Don't clear md5/mtime in item JSON if skipped in patch mode

The client skips synced storage properties (md5, mtime) when uploading items to
ZFS-enabled libraries, but since the API returns JSON with those values
included after writes, they do get saved to the sync cache. If the local
attachment is then modified and the client generates a diff from the cached
version with those properties skipped, they'll be included in the patch JSON as
empty strings in order to clear them. This changes Zotero.Item::toJSON() to
skip those properties in patch mode as well.

This fixes a sync error ("Cannot change 'md5' directly in group library") when
a group attachment is updated locally.

chrome/content/zotero/xpcom/data/item.js

@@ -4237,7 +4237,12 @@ Zotero.Item.prototype.toJSON = function (options = {}) {
 		obj.dateModified = Zotero.Date.sqlToISO8601(this.dateModified);
 	}
 	
-	return this._postToJSON(env);
+	var json = this._postToJSON(env);
+	if (options.skipStorageProperties) {
+		delete json.md5;
+		delete json.mtime;
+	}
+	return json;
 }
 
 

test/tests/itemTest.js

@@ -1192,6 +1192,28 @@ describe("Zotero.Item", function () {
 				var json = note.toJSON({ patchBase });
 				assert.isFalse(json.parentItem);
 			});
+			
+			it("shouldn't clear storage properties from original in .skipStorageProperties mode", function* () {
+				var item = new Zotero.Item('attachment');
+				item.attachmentLinkMode = 'imported_file';
+				item.attachmentFilename = 'test.txt';
+				item.attachmentContentType = 'text/plain';
+				item.attachmentCharset = 'utf-8';
+				item.attachmentSyncedModificationTime = 1234567890000;
+				item.attachmentSyncedHash = '18d21750c8abd5e3afa8ea89e3dfa570';
+				var patchBase = item.toJSON({
+					syncedStorageProperties: true
+				});
+				item.setNote("Test");
+				var json = item.toJSON({
+					patchBase,
+					skipStorageProperties: true
+				});
+				Zotero.debug(json);
+				assert.equal(json.note, "Test");
+				assert.notProperty(json, "md5");
+				assert.notProperty(json, "mtime");
+			});
 		})
 	})