Fix template name separator for Windows users

See: https://github.com/overhangio/tutor/issues/381

CHANGELOG.md

@@ -4,6 +4,7 @@ Note: Breaking changes between versions are indicated by "💥".
 
 ## Unreleased
 
+- [Bugfix] Fix template rendering for Windows users.
 - [Improvement] Switch to `bcrypt` for htpasswd password generation, for better portability on Windows.
 - [Improvement] In the openedx production docker image, add some jitter to the gunicorn worker restart process to prevent all workers from restarting at the same time.
 

tests/test_env.py

@@ -28,9 +28,9 @@ class EnvTests(unittest.TestCase):
     def test_is_binary_file(self):
         self.assertTrue(env.is_binary_file("/home/somefile.ico"))
 
-    def test_find_path(self):
+    def test_find_os_path(self):
         renderer = env.Renderer({}, [env.TEMPLATES_ROOT])
-        path = renderer.find_path("local/docker-compose.yml")
+        path = renderer.find_os_path("local/docker-compose.yml")
         self.assertTrue(os.path.exists(path))
 
     def test_pathjoin(self):

tutor/commands/config.py

@@ -101,8 +101,10 @@ def printvalue(context, key):
     try:
         # Note that this will incorrectly print None values
         fmt.echo(config[key])
-    except KeyError:
-        raise exceptions.TutorError("Missing configuration value: {}".format(key))
+    except KeyError as e:
+        raise exceptions.TutorError(
+            "Missing configuration value: {}".format(key)
+        ) from e
 
 
 config_command.add_command(save)

tutor/env.py

@@ -57,8 +57,11 @@ class Renderer:
         environment.globals["TUTOR_VERSION"] = __version__
         self.environment = environment
 
-    def iter_templates_in(self, *path):
-        prefix = "/".join(path)
+    def iter_templates_in(self, *prefix):
+        """
+        The elements of `prefix` must contain only "/", and not os.sep.
+        """
+        prefix = "/".join(prefix)
         for template in self.environment.loader.list_templates():
             if template.startswith(prefix) and self.is_part_of_env(template):
                 yield template
@@ -88,7 +91,8 @@ class Renderer:
             is_excluded = is_excluded or ignore_folder in parts
         return not is_excluded
 
-    def find_path(self, path):
+    def find_os_path(self, template_name):
+        path = template_name.replace("/", os.sep)
         for templates_root in self.template_roots:
             full_path = os.path.join(templates_root, path)
             if os.path.exists(full_path):
@@ -119,35 +123,41 @@ class Renderer:
         template = self.environment.from_string(text)
         return self.__render(template)
 
-    def render_file(self, path):
+    def render_template(self, template_name):
         """
         Render a template file. Return the corresponding string. If it's a binary file
         (as indicated by its path), return bytes.
+
+        The template_name *always* uses "/" separators, and is not os-dependent. Do not pass the result of
+        os.path.join(...) to this function.
         """
-        if is_binary_file(path):
+        if is_binary_file(template_name):
             # Don't try to render binary files
-            with open(self.find_path(path), "rb") as f:
+            with open(self.find_os_path(template_name), "rb") as f:
                 return f.read()
 
         try:
-            template = self.environment.get_template(path)
+            template = self.environment.get_template(template_name)
         except Exception:
-            fmt.echo_error("Error loading template " + path)
+            fmt.echo_error("Error loading template " + template_name)
             raise
 
         try:
             return self.__render(template)
         except (jinja2.exceptions.TemplateError, exceptions.TutorError):
-            fmt.echo_error("Error rendering template " + path)
+            fmt.echo_error("Error rendering template " + template_name)
             raise
         except Exception:
-            fmt.echo_error("Unknown error rendering template " + path)
+            fmt.echo_error("Unknown error rendering template " + template_name)
             raise
 
-    def render_all_to(self, root):
-        for template in self.iter_templates_in():
-            rendered = self.render_file(template)
-            dst = os.path.join(root, template)
+    def render_all_to(self, root, *prefix):
+        """
+        `prefix` can be used to limit the templates to render.
+        """
+        for template_name in self.iter_templates_in(*prefix):
+            rendered = self.render_template(template_name)
+            dst = os.path.join(root, template_name.replace("/", os.sep))
             write_to(rendered, dst)
 
     def __render(self, template):
@@ -207,13 +217,10 @@ def save_plugin_templates(plugin, root, config):
 def save_all_from(prefix, root, config):
     """
     Render the templates that start with `prefix` and store them with the same
-    hierarchy at `root`.
+    hierarchy at `root`. Here, `prefix` can be the result of os.path.join(...).
     """
     renderer = Renderer.instance(config)
-    for template in renderer.iter_templates_in(prefix):
-        rendered = renderer.render_file(template)
-        dst = os.path.join(root, template)
-        write_to(rendered, dst)
+    renderer.render_all_to(root, prefix.replace(os.sep, "/"))
 
 
 def write_to(content, path):
@@ -233,8 +240,8 @@ def render_file(config, *path):
     Return the rendered contents of a template.
     """
     renderer = Renderer.instance(config)
-    file_path = os.path.join(*path)
-    return renderer.render_file(file_path)
+    template_name = "/".join(path)
+    return renderer.render_template(template_name)
 
 
 def render_dict(config):