AK: Fix bad parsing of some file:/// URLs with base URL

We were dropping the base URL path components in the resulting URL due
to mistakenly determining the input URL to start with a Windows drive
letter. Fix this, add a spec link, and a test.

2 files changed, 16 insertions, 1 deletions

diff --git a/AK/URLParser.cpp b/AK/URLParser.cpp
index 98f218a2ea..e39e0667fc 100644
--- a/AK/URLParser.cpp
+++ b/AK/URLParser.cpp
@@ -84,11 +84,12 @@ static Optional<String> parse_host(StringView input, bool is_not_special = false
     return ipv4_host;
 }
 
+// https://url.spec.whatwg.org/#start-with-a-windows-drive-letter
 constexpr bool starts_with_windows_drive_letter(StringView input)
 {
     if (input.length() < 2)
         return false;
-    if (!is_ascii_alpha(input[0]) && !(input[1] == ':' || input[1] == '|'))
+    if (!is_ascii_alpha(input[0]) || !(input[1] == ':' || input[1] == '|'))
         return false;
     if (input.length() == 2)
         return true;
diff --git a/Tests/AK/TestURL.cpp b/Tests/AK/TestURL.cpp
index a9fbf426a3..66569e9a7e 100644
--- a/Tests/AK/TestURL.cpp
+++ b/Tests/AK/TestURL.cpp
@@ -392,3 +392,17 @@ TEST_CASE(unicode)
     EXPECT(url.query().is_null());
     EXPECT(url.fragment().is_null());
 }
+
+TEST_CASE(complete_file_url_with_base)
+{
+    URL url { "file:///home/index.html" };
+    EXPECT(url.is_valid());
+    EXPECT_EQ(url.path(), "/home/index.html");
+    EXPECT_EQ(url.paths().size(), 2u);
+    EXPECT_EQ(url.paths()[0], "home");
+    EXPECT_EQ(url.paths()[1], "index.html");
+
+    auto sub_url = url.complete_url("js/app.js");
+    EXPECT(sub_url.is_valid());
+    EXPECT_EQ(sub_url.path(), "/home/js/app.js");
+}