configure: bootstrap sphinx with mkvenv

When docs are explicitly requested, require Sphinx>=1.6.0. When docs are
explicitly disabled, don't bother to check for Sphinx at all. If docs
are set to "auto", attempt to locate Sphinx, but continue onward if it
wasn't located.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20230511035435.734312-22-jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -1115,9 +1115,9 @@ fi
 
 # Suppress writing compiled files
 python="$python -B"
+mkvenv="$python ${source_path}/python/scripts/mkvenv.py"
 
-
-if ! $python "${source_path}/python/scripts/mkvenv.py" ensure \
+if ! $mkvenv ensure \
      --dir "${source_path}/python/wheels" \
      --diagnose "meson" \
      "meson>=0.61.5" ;
@@ -1132,6 +1132,23 @@ fi
 
 meson="$(cd pyvenv/bin; pwd)/meson"
 
+# Conditionally ensure Sphinx is installed.
+
+if test "$docs" != "disabled" ; then
+    if ! $mkvenv ensure \
+         --diagnose "sphinx-build" \
+         "sphinx>=1.6.0" "sphinx-rtd-theme>=0.5.0";
+    then
+        if test "$docs" = "enabled" ; then
+            exit 1
+        fi
+        echo "Sphinx not found/usable, disabling docs."
+        docs=disabled
+    else
+        docs=enabled
+    fi
+fi
+
 # Probe for ninja
 
 if test -z "$ninja"; then

docs/conf.py

@@ -32,15 +32,6 @@ import sphinx
 from distutils.version import LooseVersion
 from sphinx.errors import ConfigError
 
-# Make Sphinx fail cleanly if using an old Python, rather than obscurely
-# failing because some code in one of our extensions doesn't work there.
-# In newer versions of Sphinx this will display nicely; in older versions
-# Sphinx will also produce a Python backtrace but at least the information
-# gets printed...
-if sys.version_info < (3,6):
-    raise ConfigError(
-        "QEMU requires a Sphinx that uses Python 3.6 or better\n")
-
 # The per-manual conf.py will set qemu_docdir for a single-manual build;
 # otherwise set it here if this is an entire-manual-set build.
 # This is always the absolute path of the docs/ directory in the source tree.

docs/meson.build

@@ -1,4 +1,4 @@
-sphinx_build = find_program(get_option('sphinx_build'),
+sphinx_build = find_program(fs.parent(python.full_path()) / 'sphinx-build',
                             required: get_option('docs'))
 
 # Check if tools are available to build documentation.

meson_options.txt

@@ -12,8 +12,6 @@ option('pkgversion', type : 'string', value : '',
        description: 'use specified string as sub-version of the package')
 option('smbd', type : 'string', value : '',
        description: 'Path to smbd for slirp networking')
-option('sphinx_build', type : 'string', value : 'sphinx-build',
-       description: 'Use specified sphinx-build for building document')
 option('iasl', type : 'string', value : '',
        description: 'Path to ACPI disassembler')
 option('tls_priority', type : 'string', value : 'NORMAL',

scripts/meson-buildoptions.sh

@@ -57,8 +57,6 @@ meson_options_help() {
   printf "%s\n" '  --localedir=VALUE        Locale data directory [share/locale]'
   printf "%s\n" '  --localstatedir=VALUE    Localstate data directory [/var/local]'
   printf "%s\n" '  --mandir=VALUE           Manual page directory [share/man]'
-  printf "%s\n" '  --sphinx-build=VALUE     Use specified sphinx-build for building document'
-  printf "%s\n" '                           [sphinx-build]'
   printf "%s\n" '  --sysconfdir=VALUE       Sysconf data directory [etc]'
   printf "%s\n" '  --tls-priority=VALUE     Default TLS protocol/cipher priority string'
   printf "%s\n" '                           [NORMAL]'
@@ -427,7 +425,6 @@ _meson_option_parse() {
     --disable-sndio) printf "%s" -Dsndio=disabled ;;
     --enable-sparse) printf "%s" -Dsparse=enabled ;;
     --disable-sparse) printf "%s" -Dsparse=disabled ;;
-    --sphinx-build=*) quote_sh "-Dsphinx_build=$2" ;;
     --enable-spice) printf "%s" -Dspice=enabled ;;
     --disable-spice) printf "%s" -Dspice=disabled ;;
     --enable-spice-protocol) printf "%s" -Dspice_protocol=enabled ;;