rescue spmsync: fix handlePackage failure when installed DB is missing

Two fixes for `equo rescue spmsync` on a system without an existing
installed packages DB:

1. client/interfaces/methods.py: Stop falling back to a GenericRepository
   (in-memory, read-only for handlePackage) when the DB file is absent.
   Instead let SQLite create the file; call initializeRepository() on a
   freshly created DB so validate() succeeds.  Corrupted DBs still fall
   back to RAM via the existing DatabaseError/SystemDatabaseError path.

2. spm/portage_plugin: Also catch OSError (not just tarfile.ReadError)
   when uncompress_tarball fails on a pure-XPAK temp file; Python 3.14
   raises OSError in this case rather than tarfile.ReadError.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/entropy/client/interfaces/methods.py

@@ -1085,36 +1085,34 @@ class RepositoryMixin:
             os.makedirs(db_dir)
 
         db_path = repo_path
-        if (self._installed_repo_enable) and (not os.path.isfile(db_path)):
-            conn = load_db_from_ram()
+        db_file_is_new = not os.path.isfile(db_path)
+        try:
+            repo_class = self.get_repository(name)
+            conn = repo_class(readOnly = False,
+                              dbFile = db_path,
+                              xcache = self.xcache,
+                              indexing = self._indexing)
+            conn.setCloseToken(name)
+            self._add_plugin_to_client_repository(conn)
+            if db_file_is_new:
+                conn.initializeRepository()
+            # TODO: remove this in future, drop useless data from clientdb
+        except (DatabaseError,):
             entropy.tools.print_traceback(f = self.logger)
+            conn = load_db_from_ram()
+
         else:
-
-            try:
-                repo_class = self.get_repository(name)
-                conn = repo_class(readOnly = False,
-                                  dbFile = db_path,
-                                  xcache = self.xcache,
-                                  indexing = self._indexing)
-                conn.setCloseToken(name)
-                self._add_plugin_to_client_repository(conn)
-                # TODO: remove this in future, drop useless data from clientdb
-            except (DatabaseError,):
-                entropy.tools.print_traceback(f = self.logger)
-                conn = load_db_from_ram()
-
-            else:
-                # validate database
-                if self._installed_repo_enable:
+            # validate database
+            if self._installed_repo_enable:
+                try:
+                    conn.validate()
+                except SystemDatabaseError:
                     try:
-                        conn.validate()
-                    except SystemDatabaseError:
-                        try:
-                            conn.close(_token = name)
-                        except (RepositoryPluginError, OSError, IOError):
-                            pass
-                        entropy.tools.print_traceback(f = self.logger)
-                        conn = load_db_from_ram()
+                        conn.close(_token = name)
+                    except (RepositoryPluginError, OSError, IOError):
+                        pass
+                    entropy.tools.print_traceback(f = self.logger)
+                    conn = load_db_from_ram()
 
         self._real_installed_repository = conn
         return conn

lib/entropy/spm/plugins/interfaces/portage_plugin/__init__.py

@@ -1421,7 +1421,7 @@ class PortagePlugin(SpmPlugin):
             try:
                 entropy.tools.uncompress_tarball(package_file,
                     extract_path = pkg_dir, catch_empty = False)
-            except tarfile.ReadError:
+            except (tarfile.ReadError, OSError):
                 empty_content = True
 
         env_bz2 = os.path.join(meta_dir, PortagePlugin.ENV_FILE_COMP)