Client to emit errors now instead of throwing them asynchronously where they're uncatchable.

Author: brycebaril

index.js

@@ -147,9 +147,7 @@ RedisClient.prototype.flush_and_error = function (message) {
             try {
                 command_obj.callback(error);
             } catch (callback_err) {
-                process.nextTick(function () {
-                    throw callback_err;
-                });
+                this.emit("error", callback_err);
             }
         }
     }
@@ -161,9 +159,7 @@ RedisClient.prototype.flush_and_error = function (message) {
             try {
                 command_obj.callback(error);
             } catch (callback_err) {
-                process.nextTick(function () {
-                    throw callback_err;
-                });
+                this.emit("error", callback_err);
             }
         }
     }
@@ -559,34 +555,26 @@ RedisClient.prototype.return_error = function (err) {
         try {
             command_obj.callback(err);
         } catch (callback_err) {
-            // if a callback throws an exception, re-throw it on a new stack so the parser can keep going
-            process.nextTick(function () {
-                throw callback_err;
-            });
+            this.emit("error", callback_err);
         }
     } else {
         console.log("node_redis: no callback to send error: " + err.message);
-        // this will probably not make it anywhere useful, but we might as well throw
-        process.nextTick(function () {
-            throw err;
-        });
+        this.emit("error", err);
     }
 };
 
 // if a callback throws an exception, re-throw it on a new stack so the parser can keep going.
 // if a domain is active, emit the error on the domain, which will serve the same function.
 // put this try/catch in its own function because V8 doesn't optimize this well yet.
-function try_callback(callback, reply) {
+function try_callback(client, callback, reply) {
     try {
         callback(null, reply);
     } catch (err) {
         if (process.domain) {
             process.domain.emit('error', err);
             process.domain.exit();
         } else {
-            process.nextTick(function () {
-                throw err;
-            });
+            client.emit("error", err);
         }
     }
 }
@@ -668,7 +656,7 @@ RedisClient.prototype.return_reply = function (reply) {
                 reply = reply_to_object(reply);
             }
 
-            try_callback(command_obj.callback, reply);
+            try_callback(this, command_obj.callback, reply);
         } else if (exports.debug_mode) {
             console.log("no callback for reply: " + (reply && reply.toString && reply.toString()));
         }
@@ -694,7 +682,7 @@ RedisClient.prototype.return_reply = function (reply) {
                 // reply[1] can be null
                 var reply1String = (reply[1] === null) ? null : reply[1].toString();
                 if (command_obj && typeof command_obj.callback === "function") {
-                    try_callback(command_obj.callback, reply1String);
+                    try_callback(this, command_obj.callback, reply1String);
                 }
                 this.emit(type, reply1String, reply[2]); // channel, count
             } else {

test.js

@@ -402,6 +402,72 @@ tests.FWD_ERRORS_1 = function () {
     }, 150);
 };
 
+tests.FWD_ERRORS_2 = function () {
+    var name = "FWD_ERRORS_2";
+
+    var toThrow = new Error("Forced exception");
+    var recordedError = null;
+
+    var originalHandler = client.listeners("error").pop();
+    client.removeAllListeners("error");
+    client.once("error", function (err) {
+        recordedError = err;
+    });
+
+    client.get("no_such_key", function (err, reply) {
+        throw toThrow;
+    });
+
+    setTimeout(function () {
+        client.listeners("error").push(originalHandler);
+        assert.equal(recordedError, toThrow, "Should have caught our forced exception");
+        next(name);
+    }, 150);
+};
+
+tests.FWD_ERRORS_3 = function () {
+    var name = "FWD_ERRORS_3";
+
+    var recordedError = null;
+
+    var originalHandler = client.listeners("error").pop();
+    client.removeAllListeners("error");
+    client.once("error", function (err) {
+        recordedError = err;
+    });
+
+    client.send_command("no_such_command", []);
+
+    setTimeout(function () {
+        client.listeners("error").push(originalHandler);
+        assert.ok(recordedError instanceof Error);
+        next(name);
+    }, 150);
+};
+
+tests.FWD_ERRORS_4 = function () {
+    var name = "FWD_ERRORS_4";
+
+    var toThrow = new Error("Forced exception");
+    var recordedError = null;
+
+    var originalHandler = client.listeners("error").pop();
+    client.removeAllListeners("error");
+    client.once("error", function (err) {
+        recordedError = err;
+    });
+
+    client.send_command("no_such_command", [], function () {
+        throw toThrow;
+    });
+
+    setTimeout(function () {
+        client.listeners("error").push(originalHandler);
+        assert.equal(recordedError, toThrow, "Should have caught our forced exception");
+        next(name);
+    }, 150);
+};
+
 tests.EVAL_1 = function () {
     var name = "EVAL_1";