[1518] Directory Name Render and Create Fix (#1991)

* Raise warning when directory name is empty

* Adding EmptyDirNameException for situation in render_and_create_dir where dirname is empty

* Include new exception type in cli.py

* Fixing linting issues and adding in test case for render_and_create_dir

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: Rafya Khan <rafya.khan@mail.utoronto.ca>
Co-authored-by: Jens W. Klein <jk@kleinundpartner.at>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Fábio C. Barrionuevo da Luz <bnafta@gmail.com>

cookiecutter/cli.py

@@ -11,6 +11,7 @@
 from cookiecutter.config import get_user_config
 from cookiecutter.exceptions import (
     ContextDecodingException,
+    EmptyDirNameException,
     FailedHookException,
     InvalidModeException,
     InvalidZipRepository,
@@ -219,6 +220,7 @@ def main(
     except (
         ContextDecodingException,
         OutputDirExistsException,
+        EmptyDirNameException,
         InvalidModeException,
         FailedHookException,
         UnknownExtension,

cookiecutter/exceptions.py

@@ -97,6 +97,14 @@ class OutputDirExistsException(CookiecutterException):
     """
 
 
+class EmptyDirNameException(CookiecutterException):
+    """
+    Exception for a empty directory name.
+
+    Raised when the directory name provided is empty.
+    """
+
+
 class InvalidModeException(CookiecutterException):
     """
     Exception for incompatible modes.

cookiecutter/generate.py

@@ -18,6 +18,7 @@
 
 from cookiecutter.exceptions import (
     ContextDecodingException,
+    EmptyDirNameException,
     OutputDirExistsException,
     UndefinedVariableInTemplate,
 )
@@ -252,6 +253,10 @@ def render_and_create_dir(
     overwrite_if_exists: bool = False,
 ) -> tuple[Path, bool]:
     """Render name of a directory, create the directory, return its path."""
+    if not dirname or dirname == "":
+        msg = 'Error: directory name is empty'
+        raise EmptyDirNameException(msg)
+
     name_tmpl = environment.from_string(dirname)
     rendered_dirname = name_tmpl.render(**context)
 

tests/test_generate_files.py

@@ -437,3 +437,15 @@ def test_raise_undefined_variable_project_dir(tmp_path) -> None:
     assert error.context == {}
 
     assert not Path(tmp_path, 'testproject').exists()
+
+
+def test_raise_empty_dir_name(output_dir, undefined_context):
+    """Verify correct error raised when directory name is empty."""
+    with pytest.raises(exceptions.EmptyDirNameException):
+        generate.render_and_create_dir(
+            dirname='',
+            output_dir=output_dir,
+            context=undefined_context,
+            environment=None,
+        )
+    assert not Path(output_dir).joinpath('testproject').exists()