fix: handle 0 value of the port option property

lib/Server.js

@@ -74,7 +74,7 @@ class Server {
   }
 
   static async getFreePort(port) {
-    if (port && port !== "auto") {
+    if (typeof port !== "undefined" && port !== null && port !== "auto") {
       return port;
     }
 

lib/options.json

@@ -554,7 +554,9 @@
     "Port": {
       "anyOf": [
         {
-          "type": "number"
+          "type": "number",
+          "minimum": 0,
+          "maximum": 65535
         },
         {
           "type": "string",

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

@@ -517,26 +517,36 @@ exports[`options validate should throw an error on the "port" option with '' val
  - options.port should be a non-empty string."
 `;
 
+exports[`options validate should throw an error on the "port" option with '-1' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.port should be >= 0 and <= 65535."
+`;
+
+exports[`options validate should throw an error on the "port" option with '65536' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.port should be >= 0 and <= 65535."
+`;
+
 exports[`options validate should throw an error on the "port" 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.port should be one of these:
-   number | non-empty string | \\"auto\\"
+   number (should be >= 0 and <= 65535) | non-empty string | \\"auto\\"
    -> Allows to specify a port to use.
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverport
    Details:
-    * options.port should be a number.
+    * options.port should be a number (should be >= 0 and <= 65535).
     * options.port should be a non-empty string.
     * options.port should be \\"auto\\"."
 `;
 
 exports[`options validate should throw an error on the "port" option with 'null' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.port should be one of these:
-   number | non-empty string | \\"auto\\"
+   number (should be >= 0 and <= 65535) | non-empty string | \\"auto\\"
    -> Allows to specify a port to use.
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverport
    Details:
-    * options.port should be a number.
+    * options.port should be a number (should be >= 0 and <= 65535).
     * options.port should be a non-empty string.
     * options.port should be \\"auto\\"."
 `;

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

@@ -517,26 +517,36 @@ exports[`options validate should throw an error on the "port" option with '' val
  - options.port should be a non-empty string."
 `;
 
+exports[`options validate should throw an error on the "port" option with '-1' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.port should be >= 0 and <= 65535."
+`;
+
+exports[`options validate should throw an error on the "port" option with '65536' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.port should be >= 0 and <= 65535."
+`;
+
 exports[`options validate should throw an error on the "port" 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.port should be one of these:
-   number | non-empty string | \\"auto\\"
+   number (should be >= 0 and <= 65535) | non-empty string | \\"auto\\"
    -> Allows to specify a port to use.
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverport
    Details:
-    * options.port should be a number.
+    * options.port should be a number (should be >= 0 and <= 65535).
     * options.port should be a non-empty string.
     * options.port should be \\"auto\\"."
 `;
 
 exports[`options validate should throw an error on the "port" option with 'null' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.port should be one of these:
-   number | non-empty string | \\"auto\\"
+   number (should be >= 0 and <= 65535) | non-empty string | \\"auto\\"
    -> Allows to specify a port to use.
    -> Read more at https://webpack.js.org/configuration/dev-server/#devserverport
    Details:
-    * options.port should be a number.
+    * options.port should be a number (should be >= 0 and <= 65535).
     * options.port should be a non-empty string.
     * options.port should be \\"auto\\"."
 `;