Skip exceptions

IPython/html/static/notebook/js/codecell.js

@@ -403,7 +403,7 b' define(['
      * Execute current code cell to the kernel
      * @method execute
      */
-    CodeCell.prototype.execute = function () {
+    CodeCell.prototype.execute = function (skip_exceptions) {
         if (!this.kernel || !this.kernel.is_connected()) {
             console.log("Can't execute, kernel is not connected.");
             return;
@@ -411,6 +411,10 b' define(['
 
         this.active_output_area.clear_output(false, true);
         
+        if (skip_exceptions === undefined) {
+            skip_exceptions = false;
+        }
+
         // Clear widget area
         for (var i = 0; i < this.widget_views.length; i++) {
             var view = this.widget_views[i];
@@ -434,7 +438,8 b' define(['
         var callbacks = this.get_callbacks();
         
         var old_msg_id = this.last_msg_id;
-        this.last_msg_id = this.kernel.execute(this.get_text(), callbacks, {silent: false, store_history: true});
+        this.last_msg_id = this.kernel.execute(this.get_text(), callbacks, {silent: false, store_history: true,
+            skip_exceptions : skip_exceptions});
         if (old_msg_id) {
             delete CodeCell.msg_cells[old_msg_id];
         }

IPython/html/tests/notebook/execute_code.js

@@ -75,4 +75,39 b' casper.notebook_test(function () {'
         var result = this.get_output_cell(0);
         this.test.assertEquals(result.text, '13\n', 'cell execute (using "play" toolbar button)')
     });
+
+    // run code with skip_exception
+    this.thenEvaluate(function () {
+        var cell0 = IPython.notebook.get_cell(0);
+        cell0.set_text('raise IOError');
+        IPython.notebook.insert_cell_below('code',0);
+        var cell1 = IPython.notebook.get_cell(1);
+        cell1.set_text('a=14; print(a)');
+        cell0.execute(skip_exception=true);
+        cell1.execute();
+    });
+
+    this.wait_for_output(1);
+
+    this.then(function () {
+        var result = this.get_output_cell(1);
+        this.test.assertEquals(result.text, '14\n', 'cell execute, skip exceptions');
+    });
+
+    this.thenEvaluate(function () {
+        var cell0 = IPython.notebook.get_cell(0);
+        cell0.set_text('raise IOError');
+        IPython.notebook.insert_cell_below('code',0);
+        var cell1 = IPython.notebook.get_cell(1);
+        cell1.set_text('a=14; print(a)');
+        cell0.execute();
+        cell1.execute();
+    });
+
+    this.wait_for_output(1);
+
+    this.then(function () {
+        var result = this.get_output_cell(1);
+        this.test.assertNotEquals(result.text, '14\n', 'cell execute, skip exceptions');
+    });
 });

IPython/kernel/client.py

@@ -196,7 +196,7 b' class KernelClient(ConnectionFileMixin):'
 
     # Methods to send specific messages on channels
     def execute(self, code, silent=False, store_history=True,
-                user_expressions=None, allow_stdin=None):
+                user_expressions=None, allow_stdin=None, skip_exceptions=False):
         """Execute code in the kernel.
 
         Parameters
@@ -224,6 +224,9 b' class KernelClient(ConnectionFileMixin):'
             If raw_input is called from code executed from such a frontend, a
             StdinNotImplementedError will be raised.
 
+        skip_exceptions: bool, optional (default False)
+            Flag whether to abort the execution queue, if an exception is encountered.
+
         Returns
         -------
         The msg_id of the message sent.
@@ -243,7 +246,7 b' class KernelClient(ConnectionFileMixin):'
         # not in Session.
         content = dict(code=code, silent=silent, store_history=store_history,
                        user_expressions=user_expressions,
-                       allow_stdin=allow_stdin,
+                       allow_stdin=allow_stdin, skip_exceptions=skip_exceptions
                        )
         msg = self.session.msg('execute_request', content)
         self.shell_channel.send(msg)

IPython/kernel/tests/test_message_spec.py

@@ -303,6 +303,24 b' def test_execute_inc():'
     count_2 = reply['execution_count']
     nt.assert_equal(count_2, count+1)
 
+def test_execute_skip_exceptions():
+    """execute request should not abort execution queue with skip_exceptions"""
+    flush_channels()
+
+    KC.execute(code='raise IOError')
+    msg_id = KC.execute(code='print("Hallo")')
+    KC.get_shell_msg(timeout=TIMEOUT)
+    reply = KC.get_shell_msg(timeout=TIMEOUT)
+    nt.assert_equal(reply['content']['status'], 'aborted')
+
+    flush_channels()
+
+    KC.execute(code='raise IOError', skip_exceptions=True)
+    msg_id = KC.execute(code='print("Hallo")')
+    KC.get_shell_msg(timeout=TIMEOUT)
+    reply = KC.get_shell_msg(timeout=TIMEOUT)
+    nt.assert_equal(reply['content']['status'], 'ok')
+
 
 def test_user_expressions():
     flush_channels()

IPython/kernel/zmq/kernelbase.py

@@ -348,6 +348,11 b' class Kernel(SingletonConfigurable):'
             self.log.error("%s", parent)
             return
         
+        if u'skip_exceptions' in content and content[u'skip_exceptions'] is True:
+            skip_exceptions = True
+        else:
+            skip_exceptions = False
+
         md = self._make_metadata(parent['metadata'])
         
         # Re-broadcast our input for the benefit of listening clients, and
@@ -382,11 +387,11 b' class Kernel(SingletonConfigurable):'
         
         self.log.debug("%s", reply_msg)
 
-        if not silent and reply_msg['content']['status'] == u'error':
+        if not silent and reply_msg['content']['status'] == u'error' and not skip_exceptions:
             self._abort_queues()
 
     def do_execute(self, code, silent, store_history=True,
-                   user_experssions=None, allow_stdin=False):
+                   user_expressions=None, allow_stdin=False):
         """Execute user code. Must be overridden by subclasses.
         """
         raise NotImplementedError

docs/source/development/messaging.rst

@@ -281,6 +281,10 b' Message type: ``execute_request``::'
     # If raw_input is called from code executed from such a frontend,
     # a StdinNotImplementedError will be raised.
     'allow_stdin' : True,
+
+    # A boolean flag, which, if True, does not abort the execution queue, if an exception is encountered.
+    # This allows the queued execution of multiple execute_requests, even if they generate exceptions.
+    'skip_exceptions' : True,
     }
 
 .. versionchanged:: 5.0