Improves the messaging when configs fail validation

app/server/lib/config.ts

@@ -67,7 +67,16 @@ export class FileConfig<FileContents> {
       rawFileContents = JSON.parse(await Deps.readFile(configPath, 'utf8'));
     }
 
-    const fileContents = validator(rawFileContents);
+    let fileContents = null;
+
+    try {
+      fileContents = validator(rawFileContents);
+    } catch (error) {
+      const configError =
+        new ConfigValidationError(`Config at ${configPath} failed validation: ${error.message}`);
+      configError.cause = error;
+      throw configError;
+    }
 
     if (!fileContents) {
       throw new ConfigValidationError(`Config at ${configPath} failed validation - check the format?`);

app/server/lib/configCoreFileFormats.ts

@@ -46,9 +46,8 @@ export function convertToCoreFileContents(input: any): IGristCoreConfigFileLates
     configObject = upgradeV0toV1(configObject);
   }
 
-  if (checkers.IGristCoreConfigFileLatest.test(configObject)) {
-    return configObject;
-  }
+  // This will throw an exception if the config object is still not in the correct format.
+  checkers.IGristCoreConfigFileLatest.check(configObject);
 
-  return null;
+  return configObject;
 }

test/server/lib/configCoreFileFormats.ts

@@ -7,7 +7,7 @@ describe('convertToCoreFileContents', () => {
       version: "This is a random version number that will never exist",
     };
 
-    assert.isNull(convertToCoreFileContents(badConfig));
+    assert.throws(() => convertToCoreFileContents(badConfig));
   });
 
   // This is necessary to handle users who don't have a config file yet.