util: access process states lazily in debuglog

`debuglog()` depends on `process.pid` and `process.env.NODE_DEBUG`, so it needs to be called lazily in top scopes of internal modules that may be loaded before these run time states are allowed to be accessed. This patch makes its implementation lazy by default, the process states are only accessed when the returned debug function is called for the first time. PR-URL: #27281 Reviewed-By: Ruben Bridgewater <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Richard Lau <[email protected]> Reviewed-By: Yongsheng Zhang <[email protected]>

Author: joyeecheung

lib/_stream_readable.js

@@ -30,14 +30,7 @@ const EE = require('events');
 constStream=require('stream');
 const{ Buffer }=require('buffer');
 
-letdebuglog;
-functiondebug(...args){
-if(!debuglog){
-debuglog=require('internal/util/debuglog').debuglog('stream');
-}
-debuglog(...args);
-}
-
+constdebug=require('internal/util/debuglog').debuglog('stream');
 constBufferList=require('internal/streams/buffer_list');
 constdestroyImpl=require('internal/streams/destroy');
 const{ getHighWaterMark }=require('internal/streams/state');

lib/internal/main/worker_thread.js

@@ -44,15 +44,14 @@ const{
 }=require('internal/process/execution');
 
 constpublicWorker=require('worker_threads');
+constdebug=require('internal/util/debuglog').debuglog('worker');
 
 constassert=require('internal/assert');
 
 patchProcessObject();
 setupInspectorHooks();
 setupDebugEnv();
 
-constdebug=require('internal/util/debuglog').debuglog('worker');
-
 setupWarningHandler();
 
 // Since worker threads cannot switch cwd, we do not need to

lib/internal/modules/cjs/loader.js

@@ -166,14 +166,7 @@ Object.defineProperty(Module, 'wrapper',{
 }
 });
 
-letdebuglog;
-functiondebug(...args){
-if(!debuglog){
-debuglog=require('internal/util/debuglog').debuglog('module');
-}
-debuglog(...args);
-}
-
+constdebug=require('internal/util/debuglog').debuglog('module');
 Module._debug=deprecate(debug,'Module._debug is deprecated.','DEP0077');
 
 // Given a module name, and a list of paths to test, returns the first

lib/internal/stream_base_commons.js

@@ -31,7 +31,7 @@ const kAfterAsyncWrite = Symbol('kAfterAsyncWrite');
 constkHandle=Symbol('kHandle');
 constkSession=Symbol('kSession');
 
-constdebug=require('util').debuglog('stream');
+constdebug=require('internal/util/debuglog').debuglog('stream');
 
 functionhandleWriteReq(req,data,encoding){
 const{ handle }=req;

lib/internal/timers.js

@@ -107,13 +107,7 @@ const L = require('internal/linkedlist');
 constPriorityQueue=require('internal/priority_queue');
 
 const{ inspect }=require('internal/util/inspect');
-letdebuglog;
-functiondebug(...args){
-if(!debuglog){
-debuglog=require('internal/util/debuglog').debuglog('timer');
-}
-debuglog(...args);
-}
+constdebug=require('internal/util/debuglog').debuglog('timer');
 
 // *Must* match Environment::ImmediateInfo::Fields in src/env.h.
 constkCount=0;

lib/internal/util/debuglog.js

@@ -31,7 +31,7 @@ function emitWarningIfNeeded(set){
 }
 }
 
-functiondebuglog(set){
+functiondebuglogImpl(set){
 set=set.toUpperCase();
 if(!debugs[set]){
 if(debugEnvRegex.test(set)){
@@ -48,6 +48,22 @@ function debuglog(set){
 returndebugs[set];
 }
 
+// debuglogImpl depends on process.pid and process.env.NODE_DEBUG,
+// so it needs to be called lazily in top scopes of internal modules
+// that may be loaded before these run time states are allowed to
+// be accessed.
+functiondebuglog(set){
+letdebug;
+returnfunction(...args){
+if(!debug){
+// Only invokes debuglogImpl() when the debug function is
+// called for the first time.
+debug=debuglogImpl(set);
+}
+debug(...args);
+};
+}
+
 module.exports={
  debuglog,
  initializeDebugEnv

lib/internal/worker.js

@@ -48,14 +48,7 @@ const kOnErrorMessage = Symbol('kOnErrorMessage');
 constkParentSideStdio=Symbol('kParentSideStdio');
 
 constSHARE_ENV=Symbol.for('nodejs.worker_threads.SHARE_ENV');
-
-letdebuglog;
-functiondebug(...args){
-if(!debuglog){
-debuglog=require('internal/util/debuglog').debuglog('worker');
-}
-debuglog(...args);
-}
+constdebug=require('internal/util/debuglog').debuglog('worker');
 
 classWorkerextendsEventEmitter{
 constructor(filename,options={}){

lib/internal/worker/io.js

@@ -21,14 +21,7 @@ const{
 const{ Readable, Writable }=require('stream');
 constEventEmitter=require('events');
 const{ inspect }=require('internal/util/inspect');
-
-letdebuglog;
-functiondebug(...args){
-if(!debuglog){
-debuglog=require('internal/util/debuglog').debuglog('worker');
-}
-debuglog(...args);
-}
+constdebug=require('internal/util/debuglog').debuglog('worker');
 
 constkIncrementsPortRef=Symbol('kIncrementsPortRef');
 constkName=Symbol('kName');

lib/timers.js

@@ -50,14 +50,7 @@ const{
  deprecate
 }=require('internal/util');
 const{ERR_INVALID_CALLBACK}=require('internal/errors').codes;
-
-letdebuglog;
-functiondebug(...args){
-if(!debuglog){
-debuglog=require('internal/util/debuglog').debuglog('timer');
-}
-debuglog(...args);
-}
+constdebug=require('internal/util/debuglog').debuglog('timer');
 
 const{
  destroyHooksExist,