Merge pull request #969 from maartenbreddels/fix_clear_output_with_wait

FIX: respect wait for clear_output
jupyter · Mar 21, 2019 · 12e148f · 12e148f
2 parents 0ef9283 + 741332a
commit 12e148f
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Showing 2 changed files with 194 additions and 18 deletions.
diff --git a/nbconvert/preprocessors/execute.py b/nbconvert/preprocessors/execute.py
@@ -440,6 +440,7 @@ def run_cell(self, cell, cell_index=0):
         exec_reply = self._wait_for_reply(msg_id, cell)
 
         outs = cell.outputs = []
+        self.clear_before_next_output = False
 
         while True:
             try:
@@ -475,13 +476,10 @@ def run_cell(self, cell, cell_index=0):
             elif msg_type == 'execute_input':
                 continue
             elif msg_type == 'clear_output':
-                outs[:] = []
-                # clear display_id mapping for this cell
-                for display_id, cell_map in self._display_id_map.items():
-                    if cell_index in cell_map:
-                        cell_map[cell_index] = []
+                self.clear_output(outs, msg, cell_index)
                 continue
             elif msg_type.startswith('comm'):
+                self.handle_comm_msg(outs, msg, cell_index)
                 continue
 
             display_id = None
@@ -493,22 +491,48 @@ def run_cell(self, cell, cell_index=0):
                     # update_display_data doesn't get recorded
                     continue
 
-            try:
-                out = output_from_msg(msg)
-            except ValueError:
-                self.log.error("unhandled iopub msg: " + msg_type)
-                continue
-            if display_id:
-                # record output index in:
-                #   _display_id_map[display_id][cell_idx]
-                cell_map = self._display_id_map.setdefault(display_id, {})
-                output_idx_list = cell_map.setdefault(cell_index, [])
-                output_idx_list.append(len(outs))
-
-            outs.append(out)
+            self.output(outs, msg, display_id, cell_index)
 
         return exec_reply, outs
 
+    def output(self, outs, msg, display_id, cell_index):
+        msg_type = msg['msg_type']
+        if self.clear_before_next_output:
+            self.log.debug('Executing delayed clear_output')
+            outs[:] = []
+            self.clear_display_id_mapping(cell_index)
+            self.clear_before_next_output = False
+
+        try:
+            out = output_from_msg(msg)
+        except ValueError:
+            self.log.error("unhandled iopub msg: " + msg_type)
+            return
+        if display_id:
+            # record output index in:
+            #   _display_id_map[display_id][cell_idx]
+            cell_map = self._display_id_map.setdefault(display_id, {})
+            output_idx_list = cell_map.setdefault(cell_index, [])
+            output_idx_list.append(len(outs))
+        outs.append(out)
+
+    def clear_output(self, outs, msg, cell_index):
+        content = msg['content']
+        if content.get('wait'):
+            self.log.debug('Wait to clear output')
+            self.clear_before_next_output = True
+        else:
+            self.log.debug('Immediate clear output')
+            outs[:] = []
+            self.clear_display_id_mapping(cell_index)
+
+    def clear_display_id_mapping(self, cell_index):
+        for display_id, cell_map in self._display_id_map.items():
+            if cell_index in cell_map:
+                cell_map[cell_index] = []
+
+    def handle_comm_msg(self, outs, msg, cell_index):
+        pass
 
 def executenb(nb, cwd=None, km=None, **kwargs):
     """Execute a notebook's code, updating outputs within the notebook object.

diff --git a/nbconvert/preprocessors/tests/files/Clear Output.ipynb b/nbconvert/preprocessors/tests/files/Clear Output.ipynb
@@ -31,6 +31,158 @@
     "    clear_output()\n",
     "    print(i)"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "print(\"Hello world\")\n",
+    "clear_output()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Hello world\n"
+     ]
+    }
+   ],
+   "source": [
+    "print(\"Hello world\")\n",
+    "clear_output(wait=True)  # no output after this"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "world\n"
+     ]
+    }
+   ],
+   "source": [
+    "print(\"Hello\")\n",
+    "clear_output(wait=True)  # here we have new output after wait=True\n",
+    "print(\"world\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Hello world'"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "handle0 = display(\"Hello world\", display_id=\"id0\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'world'"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "handle1 = display(\"Hello\", display_id=\"id1\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "handle1.update('world')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "handle2 = display(\"Hello world\", display_id=\"id2\")\n",
+    "clear_output()  # clears all output, also with display_ids"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Hello world'"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "handle3 = display(\"Hello world\", display_id=\"id3\")\n",
+    "clear_output(wait=True)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "world\n"
+     ]
+    }
+   ],
+   "source": [
+    "handle4 = display(\"Hello\", display_id=\"id4\")\n",
+    "clear_output(wait=True)\n",
+    "print('world')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "handle4.update('Hello world')  # it is cleared, so it should not show up in the above cell"
+   ]
   }
  ],
  "metadata": {},