C, distinguish between tag names and ordinary names

[jakobandersen]

Feature or Bugfix

• Feature
• Bugfix
• Refactoring

Purpose

Introduce tagged names, as in the language, in the end fixing #7819. That is,

.. c:struct:: A
.. c:union:: B
.. c:enum:: C

declares the names struct A, union B, and enum C, while

.. c:function:: void A(void)

declares the name A. Macros, enumerators, typedefs, and (member) variables are in the same space as functions. ~~(TODO: there is not yet a duplicate check in the tagged space, so two struct/union/enum can have the same name right now)~~

This means that nested names potentially must include the full tagging. E.g., for

.. c:struct:: A

   .. c::union:: B

      .. c::enum:: C

         .. c:enumerator:: D

then the fully qualified name for D is struct A.unioin B.enum C.D. For names appearing inside declarations, the tagging must be present, which may give extra warnings. E.g., for

.. c:struct:: A
.. c:function:: A f(void)
.. c:function:: struct A g(void)

there will now be a warning about missing target for the A in f, because it should be tagged, like in g. However, for now, for backwards compatibility, when writing cross-references an untagged nested name component will match also a tagged declaration (the first one). This means the following works

.. c:struct:: A

	.. c:struct:: B

		.. c:var:: int i

- :c:var:`struct A.struct B.i`
- :c:var:`struct A.B.i`
- :c:var:`A.struct B.i`
- :c:var:`A.B.i`

As a nice side-effect, this incidentally now lets c:type roles properly parse tagged names, without the pre-v3 flag.

However, note that if a function has the same name as a tagged entity and a cross-reference does not explicitly contain a tag, then the function is selected. That is, lookup is tried first with the explicit name written in the role and only if unsuccessfully it will then try a relaxed lookup. E.g.,:

.. c:function:: void f1(int i)

.. c:struct:: f1

	.. c:var:: int i


.. c:struct:: f2

	.. c:var:: int i

.. c:function:: void f2(int i)

- :c:var:`f1.i`, resolves to the function parameter
- :c:var:`struct f1.i`, resolves to struct f1.i
- :c:var:`f2.i`, resolves to the function parameter
- :c:var:`struct f2.i`, resolves to struct f2.i

~~However, this is not ideal, as there can be ambiguity when referencing function parameters~~ ~~(though note #8310 is not in this branch yet)~~:

.. c:function:: void f1(int i)

.. c:struct:: f1

	.. c:var:: int i


.. c:struct:: f2

	.. c:var:: int i

.. c:function:: void f2(int i)

- :c:var:`f1.i`, resolves to the function parameter, as f1 is before struct f1
- :c:var:`struct f1.i`, always resolves to struct f1.i
- :c:var:`f2.i`, resolves to struct f2.i, as struct f2 is before f2
- :c:var:`struct f2.i`, always resolves to struct2.i

~~Here, because the lookup for untagged names selects the first matching entry in the symbol table, we get inconsistency in what f1.i and f2.i points to.~~

• ~~How should cross-references be written to not rely on declaration order, and still allow referencing all entities?~~
• ~~Would it be ok always to explicitly write tags in cross references? The (temporary) config var c_strict_xref_tags can be set to True to enforce explicit tagging in cross references.~~

[jakobandersen]

I believe the PR is ready for more throughout testing. It would be great if users of the C domain can try it out, both directly and with the config c_strict_xref_tags = True to see both which warnings are fixed, and which new ones pop up.

(Ping for those I remember may have interest: @Shamino0, @vstinner, @mchehab, @utzig)

[mchehab]

On a quick test, the remaining warnings I was getting with the Linux Kernel docs with Sphinx 3.x have gone after this patch set.

Thanks!

I'm looking forward to see those patches applied to 3.2.2 ;-)

[jakobandersen]

On a quick test, the remaining warnings I was getting with the Linux Kernel docs with Sphinx 3.x have gone after this patch set.

Just to be sure, this is also the case with c_strict_xref_tags = True in conf.py?

I'm looking forward to see those patches applied to 3.2.2 ;-)

I'm afraid the changes are too large to put them in 3.2.2, but if nothing major breaks it may be possible to move it to 3.3 instead.

[mchehab]

On a quick test, the remaining warnings I was getting with the Linux Kernel docs with Sphinx 3.x have gone after this patch set.

Just to be sure, this is also the case with c_strict_xref_tags = True in conf.py?

Yes. I'm attaching the full conf.py I'm using on such test.

I'm looking forward to see those patches applied to 3.2.2 ;-)

I'm afraid the changes are too large to put them in 3.2.2,

That's a bad news. We want this bug to be solved as soon as possible, as we want to ensure that new patches won't be introducing more htmldocs build warnings.

but if nothing major breaks it may be possible to move it to 3.3 instead.

Well, this would be better than having to wait until a next major release. When 3.3 is planned to be released?

# -*- coding: utf-8 -*-
#
# The Linux Kernel documentation build configuration file, created by
# sphinx-quickstart on Fri Feb 12 13:51:46 2016.
#
# This file is execfile()d with the current directory set to its
# containing dir.
#
# Note that not all possible configuration values are present in this
# autogenerated file.
#
# All configuration values have a default; values that are commented out
# serve to show the default.

import sys
import os
import sphinx

from subprocess import check_output

# Get Sphinx version
major, minor, patch = sphinx.version_info[:3]


# If extensions (or modules to document with autodoc) are in another directory,
# add these directories to sys.path here. If the directory is relative to the
# documentation root, use os.path.abspath to make it absolute, like shown here.
sys.path.insert(0, os.path.abspath('sphinx'))
from load_config import loadConfig

# -- General configuration ------------------------------------------------

# If your documentation needs a minimal Sphinx version, state it here.
needs_sphinx = '1.3'

# Add any Sphinx extension module names here, as strings. They can be
# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
# ones.
extensions = ['kerneldoc', 'rstFlatTable', 'kernel_include',
              'kfigure', 'sphinx.ext.ifconfig',
              'maintainers_include', 'sphinx.ext.autosectionlabel' ]

#
# cdomain is badly broken in Sphinx 3+.  Leaving it out generates *most*
# of the docs correctly, but not all.  Scream bloody murder but allow
# the process to proceed; hopefully somebody will fix this properly soon.
#
if major >= 3:
    sys.stderr.write('''WARNING: The kernel documentation build process
        support for Sphinx v3.0 and above is brand new. Be prepared for
        possible issues in the generated output.
        ''')
    if (major > 3) or (minor > 0 or patch >= 2):
        # Sphinx c function parser is more pedantic with regards to type
        # checking. Due to that, having macros at c:function cause problems.
        # Those needed to be scaped by using c_id_attributes[] array
        c_strict_xref_tags = True
        c_id_attributes = [
            # GCC Compiler types not parsed by Sphinx:
            "__restrict__",

            # include/linux/compiler_types.h:
            "__iomem",
            "__kernel",
            "noinstr",
            "notrace",
            "__percpu",
            "__rcu",
            "__user",

            # include/linux/compiler_attributes.h:
            "__alias",
            "__aligned",
            "__aligned_largest",
            "__always_inline",
            "__assume_aligned",
            "__cold",
            "__attribute_const__",
            "__copy",
            "__pure",
            "__designated_init",
            "__visible",
            "__printf",
            "__scanf",
            "__gnu_inline",
            "__malloc",
            "__mode",
            "__no_caller_saved_registers",
            "__noclone",
            "__nonstring",
            "__noreturn",
            "__packed",
            "__pure",
            "__section",
            "__always_unused",
            "__maybe_unused",
            "__used",
            "__weak",
            "noinline",

            # include/linux/memblock.h:
            "__init_memblock",
            "__meminit",

            # include/linux/init.h:
            "__init",
            "__ref",

            # include/linux/linkage.h:
            "asmlinkage",
        ]

else:
    extensions.append('cdomain')
    extensions.append('automarkup')

# Ensure that autosectionlabel will produce unique names
autosectionlabel_prefix_document = True
autosectionlabel_maxdepth = 2

# The name of the math extension changed on Sphinx 1.4
if (major == 1 and minor > 3) or (major > 1):
    extensions.append("sphinx.ext.imgmath")
else:
    extensions.append("sphinx.ext.pngmath")

# Add any paths that contain templates here, relative to this directory.
templates_path = ['_templates']

# The suffix(es) of source filenames.
# You can specify multiple suffix as a list of string:
# source_suffix = ['.rst', '.md']
source_suffix = '.rst'

# The encoding of source files.
#source_encoding = 'utf-8-sig'

# The master toctree document.
master_doc = 'index'

# General information about the project.
project = 'The Linux Kernel'
copyright = 'The kernel development community'
author = 'The kernel development community'

# The version info for the project you're documenting, acts as replacement for
# |version| and |release|, also used in various other places throughout the
# built documents.
#
# In a normal build, version and release are are set to KERNELVERSION and
# KERNELRELEASE, respectively, from the Makefile via Sphinx command line
# arguments.
#
# The following code tries to extract the information by reading the Makefile,
# when Sphinx is run directly (e.g. by Read the Docs).
try:
    makefile_version = None
    makefile_patchlevel = None
    for line in open('../Makefile'):
        key, val = [x.strip() for x in line.split('=', 2)]
        if key == 'VERSION':
            makefile_version = val
        elif key == 'PATCHLEVEL':
            makefile_patchlevel = val
        if makefile_version and makefile_patchlevel:
            break
except:
    pass
finally:
    if makefile_version and makefile_patchlevel:
        version = release = makefile_version + '.' + makefile_patchlevel
    else:
        version = release = "unknown version"

# The language for content autogenerated by Sphinx. Refer to documentation
# for a list of supported languages.
#
# This is also used if you do content translation via gettext catalogs.
# Usually you set "language" from the command line for these cases.
language = None

# There are two options for replacing |today|: either, you set today to some
# non-false value, then it is used:
#today = ''
# Else, today_fmt is used as the format for a strftime call.
#today_fmt = '%B %d, %Y'

# List of patterns, relative to source directory, that match files and
# directories to ignore when looking for source files.
exclude_patterns = ['output']

# The reST default role (used for this markup: `text`) to use for all
# documents.
#default_role = None

# If true, '()' will be appended to :func: etc. cross-reference text.
#add_function_parentheses = True

# If true, the current module name will be prepended to all description
# unit titles (such as .. function::).
#add_module_names = True

# If true, sectionauthor and moduleauthor directives will be shown in the
# output. They are ignored by default.
#show_authors = False

# The name of the Pygments (syntax highlighting) style to use.
pygments_style = 'sphinx'

# A list of ignored prefixes for module index sorting.
#modindex_common_prefix = []

# If true, keep warnings as "system message" paragraphs in the built documents.
#keep_warnings = False

# If true, `todo` and `todoList` produce output, else they produce nothing.
todo_include_todos = False

primary_domain = 'c'
highlight_language = 'none'

# -- Options for HTML output ----------------------------------------------

# The theme to use for HTML and HTML Help pages.  See the documentation for
# a list of builtin themes.

# The Read the Docs theme is available from
# - https://github.com/snide/sphinx_rtd_theme
# - https://pypi.python.org/pypi/sphinx_rtd_theme
# - python-sphinx-rtd-theme package (on Debian)
try:
    import sphinx_rtd_theme
    html_theme = 'sphinx_rtd_theme'
    html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
except ImportError:
    sys.stderr.write('Warning: The Sphinx \'sphinx_rtd_theme\' HTML theme was not found. Make sure you have the theme installed to produce pretty HTML output. Falling back to the default theme.\n')

# Theme options are theme-specific and customize the look and feel of a theme
# further.  For a list of options available for each theme, see the
# documentation.
#html_theme_options = {}

# Add any paths that contain custom themes here, relative to this directory.
#html_theme_path = []

# The name for this set of Sphinx documents.  If None, it defaults to
# "<project> v<release> documentation".
#html_title = None

# A shorter title for the navigation bar.  Default is the same as html_title.
#html_short_title = None

# The name of an image file (relative to this directory) to place at the top
# of the sidebar.
#html_logo = None

# The name of an image file (within the static path) to use as favicon of the
# docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
# pixels large.
#html_favicon = None

# Add any paths that contain custom static files (such as style sheets) here,
# relative to this directory. They are copied after the builtin static files,
# so a file named "default.css" will overwrite the builtin "default.css".

html_static_path = ['sphinx-static']

html_context = {
    'css_files': [
        '_static/theme_overrides.css',
    ],
}

# Add any extra paths that contain custom files (such as robots.txt or
# .htaccess) here, relative to this directory. These files are copied
# directly to the root of the documentation.
#html_extra_path = []

# If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
# using the given strftime format.
#html_last_updated_fmt = '%b %d, %Y'

# If true, SmartyPants will be used to convert quotes and dashes to
# typographically correct entities.
html_use_smartypants = False

# Custom sidebar templates, maps document names to template names.
#html_sidebars = {}

# Additional templates that should be rendered to pages, maps page names to
# template names.
#html_additional_pages = {}

# If false, no module index is generated.
#html_domain_indices = True

# If false, no index is generated.
#html_use_index = True

# If true, the index is split into individual pages for each letter.
#html_split_index = False

# If true, links to the reST sources are added to the pages.
#html_show_sourcelink = True

# If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
#html_show_sphinx = True

# If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
#html_show_copyright = True

# If true, an OpenSearch description file will be output, and all pages will
# contain a <link> tag referring to it.  The value of this option must be the
# base URL from which the finished HTML is served.
#html_use_opensearch = ''

# This is the file name suffix for HTML files (e.g. ".xhtml").
#html_file_suffix = None

# Language to be used for generating the HTML full-text search index.
# Sphinx supports the following languages:
#   'da', 'de', 'en', 'es', 'fi', 'fr', 'h', 'it', 'ja'
#   'nl', 'no', 'pt', 'ro', 'r', 'sv', 'tr'
#html_search_language = 'en'

# A dictionary with options for the search language support, empty by default.
# Now only 'ja' uses this config value
#html_search_options = {'type': 'default'}

# The name of a javascript file (relative to the configuration directory) that
# implements a search results scorer. If empty, the default will be used.
#html_search_scorer = 'scorer.js'

# Output file base name for HTML help builder.
htmlhelp_basename = 'TheLinuxKerneldoc'

# -- Options for LaTeX output ---------------------------------------------

latex_elements = {
# The paper size ('letterpaper' or 'a4paper').
'papersize': 'a4paper',

# The font size ('10pt', '11pt' or '12pt').
'pointsize': '11pt',

# Latex figure (float) alignment
#'figure_align': 'htbp',

# Don't mangle with UTF-8 chars
'inputenc': '',
'utf8extra': '',

# Additional stuff for the LaTeX preamble.
    'preamble': '''
	% Use some font with UTF-8 support with XeLaTeX
        \\usepackage{fontspec}
        \\setsansfont{DejaVu Sans}
        \\setromanfont{DejaVu Serif}
        \\setmonofont{DejaVu Sans Mono}
     '''
}

# At least one book (translations) may have Asian characters
# with are only displayed if xeCJK is used

cjk_cmd = check_output(['fc-list', '--format="%{family[0]}\n"']).decode('utf-8', 'ignore')
if cjk_cmd.find("Noto Sans CJK SC") >= 0:
    print ("enabling CJK for LaTeX builder")
    latex_elements['preamble']  += '''
	% This is needed for translations
        \\usepackage{xeCJK}
        \\setCJKmainfont{Noto Sans CJK SC}
     '''

# Fix reference escape troubles with Sphinx 1.4.x
if major == 1 and minor > 3:
    latex_elements['preamble']  += '\\renewcommand*{\\DUrole}[2]{ #2 }\n'

if major == 1 and minor <= 4:
    latex_elements['preamble']  += '\\usepackage[margin=0.5in, top=1in, bottom=1in]{geometry}'
elif major == 1 and (minor > 5 or (minor == 5 and patch >= 3)):
    latex_elements['sphinxsetup'] = 'hmargin=0.5in, vmargin=1in'
    latex_elements['preamble']  += '\\fvset{fontsize=auto}\n'

# Customize notice background colors on Sphinx < 1.6:
if major == 1 and minor < 6:
   latex_elements['preamble']  += '''
        \\usepackage{ifthen}

        % Put notes in color and let them be inside a table
	\\definecolor{NoteColor}{RGB}{204,255,255}
	\\definecolor{WarningColor}{RGB}{255,204,204}
	\\definecolor{AttentionColor}{RGB}{255,255,204}
	\\definecolor{ImportantColor}{RGB}{192,255,204}
	\\definecolor{OtherColor}{RGB}{204,204,204}
        \\newlength{\\mynoticelength}
        \\makeatletter\\newenvironment{coloredbox}[1]{%
	   \\setlength{\\fboxrule}{1pt}
	   \\setlength{\\fboxsep}{7pt}
	   \\setlength{\\mynoticelength}{\\linewidth}
	   \\addtolength{\\mynoticelength}{-2\\fboxsep}
	   \\addtolength{\\mynoticelength}{-2\\fboxrule}
           \\begin{lrbox}{\\@tempboxa}\\begin{minipage}{\\mynoticelength}}{\\end{minipage}\\end{lrbox}%
	   \\ifthenelse%
	      {\\equal{\\py@noticetype}{note}}%
	      {\\colorbox{NoteColor}{\\usebox{\\@tempboxa}}}%
	      {%
	         \\ifthenelse%
	         {\\equal{\\py@noticetype}{warning}}%
	         {\\colorbox{WarningColor}{\\usebox{\\@tempboxa}}}%
		 {%
	            \\ifthenelse%
	            {\\equal{\\py@noticetype}{attention}}%
	            {\\colorbox{AttentionColor}{\\usebox{\\@tempboxa}}}%
		    {%
	               \\ifthenelse%
	               {\\equal{\\py@noticetype}{important}}%
	               {\\colorbox{ImportantColor}{\\usebox{\\@tempboxa}}}%
	               {\\colorbox{OtherColor}{\\usebox{\\@tempboxa}}}%
		    }%
		 }%
	      }%
        }\\makeatother

        \\makeatletter
        \\renewenvironment{notice}[2]{%
          \\def\\py@noticetype{#1}
          \\begin{coloredbox}{#1}
          \\bf\\it
          \\par\\strong{#2}
          \\csname py@noticestart@#1\\endcsname
        }
	{
          \\csname py@noticeend@\\py@noticetype\\endcsname
          \\end{coloredbox}
        }
	\\makeatother

     '''

# With Sphinx 1.6, it is possible to change the Bg color directly
# by using:
#	\definecolor{sphinxnoteBgColor}{RGB}{204,255,255}
#	\definecolor{sphinxwarningBgColor}{RGB}{255,204,204}
#	\definecolor{sphinxattentionBgColor}{RGB}{255,255,204}
#	\definecolor{sphinximportantBgColor}{RGB}{192,255,204}
#
# However, it require to use sphinx heavy box with:
#
#	\renewenvironment{sphinxlightbox} {%
#		\\begin{sphinxheavybox}
#	}
#		\\end{sphinxheavybox}
#	}
#
# Unfortunately, the implementation is buggy: if a note is inside a
# table, it isn't displayed well. So, for now, let's use boring
# black and white notes.

# Grouping the document tree into LaTeX files. List of tuples
# (source start file, target name, title,
#  author, documentclass [howto, manual, or own class]).
# Sorted in alphabetical order
latex_documents = [
]

# Add all other index files from Documentation/ subdirectories
for fn in os.listdir('.'):
    doc = os.path.join(fn, "index")
    if os.path.exists(doc + ".rst"):
        has = False
        for l in latex_documents:
            if l[0] == doc:
                has = True
                break
        if not has:
            latex_documents.append((doc, fn + '.tex',
                                    'Linux %s Documentation' % fn.capitalize(),
                                    'The kernel development community',
                                    'manual'))

# The name of an image file (relative to this directory) to place at the top of
# the title page.
#latex_logo = None

# For "manual" documents, if this is true, then toplevel headings are parts,
# not chapters.
#latex_use_parts = False

# If true, show page references after internal links.
#latex_show_pagerefs = False

# If true, show URL addresses after external links.
#latex_show_urls = False

# Documents to append as an appendix to all manuals.
#latex_appendices = []

# If false, no module index is generated.
#latex_domain_indices = True


# -- Options for manual page output ---------------------------------------

# One entry per manual page. List of tuples
# (source start file, name, description, authors, manual section).
man_pages = [
    (master_doc, 'thelinuxkernel', 'The Linux Kernel Documentation',
     [author], 1)
]

# If true, show URL addresses after external links.
#man_show_urls = False


# -- Options for Texinfo output -------------------------------------------

# Grouping the document tree into Texinfo files. List of tuples
# (source start file, target name, title, author,
#  dir menu entry, description, category)
texinfo_documents = [
    (master_doc, 'TheLinuxKernel', 'The Linux Kernel Documentation',
     author, 'TheLinuxKernel', 'One line description of project.',
     'Miscellaneous'),
]

# Documents to append as an appendix to all manuals.
#texinfo_appendices = []

# If false, no module index is generated.
#texinfo_domain_indices = True

# How to display URL addresses: 'footnote', 'no', or 'inline'.
#texinfo_show_urls = 'footnote'

# If true, do not generate a @detailmenu in the "Top" node's menu.
#texinfo_no_detailmenu = False


# -- Options for Epub output ----------------------------------------------

# Bibliographic Dublin Core info.
epub_title = project
epub_author = author
epub_publisher = author
epub_copyright = copyright

# The basename for the epub file. It defaults to the project name.
#epub_basename = project

# The HTML theme for the epub output. Since the default themes are not
# optimized for small screen space, using the same theme for HTML and epub
# output is usually not wise. This defaults to 'epub', a theme designed to save
# visual space.
#epub_theme = 'epub'

# The language of the text. It defaults to the language option
# or 'en' if the language is not set.
#epub_language = ''

# The scheme of the identifier. Typical schemes are ISBN or URL.
#epub_scheme = ''

# The unique identifier of the text. This can be a ISBN number
# or the project homepage.
#epub_identifier = ''

# A unique identification for the text.
#epub_uid = ''

# A tuple containing the cover image and cover page html template filenames.
#epub_cover = ()

# A sequence of (type, uri, title) tuples for the guide element of content.opf.
#epub_guide = ()

# HTML files that should be inserted before the pages created by sphinx.
# The format is a list of tuples containing the path and title.
#epub_pre_files = []

# HTML files that should be inserted after the pages created by sphinx.
# The format is a list of tuples containing the path and title.
#epub_post_files = []

# A list of files that should not be packed into the epub file.
epub_exclude_files = ['search.html']

# The depth of the table of contents in toc.ncx.
#epub_tocdepth = 3

# Allow duplicate toc entries.
#epub_tocdup = True

# Choose between 'default' and 'includehidden'.
#epub_tocscope = 'default'

# Fix unsupported image types using the Pillow.
#epub_fix_images = False

# Scale large images.
#epub_max_image_width = 0

# How to display URL addresses: 'footnote', 'no', or 'inline'.
#epub_show_urls = 'inline'

# If false, no index is generated.
#epub_use_index = True

#=======
# rst2pdf
#
# Grouping the document tree into PDF files. List of tuples
# (source start file, target name, title, author, options).
#
# See the Sphinx chapter of https://ralsina.me/static/manual.pdf
#
# FIXME: Do not add the index file here; the result will be too big. Adding
# multiple PDF files here actually tries to get the cross-referencing right
# *between* PDF files.
pdf_documents = [
    ('kernel-documentation', u'Kernel', u'Kernel', u'J. Random Bozo'),
]

# kernel-doc extension configuration for running Sphinx directly (e.g. by Read
# the Docs). In a normal build, these are supplied from the Makefile via command
# line arguments.
kerneldoc_bin = '../scripts/kernel-doc'
kerneldoc_srctree = '..'

# ------------------------------------------------------------------------------
# Since loadConfig overwrites settings from the global namespace, it has to be
# the last statement in the conf.py file
# ------------------------------------------------------------------------------
loadConfig(globals())

[utzig]

@jakobandersen I run this PR now and it fixes most of the duplicate symbol issues, but I see a few new warnings:

WARNING: C 'identifier' cross-reference uses wrong tag: reference name is 'union bt_conn_info' but found name is 'struct bt_conn_info'. Full reference name is 'union bt_conn_info'. Full found name is 'struct bt_conn_info'.
WARNING: C 'identifier' cross-reference uses wrong tag: reference name is 'enum bt_conn_oob_info' but found name is 'struct bt_conn_oob_info'. Full reference name is 'enum bt_conn_oob_info'. Full found name is 'struct bt_conn_oob_info'.

Those come from these definitions:

https://github.com/zephyrproject-rtos/zephyr/blob/master/include/bluetooth/conn.h#L310 https://github.com/zephyrproject-rtos/zephyr/blob/master/include/bluetooth/conn.h#L1040

Probably related to the anonymous unions.

Also:

WARNING: C 'identifier' cross-reference uses wrong tag: reference name is 'union mbedtls_ccm_context' but found name is 'struct mbedtls_ccm_context'. Full reference name is 'union mbedtls_ccm_context'. Full found name is 'struct mbedtls_ccm_context'.
WARNING: C 'identifier' cross-reference uses wrong tag: reference name is 'union mbedtls_rsa_context' but found name is 'struct mbedtls_rsa_context'. Full reference name is 'union mbedtls_rsa_context'. Full found name is 'struct mbedtls_rsa_context'.

From these definitions:

https://github.com/nrfconnect/sdk-nrfxlib/blob/master/nrf_security/include/mbedcrypto_glue/mbedtls/ccm_alt.h#L40 https://github.com/nrfconnect/sdk-nrfxlib/blob/master/nrf_security/include/mbedcrypto_glue/mbedtls/rsa_alt.h#L29

Not sure if it's because of the redefinition in the typedef and struct names. There are more such issues but all seem somewhat related.

Using c_strict_xref_tags = True only changed the html links for me, the warning are the same.

[return42]

What is the state of this PR .. actually in process?

[jakobandersen]

It's not dead, just progressing very very slowly :-). I will update it to take the anonymous types into account as soon as possible, so we can do another round of testing.

[jakobandersen]

So, I think the PR is ready for another test:

• Lookups should no longer depend on the order of declaration.
• A/the problem with anon declarations should be fixed, hopefully covering the problem @utzig indicated.
• The config variable c_strict_xref_tags was removed again. I believe leaving out the tags in cross-references is a nice convenience feature, with the only pitfall begin when a tagged entity and a function share the same name (see example in the bottom of the OP).

[gmarull]

@jakobandersen Have you been able to make any progress on this PR?

[jakobandersen]

Yes, in isolation it is ready, but it will break intersphinx support in icky ways: Let's call the current Sphinx "(untagged, string)" for C names without tagging and intersphinx lookup by string comparison, and let's call the format for objects.inv it produces be called (untagged, plain). With this PR we get (tagged, string) and (tagged, plain), but without objects.inv explicitly stating that. However, that means cross-references with tags will not find names in old (untagged, plain) objects.inv. Therefore I made #8929 which doesn't change the objects.inv format but changes lookup to be delegated to each domain (so we can call it (untagged, delegated)), thus enabling fuzzy tag lookup, as this PR also introduces for internal lookups. But #8929 also has problems as ( However, in the long run we need a structured format for objects.inv as the current plain string-based storage is insufficient for some domains (at least C++). This would then give us the formats (untagged, structured) and (tagged, structured), but with the notable difference to the plain formats that we here will know explicitly their tagged-ness.

So, if we merge this PR right now, there will be both (untagged, plain) and (tagged, plain) objects.inv files in the wild and it will be very complicated/impossible to get all reasonable combinations to work. Therefore, if people would like this PR merged as soon as possible (i.e., for v4), I suggest changing it to produce (untagged, plain) objects.inv, such that all plain formats are the same. This will intentionally break intersphinx lookups of tagged names for now, but can be fixed with a modified version of #8929 in a future minor release. That is, we will get the following combinations of Sphinx and objects.inv:

• (untagged, string), (untagged, plain): current, works (right?)
• (tagged, string), (untagged, plain): this PR modified, broken for tagged lookup
• (tagged, delegated), (untagged, plain): this PR modified + #8929 modified, will resolve names, but some tag checking my be as broken as now
• (tagged, delegated), (tagged, structured): this PR modified + #8929 modified + completely new objects.inv format, should work

Thoughts?

[protobits]

Hi, I've been monitoring this since in our project the only outstanding warning is a clash between C sigaction function and struct. As I see this is a complex issue to solve I was wondering if there's any workaround that can silence this warning about the duplicate definition.

[AA-Turner]

@jakobandersen would a review be useful here?

On your question: I think "(tagged, plain) objects.inv" makes more sense as systems will upgrade over time, and it would be odd not to be able to reference the "better" tagged format. Longer term it seems we should look at objects.inv and moving it away from plain string comparisons.

If you're concerned about cross-lookups failing, we could bump the objects.inv version number:

https://github.com/sphinx-doc/sphinx/blob/431caac943adb39bb4fb0d96e6355fb91c8f7487/sphinx/util/inventory.py#L145

A

[jakobandersen]

@jakobandersen would a review be useful here?

Not yet, #8929 is needed to not break intersphinx.

On your question: I think "(tagged, plain) objects.inv" makes more sense as systems will upgrade over time, and it would be odd not to be able to reference the "better" tagged format. Longer term it seems we should look at objects.inv and moving it away from plain string comparisons.

It would indeed be odd to merge this while not having it work fully.

If you're concerned about cross-lookups failing, we could bump the objects.inv version number

That will only work for new inventories. Current Sphinx users still need to be able to refer to inventories that were build using an older Sphinx version, which does not contain tagging info. Once we get intersphinx delegation to each domain, then maybe we can do something better. But having the plain text format would still be a pain.

[mchehab]

Any news about when this will finally be fixed? This bug is opened since Sphinx 3.1. The Linux Kernel documentation build is still hitting troubles because this PR was not merged.

[return42]

Any news about when this will finally be fixed? This bug is opened since Sphinx 3.1. The Linux Kernel documentation build is still hitting troubles because this PR was not merged.

yeah, same to the spin-off https://return42.github.io/linuxdoc/

[bpatath]

Hi, what's the state of this PR ? Is it abandoned or is there any hope that it will be merged some day ?

Edit: I guess there is still the intersphinx issue ? Is this second PR still making progress ?