Accept lualatex and platex as a PDF builder

Author: humitos

docs/guides/feature-flags.rst

@@ -18,6 +18,10 @@ Available Flags
 
 ``USE_XELATEX_BINARY``: :featureflags:`USE_XELATEX_BINARY`
 
+``USE_LUALATEX_BINARY``: :featureflags:`USE_LUALATEX_BINARY`
+
+``USE_PLATEX_BINARY``: :featureflags:`USE_PLATEX_BINARY`
+
 ``ALLOW_DEPRECATED_WEBHOOKS``: :featureflags:`ALLOW_DEPRECATED_WEBHOOKS`
 
 ``PIP_ALWAYS_UPGRADE``: :featureflags:`PIP_ALWAYS_UPGRADE`

readthedocs/doc_builder/backends/sphinx.py

@@ -395,6 +395,10 @@ def build(self):
         # https://github.com/rtfd/readthedocs.org/issues/4454
         if self.project.has_feature(Feature.USE_XELATEX_BINARY):
             latex_cmd = 'xelatex'
+        elif self.project.has_feature(Feature.USE_LUALATEX_BINARY):
+            latex_cmd = 'lualatex'
+        elif self.project.has_feature(Feature.USE_PLATEX_BINARY):
+            latex_cmd = 'platex'
         else:
             latex_cmd = 'pdflatex'
 

readthedocs/projects/models.py

@@ -1314,13 +1314,17 @@ def add_features(sender, **kwargs):
     DONT_SHALLOW_CLONE = 'dont_shallow_clone'
     USE_TESTING_BUILD_IMAGE = 'use_testing_build_image'
     USE_XELATEX_BINARY = 'use_xelatex_binary'
+    USE_LUALATEX_BINARY = 'use_lualatex_binary'
+    USE_PLATEX_BINARY = 'use_platex_binary'
 
     FEATURES = (
         (USE_SPHINX_LATEST, _('Use latest version of Sphinx')),
         (USE_SETUPTOOLS_LATEST, _('Use latest version of setuptools')),
         (ALLOW_DEPRECATED_WEBHOOKS, _('Allow deprecated webhook views')),
         (PIP_ALWAYS_UPGRADE, _('Always run pip install --upgrade')),
         (USE_XELATEX_BINARY, _('Use "xelatex" binary to build PDF files')),
+        (USE_LUALATEX_BINARY, _('Use "lualatex" binary to build PDF files')),
+        (USE_PLATEX_BINARY, _('Use "platex" binary to build PDF files')),
         (SKIP_SUBMODULES, _('Skip git submodule checkout')), (
             DONT_OVERWRITE_SPHINX_CONTEXT,
             _(