Re: Documentation: build failure with sphinx >= 3.0.0: exception: cannot import name 'c_funcptr_sig_re' from 'sphinx.domains.c'

[Markus Heiser]

Am 12.08.20 um 09:30 schrieb Salvatore Bonaccorso:
[..]
> > The problem is actually related to changes happening in Sphinx 3.0.0.
> > There is the followign issue filled upstream:
> >
> > https://github.com/sphinx-doc/sphinx/issues/7421
> >
> > 'c_funcptr_sig_re' was removed upstream in sphinx v3.0.0b1 and so the
> > kernel documentation build fails. This is reproducible with a recent
> > sphinx version (in attached case it is 3.2.0):
> >
> > $ make PYTHON=python3 xmldocs
> >    SPHINX  xmldocs --> file:///home/build/linux/Documentation/output/xml
> > make[2]: Nothing to be done for 'xml'.
> > Running Sphinx v3.2.0
> >
> > Extension error:
> > Could not import extension cdomain (exception: cannot import name 'c_funcptr_sig_re' from 'sphinx.domains.c' (/usr/lib/python3/dist-packages/sphinx/domains/c.py))
> > make[1]: *** [Documentation/Makefile:115: xmldocs] Error 2
> > make: *** [Makefile:1655: xmldocs] Error 2
> >
> > Distribution reports related to this issue:
> > https://bugs.debian.org/963636
> > https://bugs.archlinux.org/task/66178
> > https://bugs.archlinux.org/task/66156
>
> As a workaround to make the documentation build again (but known that
> parts of the documentation will be broken), we could drop the cdomain
> extension.
>
> Regards,
> Salvatore

@jon, do you have time to implement a patch?
.. sorry, I'am in a hurry :o

In the linked github issue you find also a patch that fixes a
cdomain.py.  I tested the patch (shee below) in the linux kernel.

  For me it works.

BTW: The patch of Documentation/sphinx/requirements.txt
was only nedded for a test.

  -- Markus --


---


diff --git a/Documentation/sphinx/cdomain.py b/Documentation/sphinx/cdomain.py
index cbac8e608dc4..65e15d48891e 100644
--- a/Documentation/sphinx/cdomain.py
+++ b/Documentation/sphinx/cdomain.py
@@ -31,16 +31,35 @@ u"""
        arguments types of function-like macros.

 """
+import re

 from docutils import nodes
 from docutils.parsers.rst import directives

 import sphinx
 from sphinx import addnodes
-from sphinx.domains.c import c_funcptr_sig_re, c_sig_re
 from sphinx.domains.c import CObject as Base_CObject
 from sphinx.domains.c import CDomain as Base_CDomain

+# C&P from commit https://github.com/return42/linuxdoc/commit/48f09de2
+# fixes 
https://github.com/sphinx-doc/sphinx/commit/0f49e30c51b5cc5055cda5b4b294c2dd9d1df573#r38750737
+
+# pylint: disable=invalid-name
+c_sig_re = re.compile(
+    r'''^([^(]*?)          # return type
+        ([\w:.]+)  \s*     # thing name (colon allowed for C++)
+        (?: \((.*)\) )?    # optionally arguments
+        (\s+const)? $      # const specifier
+    ''', re.VERBOSE)
+
+c_funcptr_sig_re = re.compile(
+    r'''^([^(]+?)          # return type
+        (\( [^()]+ \)) \s* # name in parentheses
+        \( (.*) \)         # arguments
+        (\s+const)? $      # const specifier
+    ''', re.VERBOSE)
+# pylint: enable=invalid-name
+
 __version__  = '1.0'

 # Get Sphinx version
diff --git a/Documentation/sphinx/requirements.txt 
b/Documentation/sphinx/requirements.txt
index 489f6626de67..f7486fd7ec85 100644
--- a/Documentation/sphinx/requirements.txt
+++ b/Documentation/sphinx/requirements.txt
@@ -1,3 +1,3 @@
 docutils
-Sphinx==2.4.4
+Sphinx==3.2.0
 sphinx_rtd_theme