fix: ensure that pin metadata files are closed after reading them in

Author: cpcloud

pins/boards.py

@@ -1,3 +1,4 @@
+import contextlib
 import logging
 import tempfile
 import shutil
@@ -160,13 +161,10 @@ def pin_meta(self, name, version: str = None) -> Meta:
         meta_name = self.meta_factory.get_meta_name(*components)
 
         path_meta = self.construct_path([*components, meta_name])
-        f, local = self._open_pin_meta(path_meta)
-
-        meta = self.meta_factory.read_pin_yaml(
-            f, pin_name, selected_version, local=local
-        )
-
-        return meta
+        with self._open_pin_meta(path_meta) as (f, local):
+            return self.meta_factory.read_pin_yaml(
+                f, pin_name, selected_version, local=local
+            )
 
     def pin_list(self):
         """List names of all pins in a board.
@@ -610,14 +608,18 @@ def _load_data(self, meta, pin_version_path):
 
     # filesystem and cache methods --------------------------------------------
 
+    @contextlib.contextmanager
     def _open_pin_meta(self, path):
         f = self.fs.open(path)
-        self._touch_cache(path)
+        try:
+            self._touch_cache(path)
 
-        # optional additional data to put in Meta.local
-        local = {}
+            # optional additional data to put in Meta.local
+            local = {}
 
-        return f, local
+            yield f, local
+        finally:
+            self.fs.close(f)
 
     def _get_cache_path(self, pin_name, version=None, fname=None):
         version_part = [version] if version is not None else []
@@ -703,8 +705,8 @@ def pin_meta(self, name, version=None):
         # note that pins on this board should point to versions, so we use an
         # empty string to mark version (it ultimately is ignored)
         path_meta = self.construct_path([pin_name, "", meta_name])
-        f, local = self._open_pin_meta(path_meta)
-        meta = self.meta_factory.read_pin_yaml(f, pin_name, VersionRaw(""), local=local)
+        with self._open_pin_meta(path_meta) as (f, local):
+            meta = self.meta_factory.read_pin_yaml(f, pin_name, VersionRaw(""), local=local)
 
         # TODO(#59,#83): handle caching, and then re-enable pin_read.
         # self._touch_cache(path_meta)