From 4b613d39765eb0529fc6b01b172d7e7e70beeaa1 Mon Sep 17 00:00:00 2001
From: Sam Ruby <rubys@intertwingly.net>
Date: Fri, 29 Jun 2018 12:49:36 -0400
Subject: [PATCH] repl: make own properties shadow prototype properties

Previously, the code displayed properties backwards (e.g., showing
prototype properties before own properties).  It also did uniqueness
checks during this processing, so these checks were done backwards.

After this change, the properties continue to be displayed backwards,
but the uniqueness checks are done in the proper order.

See also: https://github.com/nodejs/node/issues/21586 which was
discovered during the testing of this fix.

Fixes: https://github.com/nodejs/node/issues/15199
PR-URL: https://github.com/nodejs/node/pull/21588
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
---
 lib/repl.js                             | 12 ++++++------
 test/parallel/test-repl-tab-complete.js | 19 ++++++++++++++++++-
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/lib/repl.js b/lib/repl.js
index 6345c742f68f33..92c90de7bb1646 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -1229,20 +1229,20 @@ function complete(line, callback) {
       // Completion group 0 is the "closest"
       // (least far up the inheritance chain)
       // so we put its completions last: to be closest in the REPL.
-      for (i = completionGroups.length - 1; i >= 0; i--) {
+      for (i = 0; i < completionGroups.length; i++) {
         group = completionGroups[i];
         group.sort();
-        for (var j = 0; j < group.length; j++) {
+        for (var j = group.length - 1; j >= 0; j--) {
           c = group[j];
           if (!hasOwnProperty(uniq, c)) {
-            completions.push(c);
+            completions.unshift(c);
             uniq[c] = true;
           }
         }
-        completions.push(''); // Separator btwn groups
+        completions.unshift(''); // Separator btwn groups
       }
-      while (completions.length && completions[completions.length - 1] === '') {
-        completions.pop();
+      while (completions.length && completions[0] === '') {
+        completions.shift();
       }
     }
 
diff --git a/test/parallel/test-repl-tab-complete.js b/test/parallel/test-repl-tab-complete.js
index 0e6c4bb654910e..9d6ecf4e284811 100644
--- a/test/parallel/test-repl-tab-complete.js
+++ b/test/parallel/test-repl-tab-complete.js
@@ -149,7 +149,10 @@ putIn.run([
   ' one:1',
   '};'
 ]);
-testMe.complete('inner.o', getNoResultsFunction());
+// See: https://github.com/nodejs/node/issues/21586
+// testMe.complete('inner.o', getNoResultsFunction());
+testMe.complete('inner.o', common.mustCall(function(error, data) {
+}));
 
 putIn.run(['.clear']);
 
@@ -206,6 +209,20 @@ testMe.complete('toSt', common.mustCall(function(error, data) {
   assert.deepStrictEqual(data, [['toString'], 'toSt']);
 }));
 
+// own properties should shadow properties on the prototype
+putIn.run(['.clear']);
+putIn.run([
+  'var x = Object.create(null);',
+  'x.a = 1;',
+  'x.b = 2;',
+  'var y = Object.create(x);',
+  'y.a = 3;',
+  'y.c = 4;'
+]);
+testMe.complete('y.', common.mustCall(function(error, data) {
+  assert.deepStrictEqual(data, [['y.b', '', 'y.a', 'y.c'], 'y.']);
+}));
+
 // Tab complete provides built in libs for require()
 putIn.run(['.clear']);