mode, user/group id/name: minor code refactor, remove None values at transfer time, #6908

https://github.com/borgbackup/borg/issues/6908#issuecomment-1224910916

src/borg/archive.py

@@ -1115,7 +1115,8 @@ class MetadataCollector:
         self.nobirthtime = nobirthtime
 
     def stat_simple_attrs(self, st):
-        attrs = dict(mode=st.st_mode, uid=st.st_uid, gid=st.st_gid)
+        attrs = {}
+        attrs["mode"] = st.st_mode
         # borg can work with archives only having mtime (very old borg archives do not have
         # atime/ctime). it can be useful to omit atime/ctime, if they change without the
         # file content changing - e.g. to get better metadata deduplication.
@@ -1127,6 +1128,8 @@ class MetadataCollector:
         if not self.nobirthtime and hasattr(st, "st_birthtime"):
             # sadly, there's no stat_result.st_birthtime_ns
             attrs["birthtime"] = safe_ns(int(st.st_birthtime * 10**9))
+        attrs["uid"] = st.st_uid
+        attrs["gid"] = st.st_gid
         if not self.numeric_ids:
             user = uid2user(st.st_uid)
             if user is not None:

src/borg/platform/posix.pyx

@@ -87,8 +87,10 @@ def uid2user(uid, default=None):
 
 @lru_cache(maxsize=None)
 def user2uid(user, default=None):
+    if not user:
+        return default
     try:
-        return user and pwd.getpwnam(user).pw_uid
+        return pwd.getpwnam(user).pw_uid
     except KeyError:
         return default
 
@@ -103,8 +105,10 @@ def gid2group(gid, default=None):
 
 @lru_cache(maxsize=None)
 def group2gid(group, default=None):
+    if not group:
+        return default
     try:
-        return group and grp.getgrnam(group).gr_gid
+        return grp.getgrnam(group).gr_gid
     except KeyError:
         return default
 

src/borg/upgrade.py

@@ -93,6 +93,11 @@ class UpgraderFrom12To20:
         # - 'acl' remnants of bug in attic <= 0.13
         # - 'hardlink_master' (superseded by hlid)
         new_item_dict = {key: value for key, value in item.as_dict().items() if key in ITEM_KEY_WHITELIST}
+        # remove some pointless entries older borg put in there:
+        for key in "user", "group":
+            if key in new_item_dict and new_item_dict[key] is None:
+                del new_item_dict[key]
+        assert not any(value is None for value in new_item_dict.values()), f"found None value in {new_item_dict}"
         new_item = Item(internal_dict=new_item_dict)
         new_item.get_size(memorize=True)  # if not already present: compute+remember size for items with chunks
         assert all(key in new_item for key in REQUIRED_ITEM_KEYS)