What causes "{processed}\n^^^ {err}" in Aider-AI/aider?

Read bottom-up: the text after '^^^' names the actual grammar problem; the text above it shows the input up to the failing line.

Aider-AI/aider · error · ValueError

{processed}\n^^^ {err}

Error message

{processed}\n^^^ {err}

What it means

This is the wrapper re-raise at the end of the generator's except ValueError block: any of the inner parse errors (missing filename, Expected =======, Expected >>>>>>> REPLACE) is re-raised with the full text processed so far prepended and a '^^^ <original error>' suffix pointing at the offending spot. It exists purely to add line context to SEARCH/REPLACE grammar errors.

Source

Thrown at aider/coders/editblock_coder.py:533

                while i < len(lines) and not (
                    updated_pattern.match(lines[i].strip())
                    or divider_pattern.match(lines[i].strip())
                ):
                    updated_text.append(lines[i])
                    i += 1

                if i >= len(lines) or not (
                    updated_pattern.match(lines[i].strip())
                    or divider_pattern.match(lines[i].strip())
                ):
                    raise ValueError(f"Expected `{UPDATED_ERR}` or `{DIVIDER_ERR}`")

                yield filename, "".join(original_text), "".join(updated_text)

            except ValueError as e:
                processed = "".join(lines[: i + 1])
                err = e.args[0]
                raise ValueError(f"{processed}\n^^^ {err}")

        i += 1


def find_filename(lines, fence, valid_fnames):
    """
    Deepseek Coder v2 has been doing this:


     ```python
    word_count.py
    ```
    ```python
    <<<<<<< SEARCH
    ...

    This is a more flexible search back for filenames.
    """

View on GitHub (pinned to 5dc9490bb3)

Solutions

Read bottom-up: the text after '^^^' names the actual grammar problem; the text above it shows the input up to the failing line.
Fix the indicated block per the underlying error (filename line, =======, or >>>>>>> REPLACE).
Feed the whole message back to the LLM for a corrected reply.
Add regression tests capturing the offending reply shape when it recurs (aider's tests do exactly this with recorded transcripts).

Defensive patterns

Strategy: try-catch

Try / catch

try:
    edits = list(parse_edits_or_raise(reply))
except ValueError as e:
    msg = str(e)
    underlying = msg.split("^^^ ")[-1]          # the real grammar error
    context = msg.split("^^^ ")[0]               # processed input up to the failure
    log_and_retry_with_model(underlying, context)

Prevention

Always split on '^^^ ' when logging this error — the suffix names the root cause, the prefix shows where.
Keep recorded transcripts of failing replies as regression fixtures.
Don't string-match the whole message; match the suffix (filename/divider errors) for routing logic.

When it happens

Trigger: Any of errors 3-5 firing inside the try block while parsing a fenced SEARCH/REPLACE block; the handler joins lines[:i+1] (everything consumed including the failing line) and re-raises with the '^' pointer.

Common situations: Debugging where exactly in an LLM reply the SEARCH/REPLACE grammar broke — the processed prefix shows the malformed block verbatim; commonly seen in logs when models produce structurally invalid edit blocks.

Related errors

AI-assisted analysis of Aider-AI/aider@5dc9490bb3 (2026-08-15). Data as JSON: /api/errors/855e94de35f59158. Report an issue: GitHub.