fix: build an empty schema when trying to scan a nonexistent directory

euberdeveloper/dree#51

Author: mikavilpas

packages/library/src/server/dirtree/index.test.ts

@@ -159,4 +159,37 @@ describe("dirtree", () => {
       export type MyTestDirectoryFile = z.infer<typeof testDirectoryFiles>"
     `)
   })
+
+  it("creates an empty schema when the directory cannot be read", async () => {
+    const tree = getDirectoryTree("nonexistent")
+    const result = await buildSchemaForDirectoryTree(tree, "MyDirectoryTree")
+    expect(result).toMatchInlineSnapshot(`
+      "
+      // Note: This file is autogenerated. Do not edit it directly.
+      //
+      // Describes the contents of the test directory, which is a blueprint for
+      // files and directories. Tests can create a unique, safe environment for
+      // interacting with the contents of such a directory.
+      //
+      // Having strong typing for the test directory contents ensures that tests can
+      // be written with confidence that the files and directories they expect are
+      // actually found. Otherwise the tests are brittle and can break easily.
+
+      import { z } from "zod"
+
+      export const MyDirectoryTreeSchema = z.object({
+        type: z.literal("directory"),
+        name: z.literal("root"),
+        contents: z.object({}),
+      })
+
+      export const MyDirectoryTreeContentsSchema = MyDirectoryTreeSchema.shape.contents
+      export type MyDirectoryTreeContentsSchemaType = z.infer<typeof MyDirectoryTreeSchema>
+
+      export type MyDirectoryTree = MyDirectoryTreeContentsSchemaType["contents"]
+
+      export const testDirectoryFiles = z.enum([])
+      export type MyTestDirectoryFile = z.infer<typeof testDirectoryFiles>"
+    `)
+  })
 })

packages/library/src/server/dirtree/index.ts

@@ -5,7 +5,7 @@ import { format, resolveConfig } from "prettier"
 import { fileURLToPath } from "url"
 import { jsonToZod } from "./json-to-zod.js"
 
-type TreeResult = { dree: Dree; allFiles: Dree[] }
+type TreeResult = { dree: Dree | undefined; allFiles: Dree[] }
 
 /** Convert a directory tree to a TypeScript type. This is useful for testing
  * as the initial state of the test directory is fully known in tests. */
@@ -25,9 +25,9 @@ export function getDirectoryTree(path: string): TreeResult {
     dir => {
       allFiles.push(dir)
     }
-  )
+  ) as Dree | null // https://github.com/euberdeveloper/dree/pull/51
 
-  return { dree: result, allFiles }
+  return { dree: result ?? undefined, allFiles }
 }
 
 type FileNode = {
@@ -63,10 +63,15 @@ export function convertDree(root: Dree): TreeNode {
 }
 
 export async function buildSchemaForDirectoryTree(result: TreeResult, name: string): Promise<string> {
-  const root = result.dree
-  assert(root.type === Type.DIRECTORY)
-  const node = convertDree(root)
-  const schema = (await jsonToZod(node, `${name}Schema`)).split("\n")
+  let root: TreeNode
+  if (result.dree) {
+    assert(result.dree.type === Type.DIRECTORY)
+    root = convertDree(result.dree)
+  } else {
+    // directory does not exist, or some other problem scanning it
+    root = { type: Type.DIRECTORY, name: "root", contents: {} }
+  }
+  const schema = (await jsonToZod(root, `${name}Schema`)).split("\n")
 
   const lines = `
 // Note: This file is autogenerated. Do not edit it directly.