Feature flag to use other pdf latex binaries

docs/guides/feature-flags.rst

@@ -16,6 +16,12 @@ Available Flags
 
 ``USE_SETUPTOOLS_LATEST``: :featureflags:`USE_SETUPTOOLS_LATEST`
 
+``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

@@ -392,13 +392,33 @@ def build(self):
             raise BuildEnvironmentError('No TeX files were found')
 
         # Run LaTeX -> PDF conversions
-        pdflatex_cmds = [
-            ['pdflatex', '-interaction=nonstopmode', tex_file]
+        # https://github.com/rtfd/readthedocs.org/issues/4454
+        if self.project.has_feature(Feature.USE_XELATEX_BINARY):
+            latex_cmd = 'xelatex'
+            makeindex_cmd = 'xindy'
+        elif self.project.has_feature(Feature.USE_LUALATEX_BINARY):
+            latex_cmd = 'lualatex'
+            makeindex_cmd = 'xindy'
+        elif self.project.has_feature(Feature.USE_PLATEX_BINARY):
+            latex_cmd = 'platex'
+            makeindex_cmd = 'xindy'
+        else:
+            latex_cmd = 'pdflatex'
+            makeindex_cmd = 'makeindex'
+
+        latex_cmds = [
+            [latex_cmd, '-interaction=nonstopmode', tex_file]
             for tex_file in tex_files
         ]  # yapf: disable
+
+        if makeindex_cmd == 'xindy':
+            makeindex_args = ['-C', 'utf8', '-M', 'texindy']
+        else:
+            makeindex_args = ['-s', 'python.ist']
+
         makeindex_cmds = [
             [
-                'makeindex', '-s', 'python.ist', '{}.idx'.format(
+                makeindex_cmd, *makeindex_args, '{}.idx'.format(
                 os.path.splitext(os.path.relpath(tex_file, latex_cwd))[0],
                 ),
             ]
@@ -410,7 +430,7 @@ def build(self):
         else:
             latex_class = LatexBuildCommand
         pdf_commands = []
-        for cmd in pdflatex_cmds:
+        for cmd in latex_cmds:
             cmd_ret = self.build_env.run_command_class(
                 cls=latex_class,
                 cmd=cmd,
@@ -426,7 +446,7 @@ def build(self):
                 warn_only=True,
             )
             pdf_commands.append(cmd_ret)
-        for cmd in pdflatex_cmds:
+        for cmd in latex_cmds:
             cmd_ret = self.build_env.run_command_class(
                 cls=latex_class,
                 cmd=cmd,

readthedocs/projects/models.py

@@ -1313,12 +1313,18 @@ def add_features(sender, **kwargs):
     API_LARGE_DATA = 'api_large_data'
     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,
             _(
@@ -1337,7 +1343,7 @@ def add_features(sender, **kwargs):
             _(
                 'Use Docker image labelled as `testing` to build the docs',
             ),
-        ), (API_LARGE_DATA, _('Try alternative method of posting large data'))
+        ), (API_LARGE_DATA, _('Try alternative method of posting large data')),
     )
 
     projects = models.ManyToManyField(