Treat dev0 versions of Briefcase as development versions (fixes bee…

…ware#926)

changes/926.misc.rst

@@ -0,0 +1 @@
+Briefcase versions containing ``dev0`` are now considered development versions for fetching templates.

src/briefcase/commands/create.py

@@ -291,9 +291,9 @@ def generate_app_template(self, app: BaseConfig):
             )
         except TemplateUnsupportedVersion:
             # If we're on a development branch, and the template branch was *not*
-            # provided explicity, we can use a fallback development template.
+            # provided explicitly, we can use a fallback development template.
             # Otherwise, re-raise the exception about the unsupported template version.
-            if version.dev and app.template_branch is None:
+            if version.dev is not None and app.template_branch is None:
                 # Development branches can use the main template.
                 self.logger.info(
                     f"Template branch {template_branch} not found; falling back to development template"

src/briefcase/commands/new.py

@@ -503,7 +503,7 @@ def new_app(self, template: Optional[str] = None, **options):
         except TemplateUnsupportedVersion:
             # If we're *not* on a development branch, raise an error about
             # the missing template branch.
-            if not version.dev:
+            if version.dev is None:
                 raise
 
             # Development branches can use the main template.