Add changelog lint script (#7320)

* Add changelog lint script

* Refactor lint script

* spell

* Fix indent

* fix templateComment

* add H4 check

* Add category in title check

* use array destructuring

* Add space check

.azure-pipelines/jobs/dev-lint.yml

@@ -11,3 +11,5 @@ steps:
     displayName: "Lint docs"
   - script: yarn spellcheck
     displayName: "Spellcheck"
+  - script: yarn lint-changelog
+    displayName: "Lint changelog"

changelog_unreleased/cli/pr-7210.md

@@ -1,4 +1,4 @@
-#### Support file extensions `.cjs` and `.yaml.sed`([#7210](https://github.com/prettier/prettier/pull/7210) by [@sosukesuzuki](https://github.com/sosukesuzuki))
+#### Support file extensions `.cjs` and `.yaml.sed` ([#7210](https://github.com/prettier/prettier/pull/7210) by [@sosukesuzuki](https://github.com/sosukesuzuki))
 
 ```sh
 # Prettier stable

changelog_unreleased/handlebars/pr-7051.md

@@ -1,4 +1,4 @@
-#### handlebars: Fix superfluous line breaks in ConcatStatement ([7051](https://github.com/prettier/prettier/pull/7051) by [@dcyriller](https://github.com/dcyriller))
+#### Fix superfluous line breaks in ConcatStatement ([#7051](https://github.com/prettier/prettier/pull/7051) by [@dcyriller](https://github.com/dcyriller))
 
 <!-- prettier-ignore -->
 ```hbs

changelog_unreleased/handlebars/pr-7157.md

@@ -1,4 +1,4 @@
-#### handlebars: Improve MustacheStatement printing ([#7157](https://github.com/prettier/prettier/pull/7157) by [@dcyriller](https://github.com/dcyriller))
+#### Improve MustacheStatement printing ([#7157](https://github.com/prettier/prettier/pull/7157) by [@dcyriller](https://github.com/dcyriller))
 
 <!-- prettier-ignore -->
 ```hbs

changelog_unreleased/javascript/pr-6984.md

@@ -1,4 +1,4 @@
-#### Fix formatting of labeled statements with comments ([#6994](https://github.com/prettier/prettier/pull/6984) by [@clement26695](https://github.com/clement26695))
+#### Fix formatting of labeled statements with comments ([#6984](https://github.com/prettier/prettier/pull/6984) by [@clement26695](https://github.com/clement26695))
 
 Formatting of comments in labeled statements was not stable
 

changelog_unreleased/javascript/pr-7070.md

@@ -1,4 +1,4 @@
-# Format `throw` like `return` ([#7070](https://github.com/prettier/prettier/pull/7070) by [@sosukesuzuki](https://github.com/sosukesuzuki))
+#### Format `throw` like `return` ([#7070](https://github.com/prettier/prettier/pull/7070) by [@sosukesuzuki](https://github.com/sosukesuzuki))
 
 <!-- prettier-ignore -->
 ```js

changelog_unreleased/javascript/pr-7140.md

@@ -1,4 +1,4 @@
-#### Fix moving semi for `return` to end of line-comment([#7140](https://github.com/prettier/prettier/pull/7140) by [@sosukesuzuki](https://github.com/sosukesuzuki))
+#### Fix moving semi for `return` to end of line-comment ([#7140](https://github.com/prettier/prettier/pull/7140) by [@sosukesuzuki](https://github.com/sosukesuzuki))
 
 <!-- prettier-ignore -->
 ```js

changelog_unreleased/mdx/pr-6398.md

@@ -1,4 +1,4 @@
-#### MDX: fix JSX Fragment format incorrectly ([#6398](https://github.com/prettier/prettier/pull/6398) by [@JounQin](https://github.com/JounQin))
+#### Fix JSX Fragment format incorrectly ([#6398](https://github.com/prettier/prettier/pull/6398) by [@JounQin](https://github.com/JounQin))
 
 Previous versions format JSX Fragment incorrectly in mdx, this has been fixed in this version.
 

changelog_unreleased/typescript/pr-7075.md

@@ -1,4 +1,4 @@
-#### Don't print trailing commas after rest elements in tuples ([#7075](https://github.com/prettier/prettier/pull/7075) by [@thorn](https://github.com/thorn0))
+#### Don't print trailing commas after rest elements in tuples ([#7075](https://github.com/prettier/prettier/pull/7075) by [@thorn0](https://github.com/thorn0))
 
 - A rest element is always the last element of a tuple type. Nothing can be added after it.
 - While TS is okay with this comma, [Babel doesn't parse it](https://github.com/babel/babel/issues/10769)

changelog_unreleased/typescript/pr-7094.md

@@ -1,4 +1,4 @@
-#### Remove extra indentation for arrow function on variable declaration with comment([#7094](https://github.com/prettier/prettier/pull/7094) by [@sosukesuzuki](https://github.com/sosukesuzuki))
+#### Remove extra indentation for arrow function on variable declaration with comment ([#7094](https://github.com/prettier/prettier/pull/7094) by [@sosukesuzuki](https://github.com/sosukesuzuki))
 
 <!-- prettier-ignore -->
 ```ts

changelog_unreleased/typescript/pr-7144.md

@@ -1,4 +1,4 @@
-#### Fix formatting comments for function-like nodes ([#6901](https://github.com/prettier/prettier/pull/7144) by [@armano2](https://github.com/armano2))
+#### Fix formatting comments for function-like nodes ([#7144](https://github.com/prettier/prettier/pull/7144) by [@armano2](https://github.com/armano2))
 
 <!-- prettier-ignore -->
 ```ts

changelog_unreleased/vue/pr-7180.md

@@ -1,4 +1,4 @@
-#### format vue SFC containing JSX script([#7180](https://github.com/prettier/prettier/pull/7180) by [@sosukesuzuki](https://github.com/sosukesuzuki))
+#### format vue SFC containing JSX script ([#7180](https://github.com/prettier/prettier/pull/7180) by [@sosukesuzuki](https://github.com/sosukesuzuki))
 
 <!-- prettier-ignore -->
 ```html

cspell.json

@@ -122,6 +122,7 @@
         "gitattributes",
         "githook",
         "gitignore",
+        "gitkeep",
         "Gitter",
         "glimmerjs",
         "globbing",

package.json

@@ -122,6 +122,7 @@
     "perf-benchmark": "yarn && yarn build && cross-env NODE_ENV=production node ./dist/bin-prettier.js --debug-benchmark --loglevel debug ${PERF_FILE:-./index.js} > /dev/null",
     "check-types": "tsc",
     "lint": "cross-env EFF_NO_LINK_RULES=true eslint . --format friendly",
+    "lint-changelog": "node ./scripts/lint-changelog.js",
     "lint-docs": "prettier {.,docs,website,website/blog,changelog_unreleased,changelog_unreleased/*}/*.md --check",
     "lint-dist": "eslint --no-eslintrc --no-ignore --env=browser \"dist/!(bin-prettier|index|third-party).js\"",
     "build": "node --max-old-space-size=3072 ./scripts/build/build.js",

scripts/lint-changelog.js

@@ -0,0 +1,131 @@
+"use strict";
+const fs = require("fs");
+const path = require("path");
+
+const CHANGELOG_DIR = "changelog_unreleased";
+const TEMPLATE_FILE = "TEMPLATE.md";
+const CHANGELOG_CATEGORIES = [
+  "angular",
+  "api",
+  "cli",
+  "css",
+  "flow",
+  "graphql",
+  "handlebars",
+  "html",
+  "javascript",
+  "json",
+  "less",
+  "lwc",
+  "markdown",
+  "mdx",
+  "scss",
+  "typescript",
+  "vue",
+  "yaml"
+];
+const CHANGELOG_ROOT = path.join(__dirname, `../${CHANGELOG_DIR}`);
+const showErrorMessage = message => {
+  console.error(message);
+  process.exitCode = 1;
+};
+
+const files = fs.readdirSync(CHANGELOG_ROOT);
+for (const file of files) {
+  if (file !== TEMPLATE_FILE && !CHANGELOG_CATEGORIES.includes(file)) {
+    showErrorMessage(`Please remove "${file}" from "${CHANGELOG_DIR}".`);
+  }
+}
+for (const file of [TEMPLATE_FILE, ...CHANGELOG_CATEGORIES]) {
+  if (!files.includes(file)) {
+    showErrorMessage(`Please don't remove "${file}" from "${CHANGELOG_DIR}".`);
+  }
+}
+
+const authorRegex = /by \[@(.*?)\]\(https:\/\/github\.com\/\1\)/;
+const titleRegex = /^#{4} (.*?)\(\[#\d{4,}]/;
+
+const template = fs.readFileSync(
+  path.join(CHANGELOG_ROOT, TEMPLATE_FILE),
+  "utf8"
+);
+const [templateComment] = template.match(/<!--[\s\S]*?-->/);
+const [templateAuthorLink] = template.match(authorRegex);
+
+for (const category of CHANGELOG_CATEGORIES) {
+  const files = fs.readdirSync(path.join(CHANGELOG_ROOT, category));
+  if (!files.includes(".gitkeep")) {
+    showErrorMessage(
+      `Please don't remove ".gitkeep" from "${CHANGELOG_DIR}/${category}".`
+    );
+  }
+
+  for (const prFile of files) {
+    if (prFile === ".gitkeep") {
+      continue;
+    }
+
+    const match = prFile.match(/^pr-(\d{4,})\.md$/);
+    const displayPath = `${CHANGELOG_DIR}/${category}/${prFile}`;
+
+    if (!match) {
+      showErrorMessage(
+        `[${displayPath}]: Filename is not in form of "pr-{PR_NUMBER}.md".`
+      );
+      continue;
+    }
+    const [, prNumber] = match;
+    const content = fs.readFileSync(
+      path.join(CHANGELOG_DIR, category, prFile),
+      "utf8"
+    );
+    const prLink = `[#${prNumber}](https://github.com/prettier/prettier/pull/${prNumber})`;
+
+    if (!content.includes(prLink)) {
+      showErrorMessage(`[${displayPath}]: PR link "${prLink}" is missing.`);
+    }
+    if (!authorRegex.test(content)) {
+      showErrorMessage(`[${displayPath}]: Author link is missing.`);
+    }
+    if (content.includes(templateComment)) {
+      showErrorMessage(
+        `[${displayPath}]: Please remove template comments at top.`
+      );
+    }
+    if (content.includes(templateAuthorLink)) {
+      showErrorMessage(
+        `[${displayPath}]: Please change author link to your github account.`
+      );
+    }
+    if (!content.startsWith("#### ")) {
+      showErrorMessage(`[${displayPath}]: Please use h4("####") for title.`);
+    }
+    const titleMatch = content.match(titleRegex);
+    if (!titleMatch) {
+      showErrorMessage(`[${displayPath}]: Something wrong in title.`);
+      continue;
+    }
+    const [, title] = titleMatch;
+    const categoryInTitle = title
+      .split(":")
+      .shift()
+      .trim();
+    if (CHANGELOG_CATEGORIES.includes(categoryInTitle.toLowerCase())) {
+      showErrorMessage(
+        `[${displayPath}]: Please remove "${categoryInTitle}:" in title.`
+      );
+    }
+
+    if (title.startsWith(" ")) {
+      showErrorMessage(
+        `[${displayPath}]: Don't add extra space(s) at beginning of title.`
+      );
+    }
+
+    if (!title.endsWith(" ") || title.length - title.trimEnd().length !== 1) {
+      showErrorMessage(
+        `[${displayPath}]: Please put one space between title and PR link.`
+      );
+    }
+  }
+}