From ded8bd3c409912e9412432f25a40a7cdd67b62ac Mon Sep 17 00:00:00 2001
From: Lev Chelyadinov <leva181777@gmail.com>
Date: Thu, 13 Jun 2024 20:33:39 +0200
Subject: [PATCH] Stop demanding public API from the App layer

---
 .../src/public-api/README.md                  |  2 +-
 .../src/public-api/index.spec.ts              | 28 +++++++++++++++++++
 .../src/public-api/index.ts                   |  4 +++
 packages/steiger/steiger.config.ts            |  2 +-
 4 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/packages/steiger-plugin-fsd/src/public-api/README.md b/packages/steiger-plugin-fsd/src/public-api/README.md
index fa0659b..18a65ea 100644
--- a/packages/steiger-plugin-fsd/src/public-api/README.md
+++ b/packages/steiger-plugin-fsd/src/public-api/README.md
@@ -1,6 +1,6 @@
 # `public-api`
 
-Require slices (and segments on sliceless layers like Shared) to have a public API definition.
+Require slices (and segments on Shared) to have a public API definition.
 
 According to the _public API rule on slices_:
 
diff --git a/packages/steiger-plugin-fsd/src/public-api/index.spec.ts b/packages/steiger-plugin-fsd/src/public-api/index.spec.ts
index e4e7448..c1ce49e 100644
--- a/packages/steiger-plugin-fsd/src/public-api/index.spec.ts
+++ b/packages/steiger-plugin-fsd/src/public-api/index.spec.ts
@@ -130,3 +130,31 @@ it('reports errors on segments that are missing a public API', () => {
     },
   ])
 })
+
+it('reports no errors when the App layer is missing a public API', () => {
+  const root = parseIntoFsdRoot(`
+    📂 shared
+      📂 ui
+        📄 index.ts
+    📂 entities
+      📂 users
+        📂 ui
+        📄 index.ts
+      📂 posts
+        📂 ui
+        📄 index.ts
+    📂 features
+      📂 comments
+        📂 ui
+        📄 index.ts
+    📂 pages
+      📂 editor
+        📂 ui
+        📄 index.ts
+    📂 app
+      📂 providers
+      📂 styles
+  `)
+
+  expect(publicApi.check(root, { sourceFileExtension: 'ts' })).toEqual({ diagnostics: [] })
+})
diff --git a/packages/steiger-plugin-fsd/src/public-api/index.ts b/packages/steiger-plugin-fsd/src/public-api/index.ts
index b9645d0..e9043f3 100644
--- a/packages/steiger-plugin-fsd/src/public-api/index.ts
+++ b/packages/steiger-plugin-fsd/src/public-api/index.ts
@@ -11,6 +11,10 @@ const publicApi = {
 
     for (const [layerName, layer] of Object.entries(getLayers(root))) {
       if (!isSliced(layer)) {
+        if (layerName === 'app') {
+          // The app layer is the top-level layer, there's no need for public API.
+          continue
+        }
         for (const [segmentName, segment] of Object.entries(getSegments(layer))) {
           if (getIndex(segment) === undefined) {
             diagnostics.push({
diff --git a/packages/steiger/steiger.config.ts b/packages/steiger/steiger.config.ts
index d5662bb..2f0dd2f 100644
--- a/packages/steiger/steiger.config.ts
+++ b/packages/steiger/steiger.config.ts
@@ -1,5 +1,5 @@
 export default {
   rules: {
-    'public-api': 'off',
+    // 'public-api': 'off',
   },
 }