Aider-AI/aider · error · ValueError

Error applying action '{action.type}' to {action.path}: {e}

Error message

Error applying action '{action.type}' to {action.path}: {e}

What it means

Wrapper: apply_edits catches DiffError, FileNotFoundError, IOError, and OSError raised while applying one action and re-raises as ValueError with the action type, path, and original message. The ValueError convention matches other coders' failure signaling, so callers only handle one exception type.

Source

Thrown at aider/coders/patch_coder.py:635

                            )
                    else:
                        self.io.tool_output(f"Updating {action.path}")

                    # Ensure parent directory exists for target
                    target_path_obj.parent.mkdir(parents=True, exist_ok=True)
                    self.io.write_text(target_full_path, new_content)

                    # Remove original file *after* successful write to new location if moved
                    if action.move_path and full_path != target_full_path:
                        path_obj.unlink()

                else:
                    # Should not happen
                    raise DiffError(f"Unknown action type encountered: {action.type}")

            except (DiffError, FileNotFoundError, IOError, OSError) as e:
                # Raise a ValueError to signal failure, consistent with other coders.
                raise ValueError(f"Error applying action '{action.type}' to {action.path}: {e}")
            except Exception as e:
                # Catch unexpected errors during application
                raise ValueError(
                    f"Unexpected error applying action '{action.type}' to {action.path}: {e}"
                )

    def _apply_update(self, text: str, action: PatchAction, path: str) -> str:
        """
        Applies UPDATE chunks to the given text content.
        Adapted from _get_updated_file in apply_patch.py.
        """
        if action.type is not ActionType.UPDATE:
            # Should not be called otherwise, but check for safety
            raise DiffError("_apply_update called with non-update action")

        orig_lines = text.splitlines()  # Use splitlines to handle endings consistently
        dest_lines: List[str] = []
        current_orig_line_idx = 0  # Tracks index in orig_lines processed so far

View on GitHub (pinned to 5dc9490bb3)

Solutions

1. Parse the embedded cause (action type + path) from the message and fix that specific condition, then re-apply
2. Verify filesystem state afterward — actions before the failing one were already applied
3. Restore/checkpoint the repo (git status) before retrying to avoid double-application

try:
    coder.apply_edits(edits)
except ValueError as e:
    # message shape: "Error applying action '<TYPE>' to <path>: <cause>"
    import re
    m = re.match(r"Error applying action '(\w+)' to (.*): (.*)", str(e), re.S)
    if m:
        action_type, path, cause = m.groups()
        log.warning("apply failed for %s on %s: %s", action_type, path, cause)
    raise

When it happens

Trigger: Any per-action failure (add-exists, update-missing, chunk mismatch, IO error) inside apply_edits; the message embeds the underlying DiffError text such as 'UPDATE Error: File does not exist: x.py'.

Common situations: Callers of coder.apply_edits (GUI, tests, automation) catching ValueError to detect failed patch application; partial application — earlier actions in the loop may already have been written.

Related errors

• Unexpected error applying action '{action.type}' to {action.
• Delete File action missing path.
• Delete File Error - file not found: {path}
• Add File action missing path.
• Duplicate action for file: {path}

AI-assisted analysis of Aider-AI/aider@5dc9490bb3 (2026-08-15). Data as JSON: /api/errors/95c652d62ead0e51. Report an issue: GitHub.