From 80489843eececb588e20c8792fdcdaef8a1669d2 Mon Sep 17 00:00:00 2001
From: Steve Howell <showell@zulipchat.com>
Date: Thu, 9 Apr 2020 21:12:03 +0000
Subject: [PATCH] message store: Report type confusion errors.

We also complain if the caller sends us
`undefined`.
---
 frontend_tests/node_tests/message_store.js | 13 ++++++++++++-
 static/js/message_store.js                 | 13 +++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/frontend_tests/node_tests/message_store.js b/frontend_tests/node_tests/message_store.js
index 1f5e22e23f..15129e9add 100644
--- a/frontend_tests/node_tests/message_store.js
+++ b/frontend_tests/node_tests/message_store.js
@@ -96,7 +96,12 @@ run_test('add_message_metadata', () => {
     assert.equal(message.alerted, true);
     assert.equal(message.is_me_message, false);
 
-    const retrieved_message = message_store.get(2067);
+    let retrieved_message = message_store.get(2067);
+    assert.equal(retrieved_message, message);
+
+    blueslip.expect('error', 'message_store got non-number: 2067');
+    retrieved_message = message_store.get('2067');
+    blueslip.reset();
     assert.equal(retrieved_message, message);
 
     // access cached previous message, and test match subject/content
@@ -297,3 +302,9 @@ run_test('message_id_change', () => {
     });
 
 });
+
+run_test('errors', () => {
+    blueslip.expect('error', 'message_store.get got bad value: undefined');
+    message_store.get(undefined);
+    blueslip.reset();
+});
diff --git a/static/js/message_store.js b/static/js/message_store.js
index 45ab39d8da..dae7e10a3a 100644
--- a/static/js/message_store.js
+++ b/static/js/message_store.js
@@ -21,6 +21,19 @@ exports.user_ids = function () {
 };
 
 exports.get = function get(message_id) {
+    if (message_id === undefined || message_id === null) {
+        blueslip.error('message_store.get got bad value: ' + message_id);
+        return;
+    }
+
+    if (typeof message_id !== 'number') {
+        blueslip.error('message_store got non-number: ' + message_id);
+
+        // Try to solider on, assuming the caller treats message
+        // ids as strings.
+        message_id = parseFloat(message_id);
+    }
+
     return stored_messages.get(message_id);
 };