refactor: Extract duplicate exception handling to helper method in ConfigManager (#66)

The get_instance_name() and get_value() methods had identical exception
handling blocks that displayed warnings for various config-related errors.
This duplicated ~12 lines of code.

Changes:
- Add _handle_config_error() helper method to centralize error handling
- Update both methods to use a single except clause delegating to helper
- Use union type syntax (X | Y) in isinstance checks per UP038 lint rule

Co-authored-by: Claude <noreply@anthropic.com>

Author: ivyleavedtoadflax

progress.md

@@ -862,3 +862,31 @@ The function calculated monthly cost estimates from hourly prices, but the actua
 
 ---
 
+## 2026-01-18: Extract duplicate exception handling in `ConfigManager` to helper method
+
+**File:** `remote/config.py`
+
+**Issue:** The `ConfigManager` class had duplicate exception handling blocks in two methods:
+- `get_instance_name()` (lines 255-264)
+- `get_value()` (lines 285-290)
+
+Both methods contained identical exception handling code:
+```python
+except (configparser.Error, OSError, PermissionError) as e:
+    typer.secho(f"Warning: Could not read config file: {e}", fg=typer.colors.YELLOW)
+except (KeyError, TypeError, AttributeError):
+    typer.secho("Warning: Config file structure is invalid", fg=typer.colors.YELLOW)
+except ValueError as e:
+    typer.secho(f"Warning: Config validation error: {e}", fg=typer.colors.YELLOW)
+```
+
+This duplication meant any changes to error handling would need to be made in multiple places.
+
+**Changes:**
+- Added new helper method `_handle_config_error(self, error: Exception)` that centralizes the error handling logic
+- Updated `get_instance_name()` to catch all config-related exceptions in a single except clause and delegate to the helper
+- Updated `get_value()` to use the same pattern
+- Reduced code duplication by ~12 lines
+
+---
+

remote/config.py

@@ -241,6 +241,15 @@ def reload(self) -> None:
         self._file_config = None
         self._pydantic_config = None
 
+    def _handle_config_error(self, error: Exception) -> None:
+        """Handle and display config-related errors."""
+        if isinstance(error, configparser.Error | OSError | PermissionError):
+            typer.secho(f"Warning: Could not read config file: {error}", fg=typer.colors.YELLOW)
+        elif isinstance(error, KeyError | TypeError | AttributeError):
+            typer.secho("Warning: Config file structure is invalid", fg=typer.colors.YELLOW)
+        elif isinstance(error, ValueError):
+            typer.secho(f"Warning: Config validation error: {error}", fg=typer.colors.YELLOW)
+
     def get_instance_name(self) -> str | None:
         """Get default instance name from config file or environment variable."""
         try:
@@ -252,18 +261,17 @@ def get_instance_name(self) -> str | None:
             # Fall back to file config for backwards compatibility
             if "DEFAULT" in self.file_config and "instance_name" in self.file_config["DEFAULT"]:
                 return self.file_config["DEFAULT"]["instance_name"]
-        except (configparser.Error, OSError, PermissionError) as e:
-            # Config file might be corrupted or inaccessible
-            # Log the specific error but don't crash the application
-            typer.secho(f"Warning: Could not read config file: {e}", fg=typer.colors.YELLOW)
-        except (KeyError, TypeError, AttributeError):
-            # Handle malformed config structure
-            typer.secho("Warning: Config file structure is invalid", fg=typer.colors.YELLOW)
-        except ValueError as e:
-            # Handle Pydantic validation errors
-            typer.secho(f"Warning: Config validation error: {e}", fg=typer.colors.YELLOW)
+        except (
+            configparser.Error,
+            OSError,
+            PermissionError,
+            KeyError,
+            TypeError,
+            AttributeError,
+            ValueError,
+        ) as e:
+            self._handle_config_error(e)
 
-        # No configuration found
         return None
 
     def set_instance_name(self, instance_name: str, config_path: str | None = None) -> None:
@@ -282,12 +290,16 @@ def get_value(self, key: str) -> str | None:
             # Fall back to file config for backwards compatibility
             if "DEFAULT" in self.file_config and key in self.file_config["DEFAULT"]:
                 return self.file_config["DEFAULT"][key]
-        except (configparser.Error, OSError, PermissionError) as e:
-            typer.secho(f"Warning: Could not read config file: {e}", fg=typer.colors.YELLOW)
-        except (KeyError, TypeError, AttributeError):
-            typer.secho("Warning: Config file structure is invalid", fg=typer.colors.YELLOW)
-        except ValueError as e:
-            typer.secho(f"Warning: Config validation error: {e}", fg=typer.colors.YELLOW)
+        except (
+            configparser.Error,
+            OSError,
+            PermissionError,
+            KeyError,
+            TypeError,
+            AttributeError,
+            ValueError,
+        ) as e:
+            self._handle_config_error(e)
         return None
 
     def set_value(self, key: str, value: str, config_path: str | None = None) -> None: