From 10e7c5800fef43fafacc0d043e6d712ab054be5b Mon Sep 17 00:00:00 2001
From: L4XB <lukas.buck@e-mail.de>
Date: Thu, 22 Oct 2026 23:51:32 +0200
Subject: [PATCH] fix(hooks): recognize Prettier's TypeScript and JSON5 config
 files

Prettier's config searcher also reads .prettierrc.json5, .prettierrc.ts/.mts/.cts and prettier.config.ts/.mts/.cts. resolve-formatter knew none of them, so a project configured only through prettier.config.ts was never formatted by post-edit-format, quality-gate or the Stop batch. config-protection's rc pattern stopped at .yaml/.toml, so an existing .prettierrc.ts or .prettierrc.json5 could be edited freely.
---
 scripts/hooks/config-protection.js    |  5 +++--
 scripts/lib/resolve-formatter.js      | 11 ++++++++++-
 tests/hooks/config-protection.test.js | 19 +++++++++++++++++++
 tests/lib/resolve-formatter.test.js   | 15 +++++++++++++++
 4 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/scripts/hooks/config-protection.js b/scripts/hooks/config-protection.js
index 75a7a0781..8dce8b2ea 100644
--- a/scripts/hooks/config-protection.js
+++ b/scripts/hooks/config-protection.js
@@ -117,8 +117,9 @@ const PROTECTED_FILES = new Set([
 const PROTECTED_PATTERNS = [
   // eslint.config.base.mjs, prettier.config.shared.cjs, stylelint.config.local.js ...
   /^(eslint|prettier|stylelint|commitlint|oxlint)\.config(\.[A-Za-z0-9_-]+)*\.(js|mjs|cjs|ts|mts|cts)$/i,
-  // .eslintrc.base.json, .prettierrc.shared.yml ...
-  /^\.(eslintrc|prettierrc|stylelintrc|markdownlintrc)(\.[A-Za-z0-9_-]+)*\.(js|cjs|mjs|json|jsonc|yml|yaml|toml)$/i,
+  // .eslintrc.base.json, .prettierrc.shared.yml ... Prettier also reads
+  // `.prettierrc.ts`, `.mts`, `.cts` and `.json5`.
+  /^\.(eslintrc|prettierrc|stylelintrc|markdownlintrc)(\.[A-Za-z0-9_-]+)*\.(js|cjs|mjs|ts|mts|cts|json|jsonc|json5|yml|yaml|toml)$/i,
 ];
 
 function isProtectedName(basename) {
diff --git a/scripts/lib/resolve-formatter.js b/scripts/lib/resolve-formatter.js
index 3fec591c9..251264e78 100644
--- a/scripts/lib/resolve-formatter.js
+++ b/scripts/lib/resolve-formatter.js
@@ -32,7 +32,16 @@ const PRETTIER_CONFIGS = [
   '.prettierrc.toml',
   'prettier.config.js',
   'prettier.config.cjs',
-  'prettier.config.mjs'
+  'prettier.config.mjs',
+  // The rest of the names Prettier's config searcher looks for
+  // (src/config/prettier-config/config-searcher.js).
+  '.prettierrc.json5',
+  '.prettierrc.ts',
+  '.prettierrc.mts',
+  '.prettierrc.cts',
+  'prettier.config.ts',
+  'prettier.config.mts',
+  'prettier.config.cts'
 ];
 
 const PROJECT_ROOT_MARKERS = ['package.json', ...BIOME_CONFIGS, ...PRETTIER_CONFIGS];
diff --git a/tests/hooks/config-protection.test.js b/tests/hooks/config-protection.test.js
index b0b88ae54..9ab7d844f 100644
--- a/tests/hooks/config-protection.test.js
+++ b/tests/hooks/config-protection.test.js
@@ -447,6 +447,25 @@ function runTests() {
     })
   );
 
+  results.push(
+    test("blocks Prettier's TypeScript and JSON5 rc files", () => {
+      return withOwnedDirectory(fs.mkdtempSync(path.join(os.tmpdir(), 'ecc-config-protect-prettier-')), tmpDir => {
+        for (const name of ['.prettierrc.ts', '.prettierrc.mts', '.prettierrc.cts', '.prettierrc.json5', '.prettierrc.shared.ts']) {
+          const absPath = path.join(tmpDir, name);
+          fs.writeFileSync(absPath, 'export default {};\n');
+
+          const result = runHook({ tool_name: 'Edit', tool_input: { file_path: absPath } });
+
+          assert.strictEqual(result.code, 2, 'Expected ' + name + ' to be blocked');
+          assert.ok(
+            result.stderr.includes('BLOCKED: Modifying ' + name + ' is not allowed.'),
+            'Expected block message for ' + name + ', got: ' + result.stderr
+          );
+        }
+      });
+    })
+  );
+
   results.push(
     test('does not block build or test tooling configs', () => {
       // Pins the boundary: this hook guards LINTER configs. A future widening
diff --git a/tests/lib/resolve-formatter.test.js b/tests/lib/resolve-formatter.test.js
index dc478fc84..42185725f 100644
--- a/tests/lib/resolve-formatter.test.js
+++ b/tests/lib/resolve-formatter.test.js
@@ -155,6 +155,21 @@ function runTests() {
     assert.strictEqual(detectFormatter(root), 'prettier');
   });
 
+  run("detectFormatter: detects Prettier's TypeScript and JSON5 config files", () => {
+    const names = ['.prettierrc.json5', '.prettierrc.ts', '.prettierrc.mts', '.prettierrc.cts',
+      'prettier.config.ts', 'prettier.config.mts', 'prettier.config.cts'];
+    for (const name of names) {
+      const root = makeTmpDir();
+      fs.writeFileSync(path.join(root, 'package.json'), JSON.stringify({ name: 'test' }));
+      fs.writeFileSync(path.join(root, name), 'export default {};\n');
+      assert.strictEqual(detectFormatter(root), 'prettier', name);
+      const nested = path.join(root, 'src');
+      fs.mkdirSync(nested);
+      fs.rmSync(path.join(root, 'package.json'));
+      assert.strictEqual(findProjectRoot(nested), root, `${name} marks the project root`);
+    }
+  });
+
   run('detectFormatter: detects prettier key in package.json', () => {
     const root = makeTmpDir();
     fs.writeFileSync(path.join(root, 'package.json'), JSON.stringify({ name: 'test', prettier: { singleQuote: true } }));