Remove bad .eval implementation

The implementation is not really good as mentioned in #722 and we pipline our commands.
That way we can't just replace the eval function as it was. This could result in violating the order of execution!

If we want to include a function like this we should not break the order of execution and also not recalculate the sha1 hash each time.

Author: Ruben Bridgewater

index.js

@@ -6,7 +6,6 @@ var net = require("net"),
     Queue = require("./lib/queue"),
     to_array = require("./lib/to_array"),
     events = require("events"),
-    crypto = require("crypto"),
     parsers = [],
     // This static list of commands is updated from time to time.
     // ./lib/commands.js can be updated with generate_commands.js
@@ -1083,37 +1082,6 @@ RedisClient.prototype.multi = RedisClient.prototype.MULTI = function (args) {
     return new Multi(this, args);
 };
 
-// stash original eval method
-var eval_orig = RedisClient.prototype.eval;
-// hook eval with an attempt to evalsha for cached scripts
-RedisClient.prototype.eval = RedisClient.prototype.EVAL = function () {
-    var self = this,
-        args = to_array(arguments),
-        callback;
-
-    if (typeof args[args.length - 1] === "function") {
-        callback = args.pop();
-    }
-
-    if (Array.isArray(args[0])) {
-        args = args[0];
-    }
-
-    // replace script source with sha value
-    var source = args[0];
-    args[0] = crypto.createHash("sha1").update(source).digest("hex");
-
-    self.evalsha(args, function (err, reply) {
-        if (err && /NOSCRIPT/.test(err.message)) {
-            args[0] = source;
-            eval_orig.call(self, args, callback);
-
-        } else if (callback) {
-            callback(err, reply);
-        }
-    });
-};
-
 var createClient_unix = function(path, options){
     var cnxOptions = {
         path: path

test/commands/eval.spec.js

@@ -12,6 +12,7 @@ describe("The 'eval' method", function () {
 
         describe("using " + parser + " and " + ip, function () {
             var client;
+            var source = "return redis.call('set', 'sha', 'test')";
 
             beforeEach(function (done) {
                 client = redis.createClient.apply(redis.createClient, args);
@@ -94,31 +95,41 @@ describe("The 'eval' method", function () {
                 });
             });
 
+            it('allows a script to be executed that accesses the redis API without callback', function (done) {
+                helper.serverVersionAtLeast.call(this, client, [2, 5, 0]);
+                client.eval(source, 0);
+                client.get('sha', helper.isString('test', done));
+            });
+
             describe('evalsha', function () {
-                var source = "return redis.call('get', 'sha test')";
                 var sha = crypto.createHash('sha1').update(source).digest('hex');
 
-                beforeEach(function (done) {
-                    client.set("sha test", "eval get sha test", function (err, res) {
-                        return done(err);
-                    });
-                });
-
                 it('allows a script to be executed that accesses the redis API', function (done) {
                     helper.serverVersionAtLeast.call(this, client, [2, 5, 0]);
-                    client.eval(source, 0, helper.isString('eval get sha test', done));
+                    client.eval(source, 0, helper.isString('OK'));
+                    client.get('sha', helper.isString('test', done));
                 });
 
                 it('can execute a script if the SHA exists', function (done) {
                     helper.serverVersionAtLeast.call(this, client, [2, 5, 0]);
-                    client.evalsha(sha, 0, helper.isString('eval get sha test', done));
+                    client.evalsha(sha, 0, helper.isString('OK'));
+                    client.get('sha', helper.isString('test', done));
                 });
 
                 it('returns an error if SHA does not exist', function (done) {
                     helper.serverVersionAtLeast.call(this, client, [2, 5, 0]);
                     client.evalsha('ffffffffffffffffffffffffffffffffffffffff', 0, helper.isError(done));
                 });
 
+                it('emit an error if SHA does not exist without any callback', function (done) {
+                    helper.serverVersionAtLeast.call(this, client, [2, 5, 0]);
+                    client.evalsha('ffffffffffffffffffffffffffffffffffffffff', 0);
+                    client.on('error', function(err) {
+                        assert(/NOSCRIPT No matching script. Please use EVAL./.test(err.message));
+                        done();
+                    });
+                });
+
                 it('emits an error if SHA does not exist and no callback has been provided', function (done) {
                     client.on('error', function (err) {
                         assert.equal(err.message, 'NOSCRIPT No matching script. Please use EVAL.');