From 644985c8e35a775b120e4b6ba45639a6e5e8fa36 Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Sun, 13 May 2018 12:57:49 -0400
Subject: [PATCH] Don't write 'undefined' to storage when deleting the
 changeset source (closes #5012)

Also includes some code to ignore/remove any 'undefined' source values which
happen to be stored in localStorage. Because the saved source/comment/hashtags
expire after 2 days, this code can go away in iD v2.9
---
 modules/ui/commit.js | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/modules/ui/commit.js b/modules/ui/commit.js
index 9fa7e1007..3b934898c 100644
--- a/modules/ui/commit.js
+++ b/modules/ui/commit.js
@@ -79,9 +79,13 @@ export function uiCommit(context) {
                 tags.hashtags = hashtags;
             }
 
+            // iD 2.8.1 could write a literal 'undefined' here.. see #5021
+            // (old source values expire after 2 days, so 'undefined' checks can go away in v2.9)
             var source = context.storage('source');
-            if (source) {
+            if (source && source !== 'undefined') {
                 tags.source = source;
+            } else if (source === 'undefined') {
+                context.storage('source', null);
             }
 
             _changeset = new osmChangeset({ tags: tags });
@@ -297,7 +301,9 @@ export function uiCommit(context) {
             }
         }
         if (changed.hasOwnProperty('source')) {
-            if (!onInput) {
+            if (changed.source === undefined) {
+                context.storage('source', null);
+            } else if (!onInput) {
                 context.storage('source', changed.source);
                 context.storage('commentDate', Date.now());
             }