nodejs
diff --git a/doc/api/util.md b/doc/api/util.md
@@ -187,6 +187,9 @@ property take precedence over `--trace-deprecation` and
 <!-- YAML
 added: v0.5.3
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/17907
+    description: The `%o` specifiers `depth` option is now set to Infinity.
   - version: v8.4.0
     pr-url: https://github.com/nodejs/node/pull/14558
     description: The `%o` and `%O` specifiers are supported now.
@@ -209,12 +212,11 @@ corresponding argument. Supported placeholders are:
 contains circular references.
 * `%o` - Object. A string representation of an object
   with generic JavaScript object formatting.
-  Similar to `util.inspect()` with options `{ showHidden: true, depth: 4, showProxy: true }`.
-  This will show the full object including non-enumerable symbols and properties.
-* `%O` - Object. A string representation of an object
-  with generic JavaScript object formatting.
-  Similar to `util.inspect()` without options.
-  This will show the full object not including non-enumerable symbols and properties.
+  Similar to `util.inspect()` with options `{ showHidden: true, showProxy: true }`.
+  This will show the full object including non-enumerable properties and proxies.
+* `%O` - Object. A string representation of an object with generic JavaScript
+  object formatting. Similar to `util.inspect()` without options. This will show
+  the full object not including non-enumerable properties and proxies.
 * `%%` - single percent sign (`'%'`). This does not consume an argument.
 
 If the placeholder does not have a corresponding argument, the placeholder is
@@ -327,6 +329,9 @@ stream.write('With ES6');
 <!-- YAML
 added: v0.3.0
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/17907
+    description: The `depth` default changed to Infinity.
   - version: REPLACEME
     pr-url: https://github.com/nodejs/node/pull/REPLACEME
     description: The `compact` option is supported now.
@@ -349,9 +354,6 @@ changes:
 * `options` {Object}
   * `showHidden` {boolean} If `true`, the `object`'s non-enumerable symbols and
     properties will be included in the formatted result. Defaults to `false`.
-  * `depth` {number} Specifies the number of times to recurse while formatting
-    the `object`. This is useful for inspecting large complicated objects.
-    Defaults to `2`. To make it recurse indefinitely pass `null`.
   * `colors` {boolean} If `true`, the output will be styled with ANSI color
     codes. Defaults to `false`. Colors are customizable, see
     [Customizing `util.inspect` colors][].
@@ -362,8 +364,8 @@ changes:
     objects. Defaults to `false`.
   * `maxArrayLength` {number} Specifies the maximum number of array and
     `TypedArray` elements to include when formatting. Defaults to `100`. Set to
-    `null` to show all array elements. Set to `0` or negative to show no array
-    elements.
+    `null` or `Infinity` to show all array elements. Set to `0` or negative to
+    show no array elements.
   * `breakLength` {number} The length at which an object's keys are split
     across multiple lines. Set to `Infinity` to format an object as a single
     line. Defaults to 60 for legacy compatibility.
@@ -374,6 +376,10 @@ changes:
     objects the same as arrays. Note that no text will be reduced below 16
     characters, no matter the `breakLength` size. For more information, see the
     example below. Defaults to `true`.
+  * `depth` {number} Specifies the number visible nested Objects in an `object`.
+    This is useful to minimize the inspection output for large complicated
+    objects. To make it recurse indefinitely pass `null` or `Infinity`. Defaults
+    to `Infinity`.
 
 The `util.inspect()` method returns a string representation of `object` that is
 intended for debugging. The output of `util.inspect` may change at any time
@@ -398,12 +404,23 @@ util.inspect(new Bar()); // 'Bar {}'
 util.inspect(baz);       // '[foo] {}'
 ```
 
-The following example inspects all properties of the `util` object:
+The following example limits the inspected output of the `paths` property:
 
 ```js
 const util = require('util');
 
-console.log(util.inspect(util, { showHidden: true, depth: null }));
+console.log(util.inspect(module, { depth: 0 }));
+// Instead of showing all entries in `paths` `[Array]` is used to limit the
+// output for readability:
+
+// Module {
+//   id: '<repl>',
+//   exports: {},
+//   parent: undefined,
+//   filename: null,
+//   loaded: false,
+//   children: [],
+//   paths: [Array] }
 ```
 
 Values may supply their own custom `inspect(depth, opts)` functions, when
@@ -423,7 +440,7 @@ const o = {
     'foo']], 4],
   b: new Map([['za', 1], ['zb', 'test']])
 };
-console.log(util.inspect(o, { compact: true, depth: 5, breakLength: 80 }));
+console.log(util.inspect(o, { compact: true, breakLength: 80 }));
 
 // This will print
 
@@ -437,7 +454,7 @@ console.log(util.inspect(o, { compact: true, depth: 5, breakLength: 80 }));
 //   b: Map { 'za' => 1, 'zb' => 'test' } }
 
 // Setting `compact` to false changes the output to be more reader friendly.
-console.log(util.inspect(o, { compact: false, depth: 5, breakLength: 80 }));
+console.log(util.inspect(o, { compact: false, breakLength: 80 }));
 
 // {
 //   a: [

diff --git a/lib/internal/streams/BufferList.js b/lib/internal/streams/BufferList.js
@@ -1,6 +1,7 @@
 'use strict';
 
 const { Buffer } = require('buffer');
+const util = require('util');
 
 function copyBuffer(src, target, offset) {
   Buffer.prototype.copy.call(src, target, offset);
@@ -73,4 +74,9 @@ module.exports = class BufferList {
     }
     return ret;
   }
+
+  [util.inspect.custom]() {
+    const obj = util.inspect({ length: this.length });
+    return `${this.constructor.name} ${obj}`;
+  }
 };
diff --git a/lib/repl.js b/lib/repl.js
@@ -104,8 +104,9 @@ function hasOwnProperty(obj, prop) {
 // Can overridden with custom print functions, such as `probe` or `eyes.js`.
 // This is the default "writer" value if none is passed in the REPL options.
 const writer = exports.writer = (obj) => util.inspect(obj, writer.options);
-writer.options =
-    Object.assign({}, util.inspect.defaultOptions, { showProxy: true });
+writer.options = Object.assign({},
+                               util.inspect.defaultOptions,
+                               { showProxy: true, depth: 2 });
 
 exports._builtinLibs = internalModule.builtinLibs;
 

diff --git a/lib/util.js b/lib/util.js
@@ -64,7 +64,7 @@ const {
 
 const inspectDefaultOptions = Object.seal({
   showHidden: false,
-  depth: 2,
+  depth: null,
   colors: false,
   customInspect: true,
   showProxy: false,
@@ -195,7 +195,7 @@ function format(f) {
             break;
           case 111: // 'o'
             tempStr = inspect(arguments[a++],
-                              { showHidden: true, depth: 4, showProxy: true });
+                              { showHidden: true, showProxy: true });
             break;
           case 105: // 'i'
             tempStr = `${parseInt(arguments[a++])}`;
@@ -317,8 +317,7 @@ Object.defineProperty(inspect, 'defaultOptions', {
     if (options === null || typeof options !== 'object') {
       throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'options', 'Object');
     }
-    Object.assign(inspectDefaultOptions, options);
-    return inspectDefaultOptions;
+    return _extend(inspectDefaultOptions, options);
   }
 });
 

diff --git a/test/parallel/test-stream-buffer-list.js b/test/parallel/test-stream-buffer-list.js
@@ -3,6 +3,7 @@
 require('../common');
 const assert = require('assert');
 const BufferList = require('internal/streams/BufferList');
+const util = require('util');
 
 // Test empty buffer list.
 const emptyList = new BufferList();
@@ -25,3 +26,10 @@ assert.strictEqual(list.join(','), 'foo');
 const shifted = list.shift();
 assert.strictEqual(shifted, 'foo');
 assert.deepStrictEqual(list, new BufferList());
+
+const tmp = util.inspect.defaultOptions.colors;
+util.inspect.defaultOptions = { colors: true };
+assert.strictEqual(
+  util.inspect(list),
+  'BufferList { length: \u001b[33m0\u001b[39m }');
+util.inspect.defaultOptions = { colors: tmp };
diff --git a/test/parallel/test-util-inspect-proxy.js b/test/parallel/test-util-inspect-proxy.js
@@ -48,13 +48,17 @@ const expected1 = 'Proxy [ {}, {} ]';
 const expected2 = 'Proxy [ Proxy [ {}, {} ], {} ]';
 const expected3 = 'Proxy [ Proxy [ Proxy [ {}, {} ], {} ], Proxy [ {}, {} ] ]';
 const expected4 = 'Proxy [ Proxy [ {}, {} ], Proxy [ Proxy [ {}, {} ], {} ] ]';
-const expected5 = 'Proxy [ Proxy [ Proxy [ Proxy [Array], {} ],' +
+const expected5 = 'Proxy [ Proxy [ Proxy [ Proxy [ {}, {} ], {} ],' +
                   ' Proxy [ {}, {} ] ],\n  Proxy [ Proxy [ {}, {} ]' +
-                  ', Proxy [ Proxy [Array], {} ] ] ]';
-const expected6 = 'Proxy [ Proxy [ Proxy [ Proxy [Array], Proxy [Array]' +
-                  ' ],\n    Proxy [ Proxy [Array], Proxy [Array] ] ],\n' +
-                  '  Proxy [ Proxy [ Proxy [Array], Proxy [Array] ],\n' +
-                  '    Proxy [ Proxy [Array], Proxy [Array] ] ] ]';
+                  ', Proxy [ Proxy [ {}, {} ], {} ] ] ]';
+const expected6 = 'Proxy [ Proxy [ Proxy [ Proxy [ Proxy [ {}, {} ], {} ], ' +
+                    'Proxy [ {}, {} ] ],\n' +
+                  '    Proxy [ Proxy [ {}, {} ], ' +
+                    'Proxy [ Proxy [ {}, {} ], {} ] ] ],\n' +
+                  '  Proxy [ Proxy [ Proxy [ Proxy [ {}, {} ], {} ], ' +
+                    'Proxy [ {}, {} ] ],\n' +
+                  '    Proxy [ Proxy [ {}, {} ], ' +
+                    'Proxy [ Proxy [ {}, {} ], {} ] ] ] ]';
 assert.strictEqual(
   util.inspect(proxy1, { showProxy: true, depth: null }),
   expected1);

diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
@@ -68,7 +68,7 @@ assert.strictEqual(util.inspect({ a: 1, b: 2 }), '{ a: 1, b: 2 }');
 assert.strictEqual(util.inspect({ 'a': {} }), '{ a: {} }');
 assert.strictEqual(util.inspect({ 'a': { 'b': 2 } }), '{ a: { b: 2 } }');
 assert.strictEqual(util.inspect({ 'a': { 'b': { 'c': { 'd': 2 } } } }),
-                   '{ a: { b: { c: [Object] } } }');
+                   '{ a: { b: { c: { d: 2 } } } }');
 assert.strictEqual(
   util.inspect({ 'a': { 'b': { 'c': { 'd': 2 } } } }, false, null),
   '{ a: { b: { c: { d: 2 } } } }');
@@ -106,7 +106,7 @@ assert.strictEqual(util.inspect((new JSStream())._externalStream),
   assert.strictEqual(util.inspect({ a: regexp }, false, 0), '{ a: /regexp/ }');
 }
 
-assert(/Object/.test(
+assert(!/Object/.test(
   util.inspect({ a: { a: { a: { a: {} } } } }, undefined, undefined, true)
 ));
 assert(!/Object/.test(
@@ -1012,15 +1012,15 @@ if (typeof Symbol !== 'undefined') {
 // Empty and circular before depth
 {
   const arr = [[[[]]]];
-  assert.strictEqual(util.inspect(arr), '[ [ [ [] ] ] ]');
+  assert.strictEqual(util.inspect(arr, { depth: 2 }), '[ [ [ [] ] ] ]');
   arr[0][0][0][0] = [];
-  assert.strictEqual(util.inspect(arr), '[ [ [ [Array] ] ] ]');
+  assert.strictEqual(util.inspect(arr, { depth: 2 }), '[ [ [ [Array] ] ] ]');
   arr[0][0][0] = {};
-  assert.strictEqual(util.inspect(arr), '[ [ [ {} ] ] ]');
+  assert.strictEqual(util.inspect(arr, { depth: 2 }), '[ [ [ {} ] ] ]');
   arr[0][0][0] = { a: 2 };
-  assert.strictEqual(util.inspect(arr), '[ [ [ [Object] ] ] ]');
+  assert.strictEqual(util.inspect(arr, { depth: 2 }), '[ [ [ [Object] ] ] ]');
   arr[0][0][0] = arr;
-  assert.strictEqual(util.inspect(arr), '[ [ [ [Circular] ] ] ]');
+  assert.strictEqual(util.inspect(arr, { depth: 2 }), '[ [ [ [Circular] ] ] ]');
 }
 
 // Corner cases.
@@ -1117,22 +1117,22 @@ if (typeof Symbol !== 'undefined') {
   assert(!/1 more item/.test(util.inspect(arr)));
   util.inspect.defaultOptions.maxArrayLength = oldOptions.maxArrayLength;
   assert(/1 more item/.test(util.inspect(arr)));
-  util.inspect.defaultOptions.depth = null;
-  assert(!/Object/.test(util.inspect(obj)));
-  util.inspect.defaultOptions.depth = oldOptions.depth;
+  util.inspect.defaultOptions.depth = 2;
   assert(/Object/.test(util.inspect(obj)));
+  util.inspect.defaultOptions.depth = oldOptions.depth;
+  assert(!/Object/.test(util.inspect(obj)));
   assert.strictEqual(
     JSON.stringify(util.inspect.defaultOptions),
     JSON.stringify(oldOptions)
   );
 
   // Set multiple options through object assignment
-  util.inspect.defaultOptions = { maxArrayLength: null, depth: null };
+  util.inspect.defaultOptions = { maxArrayLength: null, depth: 2 };
   assert(!/1 more item/.test(util.inspect(arr)));
-  assert(!/Object/.test(util.inspect(obj)));
+  assert(/Object/.test(util.inspect(obj)));
   util.inspect.defaultOptions = oldOptions;
   assert(/1 more item/.test(util.inspect(arr)));
-  assert(/Object/.test(util.inspect(obj)));
+  assert(!/Object/.test(util.inspect(obj)));
   assert.strictEqual(
     JSON.stringify(util.inspect.defaultOptions),
     JSON.stringify(oldOptions)