Compatibility fixes for Bluebird >=3.4.2

Before 3.4.2, `yield` in a Bluebird `coroutine()` released Zalgo if an
already-resolved promise (e.g., from `Promise.resolve()`) was yielded,
continuing immediately instead of on the next turn of the event loop. We
apparently relied on that broken behavior in a few places, particularly from
`Zotero.DB.waitForTransaction()`. All the transaction-queueing stuff probably
needs to be reevaluated in general, but for now, mirror the previous possibly
ill-advised behavior by checking explicitly for a transaction before yielding
on `waitForTransaction()` (as well as the result of a 'load' event from
`libraryTreeView`).

chrome/content/zotero/browser.js

@@ -605,7 +605,7 @@ var Zotero_Browser = new function() {
 			return;
 		}
 
-		if (!Zotero.isConnector) {
+		if (!Zotero.isConnector && Zotero.DB.inTransaction()) {
 			yield Zotero.DB.waitForTransaction();
 		}
 

chrome/content/zotero/xpcom/db.js

@@ -953,7 +953,9 @@ Zotero.DBConnection.prototype.backupDatabase = Zotero.Promise.coroutine(function
 
 	// Start a promise that will be resolved when the backup is finished
 	var resolveBackupPromise;
-	yield this.waitForTransaction();
+	if (this.inTransaction()) {
+		yield this.waitForTransaction();
+	}
 	this._backupPromise = new Zotero.Promise(function () {
 		resolveBackupPromise = arguments[0];
 	});

chrome/content/zotero/xpcom/schema.js

@@ -1010,8 +1010,9 @@ Zotero.Schema = new function(){
 			return;
 		}
 
-		// If transaction already in progress, delay by ten minutes
-		yield Zotero.DB.waitForTransaction();
+		if (Zotero.DB.inTransaction()) {
+			yield Zotero.DB.waitForTransaction();
+		}
 
 		// Get the last timestamp we got from the server
 		var lastUpdated = yield this.getDBVersion('repository');

chrome/content/zotero/zoteroPane.js

@@ -947,7 +947,9 @@ var ZoteroPane = new function()
 
 
 	this.newSearch = Zotero.Promise.coroutine(function* () {
-		yield Zotero.DB.waitForTransaction();
+		if (Zotero.DB.inTransaction()) {
+			yield Zotero.DB.waitForTransaction();
+		}
 
 		var s = new Zotero.Search();
 		s.libraryID = this.getSelectedLibraryID();
@@ -1011,7 +1013,9 @@ var ZoteroPane = new function()
 
 
 	this.openLookupWindow = Zotero.Promise.coroutine(function* () {
-		yield Zotero.DB.waitForTransaction();
+		if (Zotero.DB.inTransaction()) {
+			yield Zotero.DB.waitForTransaction();
+		}
 
 		if (!this.canEdit()) {
 			this.displayCannotEditLibraryMessage();
@@ -1379,8 +1383,10 @@ var ZoteroPane = new function()
 	 *                              be a better test for whether the item pane changed)
 	 */
 	this.itemSelected = function (event) {
-		return Zotero.spawn(function* () {
-			yield Zotero.DB.waitForTransaction();
+		return Zotero.Promise.coroutine(function* () {
+			if (Zotero.DB.inTransaction()) {
+				yield Zotero.DB.waitForTransaction();
+			}
 
 			// Don't select item until items list has loaded
 			//
@@ -1389,7 +1395,9 @@ var ZoteroPane = new function()
 			this.itemsView.addEventListener('load', function () {
 				deferred.resolve();
 			});
-			yield deferred.promise;
+			if (deferred.promise.isPending()) {
+				yield deferred.promise;
+			}
 
 			if (!this.itemsView || !this.itemsView.selection) {
 				Zotero.debug("Items view not available in itemSelected", 2);
@@ -1592,7 +1600,7 @@ var ZoteroPane = new function()
 			}
 
 			return true;
-		}, this)
+		}.bind(this))()
 		.finally(function () {
 			return this.itemsView.onSelect();
 		}.bind(this));
@@ -3686,7 +3694,9 @@ var ZoteroPane = new function()
 				//
 				// Duplicate newItem() checks here
 				//
-				yield Zotero.DB.waitForTransaction();
+				if (Zotero.DB.inTransaction()) {
+					yield Zotero.DB.waitForTransaction();
+				}
 
 				// Currently selected row
 				if (row === undefined && this.collectionsView && this.collectionsView.selection) {
@@ -3806,7 +3816,9 @@ var ZoteroPane = new function()
 					//
 					// Duplicate newItem() checks here
 					//
-					yield Zotero.DB.waitForTransaction();
+					if (Zotero.DB.inTransaction()) {
+						yield Zotero.DB.waitForTransaction();
+					}
 
 					// Currently selected row
 					if (row === undefined) {
@@ -3894,7 +3906,9 @@ var ZoteroPane = new function()
 	 * |link|      -- create web link instead of snapshot
 	 */
 	this.addAttachmentFromPage = Zotero.Promise.coroutine(function* (link, itemID) {
-		yield Zotero.DB.waitForTransaction();
+		if (Zotero.DB.inTransaction()) {
+			yield Zotero.DB.waitForTransaction();
+		}
 
 		if (typeof itemID != 'number') {
 			throw new Error("itemID must be an integer");