Fix url constructor

url, base were being joined in the wrong order. Switch to using URL.stitch if
a base is given.

src/browser/page.zig

@@ -145,7 +145,7 @@ pub const Page = struct {
 
         const file_src = blk: {
             if (base) |_base| {
-                break :blk try URL.stitch(self.arena, specifier, _base);
+                break :blk try URL.stitch(self.arena, specifier, _base, .{});
             } else break :blk specifier;
         };
 
@@ -451,7 +451,7 @@ pub const Page = struct {
 
         // if a base path is given, we resolve src using base.
         if (base) |_base| {
-            res_src = try URL.stitch(arena, src, _base);
+            res_src = try URL.stitch(arena, src, _base, .{});
         }
 
         var origin_url = &self.url;

src/browser/url/url.zig

@@ -50,7 +50,14 @@ pub const URL = struct {
         page: *Page,
     ) !URL {
         const arena = page.arena;
-        const raw = try std.mem.concat(arena, u8, &[_][]const u8{ url, base orelse "" });
+        var raw: []const u8 = undefined;
+        if (base) |b| {
+            raw = try @import("../../url.zig").URL.stitch(arena, url, b, .{
+                .alloc = .always,
+            });
+        } else {
+            raw = try arena.dupe(u8, url);
+        }
 
         const uri = std.Uri.parse(raw) catch return error.TypeError;
         return init(arena, uri);
@@ -276,4 +283,9 @@ test "Browser.URL" {
         .{ "url.searchParams.delete('a')", "undefined" },
         .{ "url.searchParams.get('a')", "" },
     }, .{});
+
+    try runner.testCases(&.{
+        .{ "var url = new URL('over?9000', 'https://lightpanda.io')", null },
+        .{ "url.href", "https://lightpanda.io/over?9000" },
+    }, .{});
 }

src/url.zig

@@ -83,12 +83,28 @@ pub const URL = struct {
         return WebApiURL.init(allocator, self.uri);
     }
 
+    const StitchOpts = struct {
+        alloc: AllocWhen = .if_needed,
+
+        const AllocWhen = enum {
+            always,
+            if_needed,
+        };
+    };
     /// Properly stitches two URL fragments together.
     ///
     /// For URLs with a path, it will replace the last entry with the src.
     /// For URLs without a path, it will add src as the path.
-    pub fn stitch(allocator: Allocator, src: []const u8, base: []const u8) ![]const u8 {
+    pub fn stitch(
+        allocator: Allocator,
+        src: []const u8,
+        base: []const u8,
+        opts: StitchOpts,
+    ) ![]const u8 {
         if (base.len == 0) {
+            if (opts.alloc == .always) {
+                return allocator.dupe(u8, src);
+            }
             return src;
         }
 
@@ -161,7 +177,7 @@ test "URL: Stitching Base & Src URLs (Basic)" {
 
     const base = "https://www.google.com/xyz/abc/123";
     const src = "something.js";
-    const result = try URL.stitch(allocator, src, base);
+    const result = try URL.stitch(allocator, src, base, .{});
     defer allocator.free(result);
     try testing.expectString("https://www.google.com/xyz/abc/something.js", result);
 }
@@ -171,7 +187,7 @@ test "URL: Stitching Base & Src URLs (Just Ending Slash)" {
 
     const base = "https://www.google.com/";
     const src = "something.js";
-    const result = try URL.stitch(allocator, src, base);
+    const result = try URL.stitch(allocator, src, base, .{});
     defer allocator.free(result);
     try testing.expectString("https://www.google.com/something.js", result);
 }
@@ -181,7 +197,7 @@ test "URL: Stitching Base & Src URLs (No Ending Slash)" {
 
     const base = "https://www.google.com";
     const src = "something.js";
-    const result = try URL.stitch(allocator, src, base);
+    const result = try URL.stitch(allocator, src, base, .{});
     defer allocator.free(result);
     try testing.expectString("https://www.google.com/something.js", result);
 }
@@ -191,7 +207,7 @@ test "URL: Stiching Base & Src URLs (Both Local)" {
 
     const base = "./abcdef/123.js";
     const src = "something.js";
-    const result = try URL.stitch(allocator, src, base);
+    const result = try URL.stitch(allocator, src, base, .{});
     defer allocator.free(result);
     try testing.expectString("./abcdef/something.js", result);
 }