[PATCH v7 00/24] Split sphinx call logic from docs Makefile

[PATCH v7 00/24] Split sphinx call logic from docs Makefile

[Mauro Carvalho Chehab]

Hi Jon,

This series should probably be called:

    "Move the trick-or-treat build hacks accumulated over time
     into a single place and document them."

as this reflects its main goal. As such:

- it places the jobserver logic on a library;
- it removes sphinx/parallel-wrapper.sh;
- the code now properly implements a jobserver-aware logic
  to do the parallelism when called via GNU make, failing back to
  "-j" when there's  no jobserver;
- converts check-variable-fonts.sh to Python and uses it via
  function call;
- drops an extra script to generate man pages, adding a makefile
  target for it;
- ensures that return code is 0 when PDF successfully builds;
- about half of the script is comments and documentation.

I tried to do my best to document all tricks that are inside the
script. This way, the docs build steps is now documented.

It should be noticed that it is out of the scope of this series
to change the implementation. Surely the process can be improved,
but first let's consolidate and document everything on a single
place.

Such script was written in a way that it can be called either
directly or via a Makefile. Running outside Makefile is
interesting specially when debug is needed. The command line
interface replaces the need of having lots of env vars before
calling sphinx-build:

    $ ./tools/docs/sphinx-build-wrapper --help
    usage: sphinx-build-wrapper [-h]
           [--sphinxdirs SPHINXDIRS [SPHINXDIRS ...]] [--conf CONF]
           [--builddir BUILDDIR] [--theme THEME] [--css CSS] [--paper {,a4,letter}] [-v]
           [-j JOBS] [-i] [-V [VENV]]
           {cleandocs,linkcheckdocs,htmldocs,epubdocs,texinfodocs,infodocs,mandocs,latexdocs,pdfdocs,xmldocs}

    Kernel documentation builder

    positional arguments:
      {cleandocs,linkcheckdocs,htmldocs,epubdocs,texinfodocs,infodocs,mandocs,latexdocs,pdfdocs,xmldocs}
                            Documentation target to build

    options:
      -h, --help            show this help message and exit
      --sphinxdirs SPHINXDIRS [SPHINXDIRS ...]
                            Specific directories to build
      --conf CONF           Sphinx configuration file
      --builddir BUILDDIR   Sphinx configuration file
      --theme THEME         Sphinx theme to use
      --css CSS             Custom CSS file for HTML/EPUB
      --paper {,a4,letter}  Paper size for LaTeX/PDF output
      -v, --verbose         place build in verbose mode
      -j, --jobs JOBS       Sets number of jobs to use with sphinx-build
      -i, --interactive     Change latex default to run in interactive mode
      -V, --venv [VENV]     If used, run Sphinx from a venv dir (default dir: sphinx_latest)

the only mandatory argument is the target, which is identical with
"make" targets.

The call inside Makefile doesn't use the last four arguments. They're
there to help identifying problems at the build:

    -v makes the output verbose;
    -j helps to test parallelism;
    -i runs latexmk in interactive mode, allowing to debug PDF
       build issues;
    -V is useful when testing it with different venvs.

When used with GNU make (or some other make which implements jobserver),
a call like:

    make -j <targets> htmldocs

will make the wrapper to automatically use POSIX jobserver to claim 
the number of available job slots, calling sphinx-build with a
"-j" parameter reflecting it. ON such case, the default can be
overriden via SPHINXDIRS argument.

Visiable changes when compared with the old behavior:

When V=0, the only visible difference is that:
- pdfdocs target now returns 0 on success, 1 on failures.
  This addresses an issue over the current process where we
  it always return success even on failures;
- it will now print the name of PDF files that failed to build,
  if any.

In verbose mode, sphinx-build-wrapper and sphinx-build command lines
are now displayed.

---

v7:
- added a --help option to ./tools/docs/check-variable-fonts.py;
- document FONTS_CONF_DENY_VF=;
- moved the python_version changes to be earlier in the series,
  before moving it to a separate library, as suggested by Jani;
- added a --rustdoc to the wrapper, cleaning up Makefile
  even further;
- solved some problems related to DENY_VF logic.

v6:
- On success, PDF output is identical as before when V=0;
- when V=1 is used, PDF output will print a build summary,
  as on v5;
- solved a problem when multiple PDF files have the same
  basename but are located on different directories;
- merged a patch series converting check-variable-fonts.sh
  to Python. Its logic is now called directly without running
  a subprocess.
- venv patch moved to the end.

v5:
- merged comments with the script;
- placed n_jobs on a separate function;
- nitpick: dropped a for loop used instead of list append.

v4:
- updated references for sphinx-pre-install after its rename;
- added some extra patches to add more options to python_version,
  allowing it to bail out and suggest alternatives;
- added a patch at the end to explicitly break doc builds when
  python3 points to python3.6 or older.

v3:
- rebased on the top of docs-next;
- added two patches to build man files that were on a separate
  patch series.

v2:
- there's no generic exception handler anymore;
- it moves sphinx-pre-install to tools/docs;
- the logic which ensures a minimal Python version got moved
  to a library, which is now used by both pre-install and wrapper;
- The first wrapper (05/13) doesn't contain comments (except for
  shebang and SPDX). The goal is to help showing the size increase
  when moving from Makefile to Python. Some file increase is
  unavoidable, as Makefile is more compact: no includes, multple
  statements per line, no argparse, etc;
- The second patch adds docstrings and comments. It has almost
  the same size of the code itself;
- I moved the venv logic to a third wrapper patch;
- I fixed an issue at the paraller build logic;
- There are no generic except blocks anymore.

Mauro Carvalho Chehab (24):
  scripts/jobserver-exec: move the code to a class
  scripts/jobserver-exec: move its class to the lib directory
  scripts/jobserver-exec: add a help message
  scripts: check-variable-fonts.sh: convert to Python
  tools/docs: check-variable-fonts.py: split into a lib and an exec file
  check-variable-fonts.py: add a helper to display instructions
  scripts: sphinx-pre-install: move it to tools/docs
  tools/docs: sphinx-pre-install: drop a debug print
  tools/docs: sphinx-pre-install: allow check for alternatives and bail
    out
  tools/docs: python_version: move version check from sphinx-pre-install
  tools/docs: sphinx-build-wrapper: add a wrapper for sphinx-build
  docs: parallel-wrapper.sh: remove script
  docs: Makefile: document latex/PDF PAPER= parameter
  docs: Makefile: document FONTS_CONF_DENY_VF= parameter
  tools/docs: sphinx-build-wrapper: add an argument for LaTeX
    interactive mode
  tools/docs: sphinx-build-wrapper: allow building PDF files in parallel
  tools/docs,scripts: sphinx-*: prevent sphinx-build crashes
  tools/docs: sphinx-build-wrapper: Fix output for duplicated names
  docs: add support to build manpages from kerneldoc output
  tools: kernel-doc: add a see also section at man pages
  scripts: kdoc_parser.py: warn about Python version only once
  tools/docs: sphinx-build-wrapper: move rust doc builder to wrapper
  tools/docs: sphinx-* break documentation bulds on openSUSE
  tools/docs: sphinx-build-wrapper: add support to run inside venv

 Documentation/Makefile                        | 144 +---
 Documentation/doc-guide/kernel-doc.rst        |  29 +-
 Documentation/doc-guide/sphinx.rst            |   4 +-
 Documentation/sphinx/kerneldoc-preamble.sty   |   2 +-
 Documentation/sphinx/parallel-wrapper.sh      |  33 -
 .../translations/it_IT/doc-guide/sphinx.rst   |   4 +-
 .../translations/zh_CN/doc-guide/sphinx.rst   |   4 +-
 Documentation/translations/zh_CN/how-to.rst   |   2 +-
 MAINTAINERS                                   |   4 +-
 Makefile                                      |   2 +-
 scripts/check-variable-fonts.sh               | 115 ---
 scripts/jobserver-exec                        |  88 +-
 scripts/lib/jobserver.py                      | 149 ++++
 scripts/lib/kdoc/kdoc_files.py                |   5 +-
 scripts/lib/kdoc/kdoc_output.py               |  84 +-
 scripts/lib/kdoc/kdoc_parser.py               |   7 +-
 scripts/split-man.pl                          |  28 -
 tools/docs/check-variable-fonts.py            |  30 +
 tools/docs/lib/latex_fonts.py                 | 166 ++++
 tools/docs/lib/python_version.py              | 178 ++++
 tools/docs/sphinx-build-wrapper               | 816 ++++++++++++++++++
 {scripts => tools/docs}/sphinx-pre-install    | 135 +--
 22 files changed, 1536 insertions(+), 493 deletions(-)
 delete mode 100644 Documentation/sphinx/parallel-wrapper.sh
 delete mode 100755 scripts/check-variable-fonts.sh
 create mode 100755 scripts/lib/jobserver.py
 delete mode 100755 scripts/split-man.pl
 create mode 100755 tools/docs/check-variable-fonts.py
 create mode 100755 tools/docs/lib/latex_fonts.py
 create mode 100644 tools/docs/lib/python_version.py
 create mode 100755 tools/docs/sphinx-build-wrapper
 rename {scripts => tools/docs}/sphinx-pre-install (93%)

-- 
2.51.0

[PATCH v7 19/24] docs: add support to build manpages from kerneldoc output

[Mauro Carvalho Chehab]

Generating man files currently requires running a separate
script. The target also doesn't appear at the docs Makefile.

Add support for mandocs at the Makefile, adding the build
logic inside sphinx-build-wrapper, updating documentation
and dropping the ancillary script.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 Documentation/Makefile                 |  3 +-
 Documentation/doc-guide/kernel-doc.rst | 29 ++++-----
 Makefile                               |  2 +-
 scripts/split-man.pl                   | 28 ---------
 tools/docs/sphinx-build-wrapper        | 81 ++++++++++++++++++++++++--
 5 files changed, 95 insertions(+), 48 deletions(-)
 delete mode 100755 scripts/split-man.pl

diff --git a/Documentation/Makefile b/Documentation/Makefile
index 05397b9d844d..aa42b2cb7030 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -53,7 +53,7 @@ ifeq ($(HAVE_SPHINX),0)
 else # HAVE_SPHINX
 
 # Common documentation targets
-infodocs texinfodocs latexdocs epubdocs xmldocs pdfdocs linkcheckdocs:
+mandocs infodocs texinfodocs latexdocs epubdocs xmldocs pdfdocs linkcheckdocs:
 	$(Q)@$(srctree)/tools/docs/sphinx-pre-install --version-check
 	+$(Q)$(PYTHON3) $(BUILD_WRAPPER) $@ \
 		--sphinxdirs="$(SPHINXDIRS)" --conf="$(SPHINX_CONF)" \
@@ -104,6 +104,7 @@ dochelp:
 	@echo  '  htmldocs        - HTML'
 	@echo  '  texinfodocs     - Texinfo'
 	@echo  '  infodocs        - Info'
+	@echo  '  mandocs         - Man pages'
 	@echo  '  latexdocs       - LaTeX'
 	@echo  '  pdfdocs         - PDF'
 	@echo  '  epubdocs        - EPUB'
diff --git a/Documentation/doc-guide/kernel-doc.rst b/Documentation/doc-guide/kernel-doc.rst
index af9697e60165..4370cc8fbcf5 100644
--- a/Documentation/doc-guide/kernel-doc.rst
+++ b/Documentation/doc-guide/kernel-doc.rst
@@ -579,20 +579,23 @@ source.
 How to use kernel-doc to generate man pages
 -------------------------------------------
 
-If you just want to use kernel-doc to generate man pages you can do this
-from the kernel git tree::
+To generate man pages for all files that contain kernel-doc markups, run::
 
-  $ scripts/kernel-doc -man \
-    $(git grep -l '/\*\*' -- :^Documentation :^tools) \
-    | scripts/split-man.pl /tmp/man
+  $ make mandocs
 
-Some older versions of git do not support some of the variants of syntax for
-path exclusion.  One of the following commands may work for those versions::
+Or calling ``script-build-wrapper`` directly::
 
-  $ scripts/kernel-doc -man \
-    $(git grep -l '/\*\*' -- . ':!Documentation' ':!tools') \
-    | scripts/split-man.pl /tmp/man
+  $ ./tools/docs/sphinx-build-wrapper mandocs
 
-  $ scripts/kernel-doc -man \
-    $(git grep -l '/\*\*' -- . ":(exclude)Documentation" ":(exclude)tools") \
-    | scripts/split-man.pl /tmp/man
+The output will be at ``/man`` directory inside the output directory
+(by default: ``Documentation/output``).
+
+Optionally, it is possible to generate a partial set of man pages by
+using SPHINXDIRS:
+
+  $ make SPHINXDIRS=driver-api/media mandocs
+
+.. note::
+
+   When SPHINXDIRS={subdir} is used, it will only generate man pages for
+   the files explicitly inside a ``Documentation/{subdir}/.../*.rst`` file.
diff --git a/Makefile b/Makefile
index 6bfe776bf3c5..9bd44afeda26 100644
--- a/Makefile
+++ b/Makefile
@@ -1800,7 +1800,7 @@ $(help-board-dirs): help-%:
 # Documentation targets
 # ---------------------------------------------------------------------------
 DOC_TARGETS := xmldocs latexdocs pdfdocs htmldocs epubdocs cleandocs \
-	       linkcheckdocs dochelp refcheckdocs texinfodocs infodocs
+	       linkcheckdocs dochelp refcheckdocs texinfodocs infodocs mandocs
 PHONY += $(DOC_TARGETS)
 $(DOC_TARGETS):
 	$(Q)$(MAKE) $(build)=Documentation $@
diff --git a/scripts/split-man.pl b/scripts/split-man.pl
deleted file mode 100755
index 96bd99dc977a..000000000000
--- a/scripts/split-man.pl
+++ /dev/null
@@ -1,28 +0,0 @@
-#!/usr/bin/env perl
-# SPDX-License-Identifier: GPL-2.0
-#
-# Author: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
-#
-# Produce manpages from kernel-doc.
-# See Documentation/doc-guide/kernel-doc.rst for instructions
-
-if ($#ARGV < 0) {
-   die "where do I put the results?\n";
-}
-
-mkdir $ARGV[0],0777;
-$state = 0;
-while (<STDIN>) {
-    if (/^\.TH \"[^\"]*\" 9 \"([^\"]*)\"/) {
-	if ($state == 1) { close OUT }
-	$state = 1;
-	$fn = "$ARGV[0]/$1.9";
-	print STDERR "Creating $fn\n";
-	open OUT, ">$fn" or die "can't open $fn: $!\n";
-	print OUT $_;
-    } elsif ($state != 0) {
-	print OUT $_;
-    }
-}
-
-close OUT;
diff --git a/tools/docs/sphinx-build-wrapper b/tools/docs/sphinx-build-wrapper
index 8d1f77c4a880..7a6eb41837e6 100755
--- a/tools/docs/sphinx-build-wrapper
+++ b/tools/docs/sphinx-build-wrapper
@@ -47,12 +47,14 @@ the newer version.
 import argparse
 import locale
 import os
+import re
 import shlex
 import shutil
 import subprocess
 import sys
 
 from concurrent import futures
+from glob import glob
 
 from lib.python_version import PythonVersion
 from lib.latex_fonts import LatexFontChecker
@@ -77,6 +79,7 @@ TARGETS = {
     "epubdocs":      { "builder": "epub",    "out_dir": "epub" },
     "texinfodocs":   { "builder": "texinfo", "out_dir": "texinfo" },
     "infodocs":      { "builder": "texinfo", "out_dir": "texinfo" },
+    "mandocs":       { "builder": "man",     "out_dir": "man" },
     "latexdocs":     { "builder": "latex",   "out_dir": "latex" },
     "pdfdocs":       { "builder": "latex",   "out_dir": "latex" },
     "xmldocs":       { "builder": "xml",     "out_dir": "xml" },
@@ -503,6 +506,71 @@ class SphinxBuilder:
             except subprocess.CalledProcessError as e:
                 sys.exit(f"Error generating info docs: {e}")
 
+    def handle_man(self, kerneldoc, docs_dir, src_dir, output_dir):
+        """
+        Create man pages from kernel-doc output
+        """
+
+        re_kernel_doc = re.compile(r"^\.\.\s+kernel-doc::\s*(\S+)")
+        re_man = re.compile(r'^\.TH "[^"]*" (\d+) "([^"]*)"')
+
+        if docs_dir == src_dir:
+            #
+            # Pick the entire set of kernel-doc markups from the entire tree
+            #
+            kdoc_files = set([self.srctree])
+        else:
+            kdoc_files = set()
+
+            for fname in glob(os.path.join(src_dir, "**"), recursive=True):
+                if os.path.isfile(fname) and fname.endswith(".rst"):
+                    with open(fname, "r", encoding="utf-8") as in_fp:
+                        data = in_fp.read()
+
+                    for line in data.split("\n"):
+                        match = re_kernel_doc.match(line)
+                        if match:
+                            if os.path.isfile(match.group(1)):
+                                kdoc_files.add(match.group(1))
+
+        if not kdoc_files:
+                sys.exit(f"Directory {src_dir} doesn't contain kernel-doc tags")
+
+        cmd = [ kerneldoc, "-m" ] + sorted(kdoc_files)
+        try:
+            if self.verbose:
+                print(" ".join(cmd))
+
+            result = subprocess.run(cmd, stdout=subprocess.PIPE, text= True)
+
+            if result.returncode:
+                print(f"Warning: kernel-doc returned {result.returncode} warnings")
+
+        except (OSError, ValueError, subprocess.SubprocessError) as e:
+            sys.exit(f"Failed to create man pages for {src_dir}: {repr(e)}")
+
+        fp = None
+        try:
+            for line in result.stdout.split("\n"):
+                match = re_man.match(line)
+                if not match:
+                    if fp:
+                        fp.write(line + '\n')
+                    continue
+
+                if fp:
+                    fp.close()
+
+                fname = f"{output_dir}/{match.group(2)}.{match.group(1)}"
+
+                if self.verbose:
+                    print(f"Creating {fname}")
+                fp = open(fname, "w", encoding="utf-8")
+                fp.write(line + '\n')
+        finally:
+            if fp:
+                fp.close()
+
     def cleandocs(self, builder):           # pylint: disable=W0613
         """Remove documentation output directory"""
         shutil.rmtree(self.builddir, ignore_errors=True)
@@ -531,7 +599,7 @@ class SphinxBuilder:
         # Other targets require sphinx-build, so check if it exists
         #
         sphinxbuild = shutil.which(self.sphinxbuild, path=self.env["PATH"])
-        if not sphinxbuild:
+        if not sphinxbuild and target != "mandocs":
             sys.exit(f"Error: {self.sphinxbuild} not found in PATH.\n")
 
         if builder == "latex":
@@ -619,10 +687,13 @@ class SphinxBuilder:
                 output_dir,
             ]
 
-            try:
-                self.run_sphinx(sphinxbuild, build_args, env=self.env)
-            except (OSError, ValueError, subprocess.SubprocessError) as e:
-                sys.exit(f"Build failed: {repr(e)}")
+            if target == "mandocs":
+                self.handle_man(kerneldoc, docs_dir, src_dir, output_dir)
+            else:
+                try:
+                    self.run_sphinx(sphinxbuild, build_args, env=self.env)
+                except (OSError, ValueError, subprocess.SubprocessError) as e:
+                    sys.exit(f"Build failed: {repr(e)}")
 
             #
             # Ensure that each html/epub output will have needed static files
-- 
2.51.0