wrap function handlers to support independently exported handler (#30078)

i've been doing this pattern so i can call my handler from other functions and from unit tests

```ts
export async function listHandler(ctx: QueryCtx) {
  return await ctx.db.query("messages").collect();
};

export const list = query({
  handler: listHandler,
});
```

unfortunately, this makes both `list` and `listHandler` get analyzed as callable queries -- in the dashboard function view, the function runner, `npx convex run`, in components codegen, etc.
l
To fix, we can avoid `query`, `mutation`, and friends modifying the handler in place. We re-wrap in a separate function, and attach the handler as `.handler` on this separate function so analyze can get source maps from it.

Tested that the dashboard still finds the function just fine.

<img width="1321" alt="Screenshot 2024-09-23 at 5 30 25 PM" src="https://github.com/user-attachments/assets/c6e37cc1-110b-4097-b817-661f1917e62d">

GitOrigin-RevId: ff0ecfdd44bf40f38ef9c377d86694b3747c15a4

Author: ldanilek

crates/isolate/src/environment/analyze.rs

@@ -623,19 +623,33 @@ fn udf_analyze<RT: Runtime>(
             },
         };
 
+        let handler_str = strings::_handler.create(scope)?;
+        let handler = match function.get(scope, handler_str.into()) {
+            Some(handler_value) if handler_value.is_function() => {
+                let handler: v8::Local<v8::Function> = handler_value.try_into()?;
+                handler
+            },
+            Some(handler_value) if handler_value.is_undefined() => function,
+            Some(_) => {
+                let message = format!("{module_path:?}:{property_name}.handler is not a function.");
+                return Ok(Err(JsError::from_message(message)));
+            },
+            None => function,
+        };
+
         // These are originally zero-indexed, so we just add 1
-        let lineno = function
+        let lineno = handler
             .get_script_line_number()
             .ok_or_else(|| anyhow!("Failed to get function line number"))?
             + 1;
-        let linecol = function
+        let linecol = handler
             .get_script_column_number()
             .ok_or_else(|| anyhow!("Failed to get function column number"))?
             + 1;
 
         // Get the appropriate source map to look in
         let (fn_source_map, fn_canon_path) = {
-            let resource_name_val = function
+            let resource_name_val = handler
                 .get_script_origin()
                 .resource_name()
                 .ok_or(anyhow!("resource_name was None"))?;
@@ -853,19 +867,33 @@ fn http_analyze<RT: Runtime>(
             return routes_error(format!("arr[{}][2] not an HttpAction", i).as_str());
         };
 
+        let handler_str = strings::_handler.create(scope)?;
+        let handler = match function.get(scope, handler_str.into()) {
+            Some(handler_value) if handler_value.is_function() => {
+                let handler: v8::Local<v8::Function> = handler_value.try_into()?;
+                handler
+            },
+            Some(handler_value) if handler_value.is_undefined() => function,
+            Some(_) => {
+                let message = format!("arr[{}][2].handler is not a function", i);
+                return Ok(Err(JsError::from_message(message)));
+            },
+            None => function,
+        };
+
         // These are originally zero-indexed, so we just add 1
-        let lineno = function
+        let lineno = handler
             .get_script_line_number()
             .ok_or_else(|| anyhow!("Failed to get function line number"))?
             + 1;
-        let linecol = function
+        let linecol = handler
             .get_script_column_number()
             .ok_or_else(|| anyhow!("Failed to get function column number"))?
             + 1;
 
         // Get the appropriate source map to look in
         let (fn_source_map, fn_canon_path) = {
-            let resource_name_val = function
+            let resource_name_val = handler
                 .get_script_origin()
                 .resource_name()
                 .ok_or(anyhow!("resource_name was None"))?;

crates/isolate/src/strings.rs

@@ -55,6 +55,7 @@ macro_rules! declare_strings {
 // identifier as a string, or explicitly name the string with the `$name =>
 // $string` syntax.
 declare_strings!(
+    _handler,
     _onInitCallbacks,
     Convex,
     asyncOp,

npm-packages/convex/src/server/impl/registration_impl.ts

@@ -173,11 +173,13 @@ function exportReturns(functionDefinition: FunctionDefinition) {
 export const mutationGeneric: MutationBuilder<any, "public"> = ((
   functionDefinition: FunctionDefinition,
 ) => {
-  const func = (
+  const handler = (
     typeof functionDefinition === "function"
       ? functionDefinition
       : functionDefinition.handler
   ) as RegisteredMutation<"public", any, any>;
+  const func = ((ctx: any, args: any) =>
+    handler(ctx, args)) as RegisteredMutation<"public", any, any>;
 
   // Helpful runtime check that functions are only be registered once
   if (func.isRegistered) {
@@ -190,6 +192,7 @@ export const mutationGeneric: MutationBuilder<any, "public"> = ((
   func.invokeMutation = (argsStr) => invokeMutation(func, argsStr);
   func.exportArgs = exportArgs(functionDefinition);
   func.exportReturns = exportReturns(functionDefinition);
+  func._handler = handler;
   return func;
 }) as MutationBuilder<any, "public">;
 
@@ -209,11 +212,13 @@ export const mutationGeneric: MutationBuilder<any, "public"> = ((
 export const internalMutationGeneric: MutationBuilder<any, "internal"> = ((
   functionDefinition: FunctionDefinition,
 ) => {
-  const func = (
+  const handler = (
     typeof functionDefinition === "function"
       ? functionDefinition
       : functionDefinition.handler
   ) as RegisteredMutation<"internal", any, any>;
+  const func = ((ctx: any, args: any) =>
+    handler(ctx, args)) as RegisteredMutation<"internal", any, any>;
 
   // Helpful runtime check that functions are only be registered once
   if (func.isRegistered) {
@@ -226,6 +231,7 @@ export const internalMutationGeneric: MutationBuilder<any, "internal"> = ((
   func.invokeMutation = (argsStr) => invokeMutation(func, argsStr);
   func.exportArgs = exportArgs(functionDefinition);
   func.exportReturns = exportReturns(functionDefinition);
+  func._handler = handler;
   return func;
 }) as MutationBuilder<any, "internal">;
 
@@ -263,11 +269,16 @@ async function invokeQuery<
 export const queryGeneric: QueryBuilder<any, "public"> = ((
   functionDefinition: FunctionDefinition,
 ) => {
-  const func = (
+  const handler = (
     typeof functionDefinition === "function"
       ? functionDefinition
       : functionDefinition.handler
   ) as RegisteredQuery<"public", any, any>;
+  const func = ((ctx: any, args: any) => handler(ctx, args)) as RegisteredQuery<
+    "public",
+    any,
+    any
+  >;
 
   // Helpful runtime check that functions are only be registered once
   if (func.isRegistered) {
@@ -280,6 +291,7 @@ export const queryGeneric: QueryBuilder<any, "public"> = ((
   func.invokeQuery = (argsStr) => invokeQuery(func, argsStr);
   func.exportArgs = exportArgs(functionDefinition);
   func.exportReturns = exportReturns(functionDefinition);
+  func._handler = handler;
   return func;
 }) as QueryBuilder<any, "public">;
 
@@ -299,11 +311,16 @@ export const queryGeneric: QueryBuilder<any, "public"> = ((
 export const internalQueryGeneric: QueryBuilder<any, "internal"> = ((
   functionDefinition: FunctionDefinition,
 ) => {
-  const func = (
+  const handler = (
     typeof functionDefinition === "function"
       ? functionDefinition
       : functionDefinition.handler
   ) as RegisteredQuery<"internal", any, any>;
+  const func = ((ctx: any, args: any) => handler(ctx, args)) as RegisteredQuery<
+    "internal",
+    any,
+    any
+  >;
 
   // Helpful runtime check that functions are only be registered once
   if (func.isRegistered) {
@@ -316,6 +333,7 @@ export const internalQueryGeneric: QueryBuilder<any, "internal"> = ((
   func.invokeQuery = (argsStr) => invokeQuery(func as any, argsStr);
   func.exportArgs = exportArgs(functionDefinition);
   func.exportReturns = exportReturns(functionDefinition);
+  func._handler = handler;
   return func;
 }) as QueryBuilder<any, "internal">;
 
@@ -349,11 +367,13 @@ async function invokeAction<
 export const actionGeneric: ActionBuilder<any, "public"> = ((
   functionDefinition: FunctionDefinition,
 ) => {
-  const func = (
+  const handler = (
     typeof functionDefinition === "function"
       ? functionDefinition
       : functionDefinition.handler
   ) as RegisteredAction<"public", any, any>;
+  const func = ((ctx: any, args: any) =>
+    handler(ctx, args)) as RegisteredAction<"public", any, any>;
 
   // Helpful runtime check that functions are only be registered once
   if (func.isRegistered) {
@@ -367,6 +387,7 @@ export const actionGeneric: ActionBuilder<any, "public"> = ((
     invokeAction(func, requestId, argsStr);
   func.exportArgs = exportArgs(functionDefinition);
   func.exportReturns = exportReturns(functionDefinition);
+  func._handler = handler;
   return func;
 }) as ActionBuilder<any, "public">;
 
@@ -384,11 +405,13 @@ export const actionGeneric: ActionBuilder<any, "public"> = ((
 export const internalActionGeneric: ActionBuilder<any, "internal"> = ((
   functionDefinition: FunctionDefinition,
 ) => {
-  const func = (
+  const handler = (
     typeof functionDefinition === "function"
       ? functionDefinition
       : functionDefinition.handler
   ) as RegisteredAction<"internal", any, any>;
+  const func = ((ctx: any, args: any) =>
+    handler(ctx, args)) as RegisteredAction<"internal", any, any>;
 
   // Helpful runtime check that functions are only be registered once
   if (func.isRegistered) {
@@ -402,6 +425,7 @@ export const internalActionGeneric: ActionBuilder<any, "internal"> = ((
     invokeAction(func, requestId, argsStr);
   func.exportArgs = exportArgs(functionDefinition);
   func.exportReturns = exportReturns(functionDefinition);
+  func._handler = handler;
   return func;
 }) as ActionBuilder<any, "internal">;
 
@@ -437,7 +461,9 @@ export const httpActionGeneric = (
     request: Request,
   ) => Promise<Response>,
 ): PublicHttpAction => {
-  const q = func as unknown as PublicHttpAction;
+  const handler = func as unknown as PublicHttpAction;
+  const q = ((ctx: any, request: any) =>
+    handler(ctx, request)) as PublicHttpAction;
   // Helpful runtime check that functions are only be registered once
   if (q.isRegistered) {
     throw new Error("Function registered twice " + func);
@@ -446,6 +472,7 @@ export const httpActionGeneric = (
   q.isRegistered = true;
   q.isHttp = true;
   q.invokeHttpAction = (request) => invokeHttpAction(func as any, request);
+  q._handler = func;
   return q;
 };
 

npm-packages/convex/src/server/registration.ts

@@ -363,6 +363,9 @@ export type RegisteredMutation<
 
   /** @internal */
   exportReturns(): string;
+
+  /** @internal */
+  _handler: (ctx: GenericMutationCtx<any>, args: Args) => Returns;
 } & VisibilityProperties<Visibility>;
 
 /**
@@ -392,6 +395,9 @@ export type RegisteredQuery<
 
   /** @internal */
   exportReturns(): string;
+
+  /** @internal */
+  _handler: (ctx: GenericQueryCtx<any>, args: Args) => Returns;
 } & VisibilityProperties<Visibility>;
 
 /**
@@ -421,6 +427,9 @@ export type RegisteredAction<
 
   /** @internal */
   exportReturns(): string;
+
+  /** @internal */
+  _handler: (ctx: GenericActionCtx<any>, args: Args) => Returns;
 } & VisibilityProperties<Visibility>;
 
 /**
@@ -438,6 +447,8 @@ export type PublicHttpAction = {
 
   /** @internal */
   invokeHttpAction(request: Request): Promise<Response>;
+  /** @internal */
+  _handler: (ctx: GenericActionCtx<any>, request: Request) => Promise<Response>;
 };
 
 /**