src: clarify OptionEnvvarSettings member names

The term `Environment` in `kAllowedInEnvironment` and
`kDisallowedInEnvironment` has nothing to do with the commonly used
term `node::Environment`. Rename the member to `kAllowedInEnvvar`
and `kDisallowedInEnvvar` respectively to reflect they are options
of `OptionEnvvarSettings`.

As `OptionEnvvarSettings` is part of the public embedder APIs, the
legacy names are still preserved.

lib/internal/process/per_thread.js

@@ -267,14 +267,14 @@ const trailingValuesRegex = /=.*$/;
 // from data in the config binding.
 function buildAllowedFlags() {
   const {
-    envSettings: { kAllowedInEnvironment },
+    envSettings: { kAllowedInEnvvar },
     types: { kBoolean },
   } = internalBinding('options');
   const { options, aliases } = require('internal/options');
 
   const allowedNodeEnvironmentFlags = [];
   for (const { 0: name, 1: info } of options) {
-    if (info.envVarSettings === kAllowedInEnvironment) {
+    if (info.envVarSettings === kAllowedInEnvvar) {
       ArrayPrototypePush(allowedNodeEnvironmentFlags, name);
       if (info.type === kBoolean) {
         const negatedName = `--no-${name.slice(2)}`;
@@ -291,7 +291,7 @@ function buildAllowedFlags() {
         ArrayPrototypeSplice(recursiveExpansion, 0, 1);
       return ArrayPrototypeEvery(recursiveExpansion, isAccepted);
     }
-    return options.get(to).envVarSettings === kAllowedInEnvironment;
+    return options.get(to).envVarSettings === kAllowedInEnvvar;
   }
   for (const { 0: from, 1: expansion } of aliases) {
     if (ArrayPrototypeEvery(expansion, isAccepted)) {

src/node.cc

@@ -769,15 +769,15 @@ static ExitCode InitializeNodeWithArgsInternal(
       env_argv.insert(env_argv.begin(), argv->at(0));
 
       const ExitCode exit_code = ProcessGlobalArgsInternal(
-          &env_argv, nullptr, errors, kAllowedInEnvironment);
+          &env_argv, nullptr, errors, kAllowedInEnvvar);
       if (exit_code != ExitCode::kNoFailure) return exit_code;
     }
   }
 #endif
 
   if (!(flags & ProcessInitializationFlags::kDisableCLIOptions)) {
-    const ExitCode exit_code = ProcessGlobalArgsInternal(
-        argv, exec_argv, errors, kDisallowedInEnvironment);
+    const ExitCode exit_code =
+        ProcessGlobalArgsInternal(argv, exec_argv, errors, kDisallowedInEnvvar);
     if (exit_code != ExitCode::kNoFailure) return exit_code;
   }
 

src/node.h

@@ -349,10 +349,25 @@ inline std::unique_ptr<InitializationResult> InitializeOncePerProcess(
 }
 
 enum OptionEnvvarSettings {
-  kAllowedInEnvironment,
-  kDisallowedInEnvironment
+  // Allow the options to be set via the environment variable, like
+  // `NODE_OPTIONS`.
+  kAllowedInEnvvar = 0,
+  // Disallow the options to be set via the environment variable, like
+  // `NODE_OPTIONS`.
+  kDisallowedInEnvvar = 1,
+  // Deprecated, use kAllowedInEnvvar instead.
+  kAllowedInEnvironment = kAllowedInEnvvar,
+  // Deprecated, use kDisallowedInEnvvar instead.
+  kDisallowedInEnvironment = kDisallowedInEnvvar,
 };
 
+// Process the arguments and set up the per-process options.
+// If the `settings` is set as OptionEnvvarSettings::kAllowedInEnvvar, the
+// options that are allowed in the environment variable are processed. Options
+// that are disallowed to be set via environment variable are processed as
+// errors.
+// Otherwise all the options that are disallowed (and those are allowed) to be
+// set via environment variable are processed.
 NODE_EXTERN int ProcessGlobalArgs(std::vector<std::string>* args,
                       std::vector<std::string>* exec_args,
                       std::vector<std::string>* errors,

src/node_options-inl.h

@@ -302,7 +302,7 @@ void OptionsParser<Options>::Parse(
     const std::string arg = args.pop_first();
 
     if (arg == "--") {
-      if (required_env_settings == kAllowedInEnvironment)
+      if (required_env_settings == kAllowedInEnvvar)
         errors->push_back(NotAllowedInEnvErr("--"));
       break;
     }
@@ -374,8 +374,8 @@ void OptionsParser<Options>::Parse(
     auto it = options_.find(name);
 
     if ((it == options_.end() ||
-         it->second.env_setting == kDisallowedInEnvironment) &&
-        required_env_settings == kAllowedInEnvironment) {
+         it->second.env_setting == kDisallowedInEnvvar) &&
+        required_env_settings == kAllowedInEnvvar) {
       errors->push_back(NotAllowedInEnvErr(original_name));
       break;
     }