From c73fda84b24c635b269fc549710cb3dff00b4899 Mon Sep 17 00:00:00 2001
From: Diamond Lewis <findlewis@gmail.com>
Date: Wed, 19 Dec 2018 17:02:41 -0600
Subject: [PATCH 1/2] PG: Fix containedIn query on empty array

---
 spec/ParseQuery.spec.js                       | 24 +++++++++++++++++++
 .../Postgres/PostgresStorageAdapter.js        |  6 ++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/spec/ParseQuery.spec.js b/spec/ParseQuery.spec.js
index f3803b168f..e12988984d 100644
--- a/spec/ParseQuery.spec.js
+++ b/spec/ParseQuery.spec.js
@@ -238,6 +238,30 @@ describe('Parse.Query testing', () => {
       });
   });
 
+  it('query notContainedIn on empty array', async () => {
+    const object = new TestObject();
+    object.set('value', 100);
+    await object.save();
+
+    const query = new Parse.Query(TestObject);
+    query.notContainedIn('value', []);
+
+    const results = await query.find();
+    equal(results.length, 0);
+  });
+
+  it('query containedIn on empty array', async () => {
+    const object = new TestObject();
+    object.set('value', 100);
+    await object.save();
+
+    const query = new Parse.Query(TestObject);
+    query.containedIn('value', []);
+
+    const results = await query.find();
+    equal(results.length, 0);
+  });
+
   it('query with limit', function(done) {
     const baz = new TestObject({ foo: 'baz' });
     const qux = new TestObject({ foo: 'qux' });
diff --git a/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js b/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
index 8df3acc9f5..e9578285d1 100644
--- a/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
+++ b/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
@@ -402,8 +402,8 @@ const buildWhereClause = ({ schema, query, index }): WhereClause => {
       index = index + 1 + inPatterns.length;
     } else if (isInOrNin) {
       var createConstraint = (baseArray, notIn) => {
+        const not = notIn ? ' NOT ' : '';
         if (baseArray.length > 0) {
-          const not = notIn ? ' NOT ' : '';
           if (isArrayField) {
             patterns.push(
               `${not} array_contains($${index}:name, $${index + 1})`
@@ -430,6 +430,10 @@ const buildWhereClause = ({ schema, query, index }): WhereClause => {
           values.push(fieldName);
           patterns.push(`$${index}:name IS NULL`);
           index = index + 1;
+        } else {
+          patterns.push(`$${index}:name ${not} IN (null)`);
+          values.push(fieldName);
+          index += 1;
         }
       };
       if (fieldValue.$in) {

From bba5f714d181dc6f38b659b0c1794ed275cfacf1 Mon Sep 17 00:00:00 2001
From: Diamond Lewis <findlewis@gmail.com>
Date: Wed, 19 Dec 2018 17:35:44 -0600
Subject: [PATCH 2/2] improve logic

---
 spec/ParseQuery.spec.js                                 | 2 +-
 src/Adapters/Storage/Postgres/PostgresStorageAdapter.js | 9 ++++++---
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/spec/ParseQuery.spec.js b/spec/ParseQuery.spec.js
index e12988984d..355689f6b7 100644
--- a/spec/ParseQuery.spec.js
+++ b/spec/ParseQuery.spec.js
@@ -247,7 +247,7 @@ describe('Parse.Query testing', () => {
     query.notContainedIn('value', []);
 
     const results = await query.find();
-    equal(results.length, 0);
+    equal(results.length, 1);
   });
 
   it('query containedIn on empty array', async () => {
diff --git a/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js b/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
index e9578285d1..dcfd34b877 100644
--- a/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
+++ b/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
@@ -431,9 +431,12 @@ const buildWhereClause = ({ schema, query, index }): WhereClause => {
           patterns.push(`$${index}:name IS NULL`);
           index = index + 1;
         } else {
-          patterns.push(`$${index}:name ${not} IN (null)`);
-          values.push(fieldName);
-          index += 1;
+          // Handle empty array
+          if (notIn) {
+            patterns.push('1 = 1'); // Return all values
+          } else {
+            patterns.push('1 = 2'); // Return no values
+          }
         }
       };
       if (fieldValue.$in) {