From 86e7c23377d9c71fc9ffb7e216332ab1c385b366 Mon Sep 17 00:00:00 2001
From: Kelly Dwan <ryelle@users.noreply.github.com>
Date: Fri, 4 Dec 2020 18:39:34 -0500
Subject: [PATCH 1/3] Core Data: Normalize _fields value for use in stableKey

---
 .../src/queried-data/get-query-parts.js       |  4 ++-
 .../src/queried-data/test/get-query-parts.js  | 12 +++++++
 packages/core-data/src/test/selectors.js      | 33 +++++++++++++++++++
 3 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/packages/core-data/src/queried-data/get-query-parts.js b/packages/core-data/src/queried-data/get-query-parts.js
index ad6ed09792c001..9b54bd4c7cfa20 100644
--- a/packages/core-data/src/queried-data/get-query-parts.js
+++ b/packages/core-data/src/queried-data/get-query-parts.js
@@ -48,7 +48,7 @@ export function getQueryParts( query ) {
 
 	for ( let i = 0; i < keys.length; i++ ) {
 		const key = keys[ i ];
-		const value = query[ key ];
+		let value = query[ key ];
 
 		switch ( key ) {
 			case 'page':
@@ -73,6 +73,8 @@ export function getQueryParts( query ) {
 				// Example: Asking for titles in posts without title support.
 				if ( key === '_fields' ) {
 					parts.fields = getNormalizedCommaSeparable( value );
+					// Make sure to normalize value for `stableKey`
+					value = parts.fields.join();
 				}
 
 				// While it could be any deterministic string, for simplicity's
diff --git a/packages/core-data/src/queried-data/test/get-query-parts.js b/packages/core-data/src/queried-data/test/get-query-parts.js
index 9390c1b36ac160..156e18c995cc4c 100644
--- a/packages/core-data/src/queried-data/test/get-query-parts.js
+++ b/packages/core-data/src/queried-data/test/get-query-parts.js
@@ -79,4 +79,16 @@ describe( 'getQueryParts', () => {
 			include: null,
 		} );
 	} );
+
+	it( 'encodes stable string key with fields parameters', () => {
+		const parts = getQueryParts( { _fields: [ 'id', 'title' ] } );
+
+		expect( parts ).toEqual( {
+			page: 1,
+			perPage: 10,
+			stableKey: '_fields=id%2Ctitle',
+			fields: [ 'id', 'title' ],
+			include: null,
+		} );
+	} );
 } );
diff --git a/packages/core-data/src/test/selectors.js b/packages/core-data/src/test/selectors.js
index 0ec684a21d33d6..f0350af96e2b7e 100644
--- a/packages/core-data/src/test/selectors.js
+++ b/packages/core-data/src/test/selectors.js
@@ -248,6 +248,39 @@ describe( 'getEntityRecords', () => {
 		] );
 	} );
 
+	it( 'should return filtered items', () => {
+		const state = deepFreeze( {
+			entities: {
+				data: {
+					postType: {
+						post: {
+							queriedData: {
+								items: {
+									1: {
+										id: 1,
+										content: 'chicken',
+										author: 'bob',
+									},
+								},
+								itemIsComplete: {
+									1: true,
+								},
+								queries: {
+									'_fields=id%2Ccontent': [ 1 ],
+								},
+							},
+						},
+					},
+				},
+			},
+		} );
+		expect(
+			getEntityRecords( state, 'postType', 'post', {
+				_fields: [ 'id', 'content' ],
+			} )
+		).toEqual( [ { id: 1, content: 'chicken' } ] );
+	} );
+
 	it( 'should return the same instance with the same arguments', () => {
 		let state = deepFreeze( {
 			entities: {

From e034c936eb9e0fd7bbba8246f5e64d48a6892aba Mon Sep 17 00:00:00 2001
From: Kelly Dwan <ryelle@users.noreply.github.com>
Date: Fri, 4 Dec 2020 19:07:02 -0500
Subject: [PATCH 2/3] Fix existing tests

---
 packages/core-data/src/queried-data/test/selectors.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/core-data/src/queried-data/test/selectors.js b/packages/core-data/src/queried-data/test/selectors.js
index f9aa52e1176cac..59ccd92016c02d 100644
--- a/packages/core-data/src/queried-data/test/selectors.js
+++ b/packages/core-data/src/queried-data/test/selectors.js
@@ -94,7 +94,7 @@ describe( 'getQueriedItems', () => {
 				2: true,
 			},
 			queries: {
-				'_fields%5B0%5D=content': [ 1, 2 ],
+				'_fields=content': [ 1, 2 ],
 			},
 		};
 
@@ -133,7 +133,7 @@ describe( 'getQueriedItems', () => {
 				2: true,
 			},
 			queries: {
-				'_fields%5B0%5D=content&_fields%5B1%5D=meta.template': [ 1, 2 ],
+				'_fields=content,meta.template': [ 1, 2 ],
 			},
 		};
 

From ffe270c7be948f458e36259693c4789f2f51743f Mon Sep 17 00:00:00 2001
From: Kelly Dwan <ryelle@users.noreply.github.com>
Date: Fri, 8 Jan 2021 15:01:17 -0500
Subject: [PATCH 3/3] Fix selector used in tests

---
 packages/core-data/src/queried-data/test/selectors.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/core-data/src/queried-data/test/selectors.js b/packages/core-data/src/queried-data/test/selectors.js
index 59ccd92016c02d..76dec520a73589 100644
--- a/packages/core-data/src/queried-data/test/selectors.js
+++ b/packages/core-data/src/queried-data/test/selectors.js
@@ -133,7 +133,7 @@ describe( 'getQueriedItems', () => {
 				2: true,
 			},
 			queries: {
-				'_fields=content,meta.template': [ 1, 2 ],
+				'_fields=content%2Cmeta.template': [ 1, 2 ],
 			},
 		};