Fix crash if the prisma client directory exists but the prisma schema…

… doesn't (#4984)

* Fix crash if the prisma client directory existed but the prisma schema didn't

* Update wet-nails-move.md

.changeset/wet-nails-move.md

@@ -0,0 +1,5 @@
+---
+'@keystonejs/adapter-prisma': patch
+---
+
+Fixed crash if the prisma client directory exists but the prisma schema doesn't.

packages/adapter-prisma/lib/adapter-prisma.js

@@ -73,28 +73,28 @@ class PrismaAdapter extends BaseKeystoneAdapter {
     // 2a2. If they're different, generate and run a migration
     // 2b. If it doesn't exist, generate and run a migration
 
-    // // If any of our critical directories are missing, or if the schema has changed, then
-    // // we've got things to do.
-    if (
-      !fs.existsSync(this.clientPath) ||
-      !fs.existsSync(this.schemaPath) ||
-      fs.readFileSync(this.schemaPath, { encoding: 'utf-8' }) !== prismaSchema
-    ) {
-      if (fs.existsSync(this.clientPath)) {
-        const existing = fs.readFileSync(this.schemaPath, { encoding: 'utf-8' });
-        if (existing === prismaSchema) {
-          // If they're the same, we're golden
-          return;
-        }
+    // If any of our critical directories are missing, or if the schema has changed, then
+    // we've got things to do.
+
+    try {
+      const existing = fs.readFileSync(this.schemaPath, { encoding: 'utf-8' });
+      if (existing === prismaSchema && fs.existsSync(this.clientPath)) {
+        // If they're the same, we're golden
+        return;
+      }
+    } catch (err) {
+      if (err.code !== 'ENOENT') {
+        throw err;
       }
-      this._writePrismaSchema({ prismaSchema });
+    }
 
-      // Generate prisma client
-      await this._generatePrismaClient();
+    this._writePrismaSchema({ prismaSchema });
 
-      // Run prisma migrations
-      await this._runMigrations();
-    }
+    // Generate prisma client
+    await this._generatePrismaClient();
+
+    // Run prisma migrations
+    await this._runMigrations();
   }
 
   async _runMigrations() {