Merge pull request #656 from lightpanda-io/module-exception

module: report module's evaluation error

Author: krichprollsch

build.zig.zon

@@ -13,8 +13,8 @@
             .hash = "tigerbeetle_io-0.0.0-ViLgxpyRBAB5BMfIcj3KMXfbJzwARs9uSl8aRy2OXULd",
         },
         .v8 = .{
-            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/6f1ee74a0e7002ea3568e337ab716c1e75c53769.tar.gz",
-            .hash = "v8-0.0.0-xddH6z2yAwCOPUGmy1IgXysI1yWt8ftd2Z3D5zp0I9tV",
+            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/240140e5b3e5a8e5e51cbdd36bc120bf28ae5c31.tar.gz",
+            .hash = "v8-0.0.0-xddH64eyAwBcX7e2x5tv9MhT0MgQbshP2rb19blo06Db",
         },
         //.v8 = .{ .path = "../zig-v8-fork" },
         //.tigerbeetle_io = .{ .path = "../tigerbeetle-io" },

src/browser/page.zig

@@ -638,7 +638,18 @@ pub const Page = struct {
             const src = self.src orelse "inline";
             const res = switch (self.kind) {
                 .javascript => page.scope.exec(body, src),
-                .module => page.scope.module(body, src),
+                .module => blk: {
+                    switch (try page.scope.module(body, src)) {
+                        .value => |v| break :blk v,
+                        .exception => |e| {
+                            log.info("eval module {s}: {s}", .{
+                                src,
+                                try e.exception(page.arena),
+                            });
+                            return error.JsErr;
+                        },
+                    }
+                },
             } catch {
                 if (try try_catch.err(page.arena)) |msg| {
                     log.info("eval script {s}: {s}", .{ src, msg });

src/runtime/js.zig

@@ -610,13 +610,12 @@ pub fn Env(comptime State: type, comptime WebApis: type) type {
 
             // compile and eval a JS module
             // It doesn't wait for callbacks execution
-            pub fn module(self: *Scope, src: []const u8, name: []const u8) !Value {
+            pub fn module(self: *Scope, src: []const u8, name: []const u8) !union(enum) { value: Value, exception: Exception } {
                 const context = self.context;
                 const m = try compileModule(self.isolate, src, name);
 
                 // instantiate
-                // TODO handle ResolveModuleCallback parameters to load module's
-                // dependencies.
+                // resolveModuleCallback loads module's dependencies.
                 const ok = m.instantiate(context, resolveModuleCallback) catch {
                     return error.ExecutionError;
                 };
@@ -626,8 +625,18 @@ pub fn Env(comptime State: type, comptime WebApis: type) type {
                 }
 
                 // evaluate
-                const value = m.evaluate(context) catch return error.ExecutionError;
-                return self.createValue(value);
+                const value = m.evaluate(context) catch {
+                    return .{ .exception = self.createException(m.getException()) };
+                };
+                return .{ .value = self.createValue(value) };
+            }
+
+            // Wrap a v8.Exception
+            fn createException(self: *const Scope, e: v8.Value) Exception {
+                return .{
+                    .inner = e,
+                    .scope = self,
+                };
             }
 
             // Wrap a v8.Value, largely so that we can provide a convenient
@@ -1133,6 +1142,17 @@ pub fn Env(comptime State: type, comptime WebApis: type) type {
 
         pub const RemoteObject = v8.RemoteObject;
 
+        pub const Exception = struct {
+            inner: v8.Value,
+            scope: *const Scope,
+
+            // the caller needs to deinit the string returned
+            pub fn exception(self: Exception, allocator: Allocator) ![]const u8 {
+                const scope = self.scope;
+                return try valueToString(allocator, self.inner, scope.isolate, scope.context);
+            }
+        };
+
         pub const Value = struct {
             value: v8.Value,
             scope: *const Scope,