cli: add --trace-exit cli option

It could be convenient to trace abnormal exit of the Node.js processes
that printing stacktrace on each `process.exit` call with a cli option.
This also takes effects on worker threads.
PR-URL: #30516
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: legendecas

doc/api/cli.md

@@ -786,6 +786,14 @@ added: v7.7.0
 
 Enables the collection of trace event tracing information.
 
+### `--trace-exit`
+<!-- YAML
+added: REPLACEME
+-->
+
+Prints a stack trace whenever an environment is exited proactively,
+i.e. invoking `process.exit()`.
+
 ### `--trace-sync-io`
 <!-- YAML
 added: v2.1.0
@@ -1128,6 +1136,7 @@ Node.js options that are allowed are:
 *`--trace-event-categories`
 *`--trace-event-file-pattern`
 *`--trace-events-enabled`
+*`--trace-exit`
 *`--trace-sync-io`
 *`--trace-tls`
 *`--trace-uncaught`

doc/node.1

@@ -353,6 +353,10 @@ and
 .ItFl-trace-events-enabled
 Enable the collection of trace event tracing information.
 .
+.ItFl-trace-exit
+Prints a stack trace whenever an environment is exited proactively,
+i.e. invoking `process.exit()`.
+.
 .ItFl-trace-sync-io
 Print a stack trace whenever synchronous I/O is detected after the first turn of the event loop.
 .

src/env.cc

@@ -931,6 +931,21 @@ void AsyncHooks::grow_async_ids_stack() {
 uv_key_t Environment::thread_local_env = {};
 
 voidEnvironment::Exit(int exit_code) {
+if (options()->trace_exit) {
+ HandleScope handle_scope(isolate());
+
+if (is_main_thread()) {
+fprintf(stderr, "(node:%d) ", uv_os_getpid());
+ } else {
+fprintf(stderr, "(node:%d, thread:%llu) ", uv_os_getpid(), thread_id());
+ }
+
+fprintf(
+ stderr, "WARNING: Exited the environment with code %d\n", exit_code);
+PrintStackTrace(
+isolate(),
+StackTrace::CurrentStackTrace(isolate(), 10, StackTrace::kDetailed));
+ }
 if (is_main_thread()) {
 stop_sub_worker_contexts();
 DisposePlatform();

src/node_options.cc

@@ -511,6 +511,10 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
 "show stack traces on deprecations",
  &EnvironmentOptions::trace_deprecation,
 kAllowedInEnvironment);
+AddOption("--trace-exit",
+"show stack trace when an environment exits",
+ &EnvironmentOptions::trace_exit,
+kAllowedInEnvironment);
 AddOption("--trace-sync-io",
 "show stack trace when use of sync IO is detected after the "
 "first tick",

src/node_options.h

@@ -142,6 +142,7 @@ class EnvironmentOptions : public Options {
 bool test_udp_no_try_send = false;
 bool throw_deprecation = false;
 bool trace_deprecation = false;
+bool trace_exit = false;
 bool trace_sync_io = false;
 bool trace_tls = false;
 bool trace_uncaught = false;

test/parallel/test-trace-exit.js

@@ -0,0 +1,59 @@
+'use strict';
+constcommon=require('../common');
+constassert=require('assert');
+const{ promisify }=require('util');
+constexecFile=promisify(require('child_process').execFile);
+const{ Worker, isMainThread, workerData }=require('worker_threads');
+
+constvariant=process.argv[process.argv.length-1];
+switch(true){
+casevariant==='main-thread': {
+return;
+}
+casevariant==='main-thread-exit': {
+returnprocess.exit(0);
+}
+casevariant.startsWith('worker-thread'): {
+constworker=newWorker(__filename,{workerData: variant});
+worker.on('error',common.mustNotCall());
+worker.on('exit',common.mustCall((code)=>{
+assert.strictEqual(code,0);
+}));
+return;
+}
+case!isMainThread: {
+if(workerData==='worker-thread-exit'){
+process.exit(0);
+}
+return;
+}
+}
+
+(asyncfunction(){
+for(const{ execArgv, variant, warnings }of[
+{execArgv: ['--trace-exit'],variant: 'main-thread-exit',warnings: 1},
+{execArgv: [],variant: 'main-thread-exit',warnings: 0},
+{execArgv: ['--trace-exit'],variant: 'main-thread',warnings: 0},
+{execArgv: [],variant: 'main-thread',warnings: 0},
+{execArgv: ['--trace-exit'],variant: 'worker-thread-exit',warnings: 1},
+{execArgv: [],variant: 'worker-thread-exit',warnings: 0},
+{execArgv: ['--trace-exit'],variant: 'worker-thread',warnings: 0},
+{execArgv: [],variant: 'worker-thread',warnings: 0},
+]){
+const{ stdout, stderr }=
+awaitexecFile(process.execPath,[...execArgv,__filename,variant]);
+assert.strictEqual(stdout,'');
+constactualWarnings=
+stderr.match(/WARNING:Exitedtheenvironmentwithcode0/g);
+if(warnings===0){
+assert.strictEqual(actualWarnings,null);
+return;
+}
+assert.strictEqual(actualWarnings.length,warnings);
+
+if(variant.startsWith('worker')){
+constworkerIds=stderr.match(/\(node:\d+,thread:\d+)/g);
+assert.strictEqual(workerIds.length,warnings);
+}
+}
+})().then(common.mustCall());