fix(build): raise clear error if mkdocs.yml config file is missing

readthedocs/doc_builder/backends/mkdocs.py

@@ -5,15 +5,17 @@
 """
 
 import os
-
 import structlog
 import yaml
 from django.conf import settings
 
 from readthedocs.core.utils.filesystem import safe_open
 from readthedocs.doc_builder.base import BaseBuilder
+from readthedocs.doc_builder.exceptions import BuildUserError
 from readthedocs.projects.constants import MKDOCS
 from readthedocs.projects.constants import MKDOCS_HTML
+from readthedocs.projects.exceptions import ProjectConfigurationError
+
 
 
 log = structlog.get_logger(__name__)
@@ -45,6 +47,8 @@ def __init__(self, *args, **kwargs):
 
         # This is the *MkDocs* yaml file
         self.yaml_file = self.get_yaml_config()
+        if not os.path.exists(self.yaml_file):
+            raise ProjectConfigurationError(ProjectConfigurationError.MKDOCS_NOT_FOUND)
 
     def get_final_doctype(self):
         """
@@ -99,6 +103,10 @@ def build(self):
             "--config-file",
             os.path.relpath(self.yaml_file, self.project_path),
         ]
+
+        if not os.path.exists(self.yaml_file):
+            raise ProjectConfigurationError(ProjectConfigurationError.NOT_FOUND)
+
         if self.config.mkdocs.fail_on_warning:
             build_command.append("--strict")
         cmd_ret = self.run(

readthedocs/projects/exceptions.py

@@ -9,6 +9,8 @@ class ProjectConfigurationError(BuildUserError):
 
     NOT_FOUND = "project:sphinx:conf-py-not-found"
     MULTIPLE_CONF_FILES = "project:sphinx:multiple-conf-py-files-found"
+    MKDOCS_NOT_FOUND = "project:configuration:mkdocs-not-found"
+
 
 
 class UserFileNotFound(BuildUserError):

readthedocs/projects/notifications.py

@@ -125,6 +125,20 @@
         ),
         type=ERROR,
     ),
+    Message(
+        id=ProjectConfigurationError.MKDOCS_NOT_FOUND,
+        header=_("MkDocs configuration file is missing"),
+        body=_(
+            textwrap.dedent(
+                """
+            A configuration file was not found.
+            Make sure you have a <code>mkdocs.yml</code> file in your repository.
+            """
+            ).strip(),
+        ),
+        type=ERROR,
+    ),
+
     Message(
         id=ProjectConfigurationError.MULTIPLE_CONF_FILES,
         header=_("Multiple Sphinx configuration files found"),