Fix URL.host setter not overriding port when set to default port

src/jsc/bindings/URLDecomposition.cpp

@@ -25,8 +25,6 @@
 
 #include "URLDecomposition.h"
 
-#include <wtf/text/StringToIntegerConversion.h>
-
 namespace WebCore {
 
 String URLDecomposition::origin() const
@@ -94,48 +92,14 @@ String URLDecomposition::host() const
     return fullURL().hostAndPort();
 }
 
-static unsigned countASCIIDigits(StringView string)
-{
-    unsigned length = string.length();
-    for (unsigned count = 0; count < length; ++count) {
-        if (!isASCIIDigit(string[count]))
-            return count;
-    }
-    return length;
-}
-
 void URLDecomposition::setHost(StringView value)
 {
     auto fullURL = this->fullURL();
     if (value.isEmpty() && !fullURL.protocolIsFile() && fullURL.hasSpecialScheme())
         return;
 
-    size_t separator = value.reverseFind(':');
-    if (!separator)
-        return;
+    fullURL.setHostAndPort(value);
 
-    if (fullURL.hasOpaquePath())
-        return;
-
-    // No port if no colon or rightmost colon is within the IPv6 section.
-    size_t ipv6Separator = value.reverseFind(']');
-    if (separator == notFound || (ipv6Separator != notFound && ipv6Separator > separator))
-        fullURL.setHost(value);
-    else {
-        // Multiple colons are acceptable only in case of IPv6.
-        if (value.find(':') != separator && ipv6Separator == notFound)
-            return;
-        unsigned portLength = countASCIIDigits(value.substring(separator + 1));
-        if (!portLength) {
-            fullURL.setHost(value.left(separator));
-        } else {
-            auto portNumber = parseInteger<uint16_t>(value.substring(separator + 1, portLength));
-            if (portNumber && WTF::isDefaultPortForProtocol(*portNumber, fullURL.protocol()))
-                fullURL.setHostAndPort(value.left(separator));
-            else
-                fullURL.setHostAndPort(value.left(separator + 1 + portLength));
-        }
-    }
     if (fullURL.isValid())
         setFullURL(fullURL);
 }
@@ -150,8 +114,6 @@ void URLDecomposition::setHostname(StringView host)
     auto fullURL = this->fullURL();
     if (host.isEmpty() && !fullURL.protocolIsFile() && fullURL.hasSpecialScheme())
         return;
-    if (fullURL.hasOpaquePath())
-        return;
     fullURL.setHost(host);
     if (fullURL.isValid())
         setFullURL(fullURL);

test/regression/issue/28661.test.ts

@@ -0,0 +1,46 @@
+// https://github.com/oven-sh/bun/issues/28661
+import { expect, test } from "bun:test";
+
+test("URL.host setter replaces port when set to default port", () => {
+  // HTTP with default port 80 — port should be stripped
+  const u1 = new URL("http://localhost:3000/foo");
+  u1.host = "some-domain:80";
+  expect(u1.href).toBe("http://some-domain/foo");
+  expect(u1.host).toBe("some-domain");
+  expect(u1.port).toBe("");
+
+  // HTTPS with default port 443 — port should be stripped
+  const u2 = new URL("https://localhost:3000/foo");
+  u2.host = "some-domain:443";
+  expect(u2.href).toBe("https://some-domain/foo");
+  expect(u2.host).toBe("some-domain");
+  expect(u2.port).toBe("");
+
+  // Non-default port should be kept
+  const u3 = new URL("http://localhost:3000/foo");
+  u3.host = "some-domain:8080";
+  expect(u3.href).toBe("http://some-domain:8080/foo");
+  expect(u3.host).toBe("some-domain:8080");
+  expect(u3.port).toBe("8080");
+
+  // Host without port only changes hostname, preserves existing port
+  const u4 = new URL("http://localhost:3000/foo");
+  u4.host = "some-domain";
+  expect(u4.href).toBe("http://some-domain:3000/foo");
+  expect(u4.host).toBe("some-domain:3000");
+  expect(u4.port).toBe("3000");
+
+  // FTP with default port 21
+  const u5 = new URL("ftp://localhost:3000/foo");
+  u5.host = "some-domain:21";
+  expect(u5.href).toBe("ftp://some-domain/foo");
+  expect(u5.host).toBe("some-domain");
+  expect(u5.port).toBe("");
+
+  // IPv6 with default port 80
+  const u6 = new URL("http://[::1]:3000/foo");
+  u6.host = "[::1]:80";
+  expect(u6.href).toBe("http://[::1]/foo");
+  expect(u6.host).toBe("[::1]");
+  expect(u6.port).toBe("");
+});