util: adhere to noDeprecation set at runtime

Until now, the docs stated that `process.noDeprecation` could be set
at runtime, but before any modules were loaded. That was not true,
because `lib/internal/util.js` was loaded during the process startup
process, so setting the flag at runtime was pointless.
Minimal test case:
process.noDeprecation = true;
process.EventEmitter;
This patch moves checking `process.noDeprecation` to the place where
it was actually used.
PR-URL: #6683
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: addaleax

doc/api/util.md

@@ -67,9 +67,9 @@ exports.puts = util.deprecate(() => {
 
 It returns a modified function which warns once by default.
 
-If `--no-deprecation`is set then this function is a NO-OP. Configurable
-at run-time through the `process.noDeprecation`boolean (only effective
-when set before a module is loaded.)
+This function does nothing if either the `--no-deprecation`command
+line flag is used, or the `process.noDeprecation`property is set to
+`true`*prior* to the first deprecation warning.
 
 If `--trace-deprecation` is set, a warning and a stack trace are logged
 to the console the first time the deprecated API is used. Configurable

lib/internal/util.js

@@ -2,7 +2,6 @@
 
 constbinding=process.binding('util');
 constprefix=`(${process.release.name}:${process.pid}) `;
-constnoDeprecation=process.noDeprecation;
 
 exports.getHiddenValue=binding.getHiddenValue;
 exports.setHiddenValue=binding.setHiddenValue;
@@ -16,7 +15,7 @@ exports.deprecate = function(fn, msg) {
 // All the internal deprecations have to use this function only, as this will
 // prepend the prefix to the actual message.
 exports.printDeprecationMessage=function(msg,warned,ctor){
-if(warned||noDeprecation)
+if(warned||process.noDeprecation)
 returntrue;
 process.emitWarning(msg,'DeprecationWarning',
 ctor||exports.printDeprecationMessage);

test/parallel/test-process-no-deprecation.js

@@ -0,0 +1,33 @@
+'use strict';
+// Flags: --expose_internals --no-warnings
+
+// The --no-warnings flag only supresses writing the warning to stderr, not the
+// emission of the corresponding event. This test file can be run without it.
+
+process.noDeprecation=true;
+
+constcommon=require('../common');
+constassert=require('assert');
+
+functionlistener(){
+common.fail('received unexpected warning');
+}
+
+process.addListener('warning',listener);
+
+constinternalUtil=require('internal/util');
+internalUtil.printDeprecationMessage('Something is deprecated.');
+
+// The warning would be emitted in the next tick, so continue after that.
+process.nextTick(common.mustCall(()=>{
+// Check that deprecations can be re-enabled.
+process.noDeprecation=false;
+process.removeListener('warning',listener);
+
+process.addListener('warning',common.mustCall((warning)=>{
+assert.strictEqual(warning.name,'DeprecationWarning');
+assert.strictEqual(warning.message,'Something else is deprecated.');
+}));
+
+internalUtil.printDeprecationMessage('Something else is deprecated.');
+}));