Add separate conf.py for the different docs types

The goal here is to allow building the `man` pages without all the
additional requirements needed for the `html` docs, so that e.g.
developers packaging `pip` can also package the man pages with minimal
dependencies.

Specifically, this should have no impact on the build output of `nox -s
docs`, but does allow:

    sphinx-build \
        -c docs/man \
        -d docs/build/doctrees/man \
        -b man \
        docs/man \
        docs/build/man

to run with only `sphinx` dependency (in addition to `pip`s
dependencies). While doing this I also used long-opts to `sphinx-build`
in the `noxfile` since I found this more understandable at a glance

An `__init__.py` was added under `docs/man` to satisfy `mypy`. If this
wasn't added it would error:

    docs/man/conf.py: error: Duplicate module named "conf" (also at
    "docs/html/conf.py")
    docs/man/conf.py: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#mapping-file-paths-to-modules for more info
    docs/man/conf.py: note: Common resolutions include: a) using `--exclude` to avoid checking one of them, b) adding `__init__.py` somewhere, c) using `--explicit-package-bases` or adjusting MYPYPATH
    Found 1 error in 1 file (errors prevented further checking)

Adding an extra `__init__.py` under `docs/html` would result in a
separate error since then the `html` module is local (and not the stdlib
one) resulting in a error from `sphinx-build`:

    Extension error:
    Could not import extension sphinx.builders.linkcheck (exception: No module named 'html.parser')

Issue: #12881

.readthedocs.yml

@@ -12,3 +12,4 @@ sphinx:
 python:
   install:
     - requirements: docs/requirements.txt
+    - requirements: docs/html/requirements.txt

MANIFEST.in

@@ -13,6 +13,7 @@ recursive-include  src/pip/_vendor *COPYING*
 
 include docs/docutils.conf
 include docs/requirements.txt
+include docs/html/requirements.txt
 
 exclude .git-blame-ignore-revs
 exclude .coveragerc

docs/common_conf.py

@@ -0,0 +1,29 @@
+import os
+import re
+from typing import Tuple
+
+
+def read_version() -> Tuple[str, str]:
+    # Find the version and release information.
+    # We have a single source of truth for our version number: pip's __init__.py file.
+    # This next bit of code reads from it.
+    file_with_version = os.path.join(
+        os.path.dirname(__file__), "..", "src", "pip", "__init__.py"
+    )
+    with open(file_with_version) as f:
+        for line in f:
+            m = re.match(r'__version__ = "(.*)"', line)
+            if m:
+                __version__ = m.group(1)
+                # The short X.Y version.
+                version = ".".join(__version__.split(".")[:2])
+                # The full version, including alpha/beta/rc tags.
+                release = __version__
+                return version, release
+        return "dev", "dev"
+
+
+# General information about the project.
+project = "pip"
+copyright = "The pip developers"
+version, release = read_version()

docs/html/conf.py

@@ -1,16 +1,16 @@
 """Sphinx configuration file for pip's documentation."""
 
-import glob
 import os
 import pathlib
-import re
 import sys
-from typing import List, Tuple
 
-# Add the docs/ directory to sys.path, because pip_sphinxext.py is there.
+# Add the docs/ directory to sys.path to load the common config,
+# and pip_sphinxext.py
 docs_dir = os.path.dirname(os.path.dirname(__file__))
 sys.path.insert(0, docs_dir)
 
+from common_conf import copyright, project, release, version  # noqa: E402, F401
+
 # -- General configuration ------------------------------------------------------------
 
 extensions = [
@@ -28,27 +28,6 @@
     "sphinxcontrib.towncrier",
 ]
 
-# General information about the project.
-project = "pip"
-copyright = "The pip developers"
-
-# Find the version and release information.
-# We have a single source of truth for our version number: pip's __init__.py file.
-# This next bit of code reads from it.
-file_with_version = os.path.join(docs_dir, "..", "src", "pip", "__init__.py")
-with open(file_with_version) as f:
-    for line in f:
-        m = re.match(r'__version__ = "(.*)"', line)
-        if m:
-            __version__ = m.group(1)
-            # The short X.Y version.
-            version = ".".join(__version__.split(".")[:2])
-            # The full version, including alpha/beta/rc tags.
-            release = __version__
-            break
-    else:  # AKA no-break
-        version = release = "dev"
-
 print("pip version:", version)
 print("pip release:", release)
 
@@ -95,43 +74,6 @@
 html_use_modindex = False
 html_use_index = False
 
-# -- Options for Manual Pages ---------------------------------------------------------
-
-
-# List of manual pages generated
-def determine_man_pages() -> List[Tuple[str, str, str, str, int]]:
-    """Determine which man pages need to be generated."""
-
-    def to_document_name(path: str, base_dir: str) -> str:
-        """Convert a provided path to a Sphinx "document name"."""
-        relative_path = os.path.relpath(path, base_dir)
-        root, _ = os.path.splitext(relative_path)
-        return root.replace(os.sep, "/")
-
-    # Crawl the entire man/commands/ directory and list every file with appropriate
-    # name and details.
-    man_dir = os.path.join(docs_dir, "man")
-    raw_subcommands = glob.glob(os.path.join(man_dir, "commands/*.rst"))
-    if not raw_subcommands:
-        raise FileNotFoundError(
-            "The individual subcommand manpages could not be found!"
-        )
-
-    retval = [
-        ("index", "pip", "package manager for Python packages", "pip developers", 1),
-    ]
-    for fname in raw_subcommands:
-        fname_base = to_document_name(fname, man_dir)
-        outname = "pip-" + fname_base.split("/")[1]
-        description = "description of {} command".format(outname.replace("-", " "))
-
-        retval.append((fname_base, outname, description, "pip developers", 1))
-
-    return retval
-
-
-man_pages = determine_man_pages()
-
 # -- Options for sphinx_copybutton ----------------------------------------------------
 
 copybutton_prompt_text = r"\$ | C\:\> "

docs/html/requirements.txt

@@ -0,0 +1,8 @@
+# currently incompatible with sphinxcontrib-towncrier
+# https://github.com/sphinx-contrib/sphinxcontrib-towncrier/issues/92
+towncrier < 24
+furo
+myst_parser
+sphinx-copybutton
+sphinx-inline-tabs
+sphinxcontrib-towncrier >= 0.2.0a0

docs/man/conf.py

@@ -0,0 +1,53 @@
+import glob
+import os
+import sys
+from typing import List, Tuple
+
+# Add the docs/ directory to sys.path to load the common config
+docs_dir = os.path.dirname(os.path.dirname(__file__))
+sys.path.insert(0, docs_dir)
+
+from common_conf import copyright, project, release, version  # noqa: E402, F401
+
+extensions = [
+    # our extensions
+    "pip_sphinxext",
+]
+
+print("pip version:", version)
+print("pip release:", release)
+
+
+# List of manual pages generated
+def determine_man_pages() -> List[Tuple[str, str, str, str, int]]:
+    """Determine which man pages need to be generated."""
+
+    def to_document_name(path: str, base_dir: str) -> str:
+        """Convert a provided path to a Sphinx "document name"."""
+        relative_path = os.path.relpath(path, base_dir)
+        root, _ = os.path.splitext(relative_path)
+        return root.replace(os.sep, "/")
+
+    # Crawl the entire man/commands/ directory and list every file with appropriate
+    # name and details.
+    man_dir = os.path.join(docs_dir, "man")
+    raw_subcommands = glob.glob(os.path.join(man_dir, "commands/*.rst"))
+    if not raw_subcommands:
+        raise FileNotFoundError(
+            "The individual subcommand manpages could not be found!"
+        )
+
+    retval = [
+        ("index", "pip", "package manager for Python packages", "pip developers", 1),
+    ]
+    for fname in raw_subcommands:
+        fname_base = to_document_name(fname, man_dir)
+        outname = "pip-" + fname_base.split("/")[1]
+        description = "description of {} command".format(outname.replace("-", " "))
+
+        retval.append((fname_base, outname, description, "pip developers", 1))
+
+    return retval
+
+
+man_pages = determine_man_pages()

docs/requirements.txt

@@ -1,12 +1,4 @@
 sphinx ~= 7.0
-# currently incompatible with sphinxcontrib-towncrier
-# https://github.com/sphinx-contrib/sphinxcontrib-towncrier/issues/92
-towncrier < 24
-furo
-myst_parser
-sphinx-copybutton
-sphinx-inline-tabs
-sphinxcontrib-towncrier >= 0.2.0a0
 
 # `docs.pipext` uses pip's internals to generate documentation. So, we install
 # the current directory to make it work.

noxfile.py

@@ -26,6 +26,7 @@
 }
 REQUIREMENTS = {
     "docs": "docs/requirements.txt",
+    "docs-html": "docs/html/requirements.txt",
     "tests": "tests/requirements.txt",
     "common-wheels": "tests/requirements-common_wheels.txt",
 }
@@ -131,18 +132,21 @@ def docs(session: nox.Session) -> None:
     session.install("-r", REQUIREMENTS["docs"])
 
     def get_sphinx_build_command(kind: str) -> List[str]:
-        # Having the conf.py in the docs/html is weird but needed because we
+        req_file = REQUIREMENTS.get(f"docs-{kind}")
+        if req_file is not None:
+            session.install("--requirement", req_file)
+        # Having the conf.py in the docs/{html,man} is weird but needed because we
         # can not use a different configuration directory vs source directory
         # on RTD currently. So, we'll pass "-c docs/html" here.
         # See https://github.com/rtfd/readthedocs.org/issues/1543.
         # fmt: off
         return [
             "sphinx-build",
             "--keep-going",
-            "-W",
-            "-c", "docs/html",  # see note above
-            "-d", "docs/build/doctrees/" + kind,
-            "-b", kind,
+            "--fail-on-warning",
+            "--conf-dir", "docs/" + kind,  # see note above
+            "--doctree-dir", "docs/build/doctrees/" + kind,
+            "--builder", kind,
             "docs/" + kind,
             "docs/build/" + kind,
         ]
@@ -155,7 +159,13 @@ def get_sphinx_build_command(kind: str) -> List[str]:
 @nox.session(name="docs-live")
 def docs_live(session: nox.Session) -> None:
     session.install("-e", ".")
-    session.install("-r", REQUIREMENTS["docs"], "sphinx-autobuild")
+    session.install(
+        "-r",
+        REQUIREMENTS["docs"],
+        "-r",
+        REQUIREMENTS["docs-html"],
+        "sphinx-autobuild",
+    )
 
     session.run(
         "sphinx-autobuild",