diff --git a/lib/command.js b/lib/command.js
index 590a271dd..d0868fd7e 100644
--- a/lib/command.js
+++ b/lib/command.js
@@ -109,6 +109,19 @@ class Command extends EventEmitter {
     return this;
   }
 
+  /**
+   * @returns {Command[]}
+   * @api private
+   */
+
+  _getCommandAndAncestors() {
+    const result = [];
+    for (let command = this; command; command = command.parent) {
+      result.push(command);
+    }
+    return result;
+  }
+
   /**
    * Define a command.
    *
@@ -825,7 +838,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
   getOptionValueSourceWithGlobals(key) {
     // global overwrites local, like optsWithGlobals
     let source;
-    getCommandAndParents(this).forEach((cmd) => {
+    this._getCommandAndAncestors().forEach((cmd) => {
       if (cmd.getOptionValueSource(key) !== undefined) {
         source = cmd.getOptionValueSource(key);
       }
@@ -1208,7 +1221,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
   _chainOrCallHooks(promise, event) {
     let result = promise;
     const hooks = [];
-    getCommandAndParents(this)
+    this._getCommandAndAncestors()
       .reverse()
       .filter(cmd => cmd._lifeCycleHooks[event] !== undefined)
       .forEach(hookedCommand => {
@@ -1365,13 +1378,13 @@ Expecting one of '${allowedValues.join("', '")}'`);
 
   _checkForMissingMandatoryOptions() {
     // Walk up hierarchy so can call in subcommand after checking for displaying help.
-    for (let cmd = this; cmd; cmd = cmd.parent) {
+    this._getCommandAndAncestors().forEach((cmd) => {
       cmd.options.forEach((anOption) => {
         if (anOption.mandatory && (cmd.getOptionValue(anOption.attributeName()) === undefined)) {
           cmd.missingMandatoryOptionValue(anOption);
         }
       });
-    }
+    });
   }
 
   /**
@@ -1412,9 +1425,9 @@ Expecting one of '${allowedValues.join("', '")}'`);
    */
   _checkForConflictingOptions() {
     // Walk up hierarchy so can call in subcommand after checking for displaying help.
-    for (let cmd = this; cmd; cmd = cmd.parent) {
+    this._getCommandAndAncestors().forEach((cmd) => {
       cmd._checkForConflictingLocalOptions();
-    }
+    });
   }
 
   /**
@@ -1577,7 +1590,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
    */
   optsWithGlobals() {
     // globals overwrite locals
-    return getCommandAndParents(this).reduce(
+    return this._getCommandAndAncestors().reduce(
       (combinedOptions, cmd) => Object.assign(combinedOptions, cmd.opts()),
       {}
     );
@@ -2022,7 +2035,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
     }
     const context = this._getHelpContext(contextOptions);
 
-    getCommandAndParents(this).reverse().forEach(command => command.emit('beforeAllHelp', context));
+    this._getCommandAndAncestors().reverse().forEach(command => command.emit('beforeAllHelp', context));
     this.emit('beforeHelp', context);
 
     let helpInformation = this.helpInformation(context);
@@ -2036,7 +2049,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
 
     this.emit(this._helpLongFlag); // deprecated
     this.emit('afterHelp', context);
-    getCommandAndParents(this).forEach(command => command.emit('afterAllHelp', context));
+    this._getCommandAndAncestors().forEach(command => command.emit('afterAllHelp', context));
   }
 
   /**
@@ -2179,18 +2192,4 @@ function incrementNodeInspectorPort(args) {
   });
 }
 
-/**
- * @param {Command} startCommand
- * @returns {Command[]}
- * @api private
- */
-
-function getCommandAndParents(startCommand) {
-  const result = [];
-  for (let command = startCommand; command; command = command.parent) {
-    result.push(command);
-  }
-  return result;
-}
-
 exports.Command = Command;
diff --git a/lib/help.js b/lib/help.js
index 14e0fb9f3..560801bd3 100644
--- a/lib/help.js
+++ b/lib/help.js
@@ -101,8 +101,8 @@ class Help {
     if (!this.showGlobalOptions) return [];
 
     const globalOptions = [];
-    for (let parentCmd = cmd.parent; parentCmd; parentCmd = parentCmd.parent) {
-      const visibleOptions = parentCmd.options.filter((option) => !option.hidden);
+    for (let ancestorCmd = cmd.parent; ancestorCmd; ancestorCmd = ancestorCmd.parent) {
+      const visibleOptions = ancestorCmd.options.filter((option) => !option.hidden);
       globalOptions.push(...visibleOptions);
     }
     if (this.sortOptions) {
@@ -240,11 +240,11 @@ class Help {
     if (cmd._aliases[0]) {
       cmdName = cmdName + '|' + cmd._aliases[0];
     }
-    let parentCmdNames = '';
-    for (let parentCmd = cmd.parent; parentCmd; parentCmd = parentCmd.parent) {
-      parentCmdNames = parentCmd.name() + ' ' + parentCmdNames;
+    let ancestorCmdNames = '';
+    for (let ancestorCmd = cmd.parent; ancestorCmd; ancestorCmd = ancestorCmd.parent) {
+      ancestorCmdNames = ancestorCmd.name() + ' ' + ancestorCmdNames;
     }
-    return parentCmdNames + cmdName + ' ' + cmd.usage();
+    return ancestorCmdNames + cmdName + ' ' + cmd.usage();
   }
 
   /**