Fail elegantly when no source files are found

Fixes #324

autoapi/mappers/python/mapper.py

@@ -5,6 +5,7 @@
 import re
 
 import sphinx.environment
+from sphinx.errors import ExtensionError
 import sphinx.util
 from sphinx.util.console import bold
 import sphinx.util.docstrings
@@ -286,6 +287,9 @@ def load(self, patterns, dirs, ignore=None):
         shortened, relative path the package/module
         """
         dir_root_files = list(self._find_files(patterns, dirs, ignore))
+        if not dir_root_files:
+            raise ExtensionError(f"No source files found in: {','.join(dirs)}")
+
         if not self._need_to_load(dir_root_files):
             LOGGER.debug(
                 "[AutoAPI] Skipping read stage because source files have not changed."

tests/python/pyemptyexample/conf.py

@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+
+templates_path = ["_templates"]
+source_suffix = ".rst"
+master_doc = "index"
+project = "pyexample"
+copyright = "2015, readthedocs"
+author = "readthedocs"
+version = "0.1"
+release = "0.1"
+language = None
+exclude_patterns = ["_build"]
+pygments_style = "sphinx"
+todo_include_todos = False
+html_theme = "alabaster"
+htmlhelp_basename = "pyexampledoc"
+extensions = ["sphinx.ext.autodoc", "autoapi.extension"]
+autoapi_type = "python"
+autoapi_dirs = ["example"]
+autoapi_python_class_content = "both"
+autoapi_options = [
+    "members",
+    "undoc-members",  # this is temporary until we add docstrings across the codebase
+    "show-inheritance",
+    "show-module-summary",
+    "special-members",
+    "imported-members",
+    "inherited-members",
+]

tests/python/pyemptyexample/index.rst

@@ -0,0 +1,25 @@
+.. pyexample documentation master file, created by
+   sphinx-quickstart on Fri May 29 13:34:37 2015.
+   You can adapt this file completely to your liking, but it should at least
+   contain the root `toctree` directive.
+
+Welcome to pyexample's documentation!
+=====================================
+
+.. toctree::
+
+   autoapi/index
+
+Contents:
+
+.. toctree::
+   :maxdepth: 2
+
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
+

tests/python/test_pyintegration.py

@@ -9,6 +9,7 @@
 import pytest
 import sphinx
 from sphinx.application import Sphinx
+from sphinx.errors import ExtensionError
 import sphinx.util.logging
 
 from autoapi.mappers.python import (
@@ -912,3 +913,11 @@ def test_renders_typehint_in_second_module(self):
             example2_file = example2_handle.read()
 
         assert "(*int*)" in example2_file
+
+
+def test_no_files_found(builder):
+    """Test that building does not fail when no sources files are found."""
+    with pytest.raises(ExtensionError) as exc_info:
+        builder("pyemptyexample")
+
+    assert os.path.dirname(__file__) in str(exc_info.value)