fix: don't allow empty array for allowedHosts option

lib/options.json

@@ -6,6 +6,7 @@
       "anyOf": [
         {
           "type": "array",
+          "minItems": 1,
           "items": {
             "$ref": "#/definitions/AllowedHostsItem"
           }

test/__snapshots__/validate-options.test.js.snap.webpack4

@@ -1,13 +1,23 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`options validate should throw an error on the "allowedHosts" option with '[""]' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.allowedHosts[0] should be an non-empty string."
+`;
+
+exports[`options validate should throw an error on the "allowedHosts" option with '[]' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.allowedHosts should be an non-empty array."
+`;
+
 exports[`options validate should throw an error on the "allowedHosts" option with '123' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.allowedHosts should be one of these:
-   [non-empty string, ...] | \\"auto\\" | \\"all\\" | non-empty string
+   [non-empty string, ...] (should not have fewer than 1 item) | \\"auto\\" | \\"all\\" | non-empty string
    -> Allows to enumerate the hosts from which access to the dev server are allowed (useful when you are proxying dev server, by default is 'auto'). https://webpack.js.org/configuration/dev-server/#devserverallowedhosts
    Details:
     * options.allowedHosts should be an array:
-      [non-empty string, ...]
+      [non-empty string, ...] (should not have fewer than 1 item)
     * options.allowedHosts should be one of these:
       \\"auto\\" | \\"all\\"
     * options.allowedHosts should be a non-empty string."
@@ -16,11 +26,11 @@ exports[`options validate should throw an error on the "allowedHosts" option wit
 exports[`options validate should throw an error on the "allowedHosts" option with 'false' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.allowedHosts should be one of these:
-   [non-empty string, ...] | \\"auto\\" | \\"all\\" | non-empty string
+   [non-empty string, ...] (should not have fewer than 1 item) | \\"auto\\" | \\"all\\" | non-empty string
    -> Allows to enumerate the hosts from which access to the dev server are allowed (useful when you are proxying dev server, by default is 'auto'). https://webpack.js.org/configuration/dev-server/#devserverallowedhosts
    Details:
     * options.allowedHosts should be an array:
-      [non-empty string, ...]
+      [non-empty string, ...] (should not have fewer than 1 item)
     * options.allowedHosts should be one of these:
       \\"auto\\" | \\"all\\"
     * options.allowedHosts should be a non-empty string."
@@ -29,11 +39,11 @@ exports[`options validate should throw an error on the "allowedHosts" option wit
 exports[`options validate should throw an error on the "allowedHosts" option with 'true' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.allowedHosts should be one of these:
-   [non-empty string, ...] | \\"auto\\" | \\"all\\" | non-empty string
+   [non-empty string, ...] (should not have fewer than 1 item) | \\"auto\\" | \\"all\\" | non-empty string
    -> Allows to enumerate the hosts from which access to the dev server are allowed (useful when you are proxying dev server, by default is 'auto'). https://webpack.js.org/configuration/dev-server/#devserverallowedhosts
    Details:
     * options.allowedHosts should be an array:
-      [non-empty string, ...]
+      [non-empty string, ...] (should not have fewer than 1 item)
     * options.allowedHosts should be one of these:
       \\"auto\\" | \\"all\\"
     * options.allowedHosts should be a non-empty string."

test/__snapshots__/validate-options.test.js.snap.webpack5

@@ -1,13 +1,23 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`options validate should throw an error on the "allowedHosts" option with '[""]' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.allowedHosts[0] should be an non-empty string."
+`;
+
+exports[`options validate should throw an error on the "allowedHosts" option with '[]' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.allowedHosts should be an non-empty array."
+`;
+
 exports[`options validate should throw an error on the "allowedHosts" option with '123' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.allowedHosts should be one of these:
-   [non-empty string, ...] | \\"auto\\" | \\"all\\" | non-empty string
+   [non-empty string, ...] (should not have fewer than 1 item) | \\"auto\\" | \\"all\\" | non-empty string
    -> Allows to enumerate the hosts from which access to the dev server are allowed (useful when you are proxying dev server, by default is 'auto'). https://webpack.js.org/configuration/dev-server/#devserverallowedhosts
    Details:
     * options.allowedHosts should be an array:
-      [non-empty string, ...]
+      [non-empty string, ...] (should not have fewer than 1 item)
     * options.allowedHosts should be one of these:
       \\"auto\\" | \\"all\\"
     * options.allowedHosts should be a non-empty string."
@@ -16,11 +26,11 @@ exports[`options validate should throw an error on the "allowedHosts" option wit
 exports[`options validate should throw an error on the "allowedHosts" option with 'false' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.allowedHosts should be one of these:
-   [non-empty string, ...] | \\"auto\\" | \\"all\\" | non-empty string
+   [non-empty string, ...] (should not have fewer than 1 item) | \\"auto\\" | \\"all\\" | non-empty string
    -> Allows to enumerate the hosts from which access to the dev server are allowed (useful when you are proxying dev server, by default is 'auto'). https://webpack.js.org/configuration/dev-server/#devserverallowedhosts
    Details:
     * options.allowedHosts should be an array:
-      [non-empty string, ...]
+      [non-empty string, ...] (should not have fewer than 1 item)
     * options.allowedHosts should be one of these:
       \\"auto\\" | \\"all\\"
     * options.allowedHosts should be a non-empty string."
@@ -29,11 +39,11 @@ exports[`options validate should throw an error on the "allowedHosts" option wit
 exports[`options validate should throw an error on the "allowedHosts" option with 'true' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.allowedHosts should be one of these:
-   [non-empty string, ...] | \\"auto\\" | \\"all\\" | non-empty string
+   [non-empty string, ...] (should not have fewer than 1 item) | \\"auto\\" | \\"all\\" | non-empty string
    -> Allows to enumerate the hosts from which access to the dev server are allowed (useful when you are proxying dev server, by default is 'auto'). https://webpack.js.org/configuration/dev-server/#devserverallowedhosts
    Details:
     * options.allowedHosts should be an array:
-      [non-empty string, ...]
+      [non-empty string, ...] (should not have fewer than 1 item)
     * options.allowedHosts should be one of these:
       \\"auto\\" | \\"all\\"
     * options.allowedHosts should be a non-empty string."

test/validate-options.test.js

@@ -167,7 +167,7 @@ const tests = {
   },
   allowedHosts: {
     success: ['auto', 'all', ['foo'], 'bar'],
-    failure: [true, false, 123],
+    failure: [true, false, 123, [], ['']],
   },
   headers: {
     success: [{}, { foo: 'bar' }, () => {}],