fix(cli): improve error handling on missing extracted schema

packages/@sanity/cli/src/actions/typegen/generateAction.ts

@@ -1,4 +1,4 @@
-import {constants, open} from 'node:fs/promises'
+import {constants, open, stat} from 'node:fs/promises'
 import {join} from 'node:path'
 
 import {readConfig} from '@sanity/codegen'
@@ -45,6 +45,19 @@ export default async function typegenGenerateAction(
     flags.configPath || flags['config-path'] || 'sanity-typegen.json',
   )
 
+  try {
+    const {isFile} = await stat(codegenConfig.schema)
+    if (!isFile) {
+      throw new Error(`Schema path is not a file: ${codegenConfig.schema}`)
+    }
+  } catch (err) {
+    if (err.code === 'ENOENT') {
+      // If the user has not provided a specific schema path (eg we're using the default), give some help
+      const hint =
+        codegenConfig.schema === './schema.json' ? ` - did you run "sanity schema extract"?` : ''
+      throw new Error(`Schema file not found: ${codegenConfig.schema}${hint}`)
+    }
+  }
   const workerPath = await getCliWorkerPath('typegenGenerate')
 
   const spinner = output.spinner({}).start('Generating types')

packages/@sanity/cli/test/__fixtures__/v3/missing-typegen.json

@@ -0,0 +1,3 @@
+{
+  "schema": "./custom-schema.json"
+}

packages/@sanity/cli/test/__fixtures__/v3/working-schema.json

@@ -0,0 +1,84 @@
+[
+  {
+    "name": "person",
+    "type": "document",
+    "attributes": {
+      "_id": {
+        "type": "objectAttribute",
+        "value": {
+          "type": "string"
+        }
+      },
+      "_type": {
+        "type": "objectAttribute",
+        "value": {
+          "type": "string",
+          "value": "person"
+        }
+      },
+      "_createdAt": {
+        "type": "objectAttribute",
+        "value": {
+          "type": "string"
+        }
+      },
+      "_updatedAt": {
+        "type": "objectAttribute",
+        "value": {
+          "type": "string"
+        }
+      },
+      "_rev": {
+        "type": "objectAttribute",
+        "value": {
+          "type": "string"
+        }
+      },
+      "name": {
+        "type": "objectAttribute",
+        "value": {
+          "type": "string"
+        },
+        "optional": true
+      },
+      "slug": {
+        "type": "objectAttribute",
+        "value": {
+          "type": "inline",
+          "name": "slug"
+        },
+        "optional": true
+      }
+    }
+  },
+  {
+    "name": "slug",
+    "type": "type",
+    "value": {
+      "type": "object",
+      "attributes": {
+        "_type": {
+          "type": "objectAttribute",
+          "value": {
+            "type": "string",
+            "value": "slug"
+          }
+        },
+        "current": {
+          "type": "objectAttribute",
+          "value": {
+            "type": "string"
+          },
+          "optional": true
+        },
+        "source": {
+          "type": "objectAttribute",
+          "value": {
+            "type": "string"
+          },
+          "optional": true
+        }
+      }
+    }
+  }
+]

packages/@sanity/cli/test/__fixtures__/v3/working-typegen.json

@@ -0,0 +1,3 @@
+{
+  "schema": "./working-schema.json"
+}

packages/@sanity/cli/test/typegen.test.ts

@@ -0,0 +1,37 @@
+import {expect, test} from '@jest/globals'
+
+import {describeCliTest} from './shared/describe'
+import {runSanityCmdCommand} from './shared/environment'
+
+describeCliTest('CLI: `sanity typegen`', () => {
+  test('sanity typegen generate: missing schema, default path', async () => {
+    const err = await runSanityCmdCommand('v3', ['typegen', 'generate']).catch((error) => error)
+    expect(err.code).toBe(1)
+    expect(err.stderr).toContain('did you run "sanity schema extract"')
+    expect(err.stderr).toContain('Schema file not found')
+  })
+
+  test('sanity typegen generate: missing schema, custom path', async () => {
+    const err = await runSanityCmdCommand('v3', [
+      'typegen',
+      'generate',
+      '--config-path',
+      'missing-typegen.json',
+    ]).catch((error) => error)
+    expect(err.code).toBe(1)
+    expect(err.stderr).not.toContain('did you run "sanity schema extract"')
+    expect(err.stderr).toContain('custom-schema.json')
+  })
+
+  test('sanity typegen generate: working schema', async () => {
+    const result = await runSanityCmdCommand('v3', [
+      'typegen',
+      'generate',
+      '--config-path',
+      'working-typegen.json',
+    ])
+
+    expect(result.code).toBe(0)
+    expect(result.stdout).toContain('Generated TypeScript types for 2 schema types')
+  })
+})