Config file: make sphinx or mkdocs configuration required for projects using Sphinx or MkDocs

docs/user/config-file/v2.rst

@@ -493,8 +493,7 @@ The ``$READTHEDOCS_OUTPUT/html`` directory will be uploaded and hosted by Read t
 sphinx
 ~~~~~~
 
-Configuration for Sphinx documentation
-(this is the default documentation type).
+Configuration for Sphinx documentation.
 
 .. code-block:: yaml
 
@@ -535,10 +534,7 @@ sphinx.configuration
 The path to the ``conf.py`` file, relative to the root of the project.
 
 :Type: ``path``
-:Default: ``null``
-
-If the value is ``null``,
-Read the Docs will try to find a ``conf.py`` file in your project.
+:Required: ``true``
 
 sphinx.fail_on_warning
 ``````````````````````
@@ -580,10 +576,7 @@ mkdocs.configuration
 The path to the ``mkdocs.yml`` file, relative to the root of the project.
 
 :Type: ``path``
-:Default: ``null``
-
-If the value is ``null``,
-Read the Docs will try to find a ``mkdocs.yml`` file in your project.
+:Required: ``true``
 
 mkdocs.fail_on_warning
 ``````````````````````

readthedocs/config/config.py

@@ -1,11 +1,12 @@
 """Build configuration for rtd."""
-
 import copy
+import datetime
 import os
 import re
 from contextlib import contextmanager
 from functools import lru_cache
 
+import pytz
 from django.conf import settings
 from pydantic import BaseModel
 
@@ -87,7 +88,13 @@ class BuildConfigBase:
 
     version = None
 
-    def __init__(self, raw_config, source_file, base_path=None):
+    def __init__(
+        self,
+        raw_config,
+        source_file,
+        base_path=None,
+        deprecate_implicit_keys=None,
+    ):
         self._raw_config = copy.deepcopy(raw_config)
         self.source_config = copy.deepcopy(raw_config)
         self.source_file = source_file
@@ -102,6 +109,25 @@ def __init__(self, raw_config, source_file, base_path=None):
 
         self._config = {}
 
+        if deprecate_implicit_keys is not None:
+            self.deprecate_implicit_keys = deprecate_implicit_keys
+        elif settings.RTD_ENFORCE_BROWNOUTS_FOR_DEPRECATIONS:
+            tzinfo = pytz.timezone("America/Los_Angeles")
+            now = datetime.datetime.now(tz=tzinfo)
+            # Dates as per https://about.readthedocs.com/blog/2024/12/deprecate-config-files-without-sphinx-or-mkdocs-config/
+            # fmt: off
+            self.deprecate_implicit_keys = (
+                # 12 hours brownout.
+                datetime.datetime(2025, 1, 6, 0, 0, 0, tzinfo=tzinfo) < now < datetime.datetime(2025, 1, 6, 12, 0, 0, tzinfo=tzinfo)
+                # 24 hours brownout.
+                or datetime.datetime(2025, 1, 20, 0, 0, 0, tzinfo=tzinfo) < now < datetime.datetime(2025, 1, 21, 0, 0, 0, tzinfo=tzinfo)
+                # Permanent removal.
+                or datetime.datetime(2025, 2, 3, 0, 0, 0, tzinfo=tzinfo) < now
+            )
+            # fmt: on
+        else:
+            self.deprecate_implicit_keys = False
+
     @contextmanager
     def catch_validation_error(self, key):
         """Catch a ``ConfigValidationError`` and raises a ``ConfigError`` error."""
@@ -219,7 +245,6 @@ def __getattr__(self, name):
 
 
 class BuildConfigV2(BuildConfigBase):
-
     """Version 2 of the configuration file."""
 
     version = "2"
@@ -251,6 +276,8 @@ def validate(self):
         self._config["sphinx"] = self.validate_sphinx()
         self._config["submodules"] = self.validate_submodules()
         self._config["search"] = self.validate_search()
+        if self.deprecate_implicit_keys:
+            self.validate_deprecated_implicit_keys()
         self.validate_keys()
 
     def validate_formats(self):
@@ -722,6 +749,50 @@ def validate_search(self):
 
         return search
 
+    def validate_deprecated_implicit_keys(self):
+        """
+        Check for deprecated usages and raise an exception if found.
+
+        - If the sphinx key is used, a path to the configuration file is required.
+        - If the mkdocs key is used, a path to the configuration file is required.
+        - If none of the sphinx or mkdocs keys are used,
+          and the user isn't overriding the new build jobs,
+          the sphinx key is explicitly required.
+        """
+        has_sphinx_key = "sphinx" in self.source_config
+        has_mkdocs_key = "mkdocs" in self.source_config
+        if has_sphinx_key and not self.sphinx.configuration:
+            raise ConfigError(
+                message_id=ConfigError.SPHINX_CONFIG_MISSING,
+            )
+
+        if has_mkdocs_key and not self.mkdocs.configuration:
+            raise ConfigError(
+                message_id=ConfigError.MKDOCS_CONFIG_MISSING,
+            )
+
+        if not self.new_jobs_overriden and not has_sphinx_key and not has_mkdocs_key:
+            raise ConfigError(
+                message_id=ConfigError.SPHINX_CONFIG_MISSING,
+            )
+
+    @property
+    def new_jobs_overriden(self):
+        """Check if any of the new (undocumented) build jobs are overridden."""
+        build_jobs = self.build.jobs
+        new_jobs = (
+            build_jobs.create_environment,
+            build_jobs.install,
+            build_jobs.build.html,
+            build_jobs.build.pdf,
+            build_jobs.build.epub,
+            build_jobs.build.htmlzip,
+        )
+        for job in new_jobs:
+            if job is not None:
+                return True
+        return False
+
     def validate_keys(self):
         """
         Checks that we don't have extra keys (invalid ones).
@@ -812,6 +883,11 @@ def doctype(self):
         if "commands" in self._config["build"] and self._config["build"]["commands"]:
             return GENERIC
 
+        has_sphinx_key = "sphinx" in self.source_config
+        has_mkdocs_key = "mkdocs" in self.source_config
+        if self.new_jobs_overriden and not has_sphinx_key and not has_mkdocs_key:
+            return GENERIC
+
         if self.mkdocs:
             return "mkdocs"
         return self.sphinx.builder

readthedocs/config/exceptions.py

@@ -26,6 +26,9 @@ class ConfigError(BuildUserError):
     SYNTAX_INVALID = "config:base:invalid-syntax"
     CONDA_KEY_REQUIRED = "config:conda:required"
 
+    SPHINX_CONFIG_MISSING = "config:sphinx:missing-config"
+    MKDOCS_CONFIG_MISSING = "config:mkdocs:missing-config"
+
 
 # TODO: improve these error messages shown to the user
 # See https://github.com/readthedocs/readthedocs.org/issues/10502

readthedocs/config/notifications.py

@@ -361,5 +361,31 @@
         ),
         type=ERROR,
     ),
+    Message(
+        id=ConfigError.SPHINX_CONFIG_MISSING,
+        header=_("Missing Sphinx configuration key"),
+        body=_(
+            textwrap.dedent(
+                """
+                The <code>sphinx.configuration</code> key is missing.
+                This key is now required, see our <a href="https://about.readthedocs.com/blog/2024/12/deprecate-config-files-without-sphinx-or-mkdocs-config/">blog post</a> for more information.
+                """
+            ).strip(),
+        ),
+        type=ERROR,
+    ),
+    Message(
+        id=ConfigError.MKDOCS_CONFIG_MISSING,
+        header=_("Missing MkDocs configuration key"),
+        body=_(
+            textwrap.dedent(
+                """
+                The <code>mkdocs.configuration</code> key is missing.
+                This key is now required, see our <a href="https://about.readthedocs.com/blog/2024/12/deprecate-config-files-without-sphinx-or-mkdocs-config/">blog post</a> for more information.
+                """
+            ).strip(),
+        ),
+        type=ERROR,
+    ),
 ]
 registry.add(messages)

readthedocs/config/tests/test_config.py

@@ -23,7 +23,7 @@
 from .utils import apply_fs
 
 
-def get_build_config(config, source_file="readthedocs.yml", validate=False):
+def get_build_config(config, source_file="readthedocs.yml", validate=False, **kwargs):
     # I'm adding these defaults here to avoid modifying all the config file from all the tests
     final_config = {
         "version": "2",
@@ -39,6 +39,7 @@ def get_build_config(config, source_file="readthedocs.yml", validate=False):
     build_config = BuildConfigV2(
         final_config,
         source_file=source_file,
+        **kwargs,
     )
     if validate:
         build_config.validate()
@@ -1805,6 +1806,64 @@ def test_pop_config_raise_exception(self):
         assert excinfo.value.format_values.get("value") == "invalid"
         assert excinfo.value.message_id == ConfigValidationError.VALUE_NOT_FOUND
 
+    def test_sphinx_without_explicit_configuration(self):
+        data = {
+            "sphinx": {},
+        }
+        get_build_config(data, validate=True)
+
+        with raises(ConfigError) as excinfo:
+            get_build_config(data, validate=True, deprecate_implicit_keys=True)
+
+        assert excinfo.value.message_id == ConfigError.SPHINX_CONFIG_MISSING
+
+        data["sphinx"]["configuration"] = "conf.py"
+        get_build_config(data, validate=True, deprecate_implicit_keys=True)
+
+    def test_mkdocs_without_explicit_configuration(self):
+        data = {
+            "mkdocs": {},
+        }
+        get_build_config(data, validate=True)
+
+        with raises(ConfigError) as excinfo:
+            get_build_config(data, validate=True, deprecate_implicit_keys=True)
+
+        assert excinfo.value.message_id == ConfigError.MKDOCS_CONFIG_MISSING
+
+        data["mkdocs"]["configuration"] = "mkdocs.yml"
+        get_build_config(data, validate=True, deprecate_implicit_keys=True)
+
+    def test_config_without_sphinx_key(self):
+        data = {
+            "build": {
+                "os": "ubuntu-22.04",
+                "tools": {
+                    "python": "3",
+                },
+                "jobs": {},
+            },
+        }
+        get_build_config(data, validate=True)
+
+        with raises(ConfigError) as excinfo:
+            get_build_config(data, validate=True, deprecate_implicit_keys=True)
+
+        assert excinfo.value.message_id == ConfigError.SPHINX_CONFIG_MISSING
+
+        # No exception should be raised when overriding any of the the new jobs.
+        data_copy = data.copy()
+        data_copy["build"]["jobs"]["create_environment"] = ["echo 'Hello World'"]
+        get_build_config(data_copy, validate=True, deprecate_implicit_keys=True)
+
+        data_copy = data.copy()
+        data_copy["build"]["jobs"]["install"] = ["echo 'Hello World'"]
+        get_build_config(data_copy, validate=True, deprecate_implicit_keys=True)
+
+        data_copy = data.copy()
+        data_copy["build"]["jobs"]["build"] = {"html": ["echo 'Hello World'"]}
+        get_build_config(data_copy, validate=True, deprecate_implicit_keys=True)
+
     def test_as_dict_new_build_config(self, tmpdir):
         build = get_build_config(
             {

readthedocs/doc_builder/director.py

@@ -23,7 +23,7 @@
 from readthedocs.doc_builder.exceptions import BuildUserError
 from readthedocs.doc_builder.loader import get_builder_class
 from readthedocs.doc_builder.python_environments import Conda, Virtualenv
-from readthedocs.projects.constants import BUILD_COMMANDS_OUTPUT_PATH_HTML
+from readthedocs.projects.constants import BUILD_COMMANDS_OUTPUT_PATH_HTML, GENERIC
 from readthedocs.projects.exceptions import RepositoryError
 from readthedocs.projects.signals import after_build, before_build, before_vcs
 from readthedocs.storage import build_tools_storage
@@ -639,6 +639,11 @@ def build_docs_class(self, builder_class):
         only raise a warning exception here. A hard error will halt the build
         process.
         """
+        # If the builder is generic, we have nothing to do here,
+        # as the commnads are provided by the user.
+        if builder_class == GENERIC:
+            return
+
         builder = get_builder_class(builder_class)(
             build_env=self.build_environment,
             python_env=self.language_environment,

readthedocs/doc_builder/python_environments.py

@@ -11,6 +11,7 @@
 from readthedocs.config.models import PythonInstall, PythonInstallRequirements
 from readthedocs.core.utils.filesystem import safe_open
 from readthedocs.doc_builder.config import load_yaml_config
+from readthedocs.projects.constants import GENERIC
 from readthedocs.projects.exceptions import UserFileNotFound
 from readthedocs.projects.models import Feature
 
@@ -168,6 +169,10 @@ def _install_latest_requirements(self, pip_install_cmd):
             cwd=self.checkout_path,
         )
 
+        # Nothing else to install for generic projects.
+        if self.config.doctype == GENERIC:
+            return
+
         # Second, install all the latest core requirements
         requirements = []