process: allow multiple uncaught exception capture calbacks

Author: Julien Gilli

doc/api/cli.md

@@ -754,7 +754,7 @@ greater than `4` (its current default value). For more information, see the
 [`--openssl-config`]: #cli_openssl_config_file
 [`Buffer`]: buffer.html#buffer_class_buffer
 [`SlowBuffer`]: buffer.html#buffer_class_slowbuffer
-[`process.setUncaughtExceptionCaptureCallback()`]: process.html#process_process_setuncaughtexceptioncapturecallback_fn
+[`process.setUncaughtExceptionCaptureCallback()`]: process.html#process_process_setuncaughtexceptioncapturecallback_owner_fn
 [Chrome DevTools Protocol]: https://chromedevtools.github.io/devtools-protocol/
 [REPL]: repl.html
 [ScriptCoverage]: https://chromedevtools.github.io/devtools-protocol/tot/Profiler#type-ScriptCoverage

doc/api/errors.md

@@ -803,23 +803,6 @@ A signing `key` was not provided to the [`sign.sign()`][] method.
 
 `c-ares` failed to set the DNS server.
 
-<a id="ERR_DOMAIN_CALLBACK_NOT_AVAILABLE"></a>
-### ERR_DOMAIN_CALLBACK_NOT_AVAILABLE
-
-The `domain` module was not usable since it could not establish the required
-error handling hooks, because
-[`process.setUncaughtExceptionCaptureCallback()`][] had been called at an
-earlier point in time.
-
-<a id="ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE"></a>
-### ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE
-
-[`process.setUncaughtExceptionCaptureCallback()`][] could not be called
-because the `domain` module has been loaded at an earlier point in time.
-
-The stack trace is extended to include the point in time at which the
-`domain` module had been loaded.
-
 <a id="ERR_ENCODING_INVALID_ENCODED_DATA"></a>
 ### ERR_ENCODING_INVALID_ENCODED_DATA
 
@@ -1720,15 +1703,6 @@ A `Transform` stream finished with data still in the write buffer.
 
 The initialization of a TTY failed due to a system error.
 
-<a id="ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET"></a>
-### ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET
-
-[`process.setUncaughtExceptionCaptureCallback()`][] was called twice,
-without first resetting the callback to `null`.
-
-This error is designed to prevent accidentally overwriting a callback registered
-from another module.
-
 <a id="ERR_UNESCAPED_CHARACTERS"></a>
 ### ERR_UNESCAPED_CHARACTERS
 
@@ -2153,7 +2127,6 @@ such as `process.stdout.on('data')`.
 [`new URL(input)`]: url.html#url_constructor_new_url_input_base
 [`new URLSearchParams(iterable)`]: url.html#url_constructor_new_urlsearchparams_iterable
 [`process.send()`]: process.html#process_process_send_message_sendhandle_options_callback
-[`process.setUncaughtExceptionCaptureCallback()`]: process.html#process_process_setuncaughtexceptioncapturecallback_fn
 [`readable._read()`]: stream.html#stream_readable_read_size_1
 [`require('crypto').setEngine()`]: crypto.html#crypto_crypto_setengine_engine_flags
 [`require()`]: modules.html#modules_require

doc/api/process.md

@@ -1807,11 +1807,12 @@ This function is only available on POSIX platforms (i.e. not Windows or
 Android).
 This feature is not available in [`Worker`][] threads.
 
-## process.setUncaughtExceptionCaptureCallback(fn)
+## process.setUncaughtExceptionCaptureCallback(owner, fn)
 <!-- YAML
 added: v9.3.0
 -->
 
+* `owner` {symbol}
 * `fn` {Function|null}
 
 The `process.setUncaughtExceptionCaptureCallback()` function sets a function
@@ -1824,12 +1825,7 @@ command line or set through [`v8.setFlagsFromString()`][], the process will
 not abort.
 
 To unset the capture function,
-`process.setUncaughtExceptionCaptureCallback(null)` may be used. Calling this
-method with a non-`null` argument while another capture function is set will
-throw an error.
-
-Using this function is mutually exclusive with using the deprecated
-[`domain`][] built-in module.
+`process.setUncaughtExceptionCaptureCallback(owner, null)` may be used.
 
 ## process.stderr
 
@@ -2137,7 +2133,6 @@ cases:
 [`Worker`]: worker_threads.html#worker_threads_class_worker
 [`console.error()`]: console.html#console_console_error_data_args
 [`console.log()`]: console.html#console_console_log_data_args
-[`domain`]: domain.html
 [`net.Server`]: net.html#net_class_net_server
 [`net.Socket`]: net.html#net_class_net_socket
 [`NODE_OPTIONS`]: cli.html#cli_node_options_options
@@ -2150,7 +2145,7 @@ cases:
 [`process.hrtime()`]: #process_process_hrtime_time
 [`process.hrtime.bigint()`]: #process_process_hrtime_bigint
 [`process.kill()`]: #process_process_kill_pid_signal
-[`process.setUncaughtExceptionCaptureCallback()`]: process.html#process_process_setuncaughtexceptioncapturecallback_fn
+[`process.setUncaughtExceptionCaptureCallback()`]: process.html#process_process_setuncaughtexceptioncapturecallback_owner_fn
 [`promise.catch()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/catch
 [`require()`]: globals.html#globals_require
 [`require.main`]: modules.html#modules_accessing_the_main_module

doc/api/repl.md

@@ -146,11 +146,8 @@ global or scoped variable, the input `fs` will be evaluated on-demand as
 The REPL uses the [`domain`][] module to catch all uncaught exceptions for that
 REPL session.
 
-This use of the [`domain`][] module in the REPL has these side effects:
-
-* Uncaught exceptions do not emit the [`'uncaughtException'`][] event.
-* Trying to use [`process.setUncaughtExceptionCaptureCallback()`][] throws
-  an [`ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE`][] error.
+This use of the [`domain`][] module in the REPL has the side effects of making
+uncaught exceptions not emit the [`'uncaughtException'`][] event.
 
 #### Assignment of the `_` (underscore) variable
 <!-- YAML
@@ -627,9 +624,7 @@ For an example of running a REPL instance over [curl(1)][], see:
 
 [`'uncaughtException'`]: process.html#process_event_uncaughtexception
 [`--experimental-repl-await`]: cli.html#cli_experimental_repl_await
-[`ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE`]: errors.html#errors_err_domain_cannot_set_uncaught_exception_capture
 [`domain`]: domain.html
-[`process.setUncaughtExceptionCaptureCallback()`]: process.html#process_process_setuncaughtexceptioncapturecallback_fn
 [`readline.InterfaceCompleter`]: readline.html#readline_use_of_the_completer_function
 [`readline.Interface`]: readline.html#readline_class_interface
 [`repl.ReplServer`]: #repl_class_replserver

lib/domain.js

@@ -29,12 +29,12 @@
 const util = require('util');
 const EventEmitter = require('events');
 const {
-  ERR_DOMAIN_CALLBACK_NOT_AVAILABLE,
-  ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE,
   ERR_UNHANDLED_ERROR
 } = require('internal/errors').codes;
 const { createHook } = require('async_hooks');
 
+const CAPTURE_CB_KEY = Symbol('domain');
+
 // overwrite process.domain with a getter/setter that will allow for more
 // effective optimizations
 var _domain = [null];
@@ -74,23 +74,7 @@ const asyncHook = createHook({
   }
 });
 
-// When domains are in use, they claim full ownership of the
-// uncaught exception capture callback.
-if (process.hasUncaughtExceptionCaptureCallback()) {
-  throw new ERR_DOMAIN_CALLBACK_NOT_AVAILABLE();
-}
-
-// Get the stack trace at the point where `domain` was required.
-// eslint-disable-next-line no-restricted-syntax
-const domainRequireStack = new Error('require(`domain`) at this point').stack;
-
 const { setUncaughtExceptionCaptureCallback } = process;
-process.setUncaughtExceptionCaptureCallback = function(fn) {
-  const err = new ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE();
-  err.stack = err.stack + '\n' + '-'.repeat(40) + '\n' + domainRequireStack;
-  throw err;
-};
-
 
 let sendMakeCallbackDeprecation = false;
 function emitMakeCallbackDeprecation() {
@@ -125,10 +109,10 @@ internalBinding('domain').enable(topLevelDomainCallback);
 
 function updateExceptionCapture() {
   if (stack.every((domain) => domain.listenerCount('error') === 0)) {
-    setUncaughtExceptionCaptureCallback(null);
+    setUncaughtExceptionCaptureCallback(CAPTURE_CB_KEY, null);
   } else {
-    setUncaughtExceptionCaptureCallback(null);
-    setUncaughtExceptionCaptureCallback((er) => {
+    setUncaughtExceptionCaptureCallback(CAPTURE_CB_KEY, null);
+    setUncaughtExceptionCaptureCallback(CAPTURE_CB_KEY, (er) => {
       return process.domain._errorHandler(er);
     });
   }
@@ -211,7 +195,7 @@ Domain.prototype._errorHandler = function(er) {
       // Clear the uncaughtExceptionCaptureCallback so that we know that, even
       // if technically the top-level domain is still active, it would
       // be ok to abort on an uncaught exception at this point
-      setUncaughtExceptionCaptureCallback(null);
+      setUncaughtExceptionCaptureCallback(CAPTURE_CB_KEY, null);
       try {
         caught = this.emit('error', er);
       } finally {

lib/internal/bootstrap/node.js

@@ -26,7 +26,7 @@
                                 _shouldAbortOnUncaughtToggle },
                               { internalBinding, NativeModule },
                               triggerFatalException) {
-  const exceptionHandlerState = { captureFn: null };
+  const exceptionHandlerState = { captureFns: new Map() };
   const isMainThread = internalBinding('worker').threadId === 0;
 
   function startup() {
@@ -579,8 +579,10 @@
       // call that threw and was never cleared. So clear it now.
       clearDefaultTriggerAsyncId();
 
-      if (exceptionHandlerState.captureFn !== null) {
-        exceptionHandlerState.captureFn(er);
+      if (exceptionHandlerState.captureFns.size !== 0) {
+        for (const fn of exceptionHandlerState.captureFns.values()) {
+          fn(er);
+        }
       } else if (!process.emit('uncaughtException', er)) {
         // If someone handled it, then great.  otherwise, die in C++ land
         // since that means that we'll exit the process, emit the 'exit' event.

lib/internal/errors.js

@@ -563,15 +563,6 @@ E('ERR_CRYPTO_TIMING_SAFE_EQUAL_LENGTH',
   'Input buffers must have the same length', RangeError);
 E('ERR_DNS_SET_SERVERS_FAILED', 'c-ares failed to set servers: "%s" [%s]',
   Error);
-E('ERR_DOMAIN_CALLBACK_NOT_AVAILABLE',
-  'A callback was registered through ' +
-     'process.setUncaughtExceptionCaptureCallback(), which is mutually ' +
-     'exclusive with using the `domain` module',
-  Error);
-E('ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE',
-  'The `domain` module is in use, which is mutually exclusive with calling ' +
-     'process.setUncaughtExceptionCaptureCallback()',
-  Error);
 E('ERR_ENCODING_INVALID_ENCODED_DATA',
   'The encoded data was not valid for encoding %s', TypeError);
 E('ERR_ENCODING_NOT_SUPPORTED', 'The "%s" encoding is not supported',
@@ -885,10 +876,6 @@ E('ERR_TRANSFORM_ALREADY_TRANSFORMING',
 E('ERR_TRANSFORM_WITH_LENGTH_0',
   'Calling transform done when writableState.length != 0', Error);
 E('ERR_TTY_INIT_FAILED', 'TTY initialization failed', SystemError);
-E('ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET',
-  '`process.setupUncaughtExceptionCapture()` was called while a capture ' +
-    'callback was already active',
-  Error);
 E('ERR_UNESCAPED_CHARACTERS', '%s contains unescaped characters', TypeError);
 E('ERR_UNHANDLED_ERROR',
   // Using a default argument here is important so the argument is not counted

lib/internal/process/main_thread_only.js

@@ -171,6 +171,8 @@ function setupChildProcessIpcChannel() {
   }
 }
 
+process.domainsMap = new Map();
+
 module.exports = {
   setupStdio,
   setupProcessMethods,

lib/internal/process/per_thread.js

@@ -12,7 +12,6 @@ const {
     ERR_INVALID_ARG_TYPE,
     ERR_INVALID_OPT_VALUE,
     ERR_OUT_OF_RANGE,
-    ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET,
     ERR_UNKNOWN_SIGNAL
   }
 } = require('internal/errors');
@@ -213,24 +212,27 @@ function setupUncaughtExceptionCapture(exceptionHandlerState,
   // shouldAbortOnUncaughtToggle is a typed array for faster
   // communication with JS.
 
-  process.setUncaughtExceptionCaptureCallback = function(fn) {
+  process.setUncaughtExceptionCaptureCallback = function(owner, fn) {
     if (fn === null) {
-      exceptionHandlerState.captureFn = fn;
+      exceptionHandlerState.captureFns.delete(owner);
       shouldAbortOnUncaughtToggle[0] = 1;
       return;
     }
+
     if (typeof fn !== 'function') {
       throw new ERR_INVALID_ARG_TYPE('fn', ['Function', 'null'], fn);
     }
-    if (exceptionHandlerState.captureFn !== null) {
-      throw new ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET();
+
+    if (typeof owner !== 'symbol') {
+      throw new ERR_INVALID_ARG_TYPE('owner', ['Symbol'], owner);
     }
-    exceptionHandlerState.captureFn = fn;
+
+    exceptionHandlerState.captureFns.set(owner, fn);
     shouldAbortOnUncaughtToggle[0] = 0;
   };
 
   process.hasUncaughtExceptionCaptureCallback = function() {
-    return exceptionHandlerState.captureFn !== null;
+    return exceptionHandlerState.captureFns.size !== 0;
   };
 }
 

lib/repl.js

@@ -348,12 +348,24 @@ function REPLServer(prompt,
           }
         }
       } catch (e) {
+        let forwardedToDomain = false;
         err = e;
 
         if (process.domain) {
           debug('not recoverable, send to domain');
+          forwardedToDomain = true;
           process.domain.emit('error', err);
           process.domain.exit();
+        }
+
+        debug('domainsMap values:' + process.domainsMap.values());
+        for (const d of process.domainsMap.values()) {
+          forwardedToDomain = true;
+          d.emit('error', err);
+          d.exit();
+        }
+
+        if (forwardedToDomain) {
           return;
         }
       }