From 7afecf0f85d0cea0c0b547dd26c93b8d35d232ff Mon Sep 17 00:00:00 2001
From: Pierre Tachoire <pierre@lightpanda.io>
Date: Thu, 9 Oct 2025 11:23:19 +0200
Subject: [PATCH] move mod specifier resolution js/context => script manager

---
 src/browser/ScriptManager.zig        | 10 ++++++++++
 src/browser/html/elements.zig        |  1 +
 src/browser/js/Context.zig           |  9 +++------
 src/tests/html/script/importmap.html | 24 ++++++++++++++++++++++++
 4 files changed, 38 insertions(+), 6 deletions(-)
 create mode 100644 src/tests/html/script/importmap.html

diff --git a/src/browser/ScriptManager.zig b/src/browser/ScriptManager.zig
index 06b6ca1d..3ee86be6 100644
--- a/src/browser/ScriptManager.zig
+++ b/src/browser/ScriptManager.zig
@@ -248,6 +248,16 @@ pub fn addFromElement(self: *ScriptManager, element: *parser.Element, comptime c
     });
 }
 
+// Resolve a module specifier to an valid URL.
+pub fn resolveSpecifier(_: *ScriptManager, arena: Allocator, specifier: []const u8, base: []const u8) ![:0]const u8 {
+    return URL.stitch(
+        arena,
+        specifier,
+        base,
+        .{ .alloc = .if_needed, .null_terminated = true },
+    );
+}
+
 pub fn getModule(self: *ScriptManager, url: [:0]const u8, referrer: []const u8) !void {
     const gop = try self.sync_modules.getOrPut(self.allocator, url);
     if (gop.found_existing) {
diff --git a/src/browser/html/elements.zig b/src/browser/html/elements.zig
index 0fc5502f..e9e95fdf 100644
--- a/src/browser/html/elements.zig
+++ b/src/browser/html/elements.zig
@@ -1353,6 +1353,7 @@ test "Browser: HTML.HtmlScriptElement" {
     try testing.htmlRunner("html/script/inline_defer.html");
     try testing.htmlRunner("html/script/import.html");
     try testing.htmlRunner("html/script/dynamic_import.html");
+    try testing.htmlRunner("html/script/importmap.html");
 }
 
 test "Browser: HTML.HtmlSlotElement" {
diff --git a/src/browser/js/Context.zig b/src/browser/js/Context.zig
index 8d298f0d..46c6261f 100644
--- a/src/browser/js/Context.zig
+++ b/src/browser/js/Context.zig
@@ -251,11 +251,10 @@ pub fn module(self: *Context, comptime want_result: bool, src: []const u8, url:
         for (0..requests.length()) |i| {
             const req = requests.get(v8_context, @intCast(i)).castTo(v8.ModuleRequest);
             const specifier = try self.jsStringToZig(req.getSpecifier(), .{});
-            const normalized_specifier = try @import("../../url.zig").stitch(
+            const normalized_specifier = try self.script_manager.?.resolveSpecifier(
                 self.call_arena,
                 specifier,
                 owned_url,
-                .{ .alloc = .if_needed, .null_terminated = true },
             );
             const gop = try self.module_cache.getOrPut(self.arena, normalized_specifier);
             if (!gop.found_existing) {
@@ -1127,11 +1126,10 @@ pub fn dynamicModuleCallback(
         return @constCast(self.rejectPromise("Out of memory").handle);
     };
 
-    const normalized_specifier = @import("../../url.zig").stitch(
+    const normalized_specifier = self.script_manager.?.resolveSpecifier(
         self.arena, // might need to survive until the module is loaded
         specifier,
         resource,
-        .{ .alloc = .if_needed, .null_terminated = true },
     ) catch |err| {
         log.err(.app, "OOM", .{ .err = err, .src = "dynamicModuleCallback3" });
         return @constCast(self.rejectPromise("Out of memory").handle);
@@ -1171,11 +1169,10 @@ fn _resolveModuleCallback(self: *Context, referrer: v8.Module, specifier: []cons
         return error.UnknownModuleReferrer;
     };
 
-    const normalized_specifier = try @import("../../url.zig").stitch(
+    const normalized_specifier = try self.script_manager.?.resolveSpecifier(
         self.call_arena,
         specifier,
         referrer_path,
-        .{ .alloc = .if_needed, .null_terminated = true },
     );
 
     const gop = try self.module_cache.getOrPut(self.arena, normalized_specifier);
diff --git a/src/tests/html/script/importmap.html b/src/tests/html/script/importmap.html
new file mode 100644
index 00000000..d3f457a9
--- /dev/null
+++ b/src/tests/html/script/importmap.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+
+<script src="../../testing.js"></script>
+
+<script id=importmap type=importmap>
+    {
+      "imports": {
+        "core": "./import.js",
+      }
+    }
+</script>
+
+<script id=use_importmap type=module>
+  import * as im from 'core';
+  testing.expectEqual('hello', im.greeting);
+</script>
+
+<script id=cached_importmpa type=module>
+  // hopefully cached, who knows, no real way to assert this
+  // but at least it works.
+  import * as im from 'core';
+  testing.expectEqual('hello', im.greeting);
+</script>
+