Fix transaction detection

This fixes an issue where two transactions started around the same time
could run separately instead of nesting, causing the statements from one
to end up running not within a transaction

chrome/content/zotero/xpcom/db.js

@@ -450,9 +450,8 @@ Zotero.DBConnection.prototype.executeTransaction = Zotero.Promise.coroutine(func
 		}
 	}
 	
-	var conn = yield this._getConnectionAsync(options);
 	try {
-		if (conn.transactionInProgress) {
+		if (this._inTransaction) {
 			Zotero.debug("Async DB transaction in progress -- increasing level to "
 				+ ++this._asyncTransactionNestingLevel, 5);
 			
@@ -469,7 +468,7 @@ Zotero.DBConnection.prototype.executeTransaction = Zotero.Promise.coroutine(func
 				var result = yield Zotero.Promise.coroutine(func)();
 			}
 			catch (e) {
-				Zotero.debug("Rolled back nested async DB transaction", 5);
+				Zotero.debug("Rolling back nested async DB transaction", 5);
 				this._asyncTransactionNestingLevel = 0;
 				throw e;
 			}
@@ -481,6 +480,8 @@ Zotero.DBConnection.prototype.executeTransaction = Zotero.Promise.coroutine(func
 		else {
 			Zotero.debug("Beginning async DB transaction", 5);
 			
+			this._inTransaction = true;
+			
 			var resolve;
 			var reject;
 			this._transactionPromise = new Zotero.Promise(function () {
@@ -497,8 +498,10 @@ Zotero.DBConnection.prototype.executeTransaction = Zotero.Promise.coroutine(func
 					this._callbacks.begin[i]();
 				}
 			}
+			var conn = yield this._getConnectionAsync(options);
 			var result = yield conn.executeTransaction(func);
 			Zotero.debug("Committed async DB transaction", 5);
+			this._inTransaction = false;
 			
 			// Clear transaction time
 			if (this._transactionDate) {
@@ -540,6 +543,7 @@ Zotero.DBConnection.prototype.executeTransaction = Zotero.Promise.coroutine(func
 	catch (e) {
 		Zotero.debug("Rolled back async DB transaction", 5);
 		Zotero.debug(e, 1);
+		this._inTransaction = false;
 		
 		if (options) {
 			// Function to run once transaction has been committed but before any

test/tests/dbTest.js

@@ -1,5 +1,41 @@
 describe("Zotero.DB", function() {
 	describe("#executeTransaction()", function () {
+		it("should nest concurrent transactions", Zotero.Promise.coroutine(function* () {
+			var tmpTable = "tmpWaitForTransactions";
+			yield Zotero.DB.queryAsync("CREATE TABLE " + tmpTable + " (foo INT)");
+			
+			var resolve1, resolve2, reject1, reject2;
+			var promise1 = new Promise(function (resolve, reject) {
+				resolve1 = resolve;
+				reject1 = reject;
+			});
+			var promise2 = new Promise(function (resolve, reject) {
+				resolve2 = resolve;
+				reject2 = reject;
+			});
+			
+			Zotero.DB.executeTransaction(function* () {
+				yield Zotero.Promise.delay(100);
+				assert.equal(Zotero.DB._asyncTransactionNestingLevel, 0);
+				yield Zotero.DB.queryAsync("INSERT INTO " + tmpTable + " VALUES (2)");
+				// Make sure we're still in a transaction
+				Zotero.DB.transactionDate;
+			})
+			.then(resolve1)
+			.catch(reject1);
+			
+			Zotero.DB.executeTransaction(function* () {
+				assert.equal(Zotero.DB._asyncTransactionNestingLevel, 1);
+				yield Zotero.DB.queryAsync("INSERT INTO " + tmpTable + " VALUES (1)");
+				// Make sure we're still in a transaction
+				Zotero.DB.transactionDate;
+			})
+			.then(resolve2)
+			.catch(reject2);
+			
+			yield Zotero.Promise.all([promise1, promise2]);
+		}));
+		
 		it("should roll back on error", function* () {
 			var tmpTable = "tmpRollbackOnError";
 			yield Zotero.DB.queryAsync("CREATE TABLE " + tmpTable + " (foo INT)");