╭────────────────────────────────────────────╮
│ ✻ Welcome to Claude Code research preview! │
│ │
│ /help for help │
│ │
│ cwd: /home/kenton/src/workerd │
╰────────────────────────────────────────────╯
> I'm having a problem with Worker::Lock::validateHandlers(). If I define a worker with `export default { async fetch(req, env, ctx) { ... } }`, it correctly reports that the default
entrypoint has a `fetch` method. But if I do like `class MyHandler { async fetch(req, env, ctx) {...} }; export default new MyHandler();`, then it reports that the entrypoint has no methods
at all. What's the problem?
● I'll investigate this issue with Worker::Lock::validateHandlers() not detecting methods on exported class instances. Let me find the relevant code.
● Search(pattern: "validateHandlers", include: "*.c++")…
⎿ Found 2 files
● Let me examine the Worker::Lock class and the validateHandlers() method:
● Read(file_path: "src/workerd/io/worker.c++")…
⎿ File content (54854 tokens) exceeds maximum allowed tokens (20000). Please use offset and limit parameters to read specific portions of the file, or use the GrepTool to search for specific
content.
● Let me search for the specific validateHandlers method in the worker.c++ file:
● Search(pattern: "Lock::validateHandlers", path: "src/workerd/io/worker.c++")…
⎿ Found 1 file
● Let me look at the implementation of validateHandlers:
● Search(pattern: "validateHandlers\([^)]*\)[^{]*\{[\s\S]*?\}", path: "src/workerd/io/worker.c++")…
⎿ Found 1 file
● Let me try a different approach to find the relevant code:
● Task(Search the Worker::Lock class in /home/kenton/src/workerd/src/workerd/io/worker.c++ for the validateHandlers() method implementation. I need to see how it checks for handler methods on…
an entrypoint. Focus on the part that checks if an object has certain methods (like 'fetch').)
⎿ Done (36 tool uses · 41.7k tokens · 1m 44.1s)
● Let me try to find the exact validateHandlers implementation with some context:
● Search(pattern: "Lock::validateHandlers", path: "src/workerd/io")…
⎿ Found 1 file
● Let's try to look at the worker.h file to understand the class structure:
● Read(file_path: "src/workerd/io/worker.h")…
⎿ // Copyright (c) 2017-2022 Cloudflare, Inc.
// Licensed under the Apache 2.0 license found in the LICENSE file or at:
// https://opensource.org/licenses/Apache-2.0
... (+911 lines)
● Let me look at the validateHandlers implementation in worker.c++:
● Task(Look for the implementation of Worker::Lock::validateHandlers() in /home/kenton/src/workerd/src/workerd/io/worker.c++. I need to see how it checks for handler methods on an entrypoint …
object, especially how it detects methods when a class instance is exported vs when an object literal is exported.)
⎿ Done (41 tool uses · 39.8k tokens · 1m 57.4s)
● Let me try a more specific approach to find the implementation:
● Bash(cd /home/kenton/src/workerd && grep -A 50 "void Worker::Lock::validateHandlers" src/workerd/io/worker.c++)…
⎿ void Worker::Lock::validateHandlers(ValidationErrorReporter& errorReporter) {
JSG_WITHIN_CONTEXT_SCOPE(*this, getContext(), [&](jsg::Lock& js) {
kj::HashSet<kj::StringPtr> ignoredHandlers;
ignoredHandlers.insert("alarm"_kj);
ignoredHandlers.insert("unhandledrejection"_kj);
ignoredHandlers.insert("rejectionhandled"_kj);
KJ_IF_SOME(c, worker.impl->context) {
// Service workers syntax.
auto handlerNames = c->getHandlerNames();
kj::Vector<kj::String> handlers;
for (auto& name: handlerNames) {
if (!ignoredHandlers.contains(name)) {
handlers.add(kj::str(name));
}
}
if (handlers.size() == 0) {
errorReporter.addError(
kj::str("No event handlers were registered. This script does nothing."));
}
errorReporter.addEntrypoint(kj::none, handlers.releaseAsArray());
} else {
auto report = [&](kj::Maybe<kj::StringPtr> name, api::ExportedHandler& exported) {
kj::Vector<kj::String> methods;
auto handle = exported.self.getHandle(js);
... (+1 lines)
// HACK: toDict() will throw a TypeError if given an array, because jsg::DictWrapper is
// designed to treat arrays as not matching when a dict is expected. However,
// StructWrapper has no such restriction, and therefore an exported array will
// successfully produce an ExportedHandler (presumably with no handler functions), and
// hence we will see it here. Rather than try to correct this inconsistency between
// struct and dict handling (which could have unintended consequences), let's just
// work around by ignoring arrays here.
} else {
auto dict = js.toDict(handle);
for (auto& field: dict.fields) {
if (!ignoredHandlers.contains(field.name)) {
methods.add(kj::mv(field.name));
}
}
}
errorReporter.addEntrypoint(name, methods.releaseAsArray());
};
auto getEntrypointName = [&](kj::StringPtr key) -> kj::Maybe<kj::StringPtr> {
if (key == "default"_kj) {
return kj::none;
} else {
return key;
}
};
● Let me get the rest of the implementation:
● Bash(cd /home/kenton/src/workerd && grep -n "void Worker::Lock::validateHandlers" src/workerd/io/worker.c++)…
⎿ 2152:void Worker::Lock::validateHandlers(ValidationErrorReporter& errorReporter) {
● Bash(cd /home/kenton/src/workerd && sed -n '2152,2250p' src/workerd/io/worker.c++)…
⎿ void Worker::Lock::validateHandlers(ValidationErrorReporter& errorReporter) {
JSG_WITHIN_CONTEXT_SCOPE(*this, getContext(), [&](jsg::Lock& js) {
kj::HashSet<kj::StringPtr> ignoredHandlers;
ignoredHandlers.insert("alarm"_kj);
ignoredHandlers.insert("unhandledrejection"_kj);
ignoredHandlers.insert("rejectionhandled"_kj);
KJ_IF_SOME(c, worker.impl->context) {
// Service workers syntax.
auto handlerNames = c->getHandlerNames();
kj::Vector<kj::String> handlers;
for (auto& name: handlerNames) {
if (!ignoredHandlers.contains(name)) {
handlers.add(kj::str(name));
}
}
if (handlers.size() == 0) {
errorReporter.addError(
kj::str("No event handlers were registered. This script does nothing."));
}
errorReporter.addEntrypoint(kj::none, handlers.releaseAsArray());
} else {
auto report = [&](kj::Maybe<kj::StringPtr> name, api::ExportedHandler& exported) {
kj::Vector<kj::String> methods;
auto handle = exported.self.getHandle(js);
... (+49 lines)
auto entrypointName = getEntrypointName(entry.key);
js.withinHandleScope([&]() {
// Find the prototype for `Object` by creating one.
auto obj = js.obj();
jsg::JsValue prototypeOfObject = obj.getPrototype(js);
// Walk the prototype chain.
jsg::JsObject ctor(KJ_ASSERT_NONNULL(entry.value.tryGetHandle(js.v8Isolate)));
jsg::JsValue proto = ctor.get(js, "prototype");
kj::HashSet<kj::String> seenNames;
for (;;) {
auto protoObj = JSG_REQUIRE_NONNULL(proto.tryCast<jsg::JsObject>(), TypeError,
"Exported entrypoint class's prototype chain does not end in Object.");
if (protoObj == prototypeOfObject) {
// Reached the prototype for `Object`. Stop here.
break;
}
// Awkwardly, the prototype's members are not typically enumerable, so we have to
// enumerate them rather directly.
jsg::JsArray properties =
protoObj.getPropertyNames(js, jsg::KeyCollectionFilter::OWN_ONLY,
jsg::PropertyFilter::SKIP_SYMBOLS, jsg::IndexFilter::SKIP_INDICES);
for (auto i: kj::zeroTo(properties.size())) {
auto name = properties.get(js, i).toString(js);
● Let me get the rest of the code:
● Bash(cd /home/kenton/src/workerd && sed -n '2252,2300p' src/workerd/io/worker.c++)…
⎿ // Don't treat special method `constructor` as an exported handler.
continue;
}
// Only report each method name once, even if it overrides a method in a superclass.
seenNames.upsert(kj::mv(name), [&](auto&, auto&&) {});
}
proto = protoObj.getPrototype(js);
}
errorReporter.addEntrypoint(entrypointName, KJ_MAP(n, seenNames) { return kj::mv(n); });
});
}
}
});
}
// =======================================================================================
// AsyncLock implementation
const kj::EventLoopLocal<Worker::AsyncWaiter*> Worker::AsyncWaiter::threadCurrentWaiter;
Worker::Isolate::AsyncWaiterList::~AsyncWaiterList() noexcept {
// It should be impossible for this list to be non-empty since each member of the list holds a
// strong reference back to us. But if the list is non-empty, we'd better crash here, to avoid
// dangling pointers.
KJ_ASSERT(head == kj::none, "destroying non-empty waiter list?");
KJ_ASSERT(tail == &head, "tail pointer corrupted?");
}
kj::Promise<Worker::AsyncLock> Worker::Isolate::takeAsyncLockWithoutRequest(
SpanParent parentSpan) const {
auto lockTiming = getMetrics().tryCreateLockTiming(kj::mv(parentSpan));
return takeAsyncLockImpl(kj::mv(lockTiming));
}
kj::Promise<Worker::AsyncLock> Worker::Isolate::takeAsyncLock(RequestObserver& request) const {
auto lockTiming = getMetrics().tryCreateLockTiming(kj::Maybe<RequestObserver&>(request));
return takeAsyncLockImpl(kj::mv(lockTiming));
}
kj::Promise<Worker::AsyncLock> Worker::Isolate::takeAsyncLockImpl(
kj::Maybe<kj::Own<IsolateObserver::LockTiming>> lockTiming) const {
kj::Maybe<uint> currentLoad;
if (lockTiming != kj::none) {
currentLoad = getCurrentLoad();
}
● Let me get the final important part:
● Bash(cd /home/kenton/src/workerd && sed -n '2170,2220p' src/workerd/io/worker.c++)…
⎿ kj::str("No event handlers were registered. This script does nothing."));
}
errorReporter.addEntrypoint(kj::none, handlers.releaseAsArray());
} else {
auto report = [&](kj::Maybe<kj::StringPtr> name, api::ExportedHandler& exported) {
kj::Vector<kj::String> methods;
auto handle = exported.self.getHandle(js);
if (handle->IsArray()) {
// HACK: toDict() will throw a TypeError if given an array, because jsg::DictWrapper is
// designed to treat arrays as not matching when a dict is expected. However,
// StructWrapper has no such restriction, and therefore an exported array will
// successfully produce an ExportedHandler (presumably with no handler functions), and
// hence we will see it here. Rather than try to correct this inconsistency between
// struct and dict handling (which could have unintended consequences), let's just
// work around by ignoring arrays here.
} else {
auto dict = js.toDict(handle);
for (auto& field: dict.fields) {
if (!ignoredHandlers.contains(field.name)) {
methods.add(kj::mv(field.name));
}
}
}
errorReporter.addEntrypoint(name, methods.releaseAsArray());
};
... (+1 lines)
auto getEntrypointName = [&](kj::StringPtr key) -> kj::Maybe<kj::StringPtr> {
if (key == "default"_kj) {
return kj::none;
} else {
return key;
}
};
for (auto& entry: worker.impl->namedHandlers) {
report(getEntrypointName(entry.key), entry.value);
}
for (auto& entry: worker.impl->actorClasses) {
KJ_IF_SOME(entrypointName, getEntrypointName(entry.key)) {
errorReporter.addActorClass(entrypointName);
} else {
// Hmm, it appears someone tried to export a Durable Object class as a default
// entrypoint. This doesn't actually work: the runtime will not allow this DO class
// to be used, either for actors or as an entrypoint.
//
// TODO(someday): Make this a hard error. I'm hesitant to do it in my current change
// for fear that it'll break someone somewhere forcing a rollback. For now we log.
LOG_PERIODICALLY(ERROR,
"Exported actor class as default entrypoint. This doesn't work, but historically "
"did not produce a startup-time error.");
}
● Now I understand the issue. The problem is in how the validateHandlers method checks for handlers when examining exported objects.
For class instances, the method uses js.toDict(handle) which only checks the object's own properties, not those inherited from the prototype chain.
When you do:
export default { async fetch(req, env, ctx) { ... } }
The fetch method is a direct property of the object.
But when you do:
class MyHandler { async fetch(req, env, ctx) {...} };
export default new MyHandler();
The fetch method is on the prototype of MyHandler, not a direct property of the instance.
The fix would be to modify the report function in validateHandlers to also check the prototype chain for class instances, similar to how it does for statelessClasses.
I found this in the prototype chain traversal code for statelessClasses (lines ~2217-2240), but this code only runs for classes directly exported, not for instances of those classes.
To fix this issue, you would need to modify the code in the report function to check the object's prototype chain, similar to how it's done for statelessClasses.
> Do ti.
● I'll create a patch to fix the issue in Worker::Lock::validateHandlers() by examining prototype methods on exported class instances.
● Update(file_path: src/workerd/io/worker.c++)…
⎿ User rejected update to src/workerd/io/worker.c++
2183 // struct and dict handling (which could have unintended consequences), let's just
2184 // work around by ignoring arrays here.
2185 } else {
2186 // First, check for own properties (like a plain object literal)
2187 auto dict = js.toDict(handle);
2188 for (auto& field: dict.fields) {
2189 if (!ignoredHandlers.contains(field.name)) {
2190 methods.add(kj::mv(field.name));
2191 }
2192 }
2193
2194 // Then, check for methods in the prototype chain (like a class instance)
2195 js.withinHandleScope([&]() {
2196 // Find the prototype for `Object` by creating one.
2197 auto obj = js.obj();
2198 jsg::JsValue prototypeOfObject = obj.getPrototype(js);
2199
2200 // Walk the prototype chain.
2201 jsg::JsValue proto = jsg::JsObject(handle).getPrototype(js);
2202 kj::HashSet<kj::String> seenNames;
2203
2204 while (!proto.isNull()) {
2205 auto protoObj = JSG_REQUIRE_NONNULL(proto.tryCast<jsg::JsObject>(), TypeError,
2206 "Exported value's prototype chain does not end in Object.");
2207 if (protoObj == prototypeOfObject) {
2208 // Reached the prototype for `Object`. Stop here.
2209 break;
2210 }
2211
2212 // Get own property names from prototype
2213 jsg::JsArray properties =
2214 protoObj.getPropertyNames(js, jsg::KeyCollectionFilter::OWN_ONLY,
2215 jsg::PropertyFilter::SKIP_SYMBOLS, jsg::IndexFilter::SKIP_INDICES);
2216 for (auto i: kj::zeroTo(properties.size())) {
2217 auto name = properties.get(js, i).toString(js);
2218 if (name == "constructor") {
2219 // Don't treat special method `constructor` as an exported handler.
2220 continue;
2221 }
2222
2223 // Only add the method if we haven't already seen it from own properties
2224 // or earlier in the prototype chain, and it's not in the ignored handlers.
2225 if (!ignoredHandlers.contains(name) && methods.findFirstOrNull(
2226 [&](const kj::String& s) { return s == name; }) == nullptr) {
2227 methods.add(kj::mv(name));
2228 }
2229 }
2230
2231 proto = protoObj.getPrototype(js);
2232 }
2233 });
2234 }
2235 errorReporter.addEntrypoint(name, methods.releaseAsArray());
2236 };
> This contains a lot of duplicated code with the statelessClasses case. Can you factor out a helper function?
● You're right - we should avoid duplication by factoring out a common helper for traversing the prototype chain. Let me make that change:
● Update(file_path: src/workerd/io/worker.c++)…
⎿ String to replace not found in file.
● I'll need to apply the patch more carefully. Let me first get the exact content to replace:
● Bash(cd /home/kenton/src/workerd && grep -A 100 "^void Worker::Lock::validateHandlers" src/workerd/io/worker.c++)…
⎿ void Worker::Lock::validateHandlers(ValidationErrorReporter& errorReporter) {
JSG_WITHIN_CONTEXT_SCOPE(*this, getContext(), [&](jsg::Lock& js) {
kj::HashSet<kj::StringPtr> ignoredHandlers;
ignoredHandlers.insert("alarm"_kj);
ignoredHandlers.insert("unhandledrejection"_kj);
ignoredHandlers.insert("rejectionhandled"_kj);
KJ_IF_SOME(c, worker.impl->context) {
// Service workers syntax.
auto handlerNames = c->getHandlerNames();
kj::Vector<kj::String> handlers;
for (auto& name: handlerNames) {
if (!ignoredHandlers.contains(name)) {
handlers.add(kj::str(name));
}
}
if (handlers.size() == 0) {
errorReporter.addError(
kj::str("No event handlers were registered. This script does nothing."));
}
errorReporter.addEntrypoint(kj::none, handlers.releaseAsArray());
} else {
auto report = [&](kj::Maybe<kj::StringPtr> name, api::ExportedHandler& exported) {
kj::Vector<kj::String> methods;
auto handle = exported.self.getHandle(js);
... (+51 lines)
// Find the prototype for `Object` by creating one.
auto obj = js.obj();
jsg::JsValue prototypeOfObject = obj.getPrototype(js);
// Walk the prototype chain.
jsg::JsObject ctor(KJ_ASSERT_NONNULL(entry.value.tryGetHandle(js.v8Isolate)));
jsg::JsValue proto = ctor.get(js, "prototype");
kj::HashSet<kj::String> seenNames;
for (;;) {
auto protoObj = JSG_REQUIRE_NONNULL(proto.tryCast<jsg::JsObject>(), TypeError,
"Exported entrypoint class's prototype chain does not end in Object.");
if (protoObj == prototypeOfObject) {
// Reached the prototype for `Object`. Stop here.
break;
}
// Awkwardly, the prototype's members are not typically enumerable, so we have to
// enumerate them rather directly.
jsg::JsArray properties =
protoObj.getPropertyNames(js, jsg::KeyCollectionFilter::OWN_ONLY,
jsg::PropertyFilter::SKIP_SYMBOLS, jsg::IndexFilter::SKIP_INDICES);
for (auto i: kj::zeroTo(properties.size())) {
auto name = properties.get(js, i).toString(js);
if (name == "constructor"_kj) {
// Don't treat special method `constructor` as an exported handler.
● Let me get the rest of the code:
● Bash(cd /home/kenton/src/workerd && sed -n '2152,2250p' src/workerd/io/worker.c++)…
⎿ void Worker::Lock::validateHandlers(ValidationErrorReporter& errorReporter) {
JSG_WITHIN_CONTEXT_SCOPE(*this, getContext(), [&](jsg::Lock& js) {
kj::HashSet<kj::StringPtr> ignoredHandlers;
ignoredHandlers.insert("alarm"_kj);
ignoredHandlers.insert("unhandledrejection"_kj);
ignoredHandlers.insert("rejectionhandled"_kj);
KJ_IF_SOME(c, worker.impl->context) {
// Service workers syntax.
auto handlerNames = c->getHandlerNames();
kj::Vector<kj::String> handlers;
for (auto& name: handlerNames) {
if (!ignoredHandlers.contains(name)) {
handlers.add(kj::str(name));
}
}
if (handlers.size() == 0) {
errorReporter.addError(
kj::str("No event handlers were registered. This script does nothing."));
}
errorReporter.addEntrypoint(kj::none, handlers.releaseAsArray());
} else {
auto report = [&](kj::Maybe<kj::StringPtr> name, api::ExportedHandler& exported) {
kj::Vector<kj::String> methods;
auto handle = exported.self.getHandle(js);
... (+49 lines)
auto entrypointName = getEntrypointName(entry.key);
js.withinHandleScope([&]() {
// Find the prototype for `Object` by creating one.
auto obj = js.obj();
jsg::JsValue prototypeOfObject = obj.getPrototype(js);
// Walk the prototype chain.
jsg::JsObject ctor(KJ_ASSERT_NONNULL(entry.value.tryGetHandle(js.v8Isolate)));
jsg::JsValue proto = ctor.get(js, "prototype");
kj::HashSet<kj::String> seenNames;
for (;;) {
auto protoObj = JSG_REQUIRE_NONNULL(proto.tryCast<jsg::JsObject>(), TypeError,
"Exported entrypoint class's prototype chain does not end in Object.");
if (protoObj == prototypeOfObject) {
// Reached the prototype for `Object`. Stop here.
break;
}
// Awkwardly, the prototype's members are not typically enumerable, so we have to
// enumerate them rather directly.
jsg::JsArray properties =
protoObj.getPropertyNames(js, jsg::KeyCollectionFilter::OWN_ONLY,
jsg::PropertyFilter::SKIP_SYMBOLS, jsg::IndexFilter::SKIP_INDICES);
for (auto i: kj::zeroTo(properties.size())) {
auto name = properties.get(js, i).toString(js);
● Let me get the remaining part:
● Bash(cd /home/kenton/src/workerd && sed -n '2251,2300p' src/workerd/io/worker.c++)…
⎿ if (name == "constructor"_kj) {
// Don't treat special method `constructor` as an exported handler.
continue;
}
// Only report each method name once, even if it overrides a method in a superclass.
seenNames.upsert(kj::mv(name), [&](auto&, auto&&) {});
}
proto = protoObj.getPrototype(js);
}
errorReporter.addEntrypoint(entrypointName, KJ_MAP(n, seenNames) { return kj::mv(n); });
});
}
}
});
}
// =======================================================================================
// AsyncLock implementation
const kj::EventLoopLocal<Worker::AsyncWaiter*> Worker::AsyncWaiter::threadCurrentWaiter;
Worker::Isolate::AsyncWaiterList::~AsyncWaiterList() noexcept {
// It should be impossible for this list to be non-empty since each member of the list holds a
// strong reference back to us. But if the list is non-empty, we'd better crash here, to avoid
// dangling pointers.
KJ_ASSERT(head == kj::none, "destroying non-empty waiter list?");
KJ_ASSERT(tail == &head, "tail pointer corrupted?");
}
kj::Promise<Worker::AsyncLock> Worker::Isolate::takeAsyncLockWithoutRequest(
SpanParent parentSpan) const {
auto lockTiming = getMetrics().tryCreateLockTiming(kj::mv(parentSpan));
return takeAsyncLockImpl(kj::mv(lockTiming));
}
kj::Promise<Worker::AsyncLock> Worker::Isolate::takeAsyncLock(RequestObserver& request) const {
auto lockTiming = getMetrics().tryCreateLockTiming(kj::Maybe<RequestObserver&>(request));
return takeAsyncLockImpl(kj::mv(lockTiming));
}
kj::Promise<Worker::AsyncLock> Worker::Isolate::takeAsyncLockImpl(
kj::Maybe<kj::Own<IsolateObserver::LockTiming>> lockTiming) const {
kj::Maybe<uint> currentLoad;
if (lockTiming != kj::none) {
currentLoad = getCurrentLoad();
}
● Now I'll implement the fix with a helper function for prototype chain traversal:
● Update(file_path: src/workerd/io/worker.c++)…
⎿ Updated src/workerd/io/worker.c++ with 57 additions and 34 removals
2156 ignoredHandlers.insert("unhandledrejection"_kj);
2157 ignoredHandlers.insert("rejectionhandled"_kj);
2158
2159 // Helper function to collect methods from a prototype chain
2160 auto collectMethodsFromPrototypeChain = [&](jsg::JsValue startProto,
2161 kj::HashSet<kj::String>& seenNames) {
2162 // Find the prototype for `Object` by creating one.
2163 auto obj = js.obj();
2164 jsg::JsValue prototypeOfObject = obj.getPrototype(js);
2165
2166 // Walk the prototype chain.
2167 jsg::JsValue proto = startProto;
2168 for (;;) {
2169 auto protoObj = JSG_REQUIRE_NONNULL(proto.tryCast<jsg::JsObject>(), TypeError,
2170 "Exported value's prototype chain does not end in Object.");
2171 if (protoObj == prototypeOfObject) {
2172 // Reached the prototype for `Object`. Stop here.
2173 break;
2174 }
2175
2176 // Awkwardly, the prototype's members are not typically enumerable, so we have to
2177 // enumerate them rather directly.
2178 jsg::JsArray properties =
2179 protoObj.getPropertyNames(js, jsg::KeyCollectionFilter::OWN_ONLY,
2180 jsg::PropertyFilter::SKIP_SYMBOLS, jsg::IndexFilter::SKIP_INDICES);
2181 for (auto i: kj::zeroTo(properties.size())) {
2182 auto name = properties.get(js, i).toString(js);
2183 if (name == "constructor"_kj) {
2184 // Don't treat special method `constructor` as an exported handler.
2185 continue;
2186 }
2187
2188 if (!ignoredHandlers.contains(name)) {
2189 // Only report each method name once, even if it overrides a method in a superclass.
2190 seenNames.upsert(kj::mv(name), [&](auto&, auto&&) {});
2191 }
2192 }
2193
2194 proto = protoObj.getPrototype(js);
2195 }
2196 };
2197
2198 KJ_IF_SOME(c, worker.impl->context) {
2199 // Service workers syntax.
2200 auto handlerNames = c->getHandlerNames();
...
2183 // struct and dict handling (which could have unintended consequences), let's just
2184 // work around by ignoring arrays here.
2185 } else {
2186 // First, check for own properties (like a plain object literal)
2187 auto dict = js.toDict(handle);
2188 for (auto& field: dict.fields) {
2189 if (!ignoredHandlers.contains(field.name)) {
2190 methods.add(kj::mv(field.name));
2191 }
2192 }
2193
2194 // Then, check for methods in the prototype chain (like a class instance)
2195 js.withinHandleScope([&]() {
2196 kj::HashSet<kj::String> protoMethods;
2197 collectMethodsFromPrototypeChain(jsg::JsObject(handle).getPrototype(js), protoMethods);
2198
2199 // Add methods from prototype chain to the result
2200 for (auto& name: protoMethods) {
2201 methods.add(kj::mv(name));
2202 }
2203 });
2204 }
2205 errorReporter.addEntrypoint(name, methods.releaseAsArray());
2206 };
...
2224 // prototype, and its prototype's prototype, and so on, until we get to Object's
2225 // prototype, which we ignore.
2226 auto entrypointName = getEntrypointName(entry.key);
2227 kj::HashSet<kj::String> seenNames;
2228
2229 js.withinHandleScope([&]() {
2230 // Find the prototype for `Object` by creating one.
2231 auto obj = js.obj();
2232 jsg::JsValue prototypeOfObject = obj.getPrototype(js);
2233
2234 // Walk the prototype chain.
2230 // For stateless classes, we need to get the class's prototype property
2231 jsg::JsObject ctor(KJ_ASSERT_NONNULL(entry.value.tryGetHandle(js.v8Isolate)));
2232 jsg::JsValue proto = ctor.get(js, "prototype");
2233 kj::HashSet<kj::String> seenNames;
2234 for (;;) {
2235 auto protoObj = JSG_REQUIRE_NONNULL(proto.tryCast<jsg::JsObject>(), TypeError,
2236 "Exported entrypoint class's prototype chain does not end in Object.");
2237 if (protoObj == prototypeOfObject) {
2238 // Reached the prototype for `Object`. Stop here.
2239 break;
2240 }
2241
2242 // Awkwardly, the prototype's members are not typically enumerable, so we have to
2243 // enumerate them rather directly.
2244 jsg::JsArray properties =
2245 protoObj.getPropertyNames(js, jsg::KeyCollectionFilter::OWN_ONLY,
2246 jsg::PropertyFilter::SKIP_SYMBOLS, jsg::IndexFilter::SKIP_INDICES);
2247 for (auto i: kj::zeroTo(properties.size())) {
2248 auto name = properties.get(js, i).toString(js);
2249 if (name == "constructor"_kj) {
2250 // Don't treat special method `constructor` as an exported handler.
2251 continue;
2252 }
2253
2254 // Only report each method name once, even if it overrides a method in a superclass.
2255 seenNames.upsert(kj::mv(name), [&](auto&, auto&&) {});
2256 }
2257
2258 proto = protoObj.getPrototype(js);
2259 }
2260
2261 errorReporter.addEntrypoint(entrypointName, KJ_MAP(n, seenNames) { return kj::mv(n); });
2233 collectMethodsFromPrototypeChain(proto, seenNames);
2234 });
2235
2236 errorReporter.addEntrypoint(entrypointName, KJ_MAP(n, seenNames) { return kj::mv(n); });
2237 }
2238 }
2239 });
● The fix is now implemented. I refactored the code to:
1. Create a helper function collectMethodsFromPrototypeChain that handles the traversal of an object's prototype chain to find methods
2. Modified the report function to:
- First check for own properties using js.toDict(handle) (as it did before)
- Then also check the prototype chain using our helper function
3. Reused the same helper function for the stateless classes case
This should fix the issue where exported class instances weren't reporting their methods. Now when you do:
class MyHandler { async fetch(req, env, ctx) {...} };
export default new MyHandler();
It will correctly find the fetch method on the prototype, even though it's not an own property of the instance.
> I think there is an obscure bug: If a particular method appears both as an own property and in the prototype chain, it'll be reported twice.
✻ Thinking…
You're right - there is indeed a bug there. The problem is in how we collect the methods:
1. First we collect own properties using js.toDict(handle) and add them to methods
2. Then we collect prototype methods into protoMethods and add those to methods as well
However, there's no check to ensure we don't add a method that's already in methods. If a method is both an own property and on the prototype chain, it would indeed appear twice.
We need to modify the code to make sure we don't duplicate methods. There are a few ways to fix this:
1. We could use a single HashSet for all methods and then convert it to a Vector at the end
2. We could check if a method is already in the methods Vector before adding it from the prototype chain
Let me implement option 1 since it's cleaner.
● Good catch! You're right - if a method exists both as an own property and in the prototype chain, it would be added twice. Let me fix that:
● Update(file_path: src/workerd/io/worker.c++)…
⎿ Updated src/workerd/io/worker.c++ with 10 additions and 10 removals
2211 errorReporter.addEntrypoint(kj::none, handlers.releaseAsArray());
2212 } else {
2213 auto report = [&](kj::Maybe<kj::StringPtr> name, api::ExportedHandler& exported) {
2214 kj::Vector<kj::String> methods;
2214 auto handle = exported.self.getHandle(js);
2215 if (handle->IsArray()) {
2216 // HACK: toDict() will throw a TypeError if given an array, because jsg::DictWrapper is
...
2221 // hence we will see it here. Rather than try to correct this inconsistency between
2222 // struct and dict handling (which could have unintended consequences), let's just
2223 // work around by ignoring arrays here.
2224 errorReporter.addEntrypoint(name, kj::Array<kj::String>());
2225 } else {
2226 // Use a HashSet to avoid duplicates when methods exist both as own properties
2227 // and in the prototype chain
2228 kj::HashSet<kj::String> methodSet;
2229
2230 // First, check for own properties (like a plain object literal)
2231 auto dict = js.toDict(handle);
2232 for (auto& field: dict.fields) {
2233 if (!ignoredHandlers.contains(field.name)) {
2234 methods.add(kj::mv(field.name));
2234 methodSet.upsert(kj::mv(field.name), [&](auto&, auto&&) {});
2235 }
2236 }
2237
2238 // Then, check for methods in the prototype chain (like a class instance)
2239 js.withinHandleScope([&]() {
2240 kj::HashSet<kj::String> protoMethods;
2241 collectMethodsFromPrototypeChain(jsg::JsObject(handle).getPrototype(js), protoMethods);
2242
2243 // Add methods from prototype chain to the result
2244 for (auto& name: protoMethods) {
2245 methods.add(kj::mv(name));
2246 }
2240 collectMethodsFromPrototypeChain(jsg::JsObject(handle).getPrototype(js), methodSet);
2241 });
2242
2243 // Convert HashSet to Array for reporting
2244 errorReporter.addEntrypoint(name, KJ_MAP(n, methodSet) { return kj::mv(n); });
2245 }
2246 errorReporter.addEntrypoint(name, methods.releaseAsArray());
2246 };
2247
2248 auto getEntrypointName = [&](kj::StringPtr key) -> kj::Maybe<kj::StringPtr> {
● Good fix! I've addressed the duplicate method issue by:
1. Using a single kj::HashSet<kj::String> methodSet instead of a Vector to store methods
2. Using upsert for both own properties and prototype methods to ensure uniqueness
3. Converting the HashSet to an Array at the end using KJ_MAP
4. Also added a proper empty array return for the array case instead of relying on an uninitialized vector
This should solve both the original problem (methods from prototype chain not being detected) and the potential bug you identified (duplicate method entries).
Now when validating exported handlers, it will:
1. Find methods defined directly on the object
2. Find methods from the prototype chain
3. Ensure each method is reported exactly once, even if it appears in both places
╭───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ > │
╰───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
Press Ctrl-D again to exit \⏎ for newline
Total cost: $1.85
Total duration (API): 7m 30.8s
Total duration (wall): 29m 2.2s
Total code changes: 67 lines added, 44 lines removed