Coalesce multiple stdout/stderr Notebook outputs into single blocks

I am struggling to understand why the cells output is split in multiple lines when the book is rendered using HTML. My stata.ipynb notebook source code looks like

 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Operators\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "(1978 Automobile Data)\n",
      "\n",
      "\n",
      "      Source |       SS           df       MS      Number of obs   =        74\n",
      "-------------+----------------------------------   F(1, 72)        =     20.26\n",
      "       Model |   139449474         1   139449474   Prob > F        =    0.0000\n",
      "    Residual |   495615923        72  6883554.48   R-squared       =    0.2196\n",
      "-------------+----------------------------------   Adj R-squared   =    0.2087\n",
      "       Total |   635065396        73  8699525.97   Root MSE        =    2623.7\n",
      "\n",
      "------------------------------------------------------------------------------\n",
      "       price |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]\n",
      "-------------+----------------------------------------------------------------\n",
      "         mpg |  -238.8943   53.07669    -4.50   0.000    -344.7008   -133.0879\n",
      "       _cons |   11253.06   1170.813     9.61   0.000     8919.088    13587.03\n",
      "------------------------------------------------------------------------------\n"
     ]
    }
   ],
   "source": [
    "sysuse auto\n",
    "reg price mpg"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Stata",
   "language": "stata",
   "name": "stata"
  },
  "language_info": {
   "codemirror_mode": "stata",
   "file_extension": ".do",
   "mimetype": "text/x-stata",
   "name": "stata",
   "version": "15.1"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 4
}

After I built the book using

(base) Federicos-MacBook-Pro:books federico$ jupyter-book clean mybook/ --all

===============================================================================

Your _build directory has been removed

===============================================================================

(base) Federicos-MacBook-Pro:books federico$ jupyter-book build mybook/
Running Jupyter-Book v0.8.1
Source Folder: /Users/federico/Desktop/Dropbox/Teaching/jupyter/books/mybook
Config Path: /Users/federico/Desktop/Dropbox/Teaching/jupyter/books/mybook/_config.yml
Output Path: /Users/federico/Desktop/Dropbox/Teaching/jupyter/books/mybook/_build/html
Running Sphinx v2.4.0
making output directory... done
myst v0.12.9: MdParserConfig(renderer='sphinx', commonmark_only=False, dmath_enable=True, dmath_allow_labels=True, dmath_allow_space=True, dmath_allow_digits=True, amsmath_enable=False, deflist_enable=False, update_mathjax=True, admonition_enable=False, figure_enable=False, disable_syntax=[], html_img_enable=False, url_schemes=['mailto', 'http', 'https'], heading_anchors=None)
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 1 source files that are out of date
updating environment: [new config] 1 added, 0 changed, 0 removed
Executing: stata in: /Users/federico/Desktop/Dropbox/Teaching/jupyter/books/mybook                                                           

looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
writing output... [100%] stata                                                                                                               
generating indices...  genindexdone
writing additional pages...  searchdone
copying static files... ... done
copying extra files... done
dumping search index in English (code: en)... done
dumping object inventory... done
build succeeded.

The HTML pages are in mybook/_build/html.

===============================================================================

Finished generating HTML for book.
Your book's HTML pages are here:
    mybook/_build/html/
You can look at your book by opening this file in a browser:
    mybook/_build/html/index.html
Or paste this line directly into your browser bar:
    file:///Users/federico/Desktop/Dropbox/Teaching/jupyter/books/mybook/_build/html/index.html            

===============================================================================

the notebook source code in the mybook/_build/jupyter_execute appears to be different and, as you can see below, the output of each “code” cell is split in separate lines

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Operators\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "(1978 Automobile Data)\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "\n",
      "      Source |       SS           df       MS      Number of obs   =        74\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "-------------+----------------------------------   F(1, 72)        =     20.26\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "       Model |   139449474         1   139449474   Prob > F        =    0.0000\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "    Residual |   495615923        72  6883554.48   R-squared       =    0.2196\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "-------------+----------------------------------   Adj R-squared   =    0.2087\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "       Total |   635065396        73  8699525.97   Root MSE        =    2623.7\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "------------------------------------------------------------------------------\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "       price |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "-------------+----------------------------------------------------------------\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "         mpg |  -238.8943   53.07669    -4.50   0.000    -344.7008   -133.0879\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "       _cons |   11253.06   1170.813     9.61   0.000     8919.088    13587.03\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "------------------------------------------------------------------------------\n"
     ]
    }
   ],
   "source": [
    "sysuse auto\n",
    "reg price mpg"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Stata",
   "language": "stata",
   "name": "stata"
  },
  "language_info": {
   "codemirror_mode": "stata",
   "file_extension": ".do",
   "mimetype": "text/x-stata",
   "name": "stata",
   "version": "15.1"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 4
}

This is how the HTML final output looks like

Do you have any idea of why this is happening?

Many thanks! Federico

Environment

• Python v3.7.6
• Jupyter-Book v0.8.1
• Sphinx v2.4.0
• myst v0.12.9
• Operating System: OsX Catalina

[chrisjsewell]

This is now available in https://github.com/executablebooks/MyST-NB/compare/v0.13.0...v0.13.1 (as nb_merge_streams=True) 😄 and so will be incorporated into jupyter-book in the next release

[fbelotti]

For those who have the same issue, a “temporary” workaround is to execute the notebooks on your own, copy and paste all the .ipynb files in the ./_build/jupyter_execute/ folder and put the execute_notebooks: off setting in the execute section of the book’s _config.yml file.

execute:
  execute_notebooks: off 

Hope this helps.