v1.8.2: session management hardening

- Fix infinite reconnect loop in terminal (_send_to_shell guard)
- Safe language switch: disconnect + reconnect instead of object transplant
- Improved SFTP reconnect flow with proper validation
- Add log.debug to all silent exception handlers in ssh_client

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

core/ssh_client.py

@@ -163,14 +163,14 @@ class ShellSession:
         if self._channel:
             try:
                 self._channel.close()
-            except Exception:
-                pass
+            except Exception as e:
+                log.debug(f"ShellSession channel close: {e}")
             self._channel = None
         if self._client:
             try:
                 self._client.close()
-            except Exception:
-                pass
+            except Exception as e:
+                log.debug(f"ShellSession client close: {e}")
             self._client = None
 
     def reconnect(self):
@@ -353,14 +353,14 @@ class SFTPSession:
         if self._sftp:
             try:
                 self._sftp.close()
-            except Exception:
-                pass
+            except Exception as e:
+                log.debug(f"SFTPSession sftp close: {e}")
             self._sftp = None
         if self._client:
             try:
                 self._client.close()
-            except Exception:
-                pass
+            except Exception as e:
+                log.debug(f"SFTPSession client close: {e}")
             self._client = None
 
     def listdir_attr(self, path: str) -> list:

gui/app.py

@@ -171,15 +171,14 @@ class App(ctk.CTk):
         # Use provided key or default to first tab
         current_key = restore_tab_key or self._tab_keys[0]
 
-        # Save live SFTP session before destroying tabs
-        saved_sftp = self.files_tab._sftp
-        saved_sftp_path = self.files_tab._remote_path
-        saved_sftp_alias = self.files_tab._current_alias
+        # Save state before destroying tabs
+        saved_remote_path = self.files_tab._remote_path
         saved_local_path = self.files_tab._local_path
-        self.files_tab._sftp = None  # Prevent disconnect on destroy
+        had_sftp = self.files_tab._sftp is not None and self.files_tab._sftp.connected
 
-        # Disconnect terminal before destroying tabs
+        # Disconnect terminal and SFTP before destroying tabs
         self.terminal_tab._disconnect()
+        self.files_tab._disconnect_sftp()
 
         # Detach tab contents
         self.terminal_tab.pack_forget()
@@ -225,23 +224,17 @@ class App(ctk.CTk):
         except Exception:
             pass
 
-        # Restore SFTP session without reconnecting
-        if saved_sftp and saved_sftp.connected:
-            self.files_tab._sftp = saved_sftp
-            self.files_tab._current_alias = saved_sftp_alias
-            self.files_tab._remote_path = saved_sftp_path
-            self.files_tab._local_path = saved_local_path
-            self.files_tab._set_remote_buttons_state("normal")
-            self.files_tab._remote_status.configure(
-                text=t("connected_sftp").format(alias=saved_sftp_alias)
-            )
-            self.files_tab._refresh_local()
-            self.files_tab._refresh_remote()
+        # Restore file paths and reconnect properly
+        self.files_tab._local_path = saved_local_path
+        self.files_tab._refresh_local()
+        if alias and had_sftp:
+            # Had active SFTP — reconnect and restore remote path
+            self.files_tab._remote_path = saved_remote_path
+            self.files_tab.set_server(alias)
         elif alias:
-            # No live session — reconnect via server selection
             self.files_tab.set_server(alias)
 
-        # Restore server selection for other tabs
+        # Restore server selection for other tabs (terminal auto-reconnects)
         if alias:
             self.terminal_tab.set_server(alias)
             self.info_tab.set_server(alias)

gui/tabs/files_tab.py

@@ -450,16 +450,25 @@ class FilesTab(ctk.CTkFrame):
             return items
 
         def _do():
-            try:
-                if not self._sftp.connected:
+            # Ensure connection is alive, reconnect if needed
+            if not self._sftp.connected:
+                try:
                     self._sftp.reconnect()
+                except Exception as e:
+                    self.after(0, lambda: self._on_sftp_error(str(e)))
+                    return
+                if not self._sftp.connected:
+                    self.after(0, lambda: self._on_sftp_error("Reconnect failed"))
+                    return
+
+            try:
                 items = _list_remote()
                 self.after(0, lambda: self._populate_remote(items))
             except PermissionError as e:
                 hint = f"\n{t('try_sudo_hint')}" if not self._sftp.sudo_mode else ""
                 self.after(0, lambda: self._on_sftp_error(str(e) + hint))
             except Exception:
-                # Connection likely dead — try reconnect once
+                # Operation failed — one reconnect attempt
                 try:
                     self._sftp.reconnect()
                     items = _list_remote()

gui/tabs/terminal_tab.py

@@ -142,9 +142,8 @@ class TerminalTab(ctk.CTkFrame):
         session = self._session  # local ref for thread safety
         if session and session.connected:
             session.send(data)
-        elif self._current_alias and not self._intentional_disconnect:
-            # Session dead — trigger reconnect
-            self._reconnect_count = 0
+        elif self._current_alias and not self._intentional_disconnect and self._reconnect_count == 0:
+            # Session dead, no reconnect in progress — trigger one attempt
             self._on_disconnected()
 
     def _on_resize(self, cols: int, rows: int):

version.py

@@ -1,6 +1,6 @@
 """Version info for ServerManager."""
 
-__version__ = "1.8.1"
+__version__ = "1.8.2"
 __app_name__ = "ServerManager"
 __author__ = "aibot777"
 __description__ = "Desktop GUI for managing remote servers"