Eth.setProvider now sets the provider on Contract instances

When Eth.setProvider is called, any Contract instances created by the
Eth instance will have their providers updated

packages/web3-eth/src/index.js

@@ -143,8 +143,20 @@ var Eth = function Eth() {
     // not create this proxy type, changing the provider in one instance of
     // web3-eth would subsequently change the provider for _all_ contract
     // instances!
+    var self = this;
     var Contract = function Contract() {
         BaseContract.apply(this, arguments);
+
+        // when Eth.setProvider is called, call packageInit
+        // on all contract instances instantiated via this Eth
+        // instances. This will update the currentProvider for
+        // the contract instances
+        var _this = this;
+        var setProvider = self.setProvider;
+        self.setProvider = function() {
+          setProvider.apply(self, arguments);
+          core.packageInit(_this, [self.currentProvider]);
+        };
     };
 
     Contract.setProvider = function() {

test/contract.js

@@ -2912,6 +2912,20 @@ var runTests = function(contractFactory) {
 describe('typical usage', function() {
     runTests(getEthContractInstance);
 
+    it('should update contract instance provider when assigned a provider to eth instance that contract instance came from', function () {
+        var provider1 = new FakeIpcProvider();
+        var provider2 = new FakeHttpProvider();
+
+        var eth = new Eth(provider1);
+        var contract = new eth.Contract(abi, address);
+        assert.deepEqual(contract.currentProvider, provider1);
+        assert.deepEqual(eth.currentProvider, provider1);
+
+        eth.setProvider(provider2);
+        assert.deepEqual(contract.currentProvider, provider2);
+        assert.deepEqual(eth.currentProvider, provider2);
+    });
+
     it('should deploy a contract, sign transaction, and return contract instance', function (done) {
         var provider = new FakeIpcProvider();
         var eth = new Eth(provider);