Fix poetry plugin crash on windows when no pyproject.toml (#81)

Also:
- Make the plugin handle unexpected errors more gracefully
- Update doc for installing plugin for correct shell syntax

README.rst

@@ -71,7 +71,7 @@ Installation
 
   .. code-block:: bash
 
-    poetry self add poethepoet[poetry_plugin]
+    poetry self add 'poethepoet[poetry_plugin]'
 
 Enable tab completion for your shell
 ------------------------------------

poethepoet/config.py

@@ -215,7 +215,7 @@ def find_pyproject_toml(self, target_dir: Optional[str] = None) -> Path:
 
         maybe_result = self.cwd.joinpath(self.TOML_NAME)
         while not maybe_result.exists():
-            if maybe_result.parent == Path("/"):
+            if len(maybe_result.parents) == 1:
                 raise PoeException(
                     f"Poe could not find a pyproject.toml file in {self.cwd} or"
                     " its parents"

poethepoet/plugin.py

@@ -74,6 +74,26 @@ def get_poe(cls, application: Application, io: IO):
 
 class PoetryPlugin(ApplicationPlugin):
     def activate(self, application: Application) -> None:
+        try:
+            return self._activate(application)
+
+        # pylint: disable=bare-except
+        except:
+            import os, sys
+
+            debug = bool(int(os.environ.get("DEBUG_POE_PLUGIN", "0")))
+            print(
+                "error: poethepoet plugin failed to activate."
+                + ("" if debug else " Set DEBUG_POE_PLUGIN=1 for details."),
+                file=sys.stderr,
+            )
+            if debug:
+                import traceback
+
+                traceback.print_exc()
+                raise SystemExit(1)
+
+    def _activate(self, application: Application) -> None:
         try:
             poe_config = self._get_config(application)
         except RuntimeError: