Respect Prettier ignore files in parent directories

.changeset/bumpy-planes-sin.md

@@ -0,0 +1,23 @@
+---
+'skuba': patch
+---
+
+format, lint: Respect Prettier ignore files in parent directories
+
+Previously, `skuba format` and `skuba lint` only looked for `.gitignore` and `.prettierignore` in the current working directory. Now, you can execute these commands in a subdirectory while centralising ignore files in the root directory.
+
+```text
+┌── apps/
+│   └── a/
+│       ├── src/
+│       ├── package.json
+│       └── ...
+│   └── b/ <- execute skuba lint here
+│       ├── src/
+│       ├── package.json
+│       └── ...
+├── .gitignore
+├── .prettierignore <- and it will respect this
+├── package.json
+└── ...
+```

integration/base/mono/.prettierignore

@@ -0,0 +1 @@
+/apps/ignore/src/ignore.json

integration/base/mono/apps/ignore/package.json

@@ -0,0 +1,13 @@
+{
+  "dependencies": {},
+  "devDependencies": {},
+  "license": "UNLICENSED",
+  "private": true,
+  "sideEffects": false,
+  "skuba": {
+    "entryPoint": null,
+    "template": null,
+    "type": "application",
+    "version": "0.0.1"
+  }
+}

integration/base/mono/apps/ignore/src/bad.json

@@ -0,0 +1,3 @@
+{
+  "key": "value"
+  }

integration/base/mono/apps/ignore/src/ignore.json

@@ -0,0 +1,3 @@
+{
+  "key": "value"
+  }

integration/base/mono/package.json

@@ -0,0 +1,13 @@
+{
+  "dependencies": {},
+  "devDependencies": {},
+  "license": "UNLICENSED",
+  "private": true,
+  "sideEffects": false,
+  "skuba": {
+    "entryPoint": null,
+    "template": null,
+    "type": "application",
+    "version": "0.0.1"
+  }
+}

integration/base/mono/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    "incremental": true,
+    "moduleResolution": "node",
+    "outDir": "lib",
+    "skipLibCheck": true
+  },
+  "extends": "tsconfig-seek"
+}

src/cli/adapter/prettier.test.ts

@@ -104,4 +104,34 @@ describe('runPrettier', () => {
       }
     `);
   });
+
+  it('handles a nested directory with a parent .prettierignore', async () => {
+    const dirname = path.join(
+      __dirname,
+      '../../../integration/base/mono/apps/ignore',
+    );
+
+    process.chdir(dirname);
+
+    // Should exclude `src/ignore.json`
+    await expect(runPrettier('lint', log, dirname)).resolves
+      .toMatchInlineSnapshot(`
+      {
+        "ok": false,
+        "result": {
+          "count": 2,
+          "errored": [
+            {
+              "filepath": "package.json",
+            },
+            {
+              "filepath": "src/bad.json",
+            },
+          ],
+          "touched": [],
+          "unparsed": [],
+        },
+      }
+    `);
+  });
 });

src/cli/adapter/prettier.ts

@@ -10,7 +10,7 @@ import {
   resolveConfig,
 } from 'prettier';
 
-import { crawlDirectory } from '../../utils/dir';
+import { crawlDirectory, locateNearestFile } from '../../utils/dir';
 import { type Logger, pluralise } from '../../utils/logging';
 import { getConsumerManifest } from '../../utils/manifest';
 import { formatPackage, parsePackage } from '../configure/processing/package';
@@ -176,11 +176,18 @@ export const runPrettier = async (
   // This avoids exhibiting different behaviour than a Prettier IDE integration,
   // though it may present headaches if `.gitignore` and `.prettierignore` rules
   // conflict.
-  const relativeFilepaths = await crawlDirectory(directory, [
-    '.gitignore',
-    '.prettierignore',
+  // TODO: should these bottom out at the project root?
+  const ignoreFilepaths = await Promise.all([
+    locateNearestFile({ cwd, filename: '.gitignore' }),
+    locateNearestFile({ cwd, filename: '.prettierignore' }),
   ]);
 
+  const ignoreFilenames = ignoreFilepaths.flatMap((filepath) =>
+    filepath ? path.relative(cwd, filepath) : [],
+  );
+
+  const relativeFilepaths = await crawlDirectory(directory, ignoreFilenames);
+
   logger.debug(`Discovered ${pluralise(relativeFilepaths.length, 'file')}.`);
 
   const result: Result = {

src/utils/dir.ts

@@ -39,14 +39,38 @@ export const crawlDirectory = async (
   root: string,
   ignoreFilenames = ['.gitignore'],
 ) => {
-  const ignoreFileFilter = await createInclusionFilter(
-    ignoreFilenames.map((ignoreFilename) => path.join(root, ignoreFilename)),
+  const ignoreFilenamesByPrefix = Object.groupBy(
+    ignoreFilenames,
+    (filename) => {
+      const prefix = path.relative(
+        path.dirname(path.resolve(root, filename)),
+        root,
+      );
+
+      return prefix;
+    },
+  );
+
+  const ignores = await Promise.all(
+    Object.entries(ignoreFilenamesByPrefix).flatMap(
+      async ([prefix, filenames]) =>
+        ({
+          prefix,
+          filter: await createInclusionFilter(
+            (filenames ?? []).map((filename) => path.join(root, filename)),
+          ),
+        }) as const,
+    ),
   );
 
   const absoluteFilenames = await crawl(root, {
     includeDirName: (dirname) => !['.git', 'node_modules'].includes(dirname),
     includeFilePath: (pathname) =>
-      ignoreFileFilter(path.relative(root, pathname)),
+      ignores.every(({ filter, prefix }) => {
+        const filepath = path.join(prefix, path.relative(root, pathname));
+
+        return filter(filepath);
+      }),
   });
 
   const relativeFilepaths = absoluteFilenames.map((filepath) =>