Enable Page Symbol For /_error

packages/next/build/utils.ts

@@ -104,7 +104,7 @@ export async function printTreeView(
 
     messages.push([
       `${symbol} ${
-        item.startsWith('/_')
+        item === '/_app'
           ? ' '
           : pageInfo && pageInfo.static
           ? '○'

test/integration/build-output/fixtures/with-error-static/pages/_error.js

@@ -0,0 +1,3 @@
+export default function Error() {
+  return <p>An error has occurred</p>
+}

test/integration/build-output/fixtures/with-error-static/pages/index.js

@@ -0,0 +1,3 @@
+export default function() {
+  return <div />
+}

test/integration/build-output/test/index.test.js

@@ -72,7 +72,7 @@ describe('Build Output', () => {
       })
 
       expect(stdout).toMatch(/\/ [ ]* \d{1,} B/)
-      expect(stdout).toMatch(/\/_error [ ]* \d{1,} B/)
+      expect(stdout).toMatch(/λ \/_error [ ]* \d{1,} B/)
       expect(stdout).toMatch(/\+ shared by all [ 0-9.]* kB/)
       expect(stdout).toMatch(/ runtime\/main\.js [ 0-9.]* kB/)
 
@@ -83,4 +83,29 @@ describe('Build Output', () => {
       expect(stdout).toContain('○ /')
     })
   })
+
+  describe('Custom Static Error Output', () => {
+    const appDir = join(fixturesDir, 'with-error-static')
+
+    beforeAll(async () => {
+      await remove(join(appDir, '.next'))
+    })
+
+    // FIXME: this should be static
+    xit('should specify /_error as static', async () => {
+      const { stdout } = await nextBuild(appDir, [], {
+        stdout: true,
+      })
+      expect(stdout).toContain('○ /_error')
+    })
+
+    // This test is not really correct.
+    // Remove this when fixed and enable the above one.
+    it('should specify /_error as lambda even when static', async () => {
+      const { stdout } = await nextBuild(appDir, [], {
+        stdout: true,
+      })
+      expect(stdout).toContain('λ /_error')
+    })
+  })
 })