Merge pull request #711 from ethereum/fixBlockPolling

fix getBlock/SetInterval && update block gas limit when provider change

remix-lib/src/execution/execution-context.js

@@ -173,6 +173,7 @@ function ExecutionContext () {
       } else {
         executionContext = context
         web3.setProvider(injectedProvider)
+        self._updateBlockGasLimit()
         self.event.trigger('contextChanged', ['injected'])
         return cb()
       }
@@ -192,8 +193,7 @@ function ExecutionContext () {
     this.listenOnLastBlockId = null
   }
 
-  this.listenOnLastBlock = function () {
-    this.listenOnLastBlockId = setInterval(() => {
+  this._updateBlockGasLimit = function () {
     if (this.getProvider() !== 'vm') {
       web3.eth.getBlock('latest', (err, block) => {
         if (!err) {
@@ -202,10 +202,15 @@ function ExecutionContext () {
         } else {
           this.blockGasLimit = this.blockGasLimitDefault
         }
-        }, 15000)
-      }
       })
     }
+  }
+
+  this.listenOnLastBlock = function () {
+    this.listenOnLastBlockId = setInterval(() => {
+      this._updateBlockGasLimit()
+    }, 15000)
+  }
 
   // TODO: not used here anymore and needs to be moved
   function setProviderFromEndpoint (endpoint, context, cb) {
@@ -218,6 +223,7 @@ function ExecutionContext () {
     }
     if (web3.isConnected()) {
       executionContext = context
+      self._updateBlockGasLimit()
       self.event.trigger('contextChanged', ['web3'])
       self.event.trigger('web3EndpointChanged')
       cb()