Ignore unknown directive options rather than aborting

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
       - name: Install Python
         uses: actions/setup-python@v2
         with:
-          python-version: "3.x"
+          python-version: "3.6"
       - name: Install dependencies
         run: python -m pip install tox
       - name: Run linting

readme_renderer/rst.py

@@ -15,13 +15,45 @@
 
 import io
 
+from docutils import utils
 from docutils.core import publish_parts
 from docutils.writers.html4css1 import HTMLTranslator, Writer
 from docutils.utils import SystemMessage
 
 from .clean import clean
 
 
+def extract_extension_options(field_list, option_spec):
+    """
+    Overrides `utils.extract_extension_options` and inlines
+    `utils.assemble_option_dict` to make it ignore unknown options passed to
+    directives (i.e. ``:caption:`` for ``.. code-block:``).
+    """
+
+    dropped = set()
+    options = {}
+    for name, value in utils.extract_options(field_list):
+        convertor = option_spec.get(name)
+        if name in options or name in dropped:
+            raise utils.DuplicateOptionError('duplicate option "%s"' % name)
+
+        # silently drop unknown options as long as they are not duplicates
+        if convertor is None:
+            dropped.add(name)
+            continue
+
+        # continue as before
+        try:
+            options[name] = convertor(value)
+        except (ValueError, TypeError) as detail:
+            raise detail.__class__('(option: "%s"; value: %r)\n%s'
+                                   % (name, value, ' '.join(detail.args)))
+    return options
+
+
+utils.extract_extension_options = extract_extension_options
+
+
 class ReadMeHTMLTranslator(HTMLTranslator):
 
     # Overrides base class not to output `<object>` tag for SVG images.

tests/fixtures/test_rst_008.html

@@ -14,3 +14,12 @@
 <span class="k">fi</span>
 </pre>
 <p>or click <a href="http://www.surveymonkey.com" rel="nofollow">SurveyMonkey</a></p>
+<p>and an ignored Sphinx option:</p>
+<pre> <span class="k">def</span> <span class="nf">fib</span><span class="p">(</span><span class="n">n</span><span class="p">):</span>
+     <span class="k">if</span> <span class="n">n</span> <span class="o">&lt;</span> <span class="mi">1</span><span class="p">:</span>
+         <span class="k">return</span> <span class="mi">0</span>
+     <span class="k">elif</span> <span class="n">n</span> <span class="o">&lt;=</span> <span class="mi">2</span><span class="p">:</span>
+         <span class="k">return</span> <span class="mi">1</span>
+
+     <span class="k">return</span> <span class="n">fib</span><span class="p">(</span><span class="n">n</span> <span class="o">-</span> <span class="mi">1</span><span class="p">)</span> <span class="o">+</span> <span class="n">fib</span><span class="p">(</span><span class="n">n</span> <span class="o">-</span> <span class="mi">2</span><span class="p">)</span>
+</pre>

tests/fixtures/test_rst_008.rst

@@ -20,3 +20,16 @@ and then here is some bash:
     fi
 
 or click `SurveyMonkey <http://www.surveymonkey.com>`_
+
+and an ignored Sphinx option:
+
+.. code-block:: python
+   :caption: Naive Fibonacci computation
+
+    def fib(n):
+        if n < 1:
+            return 0
+        elif n <= 2:
+            return 1
+
+        return fib(n - 1) + fib(n - 2)