Vendor Sphinx viewcode from Sphinx 3.4.3

viewcode documents that it can import modules at any
time, so vendor the parts we need so that there is no
chance of an unexpected module import due to sphinx
code changes such as sphinx-doc/sphinx#8681.

Reformat comment in docs.scss that seemed to be failing
for most recent pyscss release.

zzzeeksphinx/themes/zzzeeksphinx/static/docs.scss

@@ -1,6 +1,4 @@
-/*
-
-  Google fonts are self-hosted so that there is no delay due to unavailable
+/*  Google fonts are self-hosted so that there is no delay due to unavailable
   network or firewalls within the @import tag, not just for loading the font
   itself, which is resolvable with "font-display: swap", but for the css import
   itself, which may still delay for a network timeout period before allowing

zzzeeksphinx/viewsource.py

@@ -7,18 +7,14 @@
 import docutils
 from docutils import nodes
 from docutils.parsers.rst import Directive
-from sphinx.ext.viewcode import collect_pages
-from sphinx.ext.viewcode import env_merge_info
+from sphinx.errors import NoUri
+from sphinx.locale import _
+from sphinx.locale import __
 from sphinx.pycode import ModuleAnalyzer
+from sphinx.util import status_iterator
 
 from . import util
 
-try:
-    # 3.0
-    from sphinx.errors import NoUri
-except:
-    from sphinx.environment import NoUri
-
 
 def view_source(name, rawtext, text, lineno, inliner, options={}, content=[]):
 
@@ -28,6 +24,133 @@ def view_source(name, rawtext, text, lineno, inliner, options={}, content=[]):
     return [node], []
 
 
+def vendored_collect_pages(app):
+    # vendored from sphinx viewcode
+    env = app.builder.env
+    if not hasattr(env, "_viewcode_modules"):
+        return
+    highlighter = app.builder.highlighter  # type: ignore
+    urito = app.builder.get_relative_uri
+
+    modnames = set(env._viewcode_modules)  # type: ignore
+
+    for modname, entry in status_iterator(
+        sorted(env._viewcode_modules.items()),  # type: ignore
+        __("highlighting module code... "),
+        "blue",
+        len(env._viewcode_modules),  # type: ignore
+        app.verbosity,
+        lambda x: x[0],
+    ):
+        if not entry:
+            continue
+        code, tags, used, refname = entry
+        # construct a page name for the highlighted source
+        pagename = "_modules/" + modname.replace(".", "/")
+        # highlight the source using the builder's highlighter
+        if env.config.highlight_language in ("python3", "default", "none"):
+            lexer = env.config.highlight_language
+        else:
+            lexer = "python"
+        highlighted = highlighter.highlight_block(code, lexer, linenos=False)
+        # split the code into lines
+        lines = highlighted.splitlines()
+        # split off wrap markup from the first line of the actual code
+        before, after = lines[0].split("<pre>")
+        lines[0:1] = [before + "<pre>", after]
+        # nothing to do for the last line; it always starts with </pre> anyway
+        # now that we have code lines (starting at index 1), insert anchors for
+        # the collected tags (HACK: this only works if the tag boundaries are
+        # properly nested!)
+        maxindex = len(lines) - 1
+        for name, docname in used.items():
+            type_, start, end = tags[name]
+            backlink = urito(pagename, docname) + "#" + refname + "." + name
+            lines[start] = (
+                '<div class="viewcode-block" id="%s"><a class="viewcode-back" '
+                'href="%s">%s</a>' % (name, backlink, _("[docs]"))
+                + lines[start]
+            )
+            lines[min(end, maxindex)] += "</div>"
+        # try to find parents (for submodules)
+        parents = []
+        parent = modname
+        while "." in parent:
+            parent = parent.rsplit(".", 1)[0]
+            if parent in modnames:
+                parents.append(
+                    {
+                        "link": urito(
+                            pagename, "_modules/" + parent.replace(".", "/")
+                        ),
+                        "title": parent,
+                    }
+                )
+        parents.append(
+            {
+                "link": urito(pagename, "_modules/index"),
+                "title": _("Module code"),
+            }
+        )
+        parents.reverse()
+        # putting it all together
+        context = {
+            "parents": parents,
+            "title": modname,
+            "body": (
+                _("<h1>Source code for %s</h1>") % modname + "\n".join(lines)
+            ),
+        }
+        yield (pagename, context, "page.html")
+
+    if not modnames:
+        return
+
+    html = ["\n"]
+    # the stack logic is needed for using nested lists for submodules
+    stack = [""]
+    for modname in sorted(modnames):
+        if modname.startswith(stack[-1]):
+            stack.append(modname + ".")
+            html.append("<ul>")
+        else:
+            stack.pop()
+            while not modname.startswith(stack[-1]):
+                stack.pop()
+                html.append("</ul>")
+            stack.append(modname + ".")
+        html.append(
+            '<li><a href="%s">%s</a></li>\n'
+            % (
+                urito(
+                    "_modules/index", "_modules/" + modname.replace(".", "/")
+                ),
+                modname,
+            )
+        )
+    html.append("</ul>" * (len(stack) - 1))
+    context = {
+        "title": _("Overview: module code"),
+        "body": (
+            _("<h1>All modules for which code is available</h1>")
+            + "".join(html)
+        ),
+    }
+
+    yield ("_modules/index", context, "page.html")
+
+
+def vendored_env_merge_info(app, env, docnames, other):
+    # vendored from sphinx viewcode
+    if not hasattr(other, "_viewcode_modules"):
+        return
+    # create a _viewcode_modules dict on the main environment
+    if not hasattr(env, "_viewcode_modules"):
+        env._viewcode_modules = {}  # type: ignore
+    # now merge in the information from the subprocess
+    env._viewcode_modules.update(other._viewcode_modules)  # type: ignore
+
+
 def _get_sphinx_py_module(env):
     base_name = env.temp_data.get("autodoc:module", None)
     if base_name is not None:
@@ -222,11 +345,10 @@ def run(self):
 
 
 def setup(app):
+
     app.add_role("viewsource", view_source)
 
     app.add_directive("autosource", AutoSourceDirective)
 
-    app.connect("env-merge-info", env_merge_info)
-
-    # from sphinx.ext.viewcode
-    app.connect("html-collect-pages", collect_pages)
+    app.connect("env-merge-info", vendored_env_merge_info)
+    app.connect("html-collect-pages", vendored_collect_pages)