Reject empty or whitespace-only configKey values in include_assets builds

Author: JoshuaWhite1

packages/app/src/cli/services/build/steps/include-assets/copy-config-key-entry.test.ts

@@ -354,4 +354,44 @@ describe('copyConfigKeyEntry', () => {
       await expect(fileExists(joinPath(outDir, 'tools.json'))).resolves.toBe(true)
     })
   })
+
+  describe('value guard', () => {
+    test('throws when value is an empty string', async () => {
+      await inTemporaryDirectory(async (tmpDir) => {
+        const outDir = joinPath(tmpDir, 'out')
+        await mkdir(outDir)
+        const context = makeContext({assets: ''})
+        const promise = copyConfigKeyEntry({key: 'assets', baseDir: tmpDir, outputDir: outDir, context})
+        await expect(promise).rejects.toThrow(AbortError)
+        await expect(promise).rejects.toThrow(`'assets' can't be empty.`)
+      })
+    })
+
+    test('throws when value is whitespace-only', async () => {
+      await inTemporaryDirectory(async (tmpDir) => {
+        const outDir = joinPath(tmpDir, 'out')
+        await mkdir(outDir)
+        const context = makeContext({assets: '   '})
+        const promise = copyConfigKeyEntry({key: 'assets', baseDir: tmpDir, outputDir: outDir, context})
+        await expect(promise).rejects.toThrow(AbortError)
+        await expect(promise).rejects.toThrow(`'assets' can't be empty.`)
+      })
+    })
+
+    test('throws with the field name only, not the full configKey, when the key is nested', async () => {
+      await inTemporaryDirectory(async (tmpDir) => {
+        const outDir = joinPath(tmpDir, 'out')
+        await mkdir(outDir)
+        const context = makeContext({extension_points: [{assets: ''}]})
+        const promise = copyConfigKeyEntry({
+          key: 'extension_points[].assets',
+          baseDir: tmpDir,
+          outputDir: outDir,
+          context,
+        })
+        await expect(promise).rejects.toThrow(AbortError)
+        await expect(promise).rejects.toThrow(`'assets' can't be empty.`)
+      })
+    })
+  })
 })

packages/app/src/cli/services/build/steps/include-assets/copy-config-key-entry.ts

@@ -62,6 +62,13 @@ export async function copyConfigKeyEntry(config: {
   // should only be copied once; the pathMap entry is reused for all references.
   const uniquePaths = [...new Set(paths)]
 
+  const fieldName = key.split('.').pop()?.replace(/\[\]$/, '') ?? key
+  for (const sourcePath of uniquePaths) {
+    if (sourcePath.trim() === '') {
+      throw new AbortError(`'${fieldName}' can't be empty.`)
+    }
+  }
+
   // Process sequentially to avoid filesystem race conditions on shared output paths.
   const pathMap = new Map<string, string | string[]>()
   let filesCopied = 0