;
-  label: string;
-  referenceType: string;
-  children: TextNode[];
-  position?: Position;
-}
-
-interface TextNode {
-  type: "text";
-  value: string;
-  position?: Position;
-}
-
-type MarkdownNode =
-  | HeadingNode
-  | DefinitionNode
-  | ListNode
-  | ParagraphNode
-  | LinkReferenceNode
-  | TextNode;
+import { MarkdownRootNode, HeadingNode, DefinitionNode, LinkReferenceNode, TextNode } from "markdown-nodes";
 
 interface Options {
   tag: string;

types/markdown-nodes/index.d.ts

@@ -0,0 +1,62 @@
+declare module "markdown-nodes" {
+  import { Position } from "unist";
+
+  type MarkdownRootNode = {
+    type: "root";
+    children: MarkdownNode[];
+  };
+
+  interface HeadingNode {
+    type: "heading";
+    depth: number;
+    children: MarkdownNode[];
+    position: Position;
+  }
+
+  interface DefinitionNode {
+    type: "definition";
+    identifier: string;
+    label: string;
+    url: string;
+    position?: Position;
+  }
+
+  interface ListNode {
+    type: "list";
+    ordered: boolean;
+    start: any;
+    spread: boolean;
+    url: string;
+    children: object[];
+    position: Position;
+  }
+
+  interface ParagraphNode {
+    type: "paragraph";
+    children: object[];
+    position: Position;
+  }
+
+  interface LinkReferenceNode {
+    type: "linkReference";
+    identifier: string;
+    label: string;
+    referenceType: string;
+    children: TextNode[];
+    position?: Position;
+  }
+
+  interface TextNode {
+    type: "text";
+    value: string;
+    position?: Position;
+  }
+
+  type MarkdownNode =
+    | HeadingNode
+    | DefinitionNode
+    | ListNode
+    | ParagraphNode
+    | LinkReferenceNode
+    | TextNode;
+}